/*
 * Kernel-based Virtual Machine driver for Linux
 *
 * AMD SVM support
 *
 * Copyright (C) 2006 Qumranet, Inc.
 *
 * Authors:
 *   Yaniv Kamay  <yaniv@qumranet.com>
 *   Avi Kivity   <avi@qumranet.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */
#include <linux/kvm_host.h>

#include "irq.h"
#include "mmu.h"
#include "kvm_cache_regs.h"
#include "x86.h"

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/vmalloc.h>
#include <linux/highmem.h>
#include <linux/sched.h>
#include <linux/ftrace_event.h>

#include <asm/desc.h>

#include <asm/virtext.h>
#include "trace.h"

#define __ex(x) __kvm_handle_fault_on_reboot(x)

MODULE_AUTHOR("Qumranet");
MODULE_LICENSE("GPL");

#define IOPM_ALLOC_ORDER 2
#define MSRPM_ALLOC_ORDER 1

#define SEG_TYPE_LDT 2
#define SEG_TYPE_BUSY_TSS16 3

#define SVM_FEATURE_NPT  (1 << 0)
#define SVM_FEATURE_LBRV (1 << 1)
#define SVM_FEATURE_SVML (1 << 2)

#define NESTED_EXIT_HOST        0       /* Exit handled on host level */
#define NESTED_EXIT_DONE        1       /* Exit caused nested vmexit  */
#define NESTED_EXIT_CONTINUE    2       /* Further checks needed      */

#define DEBUGCTL_RESERVED_BITS (~(0x3fULL))

/* Turn on to get debugging output*/
/* #define NESTED_DEBUG */

#ifdef NESTED_DEBUG
#define nsvm_printk(fmt, args...) printk(KERN_INFO fmt, ## args)
#else
#define nsvm_printk(fmt, args...) do {} while(0)
#endif

static const u32 host_save_user_msrs[] = {
#ifdef CONFIG_X86_64
        MSR_STAR, MSR_LSTAR, MSR_CSTAR, MSR_SYSCALL_MASK, MSR_KERNEL_GS_BASE,
        MSR_FS_BASE,
#endif
        MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
};

#define NR_HOST_SAVE_USER_MSRS ARRAY_SIZE(host_save_user_msrs)

struct kvm_vcpu;

struct nested_state {
        struct vmcb *hsave;
        u64 hsave_msr;
        u64 vmcb;

        /* These are the merged vectors */
        u32 *msrpm;

        /* gpa pointers to the real vectors */
        u64 vmcb_msrpm;

        /* cache for intercepts of the guest */
        u16 intercept_cr_read;
        u16 intercept_cr_write;
        u16 intercept_dr_read;
        u16 intercept_dr_write;
        u32 intercept_exceptions;
        u64 intercept;

};

struct vcpu_svm {
        struct kvm_vcpu vcpu;
        struct vmcb *vmcb;
        unsigned long vmcb_pa;
        struct svm_cpu_data *svm_data;
        uint64_t asid_generation;
        uint64_t sysenter_esp;
        uint64_t sysenter_eip;

        u64 next_rip;

        u64 host_user_msrs[NR_HOST_SAVE_USER_MSRS];
        u64 host_gs_base;

        u32 *msrpm;

        struct nested_state nested;
};

/* enable NPT for AMD64 and X86 with PAE */
#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
static bool npt_enabled = true;
#else
static bool npt_enabled = false;
#endif
static int npt = 1;

module_param(npt, int, S_IRUGO);

static int nested = 1;
module_param(nested, int, S_IRUGO);

static void svm_flush_tlb(struct kvm_vcpu *vcpu);
static void svm_complete_interrupts(struct vcpu_svm *svm);

static int nested_svm_exit_handled(struct vcpu_svm *svm);
static int nested_svm_vmexit(struct vcpu_svm *svm);
static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
                                      bool has_error_code, u32 error_code);

static inline struct vcpu_svm *to_svm(struct kvm_vcpu *vcpu)
{
        return container_of(vcpu, struct vcpu_svm, vcpu);
}

static inline bool is_nested(struct vcpu_svm *svm)
{
        return svm->nested.vmcb;
}

static inline void enable_gif(struct vcpu_svm *svm)
{
        svm->vcpu.arch.hflags |= HF_GIF_MASK;
}

static inline void disable_gif(struct vcpu_svm *svm)
{
        svm->vcpu.arch.hflags &= ~HF_GIF_MASK;
}

static inline bool gif_set(struct vcpu_svm *svm)
{
        return !!(svm->vcpu.arch.hflags & HF_GIF_MASK);
}

static unsigned long iopm_base;

struct kvm_ldttss_desc {
        u16 limit0;
        u16 base0;
        unsigned base1 : 8, type : 5, dpl : 2, p : 1;
        unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
        u32 base3;
        u32 zero1;
} __attribute__((packed));

struct svm_cpu_data {
        int cpu;

        u64 asid_generation;
        u32 max_asid;
        u32 next_asid;
        struct kvm_ldttss_desc *tss_desc;

        struct page *save_area;
};

static DEFINE_PER_CPU(struct svm_cpu_data *, svm_data);
static uint32_t svm_features;

struct svm_init_data {
        int cpu;
        int r;
};

static u32 msrpm_ranges[] = {0, 0xc0000000, 0xc0010000};

#define NUM_MSR_MAPS ARRAY_SIZE(msrpm_ranges)
#define MSRS_RANGE_SIZE 2048
#define MSRS_IN_RANGE (MSRS_RANGE_SIZE * 8 / 2)

#define MAX_INST_SIZE 15

static inline u32 svm_has(u32 feat)
{
        return svm_features & feat;
}

static inline void clgi(void)
{
        asm volatile (__ex(SVM_CLGI));
}

static inline void stgi(void)
{
        asm volatile (__ex(SVM_STGI));
}

static inline void invlpga(unsigned long addr, u32 asid)
{
        asm volatile (__ex(SVM_INVLPGA) :: "a"(addr), "c"(asid));
}

static inline void force_new_asid(struct kvm_vcpu *vcpu)
{
        to_svm(vcpu)->asid_generation--;
}

static inline void flush_guest_tlb(struct kvm_vcpu *vcpu)
{
        force_new_asid(vcpu);
}

static void svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
{
        if (!npt_enabled && !(efer & EFER_LMA))
                efer &= ~EFER_LME;

        to_svm(vcpu)->vmcb->save.efer = efer | EFER_SVME;
        vcpu->arch.shadow_efer = efer;
}

static void svm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
                                bool has_error_code, u32 error_code)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        /* If we are within a nested VM we'd better #VMEXIT and let the
           guest handle the exception */
        if (nested_svm_check_exception(svm, nr, has_error_code, error_code))
                return;

        svm->vmcb->control.event_inj = nr
                | SVM_EVTINJ_VALID
                | (has_error_code ? SVM_EVTINJ_VALID_ERR : 0)
                | SVM_EVTINJ_TYPE_EXEPT;
        svm->vmcb->control.event_inj_err = error_code;
}

static int is_external_interrupt(u32 info)
{
        info &= SVM_EVTINJ_TYPE_MASK | SVM_EVTINJ_VALID;
        return info == (SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR);
}

static u32 svm_get_interrupt_shadow(struct kvm_vcpu *vcpu, int mask)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        u32 ret = 0;

        if (svm->vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK)
                ret |= X86_SHADOW_INT_STI | X86_SHADOW_INT_MOV_SS;
        return ret & mask;
}

static void svm_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        if (mask == 0)
                svm->vmcb->control.int_state &= ~SVM_INTERRUPT_SHADOW_MASK;
        else
                svm->vmcb->control.int_state |= SVM_INTERRUPT_SHADOW_MASK;

}

static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        if (!svm->next_rip) {
                if (emulate_instruction(vcpu, vcpu->run, 0, 0, EMULTYPE_SKIP) !=
                                EMULATE_DONE)
                        printk(KERN_DEBUG "%s: NOP\n", __func__);
                return;
        }
        if (svm->next_rip - kvm_rip_read(vcpu) > MAX_INST_SIZE)
                printk(KERN_ERR "%s: ip 0x%lx next 0x%llx\n",
                       __func__, kvm_rip_read(vcpu), svm->next_rip);

        kvm_rip_write(vcpu, svm->next_rip);
        svm_set_interrupt_shadow(vcpu, 0);
}

static int has_svm(void)
{
        const char *msg;

        if (!cpu_has_svm(&msg)) {
                printk(KERN_INFO "has_svm: %s\n", msg);
                return 0;
        }

        return 1;
}

static void svm_hardware_disable(void *garbage)
{
        cpu_svm_disable();
}

static void svm_hardware_enable(void *garbage)
{

        struct svm_cpu_data *svm_data;
        uint64_t efer;
        struct descriptor_table gdt_descr;
        struct desc_struct *gdt;
        int me = raw_smp_processor_id();

        if (!has_svm()) {
                printk(KERN_ERR "svm_cpu_init: err EOPNOTSUPP on %d\n", me);
                return;
        }
        svm_data = per_cpu(svm_data, me);

        if (!svm_data) {
                printk(KERN_ERR "svm_cpu_init: svm_data is NULL on %d\n",
                       me);
                return;
        }

        svm_data->asid_generation = 1;
        svm_data->max_asid = cpuid_ebx(SVM_CPUID_FUNC) - 1;
        svm_data->next_asid = svm_data->max_asid + 1;

        kvm_get_gdt(&gdt_descr);
        gdt = (struct desc_struct *)gdt_descr.base;
        svm_data->tss_desc = (struct kvm_ldttss_desc *)(gdt + GDT_ENTRY_TSS);

        rdmsrl(MSR_EFER, efer);
        wrmsrl(MSR_EFER, efer | EFER_SVME);

        wrmsrl(MSR_VM_HSAVE_PA,
               page_to_pfn(svm_data->save_area) << PAGE_SHIFT);
}

static void svm_cpu_uninit(int cpu)
{
        struct svm_cpu_data *svm_data
                = per_cpu(svm_data, raw_smp_processor_id());

        if (!svm_data)
                return;

        per_cpu(svm_data, raw_smp_processor_id()) = NULL;
        __free_page(svm_data->save_area);
        kfree(svm_data);
}

static int svm_cpu_init(int cpu)
{
        struct svm_cpu_data *svm_data;
        int r;

        svm_data = kzalloc(sizeof(struct svm_cpu_data), GFP_KERNEL);
        if (!svm_data)
                return -ENOMEM;
        svm_data->cpu = cpu;
        svm_data->save_area = alloc_page(GFP_KERNEL);
        r = -ENOMEM;
        if (!svm_data->save_area)
                goto err_1;

        per_cpu(svm_data, cpu) = svm_data;

        return 0;

err_1:
        kfree(svm_data);
        return r;

}

static void set_msr_interception(u32 *msrpm, unsigned msr,
                                 int read, int write)
{
        int i;

        for (i = 0; i < NUM_MSR_MAPS; i++) {
                if (msr >= msrpm_ranges[i] &&
                    msr < msrpm_ranges[i] + MSRS_IN_RANGE) {
                        u32 msr_offset = (i * MSRS_IN_RANGE + msr -
                                          msrpm_ranges[i]) * 2;

                        u32 *base = msrpm + (msr_offset / 32);
                        u32 msr_shift = msr_offset % 32;
                        u32 mask = ((write) ? 0 : 2) | ((read) ? 0 : 1);
                        *base = (*base & ~(0x3 << msr_shift)) |
                                (mask << msr_shift);
                        return;
                }
        }
        BUG();
}

static void svm_vcpu_init_msrpm(u32 *msrpm)
{
        memset(msrpm, 0xff, PAGE_SIZE * (1 << MSRPM_ALLOC_ORDER));

#ifdef CONFIG_X86_64
        set_msr_interception(msrpm, MSR_GS_BASE, 1, 1);
        set_msr_interception(msrpm, MSR_FS_BASE, 1, 1);
        set_msr_interception(msrpm, MSR_KERNEL_GS_BASE, 1, 1);
        set_msr_interception(msrpm, MSR_LSTAR, 1, 1);
        set_msr_interception(msrpm, MSR_CSTAR, 1, 1);
        set_msr_interception(msrpm, MSR_SYSCALL_MASK, 1, 1);
#endif
        set_msr_interception(msrpm, MSR_K6_STAR, 1, 1);
        set_msr_interception(msrpm, MSR_IA32_SYSENTER_CS, 1, 1);
}

static void svm_enable_lbrv(struct vcpu_svm *svm)
{
        u32 *msrpm = svm->msrpm;

        svm->vmcb->control.lbr_ctl = 1;
        set_msr_interception(msrpm, MSR_IA32_LASTBRANCHFROMIP, 1, 1);
        set_msr_interception(msrpm, MSR_IA32_LASTBRANCHTOIP, 1, 1);
        set_msr_interception(msrpm, MSR_IA32_LASTINTFROMIP, 1, 1);
        set_msr_interception(msrpm, MSR_IA32_LASTINTTOIP, 1, 1);
}

static void svm_disable_lbrv(struct vcpu_svm *svm)
{
        u32 *msrpm = svm->msrpm;

        svm->vmcb->control.lbr_ctl = 0;
        set_msr_interception(msrpm, MSR_IA32_LASTBRANCHFROMIP, 0, 0);
        set_msr_interception(msrpm, MSR_IA32_LASTBRANCHTOIP, 0, 0);
        set_msr_interception(msrpm, MSR_IA32_LASTINTFROMIP, 0, 0);
        set_msr_interception(msrpm, MSR_IA32_LASTINTTOIP, 0, 0);
}

static __init int svm_hardware_setup(void)
{
        int cpu;
        struct page *iopm_pages;
        void *iopm_va;
        int r;

        iopm_pages = alloc_pages(GFP_KERNEL, IOPM_ALLOC_ORDER);

        if (!iopm_pages)
                return -ENOMEM;

        iopm_va = page_address(iopm_pages);
        memset(iopm_va, 0xff, PAGE_SIZE * (1 << IOPM_ALLOC_ORDER));
        iopm_base = page_to_pfn(iopm_pages) << PAGE_SHIFT;

        if (boot_cpu_has(X86_FEATURE_NX))
                kvm_enable_efer_bits(EFER_NX);

        if (boot_cpu_has(X86_FEATURE_FXSR_OPT))
                kvm_enable_efer_bits(EFER_FFXSR);

        if (nested) {
                printk(KERN_INFO "kvm: Nested Virtualization enabled\n");
                kvm_enable_efer_bits(EFER_SVME);
        }

        for_each_online_cpu(cpu) {
                r = svm_cpu_init(cpu);
                if (r)
                        goto err;
        }

        svm_features = cpuid_edx(SVM_CPUID_FUNC);

        if (!svm_has(SVM_FEATURE_NPT))
                npt_enabled = false;

        if (npt_enabled && !npt) {
                printk(KERN_INFO "kvm: Nested Paging disabled\n");
                npt_enabled = false;
        }

        if (npt_enabled) {
                printk(KERN_INFO "kvm: Nested Paging enabled\n");
                kvm_enable_tdp();
        } else
                kvm_disable_tdp();

        return 0;

err:
        __free_pages(iopm_pages, IOPM_ALLOC_ORDER);
        iopm_base = 0;
        return r;
}

static __exit void svm_hardware_unsetup(void)
{
        int cpu;

        for_each_online_cpu(cpu)
                svm_cpu_uninit(cpu);

        __free_pages(pfn_to_page(iopm_base >> PAGE_SHIFT), IOPM_ALLOC_ORDER);
        iopm_base = 0;
}

static void init_seg(struct vmcb_seg *seg)
{
        seg->selector = 0;
        seg->attrib = SVM_SELECTOR_P_MASK | SVM_SELECTOR_S_MASK |
                SVM_SELECTOR_WRITE_MASK; /* Read/Write Data Segment */
        seg->limit = 0xffff;
        seg->base = 0;
}

static void init_sys_seg(struct vmcb_seg *seg, uint32_t type)
{
        seg->selector = 0;
        seg->attrib = SVM_SELECTOR_P_MASK | type;
        seg->limit = 0xffff;
        seg->base = 0;
}

static void init_vmcb(struct vcpu_svm *svm)
{
        struct vmcb_control_area *control = &svm->vmcb->control;
        struct vmcb_save_area *save = &svm->vmcb->save;

        control->intercept_cr_read =    INTERCEPT_CR0_MASK |
                                        INTERCEPT_CR3_MASK |
                                        INTERCEPT_CR4_MASK;

        control->intercept_cr_write =   INTERCEPT_CR0_MASK |
                                        INTERCEPT_CR3_MASK |
                                        INTERCEPT_CR4_MASK |
                                        INTERCEPT_CR8_MASK;

        control->intercept_dr_read =    INTERCEPT_DR0_MASK |
                                        INTERCEPT_DR1_MASK |
                                        INTERCEPT_DR2_MASK |
                                        INTERCEPT_DR3_MASK;

        control->intercept_dr_write =   INTERCEPT_DR0_MASK |
                                        INTERCEPT_DR1_MASK |
                                        INTERCEPT_DR2_MASK |
                                        INTERCEPT_DR3_MASK |
                                        INTERCEPT_DR5_MASK |
                                        INTERCEPT_DR7_MASK;

        control->intercept_exceptions = (1 << PF_VECTOR) |
                                        (1 << UD_VECTOR) |
                                        (1 << MC_VECTOR);


        control->intercept =    (1ULL << INTERCEPT_INTR) |
                                (1ULL << INTERCEPT_NMI) |
                                (1ULL << INTERCEPT_SMI) |
                                (1ULL << INTERCEPT_CPUID) |
                                (1ULL << INTERCEPT_INVD) |
                                (1ULL << INTERCEPT_HLT) |
                                (1ULL << INTERCEPT_INVLPG) |
                                (1ULL << INTERCEPT_INVLPGA) |
                                (1ULL << INTERCEPT_IOIO_PROT) |
                                (1ULL << INTERCEPT_MSR_PROT) |
                                (1ULL << INTERCEPT_TASK_SWITCH) |
                                (1ULL << INTERCEPT_SHUTDOWN) |
                                (1ULL << INTERCEPT_VMRUN) |
                                (1ULL << INTERCEPT_VMMCALL) |
                                (1ULL << INTERCEPT_VMLOAD) |
                                (1ULL << INTERCEPT_VMSAVE) |
                                (1ULL << INTERCEPT_STGI) |
                                (1ULL << INTERCEPT_CLGI) |
                                (1ULL << INTERCEPT_SKINIT) |
                                (1ULL << INTERCEPT_WBINVD) |
                                (1ULL << INTERCEPT_MONITOR) |
                                (1ULL << INTERCEPT_MWAIT);

        control->iopm_base_pa = iopm_base;
        control->msrpm_base_pa = __pa(svm->msrpm);
        control->tsc_offset = 0;
        control->int_ctl = V_INTR_MASKING_MASK;

        init_seg(&save->es);
        init_seg(&save->ss);
        init_seg(&save->ds);
        init_seg(&save->fs);
        init_seg(&save->gs);

        save->cs.selector = 0xf000;
        /* Executable/Readable Code Segment */
        save->cs.attrib = SVM_SELECTOR_READ_MASK | SVM_SELECTOR_P_MASK |
                SVM_SELECTOR_S_MASK | SVM_SELECTOR_CODE_MASK;
        save->cs.limit = 0xffff;
        /*
         * cs.base should really be 0xffff0000, but vmx can't handle that, so
         * be consistent with it.
         *
         * Replace when we have real mode working for vmx.
         */
        save->cs.base = 0xf0000;

        save->gdtr.limit = 0xffff;
        save->idtr.limit = 0xffff;

        init_sys_seg(&save->ldtr, SEG_TYPE_LDT);
        init_sys_seg(&save->tr, SEG_TYPE_BUSY_TSS16);

        save->efer = EFER_SVME;
        save->dr6 = 0xffff0ff0;
        save->dr7 = 0x400;
        save->rflags = 2;
        save->rip = 0x0000fff0;
        svm->vcpu.arch.regs[VCPU_REGS_RIP] = save->rip;

        /*
         * cr0 val on cpu init should be 0x60000010, we enable cpu
         * cache by default. the orderly way is to enable cache in bios.
         */
        save->cr0 = 0x00000010 | X86_CR0_PG | X86_CR0_WP;
        save->cr4 = X86_CR4_PAE;
        /* rdx = ?? */

        if (npt_enabled) {
                /* Setup VMCB for Nested Paging */
                control->nested_ctl = 1;
                control->intercept &= ~((1ULL << INTERCEPT_TASK_SWITCH) |
                                        (1ULL << INTERCEPT_INVLPG));
                control->intercept_exceptions &= ~(1 << PF_VECTOR);
                control->intercept_cr_read &= ~(INTERCEPT_CR0_MASK|
                                                INTERCEPT_CR3_MASK);
                control->intercept_cr_write &= ~(INTERCEPT_CR0_MASK|
                                                 INTERCEPT_CR3_MASK);
                save->g_pat = 0x0007040600070406ULL;
                /* enable caching because the QEMU Bios doesn't enable it */
                save->cr0 = X86_CR0_ET;
                save->cr3 = 0;
                save->cr4 = 0;
        }
        force_new_asid(&svm->vcpu);

        svm->nested.vmcb = 0;
        svm->vcpu.arch.hflags = 0;

        enable_gif(svm);
}

static int svm_vcpu_reset(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        init_vmcb(svm);

        if (!kvm_vcpu_is_bsp(vcpu)) {
                kvm_rip_write(vcpu, 0);
                svm->vmcb->save.cs.base = svm->vcpu.arch.sipi_vector << 12;
                svm->vmcb->save.cs.selector = svm->vcpu.arch.sipi_vector << 8;
        }
        vcpu->arch.regs_avail = ~0;
        vcpu->arch.regs_dirty = ~0;

        return 0;
}

static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
{
        struct vcpu_svm *svm;
        struct page *page;
        struct page *msrpm_pages;
        struct page *hsave_page;
        struct page *nested_msrpm_pages;
        int err;

        svm = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
        if (!svm) {
                err = -ENOMEM;
                goto out;
        }

        err = kvm_vcpu_init(&svm->vcpu, kvm, id);
        if (err)
                goto free_svm;

        page = alloc_page(GFP_KERNEL);
        if (!page) {
                err = -ENOMEM;
                goto uninit;
        }

        err = -ENOMEM;
        msrpm_pages = alloc_pages(GFP_KERNEL, MSRPM_ALLOC_ORDER);
        if (!msrpm_pages)
                goto uninit;

        nested_msrpm_pages = alloc_pages(GFP_KERNEL, MSRPM_ALLOC_ORDER);
        if (!nested_msrpm_pages)
                goto uninit;

        svm->msrpm = page_address(msrpm_pages);
        svm_vcpu_init_msrpm(svm->msrpm);

        hsave_page = alloc_page(GFP_KERNEL);
        if (!hsave_page)
                goto uninit;
        svm->nested.hsave = page_address(hsave_page);

        svm->nested.msrpm = page_address(nested_msrpm_pages);

        svm->vmcb = page_address(page);
        clear_page(svm->vmcb);
        svm->vmcb_pa = page_to_pfn(page) << PAGE_SHIFT;
        svm->asid_generation = 0;
        init_vmcb(svm);

        fx_init(&svm->vcpu);
        svm->vcpu.fpu_active = 1;
        svm->vcpu.arch.apic_base = 0xfee00000 | MSR_IA32_APICBASE_ENABLE;
        if (kvm_vcpu_is_bsp(&svm->vcpu))
                svm->vcpu.arch.apic_base |= MSR_IA32_APICBASE_BSP;

        return &svm->vcpu;

uninit:
        kvm_vcpu_uninit(&svm->vcpu);
free_svm:
        kmem_cache_free(kvm_vcpu_cache, svm);
out:
        return ERR_PTR(err);
}

static void svm_free_vcpu(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        __free_page(pfn_to_page(svm->vmcb_pa >> PAGE_SHIFT));
        __free_pages(virt_to_page(svm->msrpm), MSRPM_ALLOC_ORDER);
        __free_page(virt_to_page(svm->nested.hsave));
        __free_pages(virt_to_page(svm->nested.msrpm), MSRPM_ALLOC_ORDER);
        kvm_vcpu_uninit(vcpu);
        kmem_cache_free(kvm_vcpu_cache, svm);
}

static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        int i;

        if (unlikely(cpu != vcpu->cpu)) {
                u64 tsc_this, delta;

                /*
                 * Make sure that the guest sees a monotonically
                 * increasing TSC.
                 */
                rdtscll(tsc_this);
                delta = vcpu->arch.host_tsc - tsc_this;
                svm->vmcb->control.tsc_offset += delta;
                if (is_nested(svm))
                        svm->nested.hsave->control.tsc_offset += delta;
                vcpu->cpu = cpu;
                kvm_migrate_timers(vcpu);
                svm->asid_generation = 0;
        }

        for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
                rdmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);
}

static void svm_vcpu_put(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        int i;

        ++vcpu->stat.host_state_reload;
        for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
                wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);

        rdtscll(vcpu->arch.host_tsc);
}

static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu)
{
        return to_svm(vcpu)->vmcb->save.rflags;
}

static void svm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
{
        to_svm(vcpu)->vmcb->save.rflags = rflags;
}

static void svm_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
{
        switch (reg) {
        case VCPU_EXREG_PDPTR:
                BUG_ON(!npt_enabled);
                load_pdptrs(vcpu, vcpu->arch.cr3);
                break;
        default:
                BUG();
        }
}

static void svm_set_vintr(struct vcpu_svm *svm)
{
        svm->vmcb->control.intercept |= 1ULL << INTERCEPT_VINTR;
}

static void svm_clear_vintr(struct vcpu_svm *svm)
{
        svm->vmcb->control.intercept &= ~(1ULL << INTERCEPT_VINTR);
}

static struct vmcb_seg *svm_seg(struct kvm_vcpu *vcpu, int seg)
{
        struct vmcb_save_area *save = &to_svm(vcpu)->vmcb->save;

        switch (seg) {
        case VCPU_SREG_CS: return &save->cs;
        case VCPU_SREG_DS: return &save->ds;
        case VCPU_SREG_ES: return &save->es;
        case VCPU_SREG_FS: return &save->fs;
        case VCPU_SREG_GS: return &save->gs;
        case VCPU_SREG_SS: return &save->ss;
        case VCPU_SREG_TR: return &save->tr;
        case VCPU_SREG_LDTR: return &save->ldtr;
        }
        BUG();
        return NULL;
}

static u64 svm_get_segment_base(struct kvm_vcpu *vcpu, int seg)
{
        struct vmcb_seg *s = svm_seg(vcpu, seg);

        return s->base;
}

static void svm_get_segment(struct kvm_vcpu *vcpu,
                            struct kvm_segment *var, int seg)
{
        struct vmcb_seg *s = svm_seg(vcpu, seg);

        var->base = s->base;
        var->limit = s->limit;
        var->selector = s->selector;
        var->type = s->attrib & SVM_SELECTOR_TYPE_MASK;
        var->s = (s->attrib >> SVM_SELECTOR_S_SHIFT) & 1;
        var->dpl = (s->attrib >> SVM_SELECTOR_DPL_SHIFT) & 3;
        var->present = (s->attrib >> SVM_SELECTOR_P_SHIFT) & 1;
        var->avl = (s->attrib >> SVM_SELECTOR_AVL_SHIFT) & 1;
        var->l = (s->attrib >> SVM_SELECTOR_L_SHIFT) & 1;
        var->db = (s->attrib >> SVM_SELECTOR_DB_SHIFT) & 1;
        var->g = (s->attrib >> SVM_SELECTOR_G_SHIFT) & 1;

        /* AMD's VMCB does not have an explicit unusable field, so emulate it
         * for cross vendor migration purposes by "not present"
         */
        var->unusable = !var->present || (var->type == 0);

        switch (seg) {
        case VCPU_SREG_CS:
                /*
                 * SVM always stores 0 for the 'G' bit in the CS selector in
                 * the VMCB on a VMEXIT. This hurts cross-vendor migration:
                 * Intel's VMENTRY has a check on the 'G' bit.
                 */
                var->g = s->limit > 0xfffff;
                break;
        case VCPU_SREG_TR:
                /*
                 * Work around a bug where the busy flag in the tr selector
                 * isn't exposed
                 */
                var->type |= 0x2;
                break;
        case VCPU_SREG_DS:
        case VCPU_SREG_ES:
        case VCPU_SREG_FS:
        case VCPU_SREG_GS:
                /*
                 * The accessed bit must always be set in the segment
                 * descriptor cache, although it can be cleared in the
                 * descriptor, the cached bit always remains at 1. Since
                 * Intel has a check on this, set it here to support
                 * cross-vendor migration.
                 */
                if (!var->unusable)
                        var->type |= 0x1;
                break;
        case VCPU_SREG_SS:
                /* On AMD CPUs sometimes the DB bit in the segment
                 * descriptor is left as 1, although the whole segment has
                 * been made unusable. Clear it here to pass an Intel VMX
                 * entry check when cross vendor migrating.
                 */
                if (var->unusable)
                        var->db = 0;
                break;
        }
}

static int svm_get_cpl(struct kvm_vcpu *vcpu)
{
        struct vmcb_save_area *save = &to_svm(vcpu)->vmcb->save;

        return save->cpl;
}

static void svm_get_idt(struct kvm_vcpu *vcpu, struct descriptor_table *dt)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        dt->limit = svm->vmcb->save.idtr.limit;
        dt->base = svm->vmcb->save.idtr.base;
}

static void svm_set_idt(struct kvm_vcpu *vcpu, struct descriptor_table *dt)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        svm->vmcb->save.idtr.limit = dt->limit;
        svm->vmcb->save.idtr.base = dt->base ;
}

static void svm_get_gdt(struct kvm_vcpu *vcpu, struct descriptor_table *dt)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        dt->limit = svm->vmcb->save.gdtr.limit;
        dt->base = svm->vmcb->save.gdtr.base;
}

static void svm_set_gdt(struct kvm_vcpu *vcpu, struct descriptor_table *dt)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        svm->vmcb->save.gdtr.limit = dt->limit;
        svm->vmcb->save.gdtr.base = dt->base ;
}

static void svm_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)
{
}

static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{
        struct vcpu_svm *svm = to_svm(vcpu);

#ifdef CONFIG_X86_64
        if (vcpu->arch.shadow_efer & EFER_LME) {
                if (!is_paging(vcpu) && (cr0 & X86_CR0_PG)) {
                        vcpu->arch.shadow_efer |= EFER_LMA;
                        svm->vmcb->save.efer |= EFER_LMA | EFER_LME;
                }

                if (is_paging(vcpu) && !(cr0 & X86_CR0_PG)) {
                        vcpu->arch.shadow_efer &= ~EFER_LMA;
                        svm->vmcb->save.efer &= ~(EFER_LMA | EFER_LME);
                }
        }
#endif
        if (npt_enabled)
                goto set;

        if ((vcpu->arch.cr0 & X86_CR0_TS) && !(cr0 & X86_CR0_TS)) {
                svm->vmcb->control.intercept_exceptions &= ~(1 << NM_VECTOR);
                vcpu->fpu_active = 1;
        }

        vcpu->arch.cr0 = cr0;
        cr0 |= X86_CR0_PG | X86_CR0_WP;
        if (!vcpu->fpu_active) {
                svm->vmcb->control.intercept_exceptions |= (1 << NM_VECTOR);
                cr0 |= X86_CR0_TS;
        }
set:
        /*
         * re-enable caching here because the QEMU bios
         * does not do it - this results in some delay at
         * reboot
         */
        cr0 &= ~(X86_CR0_CD | X86_CR0_NW);
        svm->vmcb->save.cr0 = cr0;
}

static void svm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
        unsigned long host_cr4_mce = read_cr4() & X86_CR4_MCE;

        unsigned long old_cr4 = to_svm(vcpu)->vmcb->save.cr4;

        if (npt_enabled && ((old_cr4 ^ cr4) & X86_CR4_PGE))
                force_new_asid(vcpu);

        vcpu->arch.cr4 = cr4;
        if (!npt_enabled)
                cr4 |= X86_CR4_PAE;
        cr4 |= host_cr4_mce;
        to_svm(vcpu)->vmcb->save.cr4 = cr4;
}

static void svm_set_segment(struct kvm_vcpu *vcpu,
                            struct kvm_segment *var, int seg)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        struct vmcb_seg *s = svm_seg(vcpu, seg);

        s->base = var->base;
        s->limit = var->limit;
        s->selector = var->selector;
        if (var->unusable)
                s->attrib = 0;
        else {
                s->attrib = (var->type & SVM_SELECTOR_TYPE_MASK);
                s->attrib |= (var->s & 1) << SVM_SELECTOR_S_SHIFT;
                s->attrib |= (var->dpl & 3) << SVM_SELECTOR_DPL_SHIFT;
                s->attrib |= (var->present & 1) << SVM_SELECTOR_P_SHIFT;
                s->attrib |= (var->avl & 1) << SVM_SELECTOR_AVL_SHIFT;
                s->attrib |= (var->l & 1) << SVM_SELECTOR_L_SHIFT;
                s->attrib |= (var->db & 1) << SVM_SELECTOR_DB_SHIFT;
                s->attrib |= (var->g & 1) << SVM_SELECTOR_G_SHIFT;
        }
        if (seg == VCPU_SREG_CS)
                svm->vmcb->save.cpl
                        = (svm->vmcb->save.cs.attrib
                           >> SVM_SELECTOR_DPL_SHIFT) & 3;

}

static void update_db_intercept(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        svm->vmcb->control.intercept_exceptions &=
                ~((1 << DB_VECTOR) | (1 << BP_VECTOR));

        if (vcpu->arch.singlestep)
                svm->vmcb->control.intercept_exceptions |= (1 << DB_VECTOR);

        if (vcpu->guest_debug & KVM_GUESTDBG_ENABLE) {
                if (vcpu->guest_debug &
                    (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))
                        svm->vmcb->control.intercept_exceptions |=
                                1 << DB_VECTOR;
                if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
                        svm->vmcb->control.intercept_exceptions |=
                                1 << BP_VECTOR;
        } else
                vcpu->guest_debug = 0;
}

static int svm_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg)
{
        int old_debug = vcpu->guest_debug;
        struct vcpu_svm *svm = to_svm(vcpu);

        vcpu->guest_debug = dbg->control;

        update_db_intercept(vcpu);

        if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
                svm->vmcb->save.dr7 = dbg->arch.debugreg[7];
        else
                svm->vmcb->save.dr7 = vcpu->arch.dr7;

        if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
                svm->vmcb->save.rflags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
        else if (old_debug & KVM_GUESTDBG_SINGLESTEP)
                svm->vmcb->save.rflags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF);

        return 0;
}

static void load_host_msrs(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_X86_64
        wrmsrl(MSR_GS_BASE, to_svm(vcpu)->host_gs_base);
#endif
}

static void save_host_msrs(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_X86_64
        rdmsrl(MSR_GS_BASE, to_svm(vcpu)->host_gs_base);
#endif
}

static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *svm_data)
{
        if (svm_data->next_asid > svm_data->max_asid) {
                ++svm_data->asid_generation;
                svm_data->next_asid = 1;
                svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ALL_ASID;
        }

        svm->asid_generation = svm_data->asid_generation;
        svm->vmcb->control.asid = svm_data->next_asid++;
}

static unsigned long svm_get_dr(struct kvm_vcpu *vcpu, int dr)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        unsigned long val;

        switch (dr) {
        case 0 ... 3:
                val = vcpu->arch.db[dr];
                break;
        case 6:
                if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
                        val = vcpu->arch.dr6;
                else
                        val = svm->vmcb->save.dr6;
                break;
        case 7:
                if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
                        val = vcpu->arch.dr7;
                else
                        val = svm->vmcb->save.dr7;
                break;
        default:
                val = 0;
        }

        return val;
}

static void svm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long value,
                       int *exception)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        *exception = 0;

        switch (dr) {
        case 0 ... 3:
                vcpu->arch.db[dr] = value;
                if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
                        vcpu->arch.eff_db[dr] = value;
                return;
        case 4 ... 5:
                if (vcpu->arch.cr4 & X86_CR4_DE)
                        *exception = UD_VECTOR;
                return;
        case 6:
                if (value & 0xffffffff00000000ULL) {
                        *exception = GP_VECTOR;
                        return;
                }
                vcpu->arch.dr6 = (value & DR6_VOLATILE) | DR6_FIXED_1;
                return;
        case 7:
                if (value & 0xffffffff00000000ULL) {
                        *exception = GP_VECTOR;
                        return;
                }
                vcpu->arch.dr7 = (value & DR7_VOLATILE) | DR7_FIXED_1;
                if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) {
                        svm->vmcb->save.dr7 = vcpu->arch.dr7;
                        vcpu->arch.switch_db_regs = (value & DR7_BP_EN_MASK);
                }
                return;
        default:
                /* FIXME: Possible case? */
                printk(KERN_DEBUG "%s: unexpected dr %u\n",
                       __func__, dr);
                *exception = UD_VECTOR;
                return;
        }
}

static int pf_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        u64 fault_address;
        u32 error_code;

        fault_address  = svm->vmcb->control.exit_info_2;
        error_code = svm->vmcb->control.exit_info_1;

        trace_kvm_page_fault(fault_address, error_code);
        if (!npt_enabled && kvm_event_needs_reinjection(&svm->vcpu))
                kvm_mmu_unprotect_page_virt(&svm->vcpu, fault_address);
        return kvm_mmu_page_fault(&svm->vcpu, fault_address, error_code);
}

static int db_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        if (!(svm->vcpu.guest_debug &
              (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP)) &&
                !svm->vcpu.arch.singlestep) {
                kvm_queue_exception(&svm->vcpu, DB_VECTOR);
                return 1;
        }

        if (svm->vcpu.arch.singlestep) {
                svm->vcpu.arch.singlestep = false;
                if (!(svm->vcpu.guest_debug & KVM_GUESTDBG_SINGLESTEP))
                        svm->vmcb->save.rflags &=
                                ~(X86_EFLAGS_TF | X86_EFLAGS_RF);
                update_db_intercept(&svm->vcpu);
        }

        if (svm->vcpu.guest_debug &
            (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP)){
                kvm_run->exit_reason = KVM_EXIT_DEBUG;
                kvm_run->debug.arch.pc =
                        svm->vmcb->save.cs.base + svm->vmcb->save.rip;
                kvm_run->debug.arch.exception = DB_VECTOR;
                return 0;
        }

        return 1;
}

static int bp_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        kvm_run->exit_reason = KVM_EXIT_DEBUG;
        kvm_run->debug.arch.pc = svm->vmcb->save.cs.base + svm->vmcb->save.rip;
        kvm_run->debug.arch.exception = BP_VECTOR;
        return 0;
}

static int ud_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        int er;

        er = emulate_instruction(&svm->vcpu, kvm_run, 0, 0, EMULTYPE_TRAP_UD);
        if (er != EMULATE_DONE)
                kvm_queue_exception(&svm->vcpu, UD_VECTOR);
        return 1;
}

static int nm_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        svm->vmcb->control.intercept_exceptions &= ~(1 << NM_VECTOR);
        if (!(svm->vcpu.arch.cr0 & X86_CR0_TS))
                svm->vmcb->save.cr0 &= ~X86_CR0_TS;
        svm->vcpu.fpu_active = 1;

        return 1;
}

static int mc_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        /*
         * On an #MC intercept the MCE handler is not called automatically in
         * the host. So do it by hand here.
         */
        asm volatile (
                "int $0x12\n");
        /* not sure if we ever come back to this point */

        return 1;
}

static int shutdown_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        /*
         * VMCB is undefined after a SHUTDOWN intercept
         * so reinitialize it.
         */
        clear_page(svm->vmcb);
        init_vmcb(svm);

        kvm_run->exit_reason = KVM_EXIT_SHUTDOWN;
        return 0;
}

static int io_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        u32 io_info = svm->vmcb->control.exit_info_1; /* address size bug? */
        int size, in, string;
        unsigned port;

        ++svm->vcpu.stat.io_exits;

        svm->next_rip = svm->vmcb->control.exit_info_2;

        string = (io_info & SVM_IOIO_STR_MASK) != 0;

        if (string) {
                if (emulate_instruction(&svm->vcpu,
                                        kvm_run, 0, 0, 0) == EMULATE_DO_MMIO)
                        return 0;
                return 1;
        }

        in = (io_info & SVM_IOIO_TYPE_MASK) != 0;
        port = io_info >> 16;
        size = (io_info & SVM_IOIO_SIZE_MASK) >> SVM_IOIO_SIZE_SHIFT;

        skip_emulated_instruction(&svm->vcpu);
        return kvm_emulate_pio(&svm->vcpu, kvm_run, in, size, port);
}

static int nmi_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        return 1;
}

static int intr_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        ++svm->vcpu.stat.irq_exits;
        return 1;
}

static int nop_on_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        return 1;
}

static int halt_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        svm->next_rip = kvm_rip_read(&svm->vcpu) + 1;
        skip_emulated_instruction(&svm->vcpu);
        return kvm_emulate_halt(&svm->vcpu);
}

static int vmmcall_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
        skip_emulated_instruction(&svm->vcpu);
        kvm_emulate_hypercall(&svm->vcpu);
        return 1;
}

static int nested_svm_check_permissions(struct vcpu_svm *svm)
{
        if (!(svm->vcpu.arch.shadow_efer & EFER_SVME)
            || !is_paging(&svm->vcpu)) {
                kvm_queue_exception(&svm->vcpu, UD_VECTOR);
                return 1;
        }

        if (svm->vmcb->save.cpl) {
                kvm_inject_gp(&svm->vcpu, 0);
                return 1;
        }

       return 0;
}

static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
                                      bool has_error_code, u32 error_code)
{
        if (!is_nested(svm))
                return 0;

        svm->vmcb->control.exit_code = SVM_EXIT_EXCP_BASE + nr;
        svm->vmcb->control.exit_code_hi = 0;
        svm->vmcb->control.exit_info_1 = error_code;
        svm->vmcb->control.exit_info_2 = svm->vcpu.arch.cr2;

        return nested_svm_exit_handled(svm);
}

static inline int nested_svm_intr(struct vcpu_svm *svm)
{
        if (!is_nested(svm))
                return 0;

        if (!(svm->vcpu.arch.hflags & HF_VINTR_MASK))
                return 0;

        if (!(svm->vcpu.arch.hflags & HF_HIF_MASK))
                return 0;

        svm->vmcb->control.exit_code = SVM_EXIT_INTR;

        if (nested_svm_exit_handled(svm)) {
                nsvm_printk("VMexit -> INTR\n");
                return 1;
        }

        return 0;
}

static void *nested_svm_map(struct vcpu_svm *svm, u64 gpa, enum km_type idx)
{
        struct page *page;

        down_read(&current->mm->mmap_sem);
        page = gfn_to_page(svm->vcpu.kvm, gpa >> PAGE_SHIFT);
        up_read(&current->mm->mmap_sem);

        if (is_error_page(page))
                goto error;

        return kmap_atomic(page, idx);

error:
        kvm_release_page_clean(page);
        kvm_inject_gp(&svm->vcpu, 0);

        return NULL;
}

static void nested_svm_unmap(void *addr, enum km_type idx)
{
        struct page *page;

        if (!addr)
                return;

        page = kmap_atomic_to_page(addr);

        kunmap_atomic(addr, idx);
        kvm_release_page_dirty(page);
}

static bool nested_svm_exit_handled_msr(struct vcpu_svm *svm)
{
        u32 param = svm->vmcb->control.exit_info_1 & 1;
        u32 msr = svm->vcpu.arch.regs[VCPU_REGS_RCX];
        bool ret = false;
        u32 t0, t1;
        u8 *msrpm;

        if (!(svm->nested.intercept & (1ULL << INTERCEPT_MSR_PROT)))
                return false;

        msrpm = nested_svm_map(svm, svm->nested.vmcb_msrpm, KM_USER0);

        if (!msrpm)
                goto out;

        switch (msr) {
        case 0 ... 0x1fff:
                t0 = (msr * 2) % 8;
                t1 = msr / 8;
                break;
        case 0xc0000000 ... 0xc0001fff:
                t0 = (8192 + msr - 0xc0000000) * 2;
                t1 = (t0 / 8);
                t0 %= 8;
                break;
        case 0xc0010000 ... 0xc0011fff:
                t0 = (16384 + msr - 0xc0010000) * 2;
                t1 = (t0 / 8);
                t0 %= 8;
                break;
        default:
                ret = true;
                goto out;
        }

        ret = msrpm[t1] & ((1 << param) << t0);

out:
        nested_svm_unmap(msrpm, KM_USER0);

        return ret;
}

static int nested_svm_exit_special(struct vcpu_svm *svm)
{
        u32 exit_code = svm->vmcb->control.exit_code;

        switch (exit_code) {
        case SVM_EXIT_INTR:
        case SVM_EXIT_NMI:
                return NESTED_EXIT_HOST;
                /* For now we are always handling NPFs when using them */
        case SVM_EXIT_NPF:
                if (npt_enabled)
                        return NESTED_EXIT_HOST;
                break;
        /* When we're shadowing, trap PFs */
        case SVM_EXIT_EXCP_BASE + PF_VECTOR:
                if (!npt_enabled)
                        return NESTED_EXIT_HOST;
                break;
        default:
                break;
        }

        return NESTED_EXIT_CONTINUE;
}

/*
 * If this function returns true, this #vmexit was already handled
 */
static int nested_svm_exit_handled(struct vcpu_svm *svm)
{
        u32 exit_code = svm->vmcb->control.exit_code;
        int vmexit = NESTED_EXIT_HOST;

        switch (exit_code) {
        case SVM_EXIT_MSR:
                vmexit = nested_svm_exit_handled_msr(svm);
                break;
        case SVM_EXIT_READ_CR0 ... SVM_EXIT_READ_CR8: {
                u32 cr_bits = 1 << (exit_code - SVM_EXIT_READ_CR0);
                if (svm->nested.intercept_cr_read & cr_bits)
                        vmexit = NESTED_EXIT_DONE;
                break;
        }
        case SVM_EXIT_WRITE_CR0 ... SVM_EXIT_WRITE_CR8: {
                u32 cr_bits = 1 << (exit_code - SVM_EXIT_WRITE_CR0);
                if (svm->nested.intercept_cr_write & cr_bits)
                        vmexit = NESTED_EXIT_DONE;
                break;
        }
        case SVM_EXIT_READ_DR0 ... SVM_EXIT_READ_DR7: {
                u32 dr_bits = 1 << (exit_code - SVM_EXIT_READ_DR0);
                if (svm->nested.intercept_dr_read & dr_bits)
                        vmexit = NESTED_EXIT_DONE;
                break;
        }
        case SVM_EXIT_WRITE_DR0 ... SVM_EXIT_WRITE_DR7: {
                u32 dr_bits = 1 << (exit_code - SVM_EXIT_WRITE_DR0);
                if (svm->nested.intercept_dr_write & dr_bits)
                        vmexit = NESTED_EXIT_DONE;
                break;
        }
        case SVM_EXIT_EXCP_BASE ... SVM_EXIT_EXCP_BASE + 0x1f: {
                u32 excp_bits = 1 << (exit_code - SVM_EXIT_EXCP_BASE);
                if (svm->nested.intercept_exceptions & excp_bits)
                        vmexit = NESTED_EXIT_DONE;
                break;
        }
        default: {
                u64 exit_bits = 1ULL << (exit_code - SVM_EXIT_INTR);
                nsvm_printk("exit code: 0x%x\n", exit_code);
                if (svm->nested.intercept & exit_bits)
                        vmexit = NESTED_EXIT_DONE;
        }
        }

        if (vmexit == NESTED_EXIT_DONE) {
                nsvm_printk("#VMEXIT reason=%04x\n", exit_code);
                nested_svm_vmexit(svm);
        }

        return vmexit;
}

static inline void copy_vmcb_control_area(struct vmcb *dst_vmcb, struct vmcb *from_vmcb)
{
        struct vmcb_control_area *dst  = &dst_vmcb->control;
        struct vmcb_control_area *from = &from_vmcb->control;

        dst->intercept_cr_read    = from->intercept_cr_read;
        dst->intercept_cr_write   = from->intercept_cr_write;
        dst->intercept_dr_read    = from->intercept_dr_read;
        dst->intercept_dr_write   = from->intercept_dr_write;
        dst->intercept_exceptions = from->intercept_exceptions;
        dst->intercept            = from->intercept;
        dst->iopm_base_pa         = from->iopm_base_pa;
        dst->msrpm_base_pa        = from->msrpm_base_pa;
        dst->tsc_offset           = from->tsc_offset;
        dst->asid                 = from->asid;
        dst->tlb_ctl              = from->tlb_ctl;
        dst->int_ctl              = from->int_ctl;
        dst->int_vector           = from->int_vector;
        dst->int_state            = from->int_state;
        dst->exit_code            = from->exit_code;
        dst->exit_code_hi         = from->exit_code_hi;
        dst->exit_info_1          = from->exit_info_1;
        dst->exit_info_2          = from->exit_info_2;
        dst->exit_int_info        = from->exit_int_info;
        dst->exit_int_info_err    = from->exit_int_info_err;
        dst->nested_ctl           = from->nested_ctl;
        dst->event_inj            = from->event_inj;
        dst->event_inj_err        = from->event_inj_err;
        dst->nested_cr3           = from->nested_cr3;
        dst->lbr_ctl              = from->lbr_ctl;
}

static int nested_svm_vmexit(struct vcpu_svm *svm)
{
        struct vmcb *nested_vmcb;
        struct vmcb *hsave = svm->nested.hsave;
        struct vmcb *vmcb = svm->vmcb;

        nested_vmcb = nested_svm_map(svm, svm->nested.vmcb, KM_USER0);
        if (!nested_vmcb)
                return 1;

        /* Give the current vmcb to the guest */
        disable_gif(svm);

        nested_vmcb->save.es     = vmcb->save.es;
        nested_vmcb->save.cs     = vmcb->save.cs;
        nested_vmcb->save.ss     = vmcb->save.ss;
        nested_vmcb->save.ds     = vmcb->save.ds;
        nested_vmcb->save.gdtr   = vmcb->save.gdtr;
        nested_vmcb->save.idtr   = vmcb->save.idtr;
        if (npt_enabled)
                nested_vmcb->save.cr3    = vmcb->save.cr3;
        nested_vmcb->save.cr2    = vmcb->save.cr2;
        nested_vmcb->save.rflags = vmcb->save.rflags;
        nested_vmcb->save.rip    = vmcb->save.rip;
        nested_vmcb->save.rsp    = vmcb->save.rsp;
        nested_vmcb->save.rax    = vmcb->save.rax;
        nested_vmcb->save.dr7    = vmcb->save.dr7;
        nested_vmcb->save.dr6    = vmcb->save.dr6;
        nested_vmcb->save.cpl    = vmcb->save.cpl;

        nested_vmcb->control.int_ctl           = vmcb->control.int_ctl;
        nested_vmcb->control.int_vector        = vmcb->control.int_vector;
        nested_vmcb->control.int_state         = vmcb->control.int_state;
        nested_vmcb->control.exit_code         = vmcb->control.exit_code;
        nested_vmcb->control.exit_code_hi      = vmcb->control.exit_code_hi;
        nested_vmcb->control.exit_info_1       = vmcb->control.exit_info_1;
        nested_vmcb->control.exit_info_2       = vmcb->control.exit_info_2;
        nested_vmcb->control.exit_int_info     = vmcb->control.exit_int_info;
        nested_vmcb->control.exit_int_info_err = vmcb->control.exit_int_info_err;
        nested_vmcb->control.tlb_ctl           = 0;
        nested_vmcb->control.event_inj         = 0;
        nested_vmcb->control.event_inj_err     = 0;

        /* We always set V_INTR_MASKING and remember the old value in hflags */
        if (!(svm->vcpu.arch.hflags & HF_VINTR_MASK))
                nested_vmcb->control.int_ctl &= ~V_INTR_MASKING_MASK;

        /* Restore the original control entries */
        copy_vmcb_control_area(vmcb, hsave);

        /* Kill any pending exceptions */
        if (svm->vcpu.arch.exception.pending == true)
                nsvm_printk("WARNING: Pending Exception\n");

        kvm_clear_exception_queue(&svm->vcpu);
        kvm_clear_interrupt_queue(&svm->vcpu);

        /* Restore selected save entries */
        svm->vmcb->save.es = hsave->save.es;
        svm->vmcb->save.cs = hsave->save.cs;
        svm->vmcb->save.ss = hsave->save.ss;
        svm->vmcb->save.ds = hsave->save.ds;
        svm->vmcb->save.gdtr = hsave->save.gdtr;
        svm->vmcb->save.idtr = hsave->save.idtr;
        svm->vmcb->save.rflags = hsave->save.rflags;
        svm_set_efer(&svm->vcpu, hsave->save.efer);
        svm_set_cr0(&svm->vcpu, hsave->save.cr0 | X86_CR0_PE);
        svm_set_cr4(&svm->vcpu, hsave->save.cr4);
        if (npt_enabled) {
                svm->vmcb->save.cr3 = hsave->save.cr3;
                svm->vcpu.arch.cr3 = hsave->save.cr3;
        } else {
                kvm_set_cr3(&svm->vcpu, hsave->save.cr3);
        }
        kvm_register_write(&svm->vcpu, VCPU_REGS_RAX, hsave->save.rax);
        kvm_register_write(&svm->vcpu, VCPU_REGS_RSP, hsave->save.rsp);
        kvm_register_write(&svm->vcpu, VCPU_REGS_RIP, hsave->save.rip);
        svm->vmcb->save.dr7 = 0;
        svm->vmcb->save.cpl = 0;
        svm->vmcb->control.exit_int_info = 0;

        /* Exit nested SVM mode */
        svm->nested.vmcb = 0;

        nested_svm_unmap(nested_vmcb, KM_USER0);

        kvm_mmu_reset_context(&svm->vcpu);
        kvm_mmu_load(&svm->vcpu);

        return 0;
}

static bool nested_svm_vmrun_msrpm(struct vcpu_svm *svm)
{
        u32 *nested_msrpm;
        int i;

        nested_msrpm = nested_svm_map(svm, svm->nested.vmcb_msrpm, KM_USER0);
        if (!nested_msrpm)
                return false;

        for (i=0; i< PAGE_SIZE * (1 << MSRPM_ALLOC_ORDER) / 4; i++)
                svm->nested.msrpm[i] = svm->msrpm[i] | nested_msrpm[i];

        svm->vmcb->control.msrpm_base_pa = __pa(svm->nested.msrpm);

        nested_svm_unmap(nested_msrpm, KM_USER0);

        return true;
}

static bool nested_svm_vmrun(struct vcpu_svm *svm)
{
        struct vmcb *nested_vmcb;
        struct vmcb *hsave = svm->nested.hsave;
        struct vmcb *vmcb = svm->vmcb;

        nested_vmcb = nested_svm_map(svm, svm->vmcb->save.rax, KM_USER0);
        if (!nested_vmcb)
                return false;

        /* nested_vmcb is our indicator if nested SVM is activated */
        svm->nested.vmcb = svm->vmcb->save.rax;

        /* Clear internal status */
        kvm_clear_exception_queue(&svm->vcpu);
        kvm_clear_interrupt_queue(&svm->vcpu);

        /* Save the old vmcb, so we don't need to pick what we save, but
           can restore everything when a VMEXIT occurs */
        hsave->save.es     = vmcb->save.es;
        hsave->save.cs     = vmcb->save.cs;
        hsave->save.ss     = vmcb->save.ss;
        hsave->save.ds     = vmcb->save.ds;
        hsave->save.gdtr   = vmcb->save.gdtr;
        hsave->save.idtr   = vmcb->save.idtr;
        hsave->save.efer   = svm->vcpu.arch.shadow_efer;
        hsave->save.cr0    = svm->vcpu.arch.cr0;
        hsave->save.cr4    = svm->vcpu.arch.cr4;
        hsave->save.rflags = vmcb->save.rflags;
        hsave->save.rip    = svm->next_rip;
        hsave->save.rsp    = vmcb->save.rsp;
        hsave->save.rax    = vmcb->save.rax;
        if (npt_enabled)
                hsave->save.cr3    = vmcb->save.cr3;
        else
                hsave->save.cr3    = svm->vcpu.arch.cr3;

        copy_vmcb_control_area(hsave, vmcb);

        if (svm->vmcb->save.rflags & X86_EFLAGS_IF)
                svm->vcpu.arch.hflags |= HF_HIF_MASK;
        else
                svm->vcpu.arch.hflags &= ~HF_HIF_MASK;

        /* Load the nested guest state */
        svm->vmcb->save.es = nested_vmcb->save.es;
        svm->vmcb->save.cs = nested_vmcb->save.cs;
        svm->vmcb->save.ss = nested_vmcb->save.ss;
        svm->vmcb->save.ds = nested_vmcb->save.ds;
        svm->vmcb->save.gdtr = nested_vmcb->save.gdtr;
        svm->vmcb->save.idtr = nested_vmcb->save.idtr;
        svm->vmcb->save.rflags = nested_vmcb->save.rflags;
        svm_set_efer(&svm->vcpu, nested_vmcb->save.efer);
        svm_set_cr0(&svm->vcpu, nested_vmcb->save.cr0);
        svm_set_cr4(&svm->vcpu, nested_vmcb->save.cr4);
        if (npt_enabled) {
                svm->vmcb->save.cr3 = nested_vmcb->save.cr3;
                svm->vcpu.arch.cr3 = nested_vmcb->save.cr3;
        } else {
                kvm_set_cr3(&svm->vcpu, nested_vmcb->save.cr3);
                kvm_mmu_reset_context(&svm->vcpu);
        }
        svm->vmcb->save.cr2 = svm->vcpu.arch.cr2 = nested_vmcb->save.cr2;
        kvm_register_write(&svm->vcpu, VCPU_REGS_RAX, nested_vmcb->save.rax);
        kvm_register_write(&svm->vcpu, VCPU_REGS_RSP, nested_vmcb->save.rsp);
        kvm_register_write(&svm->vcpu, VCPU_REGS_RIP, nested_vmcb->save.rip);
        /* In case we don't even reach vcpu_run, the fields are not updated */
        svm->vmcb->save.rax = nested_vmcb->save.rax;
        svm->vmcb->save.rsp = nested_vmcb->save.rsp;
        svm->vmcb->save.rip = nested_vmcb->save.rip;
        svm->vmcb->save.dr7 = nested_vmcb->save.dr7;
        svm->vmcb->save.dr6 = nested_vmcb->save.dr6;
        svm->vmcb->save.cpl = nested_vmcb->save.cpl;

        /* We don't want a nested guest to be more powerful than the guest,
           so all intercepts are ORed */
        svm->vmcb->control.intercept_cr_read |=
                nested_vmcb->control.intercept_cr_read;
        svm->vmcb->control.intercept_cr_write |=
                nested_vmcb->control.intercept_cr_write;
        svm->vmcb->control.intercept_dr_read |=
                nested_vmcb->control.intercept_dr_read;
        svm->vmcb->control.intercept_dr_write |=
                nested_vmcb->control.intercept_dr_write;
        svm->vmcb->control.intercept_exceptions |=
                nested_vmcb->control.intercept_exceptions;

        svm->vmcb->control.intercept |= nested_vmcb->control.intercept;

        svm->nested.vmcb_msrpm = nested_vmcb->control.msrpm_base_pa;

        /* cache intercepts */
        svm->nested.intercept_cr_read    = nested_vmcb->control.intercept_cr_read;
        svm->nested.intercept_cr_write   = nested_vmcb->control.intercept_cr_write;
        svm->nested.intercept_dr_read    = nested_vmcb->control.intercept_dr_read;
        svm->nested.intercept_dr_write   = nested_vmcb->control.intercept_dr_write;
        svm->nested.intercept_exceptions = nested_vmcb->control.intercept_exceptions;
        svm->nested.intercept            = nested_vmcb->control.intercept;

        force_new_asid(&svm->vcpu);
        svm->vmcb->control.exit_int_info = nested_vmcb->control.exit_int_info;
        svm->vmcb->control.exit_int_info_err = nested_vmcb->control.exit_int_info_err;
        svm->vmcb->control.int_ctl = nested_vmcb->control.int_ctl | V_INTR_MASKING_MASK;
        if (nested_vmcb->control.int_ctl & V_IRQ_MASK) {
                nsvm_printk("nSVM Injecting Interrupt: 0x%x\n",
                                nested_vmcb->control.int_ctl);
        }
        if (nested_vmcb->control.int_ctl & V_INTR_MASKING_MASK)
                svm->vcpu.arch.hflags |= HF_VINTR_MASK;
        else
                svm->vcpu.arch.hflags &= ~HF_VINTR_MASK;

        nsvm_printk("nSVM exit_int_info: 0x%x | int_state: 0x%x\n",
                        nested_vmcb->control.exit_int_info,
                        nested_vmcb->control.int_state);

        svm->vmcb->control.int_vector = nested_vmcb->control.int_vector;
        svm->vmcb->control.int_state = nested_vmcb->control.int_state;
        svm->vmcb->control.tsc_offset += nested_vmcb->control.tsc_offset;
        if (nested_vmcb->control.event_inj & SVM_EVTINJ_VALID)
                nsvm_printk("Injecting Event: 0x%x\n",
                                nested_vmcb->control.event_inj);
        svm->vmcb->control.event_inj = nested_vmcb->control.event_inj;
        svm->vmcb->control.event_inj_err = nested_vmcb->control.event_inj_err;

        nested_svm_unmap(nested_vmcb, KM_USER0);

        enable_gif(svm);

        return true;
}

static void nested_svm_vmloadsave(struct vmcb *from_vmcb, struct vmcb *to_vmcb)
{
        to_vmcb->save.fs = from_vmcb->save.fs;
        to_vmcb->save.gs = from_vmcb->save.gs;
        to_vmcb->save.tr = from_vmcb->save.tr;
        to_vmcb->save.ldtr = from_vmcb->save.ldtr;
        to_vmcb->save.kernel_gs_base = from_vmcb->save.kernel_gs_base;
        to_vmcb->save.star = from_vmcb->save.star;
        to_vmcb->save.lstar = from_vmcb->save.lstar;
        to_vmcb->save.cstar = from_vmcb->save.cstar;
        to_vmcb->save.sfmask = from_vmcb->save.sfmask;
        to_vmcb->save.sysenter_cs = from_vmcb->save.sysenter_cs;
        to_vmcb->save.sysenter_esp = from_vmcb->save.sysenter_esp;
        to_vmcb->save.sysenter_eip = from_vmcb->save.sysenter_eip;
}

static int vmload_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        struct vmcb *nested_vmcb;

        if (nested_svm_check_permissions(svm))
                return 1;

        svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
        skip_emulated_instruction(&svm->vcpu);

        nested_vmcb = nested_svm_map(svm, svm->vmcb->save.rax, KM_USER0);
        if (!nested_vmcb)
                return 1;

        nested_svm_vmloadsave(nested_vmcb, svm->vmcb);
        nested_svm_unmap(nested_vmcb, KM_USER0);

        return 1;
}

static int vmsave_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        struct vmcb *nested_vmcb;

        if (nested_svm_check_permissions(svm))
                return 1;

        svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
        skip_emulated_instruction(&svm->vcpu);

        nested_vmcb = nested_svm_map(svm, svm->vmcb->save.rax, KM_USER0);
        if (!nested_vmcb)
                return 1;

        nested_svm_vmloadsave(svm->vmcb, nested_vmcb);
        nested_svm_unmap(nested_vmcb, KM_USER0);

        return 1;
}

static int vmrun_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        nsvm_printk("VMrun\n");

        if (nested_svm_check_permissions(svm))
                return 1;

        svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
        skip_emulated_instruction(&svm->vcpu);

        if (!nested_svm_vmrun(svm))
                return 1;

        if (!nested_svm_vmrun_msrpm(svm))
                goto failed;

        return 1;

failed:

        svm->vmcb->control.exit_code    = SVM_EXIT_ERR;
        svm->vmcb->control.exit_code_hi = 0;
        svm->vmcb->control.exit_info_1  = 0;
        svm->vmcb->control.exit_info_2  = 0;

        nested_svm_vmexit(svm);

        return 1;
}

static int stgi_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        if (nested_svm_check_permissions(svm))
                return 1;

        svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
        skip_emulated_instruction(&svm->vcpu);

        enable_gif(svm);

        return 1;
}

static int clgi_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        if (nested_svm_check_permissions(svm))
                return 1;

        svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
        skip_emulated_instruction(&svm->vcpu);

        disable_gif(svm);

        /* After a CLGI no interrupts should come */
        svm_clear_vintr(svm);
        svm->vmcb->control.int_ctl &= ~V_IRQ_MASK;

        return 1;
}

static int invlpga_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        struct kvm_vcpu *vcpu = &svm->vcpu;
        nsvm_printk("INVLPGA\n");

        /* Let's treat INVLPGA the same as INVLPG (can be optimized!) */
        kvm_mmu_invlpg(vcpu, vcpu->arch.regs[VCPU_REGS_RAX]);

        svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
        skip_emulated_instruction(&svm->vcpu);
        return 1;
}

static int invalid_op_interception(struct vcpu_svm *svm,
                                   struct kvm_run *kvm_run)
{
        kvm_queue_exception(&svm->vcpu, UD_VECTOR);
        return 1;
}

static int task_switch_interception(struct vcpu_svm *svm,
                                    struct kvm_run *kvm_run)
{
        u16 tss_selector;
        int reason;
        int int_type = svm->vmcb->control.exit_int_info &
                SVM_EXITINTINFO_TYPE_MASK;
        int int_vec = svm->vmcb->control.exit_int_info & SVM_EVTINJ_VEC_MASK;
        uint32_t type =
                svm->vmcb->control.exit_int_info & SVM_EXITINTINFO_TYPE_MASK;
        uint32_t idt_v =
                svm->vmcb->control.exit_int_info & SVM_EXITINTINFO_VALID;

        tss_selector = (u16)svm->vmcb->control.exit_info_1;

        if (svm->vmcb->control.exit_info_2 &
            (1ULL << SVM_EXITINFOSHIFT_TS_REASON_IRET))
                reason = TASK_SWITCH_IRET;
        else if (svm->vmcb->control.exit_info_2 &
                 (1ULL << SVM_EXITINFOSHIFT_TS_REASON_JMP))
                reason = TASK_SWITCH_JMP;
        else if (idt_v)
                reason = TASK_SWITCH_GATE;
        else
                reason = TASK_SWITCH_CALL;

        if (reason == TASK_SWITCH_GATE) {
                switch (type) {
                case SVM_EXITINTINFO_TYPE_NMI:
                        svm->vcpu.arch.nmi_injected = false;
                        break;
                case SVM_EXITINTINFO_TYPE_EXEPT:
                        kvm_clear_exception_queue(&svm->vcpu);
                        break;
                case SVM_EXITINTINFO_TYPE_INTR:
                        kvm_clear_interrupt_queue(&svm->vcpu);
                        break;
                default:
                        break;
                }
        }

        if (reason != TASK_SWITCH_GATE ||
            int_type == SVM_EXITINTINFO_TYPE_SOFT ||
            (int_type == SVM_EXITINTINFO_TYPE_EXEPT &&
             (int_vec == OF_VECTOR || int_vec == BP_VECTOR)))
                skip_emulated_instruction(&svm->vcpu);

        return kvm_task_switch(&svm->vcpu, tss_selector, reason);
}

static int cpuid_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;
        kvm_emulate_cpuid(&svm->vcpu);
        return 1;
}

static int iret_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        ++svm->vcpu.stat.nmi_window_exits;
        svm->vmcb->control.intercept &= ~(1UL << INTERCEPT_IRET);
        svm->vcpu.arch.hflags |= HF_IRET_MASK;
        return 1;
}

static int invlpg_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        if (emulate_instruction(&svm->vcpu, kvm_run, 0, 0, 0) != EMULATE_DONE)
                pr_unimpl(&svm->vcpu, "%s: failed\n", __func__);
        return 1;
}

static int emulate_on_interception(struct vcpu_svm *svm,
                                   struct kvm_run *kvm_run)
{
        if (emulate_instruction(&svm->vcpu, NULL, 0, 0, 0) != EMULATE_DONE)
                pr_unimpl(&svm->vcpu, "%s: failed\n", __func__);
        return 1;
}

static int cr8_write_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        u8 cr8_prev = kvm_get_cr8(&svm->vcpu);
        /* instruction emulation calls kvm_set_cr8() */
        emulate_instruction(&svm->vcpu, NULL, 0, 0, 0);
        if (irqchip_in_kernel(svm->vcpu.kvm)) {
                svm->vmcb->control.intercept_cr_write &= ~INTERCEPT_CR8_MASK;
                return 1;
        }
        if (cr8_prev <= kvm_get_cr8(&svm->vcpu))
                return 1;
        kvm_run->exit_reason = KVM_EXIT_SET_TPR;
        return 0;
}

static int svm_get_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 *data)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        switch (ecx) {
        case MSR_IA32_TSC: {
                u64 tsc_offset;

                if (is_nested(svm))
                        tsc_offset = svm->nested.hsave->control.tsc_offset;
                else
                        tsc_offset = svm->vmcb->control.tsc_offset;

                *data = tsc_offset + native_read_tsc();
                break;
        }
        case MSR_K6_STAR:
                *data = svm->vmcb->save.star;
                break;
#ifdef CONFIG_X86_64
        case MSR_LSTAR:
                *data = svm->vmcb->save.lstar;
                break;
        case MSR_CSTAR:
                *data = svm->vmcb->save.cstar;
                break;
        case MSR_KERNEL_GS_BASE:
                *data = svm->vmcb->save.kernel_gs_base;
                break;
        case MSR_SYSCALL_MASK:
                *data = svm->vmcb->save.sfmask;
                break;
#endif
        case MSR_IA32_SYSENTER_CS:
                *data = svm->vmcb->save.sysenter_cs;
                break;
        case MSR_IA32_SYSENTER_EIP:
                *data = svm->sysenter_eip;
                break;
        case MSR_IA32_SYSENTER_ESP:
                *data = svm->sysenter_esp;
                break;
        /* Nobody will change the following 5 values in the VMCB so
           we can safely return them on rdmsr. They will always be 0
           until LBRV is implemented. */
        case MSR_IA32_DEBUGCTLMSR:
                *data = svm->vmcb->save.dbgctl;
                break;
        case MSR_IA32_LASTBRANCHFROMIP:
                *data = svm->vmcb->save.br_from;
                break;
        case MSR_IA32_LASTBRANCHTOIP:
                *data = svm->vmcb->save.br_to;
                break;
        case MSR_IA32_LASTINTFROMIP:
                *data = svm->vmcb->save.last_excp_from;
                break;
        case MSR_IA32_LASTINTTOIP:
                *data = svm->vmcb->save.last_excp_to;
                break;
        case MSR_VM_HSAVE_PA:
                *data = svm->nested.hsave_msr;
                break;
        case MSR_VM_CR:
                *data = 0;
                break;
        case MSR_IA32_UCODE_REV:
                *data = 0x01000065;
                break;
        default:
                return kvm_get_msr_common(vcpu, ecx, data);
        }
        return 0;
}

static int rdmsr_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        u32 ecx = svm->vcpu.arch.regs[VCPU_REGS_RCX];
        u64 data;

        if (svm_get_msr(&svm->vcpu, ecx, &data))
                kvm_inject_gp(&svm->vcpu, 0);
        else {
                trace_kvm_msr_read(ecx, data);

                svm->vcpu.arch.regs[VCPU_REGS_RAX] = data & 0xffffffff;
                svm->vcpu.arch.regs[VCPU_REGS_RDX] = data >> 32;
                svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;
                skip_emulated_instruction(&svm->vcpu);
        }
        return 1;
}

static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        switch (ecx) {
        case MSR_IA32_TSC: {
                u64 tsc_offset = data - native_read_tsc();
                u64 g_tsc_offset = 0;

                if (is_nested(svm)) {
                        g_tsc_offset = svm->vmcb->control.tsc_offset -
                                       svm->nested.hsave->control.tsc_offset;
                        svm->nested.hsave->control.tsc_offset = tsc_offset;
                }

                svm->vmcb->control.tsc_offset = tsc_offset + g_tsc_offset;

                break;
        }
        case MSR_K6_STAR:
                svm->vmcb->save.star = data;
                break;
#ifdef CONFIG_X86_64
        case MSR_LSTAR:
                svm->vmcb->save.lstar = data;
                break;
        case MSR_CSTAR:
                svm->vmcb->save.cstar = data;
                break;
        case MSR_KERNEL_GS_BASE:
                svm->vmcb->save.kernel_gs_base = data;
                break;
        case MSR_SYSCALL_MASK:
                svm->vmcb->save.sfmask = data;
                break;
#endif
        case MSR_IA32_SYSENTER_CS:
                svm->vmcb->save.sysenter_cs = data;
                break;
        case MSR_IA32_SYSENTER_EIP:
                svm->sysenter_eip = data;
                svm->vmcb->save.sysenter_eip = data;
                break;
        case MSR_IA32_SYSENTER_ESP:
                svm->sysenter_esp = data;
                svm->vmcb->save.sysenter_esp = data;
                break;
        case MSR_IA32_DEBUGCTLMSR:
                if (!svm_has(SVM_FEATURE_LBRV)) {
                        pr_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTL 0x%llx, nop\n",
                                        __func__, data);
                        break;
                }
                if (data & DEBUGCTL_RESERVED_BITS)
                        return 1;

                svm->vmcb->save.dbgctl = data;
                if (data & (1ULL<<0))
                        svm_enable_lbrv(svm);
                else
                        svm_disable_lbrv(svm);
                break;
        case MSR_VM_HSAVE_PA:
                svm->nested.hsave_msr = data;
                break;
        case MSR_VM_CR:
        case MSR_VM_IGNNE:
                pr_unimpl(vcpu, "unimplemented wrmsr: 0x%x data 0x%llx\n", ecx, data);
                break;
        default:
                return kvm_set_msr_common(vcpu, ecx, data);
        }
        return 0;
}

static int wrmsr_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        u32 ecx = svm->vcpu.arch.regs[VCPU_REGS_RCX];
        u64 data = (svm->vcpu.arch.regs[VCPU_REGS_RAX] & -1u)
                | ((u64)(svm->vcpu.arch.regs[VCPU_REGS_RDX] & -1u) << 32);

        trace_kvm_msr_write(ecx, data);

        svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;
        if (svm_set_msr(&svm->vcpu, ecx, data))
                kvm_inject_gp(&svm->vcpu, 0);
        else
                skip_emulated_instruction(&svm->vcpu);
        return 1;
}

static int msr_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
        if (svm->vmcb->control.exit_info_1)
                return wrmsr_interception(svm, kvm_run);
        else
                return rdmsr_interception(svm, kvm_run);
}

static int interrupt_window_interception(struct vcpu_svm *svm,
                                   struct kvm_run *kvm_run)
{
        svm_clear_vintr(svm);
        svm->vmcb->control.int_ctl &= ~V_IRQ_MASK;
        /*
         * If the user space waits to inject interrupts, exit as soon as
         * possible
         */
        if (!irqchip_in_kernel(svm->vcpu.kvm) &&
            kvm_run->request_interrupt_window &&
            !kvm_cpu_has_interrupt(&svm->vcpu)) {
                ++svm->vcpu.stat.irq_window_exits;
                kvm_run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
                return 0;
        }

        return 1;
}

static int (*svm_exit_handlers[])(struct vcpu_svm *svm,
                                      struct kvm_run *kvm_run) = {
        [SVM_EXIT_READ_CR0]                     = emulate_on_interception,
        [SVM_EXIT_READ_CR3]                     = emulate_on_interception,
        [SVM_EXIT_READ_CR4]                     = emulate_on_interception,
        [SVM_EXIT_READ_CR8]                     = emulate_on_interception,
        /* for now: */
        [SVM_EXIT_WRITE_CR0]                    = emulate_on_interception,
        [SVM_EXIT_WRITE_CR3]                    = emulate_on_interception,
        [SVM_EXIT_WRITE_CR4]                    = emulate_on_interception,
        [SVM_EXIT_WRITE_CR8]                    = cr8_write_interception,
        [SVM_EXIT_READ_DR0]                     = emulate_on_interception,
        [SVM_EXIT_READ_DR1]                     = emulate_on_interception,
        [SVM_EXIT_READ_DR2]                     = emulate_on_interception,
        [SVM_EXIT_READ_DR3]                     = emulate_on_interception,
        [SVM_EXIT_WRITE_DR0]                    = emulate_on_interception,
        [SVM_EXIT_WRITE_DR1]                    = emulate_on_interception,
        [SVM_EXIT_WRITE_DR2]                    = emulate_on_interception,
        [SVM_EXIT_WRITE_DR3]                    = emulate_on_interception,
        [SVM_EXIT_WRITE_DR5]                    = emulate_on_interception,
        [SVM_EXIT_WRITE_DR7]                    = emulate_on_interception,
        [SVM_EXIT_EXCP_BASE + DB_VECTOR]        = db_interception,
        [SVM_EXIT_EXCP_BASE + BP_VECTOR]        = bp_interception,
        [SVM_EXIT_EXCP_BASE + UD_VECTOR]        = ud_interception,
        [SVM_EXIT_EXCP_BASE + PF_VECTOR]        = pf_interception,
        [SVM_EXIT_EXCP_BASE + NM_VECTOR]        = nm_interception,
        [SVM_EXIT_EXCP_BASE + MC_VECTOR]        = mc_interception,
        [SVM_EXIT_INTR]                         = intr_interception,
        [SVM_EXIT_NMI]                          = nmi_interception,
        [SVM_EXIT_SMI]                          = nop_on_interception,
        [SVM_EXIT_INIT]                         = nop_on_interception,
        [SVM_EXIT_VINTR]                        = interrupt_window_interception,
        /* [SVM_EXIT_CR0_SEL_WRITE]             = emulate_on_interception, */
        [SVM_EXIT_CPUID]                        = cpuid_interception,
        [SVM_EXIT_IRET]                         = iret_interception,
        [SVM_EXIT_INVD]                         = emulate_on_interception,
        [SVM_EXIT_HLT]                          = halt_interception,
        [SVM_EXIT_INVLPG]                       = invlpg_interception,
        [SVM_EXIT_INVLPGA]                      = invlpga_interception,
        [SVM_EXIT_IOIO]                         = io_interception,
        [SVM_EXIT_MSR]                          = msr_interception,
        [SVM_EXIT_TASK_SWITCH]                  = task_switch_interception,
        [SVM_EXIT_SHUTDOWN]                     = shutdown_interception,
        [SVM_EXIT_VMRUN]                        = vmrun_interception,
        [SVM_EXIT_VMMCALL]                      = vmmcall_interception,
        [SVM_EXIT_VMLOAD]                       = vmload_interception,
        [SVM_EXIT_VMSAVE]                       = vmsave_interception,
        [SVM_EXIT_STGI]                         = stgi_interception,
        [SVM_EXIT_CLGI]                         = clgi_interception,
        [SVM_EXIT_SKINIT]                       = invalid_op_interception,
        [SVM_EXIT_WBINVD]                       = emulate_on_interception,
        [SVM_EXIT_MONITOR]                      = invalid_op_interception,
        [SVM_EXIT_MWAIT]                        = invalid_op_interception,
        [SVM_EXIT_NPF]                          = pf_interception,
};

static int handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        u32 exit_code = svm->vmcb->control.exit_code;

        trace_kvm_exit(exit_code, svm->vmcb->save.rip);

        if (is_nested(svm)) {
                int vmexit;

                nsvm_printk("nested handle_exit: 0x%x | 0x%lx | 0x%lx | 0x%lx\n",
                            exit_code, svm->vmcb->control.exit_info_1,
                            svm->vmcb->control.exit_info_2, svm->vmcb->save.rip);

                vmexit = nested_svm_exit_special(svm);

                if (vmexit == NESTED_EXIT_CONTINUE)
                        vmexit = nested_svm_exit_handled(svm);

                if (vmexit == NESTED_EXIT_DONE)
                        return 1;
        }

        svm_complete_interrupts(svm);

        if (npt_enabled) {
                int mmu_reload = 0;
                if ((vcpu->arch.cr0 ^ svm->vmcb->save.cr0) & X86_CR0_PG) {
                        svm_set_cr0(vcpu, svm->vmcb->save.cr0);
                        mmu_reload = 1;
                }
                vcpu->arch.cr0 = svm->vmcb->save.cr0;
                vcpu->arch.cr3 = svm->vmcb->save.cr3;
                if (mmu_reload) {
                        kvm_mmu_reset_context(vcpu);
                        kvm_mmu_load(vcpu);
                }
        }


        if (svm->vmcb->control.exit_code == SVM_EXIT_ERR) {
                kvm_run->exit_reason = KVM_EXIT_FAIL_ENTRY;
                kvm_run->fail_entry.hardware_entry_failure_reason
                        = svm->vmcb->control.exit_code;
                return 0;
        }

        if (is_external_interrupt(svm->vmcb->control.exit_int_info) &&
            exit_code != SVM_EXIT_EXCP_BASE + PF_VECTOR &&
            exit_code != SVM_EXIT_NPF && exit_code != SVM_EXIT_TASK_SWITCH)
                printk(KERN_ERR "%s: unexpected exit_ini_info 0x%x "
                       "exit_code 0x%x\n",
                       __func__, svm->vmcb->control.exit_int_info,
                       exit_code);

        if (exit_code >= ARRAY_SIZE(svm_exit_handlers)
            || !svm_exit_handlers[exit_code]) {
                kvm_run->exit_reason = KVM_EXIT_UNKNOWN;
                kvm_run->hw.hardware_exit_reason = exit_code;
                return 0;
        }

        return svm_exit_handlers[exit_code](svm, kvm_run);
}

static void reload_tss(struct kvm_vcpu *vcpu)
{
        int cpu = raw_smp_processor_id();

        struct svm_cpu_data *svm_data = per_cpu(svm_data, cpu);
        svm_data->tss_desc->type = 9; /* available 32/64-bit TSS */
        load_TR_desc();
}

static void pre_svm_run(struct vcpu_svm *svm)
{
        int cpu = raw_smp_processor_id();

        struct svm_cpu_data *svm_data = per_cpu(svm_data, cpu);

        svm->vmcb->control.tlb_ctl = TLB_CONTROL_DO_NOTHING;
        /* FIXME: handle wraparound of asid_generation */
        if (svm->asid_generation != svm_data->asid_generation)
                new_asid(svm, svm_data);
}

static void svm_inject_nmi(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        svm->vmcb->control.event_inj = SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_NMI;
        vcpu->arch.hflags |= HF_NMI_MASK;
        svm->vmcb->control.intercept |= (1UL << INTERCEPT_IRET);
        ++vcpu->stat.nmi_injections;
}

static inline void svm_inject_irq(struct vcpu_svm *svm, int irq)
{
        struct vmcb_control_area *control;

        trace_kvm_inj_virq(irq);

        ++svm->vcpu.stat.irq_injections;
        control = &svm->vmcb->control;
        control->int_vector = irq;
        control->int_ctl &= ~V_INTR_PRIO_MASK;
        control->int_ctl |= V_IRQ_MASK |
                ((/*control->int_vector >> 4*/ 0xf) << V_INTR_PRIO_SHIFT);
}

static void svm_set_irq(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        BUG_ON(!(gif_set(svm)));

        svm->vmcb->control.event_inj = vcpu->arch.interrupt.nr |
                SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR;
}

static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        if (irr == -1)
                return;

        if (tpr >= irr)
                svm->vmcb->control.intercept_cr_write |= INTERCEPT_CR8_MASK;
}

static int svm_nmi_allowed(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        struct vmcb *vmcb = svm->vmcb;
        return !(vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) &&
                !(svm->vcpu.arch.hflags & HF_NMI_MASK);
}

static int svm_interrupt_allowed(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        struct vmcb *vmcb = svm->vmcb;
        return (vmcb->save.rflags & X86_EFLAGS_IF) &&
                !(vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) &&
                gif_set(svm) &&
                !(is_nested(svm) && (svm->vcpu.arch.hflags & HF_VINTR_MASK));
}

static void enable_irq_window(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        nsvm_printk("Trying to open IRQ window\n");

        nested_svm_intr(svm);

        /* In case GIF=0 we can't rely on the CPU to tell us when
         * GIF becomes 1, because that's a separate STGI/VMRUN intercept.
         * The next time we get that intercept, this function will be
         * called again though and we'll get the vintr intercept. */
        if (gif_set(svm)) {
                svm_set_vintr(svm);
                svm_inject_irq(svm, 0x0);
        }
}

static void enable_nmi_window(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        if ((svm->vcpu.arch.hflags & (HF_NMI_MASK | HF_IRET_MASK))
            == HF_NMI_MASK)
                return; /* IRET will cause a vm exit */

        /* Something prevents NMI from been injected. Single step over
           possible problem (IRET or exception injection or interrupt
           shadow) */
        vcpu->arch.singlestep = true;
        svm->vmcb->save.rflags |= (X86_EFLAGS_TF | X86_EFLAGS_RF);
        update_db_intercept(vcpu);
}

static int svm_set_tss_addr(struct kvm *kvm, unsigned int addr)
{
        return 0;
}

static void svm_flush_tlb(struct kvm_vcpu *vcpu)
{
        force_new_asid(vcpu);
}

static void svm_prepare_guest_switch(struct kvm_vcpu *vcpu)
{
}

static inline void sync_cr8_to_lapic(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        if (!(svm->vmcb->control.intercept_cr_write & INTERCEPT_CR8_MASK)) {
                int cr8 = svm->vmcb->control.int_ctl & V_TPR_MASK;
                kvm_set_cr8(vcpu, cr8);
        }
}

static inline void sync_lapic_to_cr8(struct kvm_vcpu *vcpu)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        u64 cr8;

        cr8 = kvm_get_cr8(vcpu);
        svm->vmcb->control.int_ctl &= ~V_TPR_MASK;
        svm->vmcb->control.int_ctl |= cr8 & V_TPR_MASK;
}

static void svm_complete_interrupts(struct vcpu_svm *svm)
{
        u8 vector;
        int type;
        u32 exitintinfo = svm->vmcb->control.exit_int_info;

        if (svm->vcpu.arch.hflags & HF_IRET_MASK)
                svm->vcpu.arch.hflags &= ~(HF_NMI_MASK | HF_IRET_MASK);

        svm->vcpu.arch.nmi_injected = false;
        kvm_clear_exception_queue(&svm->vcpu);
        kvm_clear_interrupt_queue(&svm->vcpu);

        if (!(exitintinfo & SVM_EXITINTINFO_VALID))
                return;

        vector = exitintinfo & SVM_EXITINTINFO_VEC_MASK;
        type = exitintinfo & SVM_EXITINTINFO_TYPE_MASK;

        switch (type) {
        case SVM_EXITINTINFO_TYPE_NMI:
                svm->vcpu.arch.nmi_injected = true;
                break;
        case SVM_EXITINTINFO_TYPE_EXEPT:
                /* In case of software exception do not reinject an exception
                   vector, but re-execute and instruction instead */
                if (is_nested(svm))
                        break;
                if (kvm_exception_is_soft(vector))
                        break;
                if (exitintinfo & SVM_EXITINTINFO_VALID_ERR) {
                        u32 err = svm->vmcb->control.exit_int_info_err;
                        kvm_queue_exception_e(&svm->vcpu, vector, err);

                } else
                        kvm_queue_exception(&svm->vcpu, vector);
                break;
        case SVM_EXITINTINFO_TYPE_INTR:
                kvm_queue_interrupt(&svm->vcpu, vector, false);
                break;
        default:
                break;
        }
}

#ifdef CONFIG_X86_64
#define R "r"
#else
#define R "e"
#endif

static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
        struct vcpu_svm *svm = to_svm(vcpu);
        u16 fs_selector;
        u16 gs_selector;
        u16 ldt_selector;

        svm->vmcb->save.rax = vcpu->arch.regs[VCPU_REGS_RAX];
        svm->vmcb->save.rsp = vcpu->arch.regs[VCPU_REGS_RSP];
        svm->vmcb->save.rip = vcpu->arch.regs[VCPU_REGS_RIP];

        pre_svm_run(svm);

        sync_lapic_to_cr8(vcpu);

        save_host_msrs(vcpu);
        fs_selector = kvm_read_fs();
        gs_selector = kvm_read_gs();
        ldt_selector = kvm_read_ldt();
        svm->vmcb->save.cr2 = vcpu->arch.cr2;
        /* required for live migration with NPT */
        if (npt_enabled)
                svm->vmcb->save.cr3 = vcpu->arch.cr3;

        clgi();

        local_irq_enable();

        asm volatile (
                "push %%"R"bp; \n\t"
                "mov %c[rbx](%[svm]), %%"R"bx \n\t"
                "mov %c[rcx](%[svm]), %%"R"cx \n\t"
                "mov %c[rdx](%[svm]), %%"R"dx \n\t"
                "mov %c[rsi](%[svm]), %%"R"si \n\t"
                "mov %c[rdi](%[svm]), %%"R"di \n\t"
                "mov %c[rbp](%[svm]), %%"R"bp \n\t"
#ifdef CONFIG_X86_64
                "mov %c[r8](%[svm]),  %%r8  \n\t"
                "mov %c[r9](%[svm]),  %%r9  \n\t"
                "mov %c[r10](%[svm]), %%r10 \n\t"
                "mov %c[r11](%[svm]), %%r11 \n\t"
                "mov %c[r12](%[svm]), %%r12 \n\t"
                "mov %c[r13](%[svm]), %%r13 \n\t"
                "mov %c[r14](%[svm]), %%r14 \n\t"
                "mov %c[r15](%[svm]), %%r15 \n\t"
#endif

                /* Enter guest mode */
                "push %%"R"ax \n\t"
                "mov %c[vmcb](%[svm]), %%"R"ax \n\t"
                __ex(SVM_VMLOAD) "\n\t"
                __ex(SVM_VMRUN) "\n\t"
                __ex(SVM_VMSAVE) "\n\t"
                "pop %%"R"ax \n\t"

                /* Save guest registers, load host registers */
                "mov %%"R"bx, %c[rbx](%[svm]) \n\t"
                "mov %%"R"cx, %c[rcx](%[svm]) \n\t"
                "mov %%"R"dx, %c[rdx](%[svm]) \n\t"
                "mov %%"R"si, %c[rsi](%[svm]) \n\t"
                "mov %%"R"di, %c[rdi](%[svm]) \n\t"
                "mov %%"R"bp, %c[rbp](%[svm]) \n\t"
#ifdef CONFIG_X86_64
                "mov %%r8,  %c[r8](%[svm]) \n\t"
                "mov %%r9,  %c[r9](%[svm]) \n\t"
                "mov %%r10, %c[r10](%[svm]) \n\t"
                "mov %%r11, %c[r11](%[svm]) \n\t"
                "mov %%r12, %c[r12](%[svm]) \n\t"
                "mov %%r13, %c[r13](%[svm]) \n\t"
                "mov %%r14, %c[r14](%[svm]) \n\t"
                "mov %%r15, %c[r15](%[svm]) \n\t"
#endif
                "pop %%"R"bp"
                :
                : [svm]"a"(svm),
                  [vmcb]"i"(offsetof(struct vcpu_svm, vmcb_pa)),
                  [rbx]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_RBX])),
                  [rcx]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_RCX])),
                  [rdx]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_RDX])),
                  [rsi]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_RSI])),
                  [rdi]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_RDI])),
                  [rbp]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_RBP]))
#ifdef CONFIG_X86_64
                  , [r8]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_R8])),
                  [r9]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_R9])),
                  [r10]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_R10])),
                  [r11]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_R11])),
                  [r12]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_R12])),
                  [r13]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_R13])),
                  [r14]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_R14])),
                  [r15]"i"(offsetof(struct vcpu_svm, vcpu.arch.regs[VCPU_REGS_R15]))
#endif
                : "cc", "memory"
                , R"bx", R"cx", R"dx", R"si", R"di"
#ifdef CONFIG_X86_64
                , "r8", "r9", "r10", "r11" , "r12", "r13", "r14", "r15"
#endif
                );

        vcpu->arch.cr2 = svm->vmcb->save.cr2;
        vcpu->arch.regs[VCPU_REGS_RAX] = svm->vmcb->save.rax;
        vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp;
        vcpu->arch.regs[VCPU_REGS_RIP] = svm->vmcb->save.rip;

        kvm_load_fs(fs_selector);
        kvm_load_gs(gs_selector);
        kvm_load_ldt(ldt_selector);
        load_host_msrs(vcpu);

        reload_tss(vcpu);

        local_irq_disable();

        stgi();

        sync_cr8_to_lapic(vcpu);

        svm->next_rip = 0;

        if (npt_enabled) {
                vcpu->arch.regs_avail &= ~(1 << VCPU_EXREG_PDPTR);
                vcpu->arch.regs_dirty &= ~(1 << VCPU_EXREG_PDPTR);
        }
}

#undef R

static void svm_set_cr3(struct kvm_vcpu *vcpu, unsigned long root)
{
        struct vcpu_svm *svm = to_svm(vcpu);

        if (npt_enabled) {
                svm->vmcb->control.nested_cr3 = root;
                force_new_asid(vcpu);
                return;
        }

        svm->vmcb->save.cr3 = root;
        force_new_asid(vcpu);

        if (vcpu->fpu_active) {
                svm->vmcb->control.intercept_exceptions |= (1 << NM_VECTOR);
                svm->vmcb->save.cr0 |= X86_CR0_TS;
                vcpu->fpu_active = 0;
        }
}

static int is_disabled(void)
{
        u64 vm_cr;

        rdmsrl(MSR_VM_CR, vm_cr);
        if (vm_cr & (1 << SVM_VM_CR_SVM_DISABLE))
                return 1;

        return 0;
}

static void
svm_patch_hypercall(struct kvm_vcpu *vcpu, unsigned char *hypercall)
{
        /*
         * Patch in the VMMCALL instruction:
         */
        hypercall[0] = 0x0f;
        hypercall[1] = 0x01;
        hypercall[2] = 0xd9;
}

static void svm_check_processor_compat(void *rtn)
{
        *(int *)rtn = 0;
}

static bool svm_cpu_has_accelerated_tpr(void)
{
        return false;
}

static int get_npt_level(void)
{
#ifdef CONFIG_X86_64
        return PT64_ROOT_LEVEL;
#else
        return PT32E_ROOT_LEVEL;
#endif
}

static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
{
        return 0;
}

static const struct trace_print_flags svm_exit_reasons_str[] = {
        { SVM_EXIT_READ_CR0,                    "read_cr0" },
        { SVM_EXIT_READ_CR3,                    "read_cr3" },
        { SVM_EXIT_READ_CR4,                    "read_cr4" },
        { SVM_EXIT_READ_CR8,                    "read_cr8" },
        { SVM_EXIT_WRITE_CR0,                   "write_cr0" },
        { SVM_EXIT_WRITE_CR3,                   "write_cr3" },
        { SVM_EXIT_WRITE_CR4,                   "write_cr4" },
        { SVM_EXIT_WRITE_CR8,                   "write_cr8" },
        { SVM_EXIT_READ_DR0,                    "read_dr0" },
        { SVM_EXIT_READ_DR1,                    "read_dr1" },
        { SVM_EXIT_READ_DR2,                    "read_dr2" },
        { SVM_EXIT_READ_DR3,                    "read_dr3" },
        { SVM_EXIT_WRITE_DR0,                   "write_dr0" },
        { SVM_EXIT_WRITE_DR1,                   "write_dr1" },
        { SVM_EXIT_WRITE_DR2,                   "write_dr2" },
        { SVM_EXIT_WRITE_DR3,                   "write_dr3" },
        { SVM_EXIT_WRITE_DR5,                   "write_dr5" },
        { SVM_EXIT_WRITE_DR7,                   "write_dr7" },
        { SVM_EXIT_EXCP_BASE + DB_VECTOR,       "DB excp" },
        { SVM_EXIT_EXCP_BASE + BP_VECTOR,       "BP excp" },
        { SVM_EXIT_EXCP_BASE + UD_VECTOR,       "UD excp" },
        { SVM_EXIT_EXCP_BASE + PF_VECTOR,       "PF excp" },
        { SVM_EXIT_EXCP_BASE + NM_VECTOR,       "NM excp" },
        { SVM_EXIT_EXCP_BASE + MC_VECTOR,       "MC excp" },
        { SVM_EXIT_INTR,                        "interrupt" },
        { SVM_EXIT_NMI,                         "nmi" },
        { SVM_EXIT_SMI,                         "smi" },
        { SVM_EXIT_INIT,                        "init" },
        { SVM_EXIT_VINTR,                       "vintr" },
        { SVM_EXIT_CPUID,                       "cpuid" },
        { SVM_EXIT_INVD,                        "invd" },
        { SVM_EXIT_HLT,                         "hlt" },
        { SVM_EXIT_INVLPG,                      "invlpg" },
        { SVM_EXIT_INVLPGA,                     "invlpga" },
        { SVM_EXIT_IOIO,                        "io" },
        { SVM_EXIT_MSR,                         "msr" },
        { SVM_EXIT_TASK_SWITCH,                 "task_switch" },
        { SVM_EXIT_SHUTDOWN,                    "shutdown" },
        { SVM_EXIT_VMRUN,                       "vmrun" },
        { SVM_EXIT_VMMCALL,                     "hypercall" },
        { SVM_EXIT_VMLOAD,                      "vmload" },
        { SVM_EXIT_VMSAVE,                      "vmsave" },
        { SVM_EXIT_STGI,                        "stgi" },
        { SVM_EXIT_CLGI,                        "clgi" },
        { SVM_EXIT_SKINIT,                      "skinit" },
        { SVM_EXIT_WBINVD,                      "wbinvd" },
        { SVM_EXIT_MONITOR,                     "monitor" },
        { SVM_EXIT_MWAIT,                       "mwait" },
        { SVM_EXIT_NPF,                         "npf" },
        { -1, NULL }
};

static bool svm_gb_page_enable(void)
{
        return true;
}

static struct kvm_x86_ops svm_x86_ops = {
        .cpu_has_kvm_support = has_svm,
        .disabled_by_bios = is_disabled,
        .hardware_setup = svm_hardware_setup,
        .hardware_unsetup = svm_hardware_unsetup,
        .check_processor_compatibility = svm_check_processor_compat,
        .hardware_enable = svm_hardware_enable,
        .hardware_disable = svm_hardware_disable,
        .cpu_has_accelerated_tpr = svm_cpu_has_accelerated_tpr,

        .vcpu_create = svm_create_vcpu,
        .vcpu_free = svm_free_vcpu,
        .vcpu_reset = svm_vcpu_reset,

        .prepare_guest_switch = svm_prepare_guest_switch,
        .vcpu_load = svm_vcpu_load,
        .vcpu_put = svm_vcpu_put,

        .set_guest_debug = svm_guest_debug,
        .get_msr = svm_get_msr,
        .set_msr = svm_set_msr,
        .get_segment_base = svm_get_segment_base,
        .get_segment = svm_get_segment,
        .set_segment = svm_set_segment,
        .get_cpl = svm_get_cpl,
        .get_cs_db_l_bits = kvm_get_cs_db_l_bits,
        .decache_cr4_guest_bits = svm_decache_cr4_guest_bits,
        .set_cr0 = svm_set_cr0,
        .set_cr3 = svm_set_cr3,
        .set_cr4 = svm_set_cr4,
        .set_efer = svm_set_efer,
        .get_idt = svm_get_idt,
        .set_idt = svm_set_idt,
        .get_gdt = svm_get_gdt,
        .set_gdt = svm_set_gdt,
        .get_dr = svm_get_dr,
        .set_dr = svm_set_dr,
        .cache_reg = svm_cache_reg,
        .get_rflags = svm_get_rflags,
        .set_rflags = svm_set_rflags,

        .tlb_flush = svm_flush_tlb,

        .run = svm_vcpu_run,
        .handle_exit = handle_exit,
        .skip_emulated_instruction = skip_emulated_instruction,
        .set_interrupt_shadow = svm_set_interrupt_shadow,
        .get_interrupt_shadow = svm_get_interrupt_shadow,
        .patch_hypercall = svm_patch_hypercall,
        .set_irq = svm_set_irq,
        .set_nmi = svm_inject_nmi,
        .queue_exception = svm_queue_exception,
        .interrupt_allowed = svm_interrupt_allowed,
        .nmi_allowed = svm_nmi_allowed,
        .enable_nmi_window = enable_nmi_window,
        .enable_irq_window = enable_irq_window,
        .update_cr8_intercept = update_cr8_intercept,

        .set_tss_addr = svm_set_tss_addr,
        .get_tdp_level = get_npt_level,
        .get_mt_mask = svm_get_mt_mask,

        .exit_reasons_str = svm_exit_reasons_str,
        .gb_page_enable = svm_gb_page_enable,
};

static int __init svm_init(void)
{
        return kvm_init(&svm_x86_ops, sizeof(struct vcpu_svm),
                              THIS_MODULE);
}

static void __exit svm_exit(void)
{
        kvm_exit();
}

module_init(svm_init)
module_exit(svm_exit)