linux/include/asm-generic/mshyperv.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2
   3/*
   4 * Linux-specific definitions for managing interactions with Microsoft's
   5 * Hyper-V hypervisor. The definitions in this file are architecture
   6 * independent. See arch/<arch>/include/asm/mshyperv.h for definitions
   7 * that are specific to architecture <arch>.
   8 *
   9 * Definitions that are specified in the Hyper-V Top Level Functional
  10 * Spec (TLFS) should not go in this file, but should instead go in
  11 * hyperv-tlfs.h.
  12 *
  13 * Copyright (C) 2019, Microsoft, Inc.
  14 *
  15 * Author : Michael Kelley <mikelley@microsoft.com>
  16 */
  17
  18#ifndef _ASM_GENERIC_MSHYPERV_H
  19#define _ASM_GENERIC_MSHYPERV_H
  20
  21#include <linux/types.h>
  22#include <linux/atomic.h>
  23#include <linux/bitops.h>
  24#include <linux/cpumask.h>
  25#include <asm/ptrace.h>
  26#include <asm/hyperv-tlfs.h>
  27
  28struct ms_hyperv_info {
  29        u32 features;
  30        u32 priv_high;
  31        u32 misc_features;
  32        u32 hints;
  33        u32 nested_features;
  34        u32 max_vp_index;
  35        u32 max_lp_index;
  36        u32 isolation_config_a;
  37        u32 isolation_config_b;
  38};
  39extern struct ms_hyperv_info ms_hyperv;
  40
  41extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
  42extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
  43
  44/* Helper functions that provide a consistent pattern for checking Hyper-V hypercall status. */
  45static inline int hv_result(u64 status)
  46{
  47        return status & HV_HYPERCALL_RESULT_MASK;
  48}
  49
  50static inline bool hv_result_success(u64 status)
  51{
  52        return hv_result(status) == HV_STATUS_SUCCESS;
  53}
  54
  55static inline unsigned int hv_repcomp(u64 status)
  56{
  57        /* Bits [43:32] of status have 'Reps completed' data. */
  58        return (status & HV_HYPERCALL_REP_COMP_MASK) >>
  59                         HV_HYPERCALL_REP_COMP_OFFSET;
  60}
  61
  62/*
  63 * Rep hypercalls. Callers of this functions are supposed to ensure that
  64 * rep_count and varhead_size comply with Hyper-V hypercall definition.
  65 */
  66static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
  67                                      void *input, void *output)
  68{
  69        u64 control = code;
  70        u64 status;
  71        u16 rep_comp;
  72
  73        control |= (u64)varhead_size << HV_HYPERCALL_VARHEAD_OFFSET;
  74        control |= (u64)rep_count << HV_HYPERCALL_REP_COMP_OFFSET;
  75
  76        do {
  77                status = hv_do_hypercall(control, input, output);
  78                if (!hv_result_success(status))
  79                        return status;
  80
  81                rep_comp = hv_repcomp(status);
  82
  83                control &= ~HV_HYPERCALL_REP_START_MASK;
  84                control |= (u64)rep_comp << HV_HYPERCALL_REP_START_OFFSET;
  85
  86                touch_nmi_watchdog();
  87        } while (rep_comp < rep_count);
  88
  89        return status;
  90}
  91
  92/* Generate the guest OS identifier as described in the Hyper-V TLFS */
  93static inline  __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version,
  94                                       __u64 d_info2)
  95{
  96        __u64 guest_id = 0;
  97
  98        guest_id = (((__u64)HV_LINUX_VENDOR_ID) << 48);
  99        guest_id |= (d_info1 << 48);
 100        guest_id |= (kernel_version << 16);
 101        guest_id |= d_info2;
 102
 103        return guest_id;
 104}
 105
 106/* Free the message slot and signal end-of-message if required */
 107static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
 108{
 109        /*
 110         * On crash we're reading some other CPU's message page and we need
 111         * to be careful: this other CPU may already had cleared the header
 112         * and the host may already had delivered some other message there.
 113         * In case we blindly write msg->header.message_type we're going
 114         * to lose it. We can still lose a message of the same type but
 115         * we count on the fact that there can only be one
 116         * CHANNELMSG_UNLOAD_RESPONSE and we don't care about other messages
 117         * on crash.
 118         */
 119        if (cmpxchg(&msg->header.message_type, old_msg_type,
 120                    HVMSG_NONE) != old_msg_type)
 121                return;
 122
 123        /*
 124         * The cmxchg() above does an implicit memory barrier to
 125         * ensure the write to MessageType (ie set to
 126         * HVMSG_NONE) happens before we read the
 127         * MessagePending and EOMing. Otherwise, the EOMing
 128         * will not deliver any more messages since there is
 129         * no empty slot
 130         */
 131        if (msg->header.message_flags.msg_pending) {
 132                /*
 133                 * This will cause message queue rescan to
 134                 * possibly deliver another msg from the
 135                 * hypervisor
 136                 */
 137                hv_set_register(HV_REGISTER_EOM, 0);
 138        }
 139}
 140
 141void hv_setup_vmbus_handler(void (*handler)(void));
 142void hv_remove_vmbus_handler(void);
 143void hv_setup_stimer0_handler(void (*handler)(void));
 144void hv_remove_stimer0_handler(void);
 145
 146void hv_setup_kexec_handler(void (*handler)(void));
 147void hv_remove_kexec_handler(void);
 148void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs));
 149void hv_remove_crash_handler(void);
 150
 151extern int vmbus_interrupt;
 152extern int vmbus_irq;
 153
 154#if IS_ENABLED(CONFIG_HYPERV)
 155/*
 156 * Hypervisor's notion of virtual processor ID is different from
 157 * Linux' notion of CPU ID. This information can only be retrieved
 158 * in the context of the calling CPU. Setup a map for easy access
 159 * to this information.
 160 */
 161extern u32 *hv_vp_index;
 162extern u32 hv_max_vp_index;
 163
 164/* Sentinel value for an uninitialized entry in hv_vp_index array */
 165#define VP_INVAL        U32_MAX
 166
 167void *hv_alloc_hyperv_page(void);
 168void *hv_alloc_hyperv_zeroed_page(void);
 169void hv_free_hyperv_page(unsigned long addr);
 170
 171/**
 172 * hv_cpu_number_to_vp_number() - Map CPU to VP.
 173 * @cpu_number: CPU number in Linux terms
 174 *
 175 * This function returns the mapping between the Linux processor
 176 * number and the hypervisor's virtual processor number, useful
 177 * in making hypercalls and such that talk about specific
 178 * processors.
 179 *
 180 * Return: Virtual processor number in Hyper-V terms
 181 */
 182static inline int hv_cpu_number_to_vp_number(int cpu_number)
 183{
 184        return hv_vp_index[cpu_number];
 185}
 186
 187static inline int cpumask_to_vpset(struct hv_vpset *vpset,
 188                                    const struct cpumask *cpus)
 189{
 190        int cpu, vcpu, vcpu_bank, vcpu_offset, nr_bank = 1;
 191
 192        /* valid_bank_mask can represent up to 64 banks */
 193        if (hv_max_vp_index / 64 >= 64)
 194                return 0;
 195
 196        /*
 197         * Clear all banks up to the maximum possible bank as hv_tlb_flush_ex
 198         * structs are not cleared between calls, we risk flushing unneeded
 199         * vCPUs otherwise.
 200         */
 201        for (vcpu_bank = 0; vcpu_bank <= hv_max_vp_index / 64; vcpu_bank++)
 202                vpset->bank_contents[vcpu_bank] = 0;
 203
 204        /*
 205         * Some banks may end up being empty but this is acceptable.
 206         */
 207        for_each_cpu(cpu, cpus) {
 208                vcpu = hv_cpu_number_to_vp_number(cpu);
 209                if (vcpu == VP_INVAL)
 210                        return -1;
 211                vcpu_bank = vcpu / 64;
 212                vcpu_offset = vcpu % 64;
 213                __set_bit(vcpu_offset, (unsigned long *)
 214                          &vpset->bank_contents[vcpu_bank]);
 215                if (vcpu_bank >= nr_bank)
 216                        nr_bank = vcpu_bank + 1;
 217        }
 218        vpset->valid_bank_mask = GENMASK_ULL(nr_bank - 1, 0);
 219        return nr_bank;
 220}
 221
 222void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die);
 223bool hv_is_hyperv_initialized(void);
 224bool hv_is_hibernation_supported(void);
 225enum hv_isolation_type hv_get_isolation_type(void);
 226bool hv_is_isolation_supported(void);
 227void hyperv_cleanup(void);
 228bool hv_query_ext_cap(u64 cap_query);
 229#else /* CONFIG_HYPERV */
 230static inline bool hv_is_hyperv_initialized(void) { return false; }
 231static inline bool hv_is_hibernation_supported(void) { return false; }
 232static inline void hyperv_cleanup(void) {}
 233#endif /* CONFIG_HYPERV */
 234
 235#endif
 236