linux/arch/powerpc/kvm/timing.c
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   1/*
   2 * This program is free software; you can redistribute it and/or modify
   3 * it under the terms of the GNU General Public License, version 2, as
   4 * published by the Free Software Foundation.
   5 *
   6 * This program is distributed in the hope that it will be useful,
   7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9 * GNU General Public License for more details.
  10 *
  11 * You should have received a copy of the GNU General Public License
  12 * along with this program; if not, write to the Free Software
  13 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  14 *
  15 * Copyright IBM Corp. 2008
  16 *
  17 * Authors: Hollis Blanchard <hollisb@us.ibm.com>
  18 *          Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
  19 */
  20
  21#include <linux/kvm_host.h>
  22#include <linux/fs.h>
  23#include <linux/seq_file.h>
  24#include <linux/debugfs.h>
  25#include <linux/uaccess.h>
  26
  27#include <asm/time.h>
  28#include <asm-generic/div64.h>
  29
  30#include "timing.h"
  31
  32void kvmppc_init_timing_stats(struct kvm_vcpu *vcpu)
  33{
  34        int i;
  35
  36        /* pause guest execution to avoid concurrent updates */
  37        local_irq_disable();
  38        mutex_lock(&vcpu->mutex);
  39
  40        vcpu->arch.last_exit_type = 0xDEAD;
  41        for (i = 0; i < __NUMBER_OF_KVM_EXIT_TYPES; i++) {
  42                vcpu->arch.timing_count_type[i] = 0;
  43                vcpu->arch.timing_max_duration[i] = 0;
  44                vcpu->arch.timing_min_duration[i] = 0xFFFFFFFF;
  45                vcpu->arch.timing_sum_duration[i] = 0;
  46                vcpu->arch.timing_sum_quad_duration[i] = 0;
  47        }
  48        vcpu->arch.timing_last_exit = 0;
  49        vcpu->arch.timing_exit.tv64 = 0;
  50        vcpu->arch.timing_last_enter.tv64 = 0;
  51
  52        mutex_unlock(&vcpu->mutex);
  53        local_irq_enable();
  54}
  55
  56static void add_exit_timing(struct kvm_vcpu *vcpu, u64 duration, int type)
  57{
  58        u64 old;
  59
  60        do_div(duration, tb_ticks_per_usec);
  61        if (unlikely(duration > 0xFFFFFFFF)) {
  62                printk(KERN_ERR"%s - duration too big -> overflow"
  63                        " duration %lld type %d exit #%d\n",
  64                        __func__, duration, type,
  65                        vcpu->arch.timing_count_type[type]);
  66                return;
  67        }
  68
  69        vcpu->arch.timing_count_type[type]++;
  70
  71        /* sum */
  72        old = vcpu->arch.timing_sum_duration[type];
  73        vcpu->arch.timing_sum_duration[type] += duration;
  74        if (unlikely(old > vcpu->arch.timing_sum_duration[type])) {
  75                printk(KERN_ERR"%s - wrap adding sum of durations"
  76                        " old %lld new %lld type %d exit # of type %d\n",
  77                        __func__, old, vcpu->arch.timing_sum_duration[type],
  78                        type, vcpu->arch.timing_count_type[type]);
  79        }
  80
  81        /* square sum */
  82        old = vcpu->arch.timing_sum_quad_duration[type];
  83        vcpu->arch.timing_sum_quad_duration[type] += (duration*duration);
  84        if (unlikely(old > vcpu->arch.timing_sum_quad_duration[type])) {
  85                printk(KERN_ERR"%s - wrap adding sum of squared durations"
  86                        " old %lld new %lld type %d exit # of type %d\n",
  87                        __func__, old,
  88                        vcpu->arch.timing_sum_quad_duration[type],
  89                        type, vcpu->arch.timing_count_type[type]);
  90        }
  91
  92        /* set min/max */
  93        if (unlikely(duration < vcpu->arch.timing_min_duration[type]))
  94                vcpu->arch.timing_min_duration[type] = duration;
  95        if (unlikely(duration > vcpu->arch.timing_max_duration[type]))
  96                vcpu->arch.timing_max_duration[type] = duration;
  97}
  98
  99void kvmppc_update_timing_stats(struct kvm_vcpu *vcpu)
 100{
 101        u64 exit = vcpu->arch.timing_last_exit;
 102        u64 enter = vcpu->arch.timing_last_enter.tv64;
 103
 104        /* save exit time, used next exit when the reenter time is known */
 105        vcpu->arch.timing_last_exit = vcpu->arch.timing_exit.tv64;
 106
 107        if (unlikely(vcpu->arch.last_exit_type == 0xDEAD || exit == 0))
 108                return; /* skip incomplete cycle (e.g. after reset) */
 109
 110        /* update statistics for average and standard deviation */
 111        add_exit_timing(vcpu, (enter - exit), vcpu->arch.last_exit_type);
 112        /* enter -> timing_last_exit is time spent in guest - log this too */
 113        add_exit_timing(vcpu, (vcpu->arch.timing_last_exit - enter),
 114                        TIMEINGUEST);
 115}
 116
 117static const char *kvm_exit_names[__NUMBER_OF_KVM_EXIT_TYPES] = {
 118        [MMIO_EXITS] =              "MMIO",
 119        [DCR_EXITS] =               "DCR",
 120        [SIGNAL_EXITS] =            "SIGNAL",
 121        [ITLB_REAL_MISS_EXITS] =    "ITLBREAL",
 122        [ITLB_VIRT_MISS_EXITS] =    "ITLBVIRT",
 123        [DTLB_REAL_MISS_EXITS] =    "DTLBREAL",
 124        [DTLB_VIRT_MISS_EXITS] =    "DTLBVIRT",
 125        [SYSCALL_EXITS] =           "SYSCALL",
 126        [ISI_EXITS] =               "ISI",
 127        [DSI_EXITS] =               "DSI",
 128        [EMULATED_INST_EXITS] =     "EMULINST",
 129        [EMULATED_MTMSRWE_EXITS] =  "EMUL_WAIT",
 130        [EMULATED_WRTEE_EXITS] =    "EMUL_WRTEE",
 131        [EMULATED_MTSPR_EXITS] =    "EMUL_MTSPR",
 132        [EMULATED_MFSPR_EXITS] =    "EMUL_MFSPR",
 133        [EMULATED_MTMSR_EXITS] =    "EMUL_MTMSR",
 134        [EMULATED_MFMSR_EXITS] =    "EMUL_MFMSR",
 135        [EMULATED_TLBSX_EXITS] =    "EMUL_TLBSX",
 136        [EMULATED_TLBWE_EXITS] =    "EMUL_TLBWE",
 137        [EMULATED_RFI_EXITS] =      "EMUL_RFI",
 138        [DEC_EXITS] =               "DEC",
 139        [EXT_INTR_EXITS] =          "EXTINT",
 140        [HALT_WAKEUP] =             "HALT",
 141        [USR_PR_INST] =             "USR_PR_INST",
 142        [FP_UNAVAIL] =              "FP_UNAVAIL",
 143        [DEBUG_EXITS] =             "DEBUG",
 144        [TIMEINGUEST] =             "TIMEINGUEST"
 145};
 146
 147static int kvmppc_exit_timing_show(struct seq_file *m, void *private)
 148{
 149        struct kvm_vcpu *vcpu = m->private;
 150        int i;
 151
 152        seq_printf(m, "%s", "type       count   min     max     sum     sum_squared\n");
 153
 154        for (i = 0; i < __NUMBER_OF_KVM_EXIT_TYPES; i++) {
 155                seq_printf(m, "%12s     %10d    %10lld  %10lld  %20lld  %20lld\n",
 156                        kvm_exit_names[i],
 157                        vcpu->arch.timing_count_type[i],
 158                        vcpu->arch.timing_min_duration[i],
 159                        vcpu->arch.timing_max_duration[i],
 160                        vcpu->arch.timing_sum_duration[i],
 161                        vcpu->arch.timing_sum_quad_duration[i]);
 162        }
 163        return 0;
 164}
 165
 166/* Write 'c' to clear the timing statistics. */
 167static ssize_t kvmppc_exit_timing_write(struct file *file,
 168                                       const char __user *user_buf,
 169                                       size_t count, loff_t *ppos)
 170{
 171        int err = -EINVAL;
 172        char c;
 173
 174        if (count > 1) {
 175                goto done;
 176        }
 177
 178        if (get_user(c, user_buf)) {
 179                err = -EFAULT;
 180                goto done;
 181        }
 182
 183        if (c == 'c') {
 184                struct seq_file *seqf = (struct seq_file *)file->private_data;
 185                struct kvm_vcpu *vcpu = seqf->private;
 186                /* Write does not affect our buffers previously generated with
 187                 * show. seq_file is locked here to prevent races of init with
 188                 * a show call */
 189                mutex_lock(&seqf->lock);
 190                kvmppc_init_timing_stats(vcpu);
 191                mutex_unlock(&seqf->lock);
 192                err = count;
 193        }
 194
 195done:
 196        return err;
 197}
 198
 199static int kvmppc_exit_timing_open(struct inode *inode, struct file *file)
 200{
 201        return single_open(file, kvmppc_exit_timing_show, inode->i_private);
 202}
 203
 204static struct file_operations kvmppc_exit_timing_fops = {
 205        .owner   = THIS_MODULE,
 206        .open    = kvmppc_exit_timing_open,
 207        .read    = seq_read,
 208        .write   = kvmppc_exit_timing_write,
 209        .llseek  = seq_lseek,
 210        .release = single_release,
 211};
 212
 213void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu, unsigned int id)
 214{
 215        static char dbg_fname[50];
 216        struct dentry *debugfs_file;
 217
 218        snprintf(dbg_fname, sizeof(dbg_fname), "vm%u_vcpu%u_timing",
 219                 current->pid, id);
 220        debugfs_file = debugfs_create_file(dbg_fname, 0666,
 221                                        kvm_debugfs_dir, vcpu,
 222                                        &kvmppc_exit_timing_fops);
 223
 224        if (!debugfs_file) {
 225                printk(KERN_ERR"%s: error creating debugfs file %s\n",
 226                        __func__, dbg_fname);
 227                return;
 228        }
 229
 230        vcpu->arch.debugfs_exit_timing = debugfs_file;
 231}
 232
 233void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu)
 234{
 235        if (vcpu->arch.debugfs_exit_timing) {
 236                debugfs_remove(vcpu->arch.debugfs_exit_timing);
 237                vcpu->arch.debugfs_exit_timing = NULL;
 238        }
 239}
 240