timing.c   Interaktion und
PortierbarkeitC

// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * Copyright IBM Corp. 2008
 *
 * Authors: Hollis Blanchard <hollisb@us.ibm.com>
 *          Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
 */

#include <linux/kvm_host.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/module.h>

#include <asm/time.h>
#include <asm-generic/div64.h>

#include "timing.h"

void kvmppc_init_timing_stats(struct kvm_vcpu *vcpu)
{
 int i;

 /* Take a lock to avoid concurrent updates */
 mutex_lock(&vcpu->arch.exit_timing_lock);

 vcpu->arch.last_exit_type = 0xDEAD;
 for (i = 0; i < __NUMBER_OF_KVM_EXIT_TYPES; i++) {
  vcpu->arch.timing_count_type[i] = 0;
  vcpu->arch.timing_max_duration[i] = 0;
  vcpu->arch.timing_min_duration[i] = 0xFFFFFFFF;
  vcpu->arch.timing_sum_duration[i] = 0;
  vcpu->arch.timing_sum_quad_duration[i] = 0;
 }
 vcpu->arch.timing_last_exit = 0;
 vcpu->arch.timing_exit.tv64 = 0;
 vcpu->arch.timing_last_enter.tv64 = 0;

 mutex_unlock(&vcpu->arch.exit_timing_lock);
}

static void add_exit_timing(struct kvm_vcpu *vcpu, u64 duration, int type)
{
 u64 old;

 mutex_lock(&vcpu->arch.exit_timing_lock);

 vcpu->arch.timing_count_type[type]++;

 /* sum */
 old = vcpu->arch.timing_sum_duration[type];
 vcpu->arch.timing_sum_duration[type] += duration;
 if (unlikely(old > vcpu->arch.timing_sum_duration[type])) {
  printk(KERN_ERR"%s - wrap adding sum of durations"
   " old %lld new %lld type %d exit # of type %d\n",
   __func__, old, vcpu->arch.timing_sum_duration[type],
   type, vcpu->arch.timing_count_type[type]);
 }

 /* square sum */
 old = vcpu->arch.timing_sum_quad_duration[type];
 vcpu->arch.timing_sum_quad_duration[type] += (duration*duration);
 if (unlikely(old > vcpu->arch.timing_sum_quad_duration[type])) {
  printk(KERN_ERR"%s - wrap adding sum of squared durations"
   " old %lld new %lld type %d exit # of type %d\n",
   __func__, old,
   vcpu->arch.timing_sum_quad_duration[type],
   type, vcpu->arch.timing_count_type[type]);
 }

 /* set min/max */
 if (unlikely(duration < vcpu->arch.timing_min_duration[type]))
  vcpu->arch.timing_min_duration[type] = duration;
 if (unlikely(duration > vcpu->arch.timing_max_duration[type]))
  vcpu->arch.timing_max_duration[type] = duration;

 mutex_unlock(&vcpu->arch.exit_timing_lock);
}

void kvmppc_update_timing_stats(struct kvm_vcpu *vcpu)
{
 u64 exit = vcpu->arch.timing_last_exit;
 u64 enter = vcpu->arch.timing_last_enter.tv64;

 /* save exit time, used next exit when the reenter time is known */
 vcpu->arch.timing_last_exit = vcpu->arch.timing_exit.tv64;

 if (unlikely(vcpu->arch.last_exit_type == 0xDEAD || exit == 0))
  return; /* skip incomplete cycle (e.g. after reset) */

 /* update statistics for average and standard deviation */
 add_exit_timing(vcpu, (enter - exit), vcpu->arch.last_exit_type);
 /* enter -> timing_last_exit is time spent in guest - log this too */
 add_exit_timing(vcpu, (vcpu->arch.timing_last_exit - enter),
   TIMEINGUEST);
}

static const char *kvm_exit_names[__NUMBER_OF_KVM_EXIT_TYPES] = {
 [MMIO_EXITS] =              "MMIO",
 [SIGNAL_EXITS] =            "SIGNAL",
 [ITLB_REAL_MISS_EXITS] =    "ITLBREAL",
 [ITLB_VIRT_MISS_EXITS] =    "ITLBVIRT",
 [DTLB_REAL_MISS_EXITS] =    "DTLBREAL",
 [DTLB_VIRT_MISS_EXITS] =    "DTLBVIRT",
 [SYSCALL_EXITS] =           "SYSCALL",
 [ISI_EXITS] =               "ISI",
 [DSI_EXITS] =               "DSI",
 [EMULATED_INST_EXITS] =     "EMULINST",
 [EMULATED_MTMSRWE_EXITS] =  "EMUL_WAIT",
 [EMULATED_WRTEE_EXITS] =    "EMUL_WRTEE",
 [EMULATED_MTSPR_EXITS] =    "EMUL_MTSPR",
 [EMULATED_MFSPR_EXITS] =    "EMUL_MFSPR",
 [EMULATED_MTMSR_EXITS] =    "EMUL_MTMSR",
 [EMULATED_MFMSR_EXITS] =    "EMUL_MFMSR",
 [EMULATED_TLBSX_EXITS] =    "EMUL_TLBSX",
 [EMULATED_TLBWE_EXITS] =    "EMUL_TLBWE",
 [EMULATED_RFI_EXITS] =      "EMUL_RFI",
 [DEC_EXITS] =               "DEC",
 [EXT_INTR_EXITS] =          "EXTINT",
 [HALT_WAKEUP] =             "HALT",
 [USR_PR_INST] =             "USR_PR_INST",
 [FP_UNAVAIL] =              "FP_UNAVAIL",
 [DEBUG_EXITS] =             "DEBUG",
 [TIMEINGUEST] =             "TIMEINGUEST"
};

static int kvmppc_exit_timing_show(struct seq_file *m, void *private)
{
 struct kvm_vcpu *vcpu = m->private;
 int i;
 u64 min, max, sum, sum_quad;

 seq_puts(m, "type count min max sum sum_squared\n");

 for (i = 0; i < __NUMBER_OF_KVM_EXIT_TYPES; i++) {

  min = vcpu->arch.timing_min_duration[i];
  do_div(min, tb_ticks_per_usec);
  max = vcpu->arch.timing_max_duration[i];
  do_div(max, tb_ticks_per_usec);
  sum = vcpu->arch.timing_sum_duration[i];
  do_div(sum, tb_ticks_per_usec);
  sum_quad = vcpu->arch.timing_sum_quad_duration[i];
  do_div(sum_quad, tb_ticks_per_usec);

  seq_printf(m, "%12s %10d %10lld %10lld %20lld %20lld\n",
   kvm_exit_names[i],
   vcpu->arch.timing_count_type[i],
   min,
   max,
   sum,
   sum_quad);

 }
 return 0;
}

/* Write 'c' to clear the timing statistics. */
static ssize_t kvmppc_exit_timing_write(struct file *file,
           const char __user *user_buf,
           size_t count, loff_t *ppos)
{
 int err = -EINVAL;
 char c;

 if (count > 1) {
  goto done;
 }

 if (get_user(c, user_buf)) {
  err = -EFAULT;
  goto done;
 }

 if (c == 'c') {
  struct seq_file *seqf = file->private_data;
  struct kvm_vcpu *vcpu = seqf->private;
  /* Write does not affect our buffers previously generated with
   * show. seq_file is locked here to prevent races of init with
 * a show call */
  mutex_lock(&seqf->lock);
  kvmppc_init_timing_stats(vcpu);
  mutex_unlock(&seqf->lock);
  err = count;
 }

done:
 return err;
}

static int kvmppc_exit_timing_open(struct inode *inode, struct file *file)
{
 return single_open(file, kvmppc_exit_timing_show, inode->i_private);
}

static const struct file_operations kvmppc_exit_timing_fops = {
 .owner   = THIS_MODULE,
 .open    = kvmppc_exit_timing_open,
 .read    = seq_read,
 .write   = kvmppc_exit_timing_write,
 .llseek  = seq_lseek,
 .release = single_release,
};

int kvmppc_create_vcpu_debugfs_e500(struct kvm_vcpu *vcpu,
        struct dentry *debugfs_dentry)
{
 debugfs_create_file("timing", 0666, debugfs_dentry,
       vcpu, &kvmppc_exit_timing_fops);
 return 0;
}