arch/powerpc/kvm/timing.c

   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 #include <linux/module.h>
  27
  28 #include <asm/time.h>
  29 #include <asm-generic/div64.h>
  30
  31 #include "timing.h"
  32
  33 void kvmppc_init_timing_stats(struct kvm_vcpu *vcpu)
  34 {
  35         int i;
  36
  37         /* pause guest execution to avoid concurrent updates */
  38         local_irq_disable();
  39         mutex_lock(&vcpu->mutex);
  40
  41         vcpu->arch.last_exit_type = 0xDEAD;
  42         for (i = 0; i < __NUMBER_OF_KVM_EXIT_TYPES; i++) {
  43                 vcpu->arch.timing_count_type[i] = 0;
  44                 vcpu->arch.timing_max_duration[i] = 0;
  45                 vcpu->arch.timing_min_duration[i] = 0xFFFFFFFF;
  46                 vcpu->arch.timing_sum_duration[i] = 0;
  47                 vcpu->arch.timing_sum_quad_duration[i] = 0;
  48         }
  49         vcpu->arch.timing_last_exit = 0;
  50         vcpu->arch.timing_exit.tv64 = 0;
  51         vcpu->arch.timing_last_enter.tv64 = 0;
  52
  53         mutex_unlock(&vcpu->mutex);
  54         local_irq_enable();
  55 }
  56
  57 static void add_exit_timing(struct kvm_vcpu *vcpu, u64 duration, int type)
  58 {
  59         u64 old;
  60
  61         do_div(duration, tb_ticks_per_usec);
  62         if (unlikely(duration > 0xFFFFFFFF)) {
  63                 printk(KERN_ERR"%s - duration too big -> overflow"
  64                         " duration %lld type %d exit #%d\n",
  65                         __func__, duration, type,
  66                         vcpu->arch.timing_count_type[type]);
  67                 return;
  68         }
  69
  70         vcpu->arch.timing_count_type[type]++;
  71
  72         /* sum */
  73         old = vcpu->arch.timing_sum_duration[type];
  74         vcpu->arch.timing_sum_duration[type] += duration;
  75         if (unlikely(old > vcpu->arch.timing_sum_duration[type])) {
  76                 printk(KERN_ERR"%s - wrap adding sum of durations"
  77                         " old %lld new %lld type %d exit # of type %d\n",
  78                         __func__, old, vcpu->arch.timing_sum_duration[type],
  79                         type, vcpu->arch.timing_count_type[type]);
  80         }
  81
  82         /* square sum */
  83         old = vcpu->arch.timing_sum_quad_duration[type];
  84         vcpu->arch.timing_sum_quad_duration[type] += (duration*duration);
  85         if (unlikely(old > vcpu->arch.timing_sum_quad_duration[type])) {
  86                 printk(KERN_ERR"%s - wrap adding sum of squared durations"
  87                         " old %lld new %lld type %d exit # of type %d\n",
  88                         __func__, old,
  89                         vcpu->arch.timing_sum_quad_duration[type],
  90                         type, vcpu->arch.timing_count_type[type]);
  91         }
  92
  93         /* set min/max */
  94         if (unlikely(duration < vcpu->arch.timing_min_duration[type]))
  95                 vcpu->arch.timing_min_duration[type] = duration;
  96         if (unlikely(duration > vcpu->arch.timing_max_duration[type]))
  97                 vcpu->arch.timing_max_duration[type] = duration;
  98 }
  99
 100 void kvmppc_update_timing_stats(struct kvm_vcpu *vcpu)
 101 {
 102         u64 exit = vcpu->arch.timing_last_exit;
 103         u64 enter = vcpu->arch.timing_last_enter.tv64;
 104
 105         /* save exit time, used next exit when the reenter time is known */
 106         vcpu->arch.timing_last_exit = vcpu->arch.timing_exit.tv64;
 107
 108         if (unlikely(vcpu->arch.last_exit_type == 0xDEAD || exit == 0))
 109                 return; /* skip incomplete cycle (e.g. after reset) */
 110
 111         /* update statistics for average and standard deviation */
 112         add_exit_timing(vcpu, (enter - exit), vcpu->arch.last_exit_type);
 113         /* enter -> timing_last_exit is time spent in guest - log this too */
 114         add_exit_timing(vcpu, (vcpu->arch.timing_last_exit - enter),
 115                         TIMEINGUEST);
 116 }
 117
 118 static const char *kvm_exit_names[__NUMBER_OF_KVM_EXIT_TYPES] = {
 119         [MMIO_EXITS] =              "MMIO",
 120         [DCR_EXITS] =               "DCR",
 121         [SIGNAL_EXITS] =            "SIGNAL",
 122         [ITLB_REAL_MISS_EXITS] =    "ITLBREAL",
 123         [ITLB_VIRT_MISS_EXITS] =    "ITLBVIRT",
 124         [DTLB_REAL_MISS_EXITS] =    "DTLBREAL",
 125         [DTLB_VIRT_MISS_EXITS] =    "DTLBVIRT",
 126         [SYSCALL_EXITS] =           "SYSCALL",
 127         [ISI_EXITS] =               "ISI",
 128         [DSI_EXITS] =               "DSI",
 129         [EMULATED_INST_EXITS] =     "EMULINST",
 130         [EMULATED_MTMSRWE_EXITS] =  "EMUL_WAIT",
 131         [EMULATED_WRTEE_EXITS] =    "EMUL_WRTEE",
 132         [EMULATED_MTSPR_EXITS] =    "EMUL_MTSPR",
 133         [EMULATED_MFSPR_EXITS] =    "EMUL_MFSPR",
 134         [EMULATED_MTMSR_EXITS] =    "EMUL_MTMSR",
 135         [EMULATED_MFMSR_EXITS] =    "EMUL_MFMSR",
 136         [EMULATED_TLBSX_EXITS] =    "EMUL_TLBSX",
 137         [EMULATED_TLBWE_EXITS] =    "EMUL_TLBWE",
 138         [EMULATED_RFI_EXITS] =      "EMUL_RFI",
 139         [DEC_EXITS] =               "DEC",
 140         [EXT_INTR_EXITS] =          "EXTINT",
 141         [HALT_WAKEUP] =             "HALT",
 142         [USR_PR_INST] =             "USR_PR_INST",
 143         [FP_UNAVAIL] =              "FP_UNAVAIL",
 144         [DEBUG_EXITS] =             "DEBUG",
 145         [TIMEINGUEST] =             "TIMEINGUEST"
 146 };
 147
 148 static int kvmppc_exit_timing_show(struct seq_file *m, void *private)
 149 {
 150         struct kvm_vcpu *vcpu = m->private;
 151         int i;
 152
 153         seq_printf(m, "%s", "type       count   min     max     sum     sum_squared\n");
 154
 155         for (i = 0; i < __NUMBER_OF_KVM_EXIT_TYPES; i++) {
 156                 seq_printf(m, "%12s     %10d    %10lld  %10lld  %20lld  %20lld\n",
 157                         kvm_exit_names[i],
 158                         vcpu->arch.timing_count_type[i],
 159                         vcpu->arch.timing_min_duration[i],
 160                         vcpu->arch.timing_max_duration[i],
 161                         vcpu->arch.timing_sum_duration[i],
 162                         vcpu->arch.timing_sum_quad_duration[i]);
 163         }
 164         return 0;
 165 }
 166
 167 /* Write 'c' to clear the timing statistics. */
 168 static ssize_t kvmppc_exit_timing_write(struct file *file,
 169                                        const char __user *user_buf,
 170                                        size_t count, loff_t *ppos)
 171 {
 172         int err = -EINVAL;
 173         char c;
 174
 175         if (count > 1) {
 176                 goto done;
 177         }
 178
 179         if (get_user(c, user_buf)) {
 180                 err = -EFAULT;
 181                 goto done;
 182         }
 183
 184         if (c == 'c') {
 185                 struct seq_file *seqf = file->private_data;
 186                 struct kvm_vcpu *vcpu = seqf->private;
 187                 /* Write does not affect our buffers previously generated with
 188                  * show. seq_file is locked here to prevent races of init with
 189                  * a show call */
 190                 mutex_lock(&seqf->lock);
 191                 kvmppc_init_timing_stats(vcpu);
 192                 mutex_unlock(&seqf->lock);
 193                 err = count;
 194         }
 195
 196 done:
 197         return err;
 198 }
 199
 200 static int kvmppc_exit_timing_open(struct inode *inode, struct file *file)
 201 {
 202         return single_open(file, kvmppc_exit_timing_show, inode->i_private);
 203 }
 204
 205 static const struct file_operations kvmppc_exit_timing_fops = {
 206         .owner   = THIS_MODULE,
 207         .open    = kvmppc_exit_timing_open,
 208         .read    = seq_read,
 209         .write   = kvmppc_exit_timing_write,
 210         .llseek  = seq_lseek,
 211         .release = single_release,
 212 };
 213
 214 void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu, unsigned int id)
 215 {
 216         static char dbg_fname[50];
 217         struct dentry *debugfs_file;
 218
 219         snprintf(dbg_fname, sizeof(dbg_fname), "vm%u_vcpu%u_timing",
 220                  current->pid, id);
 221         debugfs_file = debugfs_create_file(dbg_fname, 0666,
 222                                         kvm_debugfs_dir, vcpu,
 223                                         &kvmppc_exit_timing_fops);
 224
 225         if (!debugfs_file) {
 226                 printk(KERN_ERR"%s: error creating debugfs file %s\n",
 227                         __func__, dbg_fname);
 228                 return;
 229         }
 230
 231         vcpu->arch.debugfs_exit_timing = debugfs_file;
 232 }
 233
 234 void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu)
 235 {
 236         if (vcpu->arch.debugfs_exit_timing) {
 237                 debugfs_remove(vcpu->arch.debugfs_exit_timing);
 238                 vcpu->arch.debugfs_exit_timing = NULL;
 239         }
 240 }