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
  27 #include <asm/time.h>
  28 #include <asm-generic/div64.h>
  29
  30 #include "timing.h"
  31
  32 void 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
  56 static 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
  99 void 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
 117 static 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
 147 static 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. */
 167 static 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
 195 done:
 196         return err;
 197 }
 198
 199 static 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
 204 static 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
 213 void 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
 233 void 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 }