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