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linux/arch/powerpc/kvm/timing.c
Greg Kroah-Hartman c4fd527f52 powerpc/kvm: no need to check return value of debugfs_create functions 
When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Because of this cleanup, we get to remove a few fields in struct
kvm_arch that are now unused.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[mpe: Fix build error in kvm/timing.c, adapt kvmppc_remove_cpu_debugfs()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200209105901.1620958-2-gregkh@linuxfoundation.org
2020-03-04 22:44:25 +11:00

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// 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,
};
void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu, unsigned int id)
{
static char dbg_fname[50];
struct dentry *debugfs_file;
snprintf(dbg_fname, sizeof(dbg_fname), "vm%u_vcpu%u_timing",
current->pid, id);
debugfs_file = debugfs_create_file(dbg_fname, 0666, kvm_debugfs_dir,
vcpu, &kvmppc_exit_timing_fops);
vcpu->arch.debugfs_exit_timing = debugfs_file;
}
void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu)
{
debugfs_remove(vcpu->arch.debugfs_exit_timing);
vcpu->arch.debugfs_exit_timing = NULL;
}
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