linux/arch/x86/kvm/pmu_amd.c
Wei Huang b6bb424b40 KVM: x86/vPMU: Fix unnecessary signed extension for AMD PERFCTRn
According to AMD programmer's manual, AMD PERFCTRn is 64-bit MSR which,
unlike Intel perf counters, doesn't require signed extension. This
patch removes the unnecessary conversion in SVM vPMU code when PERFCTRn
is being updated.

Signed-off-by: Wei Huang <wei@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-08-11 15:19:41 +02:00

206 lines
5.1 KiB
C

/*
* KVM PMU support for AMD
*
* Copyright 2015, Red Hat, Inc. and/or its affiliates.
*
* Author:
* Wei Huang <wei@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Implementation is based on pmu_intel.c file
*/
#include <linux/types.h>
#include <linux/kvm_host.h>
#include <linux/perf_event.h>
#include "x86.h"
#include "cpuid.h"
#include "lapic.h"
#include "pmu.h"
/* duplicated from amd_perfmon_event_map, K7 and above should work. */
static struct kvm_event_hw_type_mapping amd_event_mapping[] = {
[0] = { 0x76, 0x00, PERF_COUNT_HW_CPU_CYCLES },
[1] = { 0xc0, 0x00, PERF_COUNT_HW_INSTRUCTIONS },
[2] = { 0x80, 0x00, PERF_COUNT_HW_CACHE_REFERENCES },
[3] = { 0x81, 0x00, PERF_COUNT_HW_CACHE_MISSES },
[4] = { 0xc2, 0x00, PERF_COUNT_HW_BRANCH_INSTRUCTIONS },
[5] = { 0xc3, 0x00, PERF_COUNT_HW_BRANCH_MISSES },
[6] = { 0xd0, 0x00, PERF_COUNT_HW_STALLED_CYCLES_FRONTEND },
[7] = { 0xd1, 0x00, PERF_COUNT_HW_STALLED_CYCLES_BACKEND },
};
static unsigned amd_find_arch_event(struct kvm_pmu *pmu,
u8 event_select,
u8 unit_mask)
{
int i;
for (i = 0; i < ARRAY_SIZE(amd_event_mapping); i++)
if (amd_event_mapping[i].eventsel == event_select
&& amd_event_mapping[i].unit_mask == unit_mask)
break;
if (i == ARRAY_SIZE(amd_event_mapping))
return PERF_COUNT_HW_MAX;
return amd_event_mapping[i].event_type;
}
/* return PERF_COUNT_HW_MAX as AMD doesn't have fixed events */
static unsigned amd_find_fixed_event(int idx)
{
return PERF_COUNT_HW_MAX;
}
/* check if a PMC is enabled by comparing it against global_ctrl bits. Because
* AMD CPU doesn't have global_ctrl MSR, all PMCs are enabled (return TRUE).
*/
static bool amd_pmc_is_enabled(struct kvm_pmc *pmc)
{
return true;
}
static struct kvm_pmc *amd_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx)
{
return get_gp_pmc(pmu, MSR_K7_EVNTSEL0 + pmc_idx, MSR_K7_EVNTSEL0);
}
/* returns 0 if idx's corresponding MSR exists; otherwise returns 1. */
static int amd_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
idx &= ~(3u << 30);
return (idx >= pmu->nr_arch_gp_counters);
}
/* idx is the ECX register of RDPMC instruction */
static struct kvm_pmc *amd_msr_idx_to_pmc(struct kvm_vcpu *vcpu, unsigned idx)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct kvm_pmc *counters;
idx &= ~(3u << 30);
if (idx >= pmu->nr_arch_gp_counters)
return NULL;
counters = pmu->gp_counters;
return &counters[idx];
}
static bool amd_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
int ret = false;
ret = get_gp_pmc(pmu, msr, MSR_K7_PERFCTR0) ||
get_gp_pmc(pmu, msr, MSR_K7_EVNTSEL0);
return ret;
}
static int amd_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct kvm_pmc *pmc;
/* MSR_K7_PERFCTRn */
pmc = get_gp_pmc(pmu, msr, MSR_K7_PERFCTR0);
if (pmc) {
*data = pmc_read_counter(pmc);
return 0;
}
/* MSR_K7_EVNTSELn */
pmc = get_gp_pmc(pmu, msr, MSR_K7_EVNTSEL0);
if (pmc) {
*data = pmc->eventsel;
return 0;
}
return 1;
}
static int amd_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct kvm_pmc *pmc;
u32 msr = msr_info->index;
u64 data = msr_info->data;
/* MSR_K7_PERFCTRn */
pmc = get_gp_pmc(pmu, msr, MSR_K7_PERFCTR0);
if (pmc) {
pmc->counter += data - pmc_read_counter(pmc);
return 0;
}
/* MSR_K7_EVNTSELn */
pmc = get_gp_pmc(pmu, msr, MSR_K7_EVNTSEL0);
if (pmc) {
if (data == pmc->eventsel)
return 0;
if (!(data & pmu->reserved_bits)) {
reprogram_gp_counter(pmc, data);
return 0;
}
}
return 1;
}
static void amd_pmu_refresh(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
pmu->nr_arch_gp_counters = AMD64_NUM_COUNTERS;
pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << 48) - 1;
pmu->reserved_bits = 0xffffffff00200000ull;
/* not applicable to AMD; but clean them to prevent any fall out */
pmu->counter_bitmask[KVM_PMC_FIXED] = 0;
pmu->nr_arch_fixed_counters = 0;
pmu->version = 0;
pmu->global_status = 0;
}
static void amd_pmu_init(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
int i;
for (i = 0; i < AMD64_NUM_COUNTERS ; i++) {
pmu->gp_counters[i].type = KVM_PMC_GP;
pmu->gp_counters[i].vcpu = vcpu;
pmu->gp_counters[i].idx = i;
}
}
static void amd_pmu_reset(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
int i;
for (i = 0; i < AMD64_NUM_COUNTERS; i++) {
struct kvm_pmc *pmc = &pmu->gp_counters[i];
pmc_stop_counter(pmc);
pmc->counter = pmc->eventsel = 0;
}
}
struct kvm_pmu_ops amd_pmu_ops = {
.find_arch_event = amd_find_arch_event,
.find_fixed_event = amd_find_fixed_event,
.pmc_is_enabled = amd_pmc_is_enabled,
.pmc_idx_to_pmc = amd_pmc_idx_to_pmc,
.msr_idx_to_pmc = amd_msr_idx_to_pmc,
.is_valid_msr_idx = amd_is_valid_msr_idx,
.is_valid_msr = amd_is_valid_msr,
.get_msr = amd_pmu_get_msr,
.set_msr = amd_pmu_set_msr,
.refresh = amd_pmu_refresh,
.init = amd_pmu_init,
.reset = amd_pmu_reset,
};