[PATCH v1 08/11] KVM: x86/pmu: PEBS MSRs emulation
From: Luwei Kang
Date: Thu Mar 05 2020 - 04:59:53 EST
This patch implement the PEBS MSRs emulation in KVM, include
IA32_PEBS_ENABLE and IA32_DS_AREA.
The IA32_DS_AREA register will be added into the MSR-load list when PEBS is
enabled in KVM guest that to make the guest's DS value can be loaded to the
real HW before VM-entry, and will be removed when PEBS is disabled.
Originally-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Luwei Kang <luwei.kang@xxxxxxxxx>
Co-developed-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 4 ++++
arch/x86/kvm/vmx/pmu_intel.c | 45 +++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/vmx/vmx.c | 4 ++--
arch/x86/kvm/vmx/vmx.h | 4 ++++
arch/x86/kvm/x86.c | 7 +++++++
5 files changed, 62 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 033d9f9..33b990b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -479,6 +479,8 @@ struct kvm_pmu {
u64 global_ovf_ctrl_mask;
u64 reserved_bits;
u64 pebs_enable;
+ u64 pebs_enable_mask;
+ u64 ds_area;
u8 version;
struct kvm_pmc gp_counters[INTEL_PMC_MAX_GENERIC];
struct kvm_pmc fixed_counters[INTEL_PMC_MAX_FIXED];
@@ -493,6 +495,8 @@ struct kvm_pmu {
*/
bool need_cleanup;
+ bool has_pebs_via_ds;
+
/*
* The total number of programmed perf_events and it helps to avoid
* redundant check before cleanup if guest don't use vPMU at all.
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index a67bd34..227589a 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -67,6 +67,21 @@ static void global_ctrl_changed(struct kvm_pmu *pmu, u64 data)
reprogram_counter(pmu, bit);
}
+static void pebs_enable_changed(struct kvm_pmu *pmu, u64 data)
+{
+ struct vcpu_vmx *vmx = to_vmx(pmu_to_vcpu(pmu));
+ u64 host_ds_area;
+
+ if (data) {
+ rdmsrl_safe(MSR_IA32_DS_AREA, &host_ds_area);
+ add_atomic_switch_msr(vmx, MSR_IA32_DS_AREA,
+ pmu->ds_area, host_ds_area, false);
+ } else
+ clear_atomic_switch_msr(vmx, MSR_IA32_DS_AREA);
+
+ pmu->pebs_enable = data;
+}
+
static unsigned intel_find_arch_event(struct kvm_pmu *pmu,
u8 event_select,
u8 unit_mask)
@@ -163,6 +178,10 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
ret = pmu->version > 1;
break;
+ case MSR_IA32_DS_AREA:
+ case MSR_IA32_PEBS_ENABLE:
+ ret = pmu->has_pebs_via_ds;
+ break;
default:
ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0) ||
get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0) ||
@@ -219,6 +238,12 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
*data = pmu->global_ovf_ctrl;
return 0;
+ case MSR_IA32_PEBS_ENABLE:
+ *data = pmu->pebs_enable;
+ return 0;
+ case MSR_IA32_DS_AREA:
+ *data = pmu->ds_area;
+ return 0;
default:
if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0))) {
u64 val = pmc_read_counter(pmc);
@@ -275,6 +300,17 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
return 0;
}
break;
+ case MSR_IA32_PEBS_ENABLE:
+ if (pmu->pebs_enable == data)
+ return 0;
+ if (!(data & pmu->pebs_enable_mask)) {
+ pebs_enable_changed(pmu, data);
+ return 0;
+ }
+ break;
+ case MSR_IA32_DS_AREA:
+ pmu->ds_area = data;
+ return 0;
default:
if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0))) {
if (!msr_info->host_initiated)
@@ -351,6 +387,15 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
pmu->global_ovf_ctrl_mask &=
~MSR_CORE_PERF_GLOBAL_OVF_CTRL_TRACE_TOPA_PMI;
+ entry = kvm_find_cpuid_entry(vcpu, 1, 0);
+ if (entry && (entry->ecx & X86_FEATURE_DTES64) &&
+ (entry->ecx & X86_FEATURE_PDCM) &&
+ (entry->edx & X86_FEATURE_DS) &&
+ intel_is_pebs_via_ds_supported()) {
+ pmu->has_pebs_via_ds = 1;
+ pmu->pebs_enable_mask = ~pmu->global_ctrl;
+ }
+
entry = kvm_find_cpuid_entry(vcpu, 7, 0);
if (entry &&
(boot_cpu_has(X86_FEATURE_HLE) || boot_cpu_has(X86_FEATURE_RTM)) &&
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index cef7089..c6d9a87 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -864,7 +864,7 @@ int vmx_find_msr_index(struct vmx_msrs *m, u32 msr)
return -ENOENT;
}
-static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
+void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
{
int i;
struct msr_autoload *m = &vmx->msr_autoload;
@@ -916,7 +916,7 @@ static void add_atomic_switch_msr_special(struct vcpu_vmx *vmx,
vm_exit_controls_setbit(vmx, exit);
}
-static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
+void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
u64 guest_val, u64 host_val, bool entry_only)
{
int i, j = 0;
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index e64da06..ea899e7 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -536,4 +536,8 @@ static inline bool vmx_has_waitpkg(struct vcpu_vmx *vmx)
void dump_vmcs(void);
+extern void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr);
+extern void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
+ u64 guest_val, u64 host_val, bool entry_only);
+
#endif /* __KVM_X86_VMX_H */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5de2006..7a23406 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1193,6 +1193,7 @@ bool kvm_rdpmc(struct kvm_vcpu *vcpu)
MSR_ARCH_PERFMON_EVENTSEL0 + 12, MSR_ARCH_PERFMON_EVENTSEL0 + 13,
MSR_ARCH_PERFMON_EVENTSEL0 + 14, MSR_ARCH_PERFMON_EVENTSEL0 + 15,
MSR_ARCH_PERFMON_EVENTSEL0 + 16, MSR_ARCH_PERFMON_EVENTSEL0 + 17,
+ MSR_IA32_PEBS_ENABLE, MSR_IA32_DS_AREA,
};
static u32 msrs_to_save[ARRAY_SIZE(msrs_to_save_all)];
@@ -5263,6 +5264,12 @@ static void kvm_init_msr_list(void)
if (!kvm_x86_ops->rdtscp_supported())
continue;
break;
+ case MSR_IA32_PEBS_ENABLE:
+ case MSR_IA32_DS_AREA:
+ if (!kvm_x86_ops->pmu_ops ||
+ !kvm_x86_ops->pmu_ops->is_pebs_via_ds_supported())
+ continue;
+ break;
case MSR_IA32_RTIT_CTL:
case MSR_IA32_RTIT_STATUS:
if (!kvm_x86_ops->pt_supported())
--
1.8.3.1