diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index dbaa175a3c2e5619e47b8edb4b4c5ebaade1c6f6..c7dbaaccbcaa1bc7de2c4bd5cee6ba8cb1bdf238 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -190,6 +190,24 @@ bool intel_pmu_lbr_is_enabled(struct kvm_vcpu *vcpu)
return lbr->nr && (vcpu_get_perf_capabilities(vcpu) & PMU_CAP_LBR_FMT);
}
+static bool intel_pmu_is_valid_lbr_msr(struct kvm_vcpu *vcpu, u32 index)
+{
+ struct x86_pmu_lbr *records = vcpu_to_lbr_records(vcpu);
+ bool ret = false;
+
+ if (!intel_pmu_lbr_is_enabled(vcpu))
+ return ret;
+
+ ret = (index == MSR_LBR_SELECT) || (index == MSR_LBR_TOS) ||
+ (index >= records->from && index < records->from + records->nr) ||
+ (index >= records->to && index < records->to + records->nr);
+
+ if (!ret && records->info)
+ ret = (index >= records->info && index < records->info + records->nr);
+
+ return ret;
+}
+
static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -205,7 +223,8 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
default:
ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0) ||
get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0) ||
- get_fixed_pmc(pmu, msr) || get_fw_gp_pmc(pmu, msr);
+ get_fixed_pmc(pmu, msr) || get_fw_gp_pmc(pmu, msr) ||
+ intel_pmu_is_valid_lbr_msr(vcpu, msr);
break;
}
@@ -284,6 +303,46 @@ int intel_pmu_create_guest_lbr_event(struct kvm_vcpu *vcpu)
return 0;
}
+/*
+ * It's safe to access LBR msrs from guest when they have not
+ * been passthrough since the host would help restore or reset
+ * the LBR msrs records when the guest LBR event is scheduled in.
+ */
+static bool intel_pmu_handle_lbr_msrs_access(struct kvm_vcpu *vcpu,
+ struct msr_data *msr_info, bool read)
+{
+ struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
+ u32 index = msr_info->index;
+
+ if (!intel_pmu_is_valid_lbr_msr(vcpu, index))
+ return false;
+
+ if (!lbr_desc->event && !intel_pmu_create_guest_lbr_event(vcpu))
+ goto dummy;
+
+ /*
+ * Disable irq to ensure the LBR feature doesn't get reclaimed by the
+ * host at the time the value is read from the msr, and this avoids the
+ * host LBR value to be leaked to the guest. If LBR has been reclaimed,
+ * return 0 on guest reads.
+ */
+ local_irq_disable();
+ if (lbr_desc->event->state == PERF_EVENT_STATE_ACTIVE) {
+ if (read)
+ rdmsrl(index, msr_info->data);
+ else
+ wrmsrl(index, msr_info->data);
+ local_irq_enable();
+ return true;
+ }
+ local_irq_enable();
+
+dummy:
+ if (read)
+ msr_info->data = 0;
+ return true;
+}
+
static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -318,7 +377,8 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
} else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) {
msr_info->data = pmc->eventsel;
return 0;
- }
+ } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, true))
+ return 0;
}
return 1;
@@ -389,7 +449,8 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
reprogram_gp_counter(pmc, data);
return 0;
}
- }
+ } else if (intel_pmu_handle_lbr_msrs_access(vcpu, msr_info, false))
+ return 0;
}
return 1;
@@ -524,6 +585,66 @@ static void intel_pmu_reset(struct kvm_vcpu *vcpu)
intel_pmu_release_guest_lbr_event(vcpu);
}
+static void vmx_update_intercept_for_lbr_msrs(struct kvm_vcpu *vcpu, bool set)
+{
+ struct x86_pmu_lbr *lbr = vcpu_to_lbr_records(vcpu);
+ int i;
+
+ for (i = 0; i < lbr->nr; i++) {
+ vmx_set_intercept_for_msr(vcpu, lbr->from + i, MSR_TYPE_RW, set);
+ vmx_set_intercept_for_msr(vcpu, lbr->to + i, MSR_TYPE_RW, set);
+ if (lbr->info)
+ vmx_set_intercept_for_msr(vcpu, lbr->info + i, MSR_TYPE_RW, set);
+ }
+
+ vmx_set_intercept_for_msr(vcpu, MSR_LBR_SELECT, MSR_TYPE_RW, set);
+ vmx_set_intercept_for_msr(vcpu, MSR_LBR_TOS, MSR_TYPE_RW, set);
+}
+
+static inline void vmx_disable_lbr_msrs_passthrough(struct kvm_vcpu *vcpu)
+{
+ vmx_update_intercept_for_lbr_msrs(vcpu, true);
+}
+
+static inline void vmx_enable_lbr_msrs_passthrough(struct kvm_vcpu *vcpu)
+{
+ vmx_update_intercept_for_lbr_msrs(vcpu, false);
+}
+
+/*
+ * Higher priority host perf events (e.g. cpu pinned) could reclaim the
+ * pmu resources (e.g. LBR) that were assigned to the guest. This is
+ * usually done via ipi calls (more details in perf_install_in_context).
+ *
+ * Before entering the non-root mode (with irq disabled here), double
+ * confirm that the pmu features enabled to the guest are not reclaimed
+ * by higher priority host events. Otherwise, disallow vcpu's access to
+ * the reclaimed features.
+ */
+void vmx_passthrough_lbr_msrs(struct kvm_vcpu *vcpu)
+{
+ struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
+
+ if (!lbr_desc->event) {
+ vmx_disable_lbr_msrs_passthrough(vcpu);
+ if (vmcs_read64(GUEST_IA32_DEBUGCTL) & DEBUGCTLMSR_LBR)
+ goto warn;
+ return;
+ }
+
+ if (lbr_desc->event->state < PERF_EVENT_STATE_ACTIVE) {
+ vmx_disable_lbr_msrs_passthrough(vcpu);
+ goto warn;
+ } else
+ vmx_enable_lbr_msrs_passthrough(vcpu);
+
+ return;
+
+warn:
+ pr_warn_ratelimited("kvm: vcpu-%d: fail to passthrough LBR.\n",
+ vcpu->vcpu_id);
+}
+
struct kvm_pmu_ops intel_pmu_ops = {
.find_arch_event = intel_find_arch_event,
.find_fixed_event = intel_find_fixed_event,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 194458077dcbcc5b1ec4be5b4e950086d77371d2..e2f8c3c68f02b0c0cc4ed9584d5f916dc5d059c0 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -658,6 +658,14 @@ static bool is_valid_passthrough_msr(u32 msr)
case MSR_IA32_RTIT_CR3_MATCH:
case MSR_IA32_RTIT_ADDR0_A ... MSR_IA32_RTIT_ADDR3_B:
/* PT MSRs. These are handled in pt_update_intercept_for_msr() */
+ case MSR_LBR_SELECT:
+ case MSR_LBR_TOS:
+ case MSR_LBR_INFO_0 ... MSR_LBR_INFO_0 + 31:
+ case MSR_LBR_NHM_FROM ... MSR_LBR_NHM_FROM + 31:
+ case MSR_LBR_NHM_TO ... MSR_LBR_NHM_TO + 31:
+ case MSR_LBR_CORE_FROM ... MSR_LBR_CORE_FROM + 8:
+ case MSR_LBR_CORE_TO ... MSR_LBR_CORE_TO + 8:
+ /* LBR MSRs. These are handled in vmx_update_intercept_for_lbr_msrs() */
return true;
}
@@ -6769,6 +6777,8 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
pt_guest_enter(vmx);
atomic_switch_perf_msrs(vmx);
+ if (intel_pmu_lbr_is_enabled(vcpu))
+ vmx_passthrough_lbr_msrs(vcpu);
if (enable_preemption_timer)
vmx_update_hv_timer(vcpu);
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 8f33832db044067890680bb51646f803f29b34f4..41bf9adfcb79bf19a488aa21fab48ba36e32c5b9 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -100,6 +100,7 @@ bool intel_pmu_lbr_is_compatible(struct kvm_vcpu *vcpu);
bool intel_pmu_lbr_is_enabled(struct kvm_vcpu *vcpu);
int intel_pmu_create_guest_lbr_event(struct kvm_vcpu *vcpu);
+void vmx_passthrough_lbr_msrs(struct kvm_vcpu *vcpu);
struct lbr_desc {
/* Basic info about guest LBR records. */