diff mbox series

[v4,1/7] kvm: x86/pmu: Correct the mask used in a pmu event filter lookup

Message ID 20220831162124.947028-2-aaronlewis@google.com (mailing list archive)
State New, archived
Headers show
Series Introduce and test masked events | expand

Commit Message

Aaron Lewis Aug. 31, 2022, 4:21 p.m. UTC 
When checking if a pmu event the guest is attempting to program should
be filtered, only consider the event select + unit mask in that
decision. Use an architecture specific mask to mask out all other bits,
including bits 35:32 on Intel.  Those bits are not part of the event
select and should not be considered in that decision.

Fixes: 66bb8a065f5a ("KVM: x86: PMU Event Filter")
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
---
 arch/x86/include/asm/kvm-x86-pmu-ops.h |  1 +
 arch/x86/kvm/pmu.c                     | 15 ++++++++++++++-
 arch/x86/kvm/pmu.h                     |  1 +
 arch/x86/kvm/svm/pmu.c                 |  6 ++++++
 arch/x86/kvm/vmx/pmu_intel.c           |  6 ++++++
 5 files changed, 28 insertions(+), 1 deletion(-)

Comments

Jim Mattson Sept. 14, 2022, 6:15 p.m. UTC | #1 
On Wed, Aug 31, 2022 at 9:21 AM Aaron Lewis <aaronlewis@google.com> wrote:
>
> When checking if a pmu event the guest is attempting to program should
> be filtered, only consider the event select + unit mask in that
> decision. Use an architecture specific mask to mask out all other bits,
> including bits 35:32 on Intel.  Those bits are not part of the event
> select and should not be considered in that decision.
>
> Fixes: 66bb8a065f5a ("KVM: x86: PMU Event Filter")
> Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
diff mbox series

Patch

diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h
index c17e3e96fc1d..e0280cc3e6e4 100644
--- a/arch/x86/include/asm/kvm-x86-pmu-ops.h
+++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h
@@ -24,6 +24,7 @@  KVM_X86_PMU_OP(set_msr)
 KVM_X86_PMU_OP(refresh)
 KVM_X86_PMU_OP(init)
 KVM_X86_PMU_OP(reset)
+KVM_X86_PMU_OP(get_eventsel_event_mask)
 KVM_X86_PMU_OP_OPTIONAL(deliver_pmi)
 KVM_X86_PMU_OP_OPTIONAL(cleanup)
 
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 02f9e4f245bd..98f383789579 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -247,6 +247,19 @@  static int cmp_u64(const void *pa, const void *pb)
 	return (a > b) - (a < b);
 }
 
+static inline u64 get_event_select(u64 eventsel)
+{
+	return eventsel & static_call(kvm_x86_pmu_get_eventsel_event_mask)();
+}
+
+static inline u64 get_raw_event(u64 eventsel)
+{
+	u64 event_select = get_event_select(eventsel);
+	u64 unit_mask = eventsel & ARCH_PERFMON_EVENTSEL_UMASK;
+
+	return event_select | unit_mask;
+}
+
 static bool check_pmu_event_filter(struct kvm_pmc *pmc)
 {
 	struct kvm_pmu_event_filter *filter;
@@ -263,7 +276,7 @@  static bool check_pmu_event_filter(struct kvm_pmc *pmc)
 		goto out;
 
 	if (pmc_is_gp(pmc)) {
-		key = pmc->eventsel & AMD64_RAW_EVENT_MASK_NB;
+		key = get_raw_event(pmc->eventsel);
 		if (bsearch(&key, filter->events, filter->nevents,
 			    sizeof(__u64), cmp_u64))
 			allow_event = filter->action == KVM_PMU_EVENT_ALLOW;
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 5cc5721f260b..4e22f9f55400 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -40,6 +40,7 @@  struct kvm_pmu_ops {
 	void (*reset)(struct kvm_vcpu *vcpu);
 	void (*deliver_pmi)(struct kvm_vcpu *vcpu);
 	void (*cleanup)(struct kvm_vcpu *vcpu);
+	u64 (*get_eventsel_event_mask)(void);
 };
 
 void kvm_pmu_ops_update(const struct kvm_pmu_ops *pmu_ops);
diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index f24613a108c5..0b35eb04aa60 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -294,6 +294,11 @@  static void amd_pmu_reset(struct kvm_vcpu *vcpu)
 	}
 }
 
+static u64 amd_pmu_get_eventsel_event_mask(void)
+{
+	return AMD64_EVENTSEL_EVENT;
+}
+
 struct kvm_pmu_ops amd_pmu_ops __initdata = {
 	.hw_event_available = amd_hw_event_available,
 	.pmc_is_enabled = amd_pmc_is_enabled,
@@ -307,4 +312,5 @@  struct kvm_pmu_ops amd_pmu_ops __initdata = {
 	.refresh = amd_pmu_refresh,
 	.init = amd_pmu_init,
 	.reset = amd_pmu_reset,
+	.get_eventsel_event_mask = amd_pmu_get_eventsel_event_mask,
 };
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index c399637a3a79..0aec7576af0c 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -793,6 +793,11 @@  void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu)
 	}
 }
 
+static u64 intel_pmu_get_eventsel_event_mask(void)
+{
+	return ARCH_PERFMON_EVENTSEL_EVENT;
+}
+
 struct kvm_pmu_ops intel_pmu_ops __initdata = {
 	.hw_event_available = intel_hw_event_available,
 	.pmc_is_enabled = intel_pmc_is_enabled,
@@ -808,4 +813,5 @@  struct kvm_pmu_ops intel_pmu_ops __initdata = {
 	.reset = intel_pmu_reset,
 	.deliver_pmi = intel_pmu_deliver_pmi,
 	.cleanup = intel_pmu_cleanup,
+	.get_eventsel_event_mask = intel_pmu_get_eventsel_event_mask,
 };