[PATCH v7 00/19] KVM: x86/pmu: selftests: Fixes and new tests

[PATCH v7 00/19] KVM: x86/pmu: selftests: Fixes and new tests

[Sean Christopherson]

Round 7!  Fix bugs where KVM incorrectly refuses to virtualize fixed
counters and events whose encodings match unsupported arch events, and add
a PMU counters selftest to verify

As an aside, my hope is that in the long term, we can build out the PMU
selftests and deprecate the PMU tests in KUT so that we have everything
in-kernel and in one spot.

v7:
 - Drop patches that unnecessarily sanitized supported CPUID. [Jim]
 - Purge the array of architectural event encodings. [Jim, Dapeng]
 - Clean up pmu.h to remove useless macros, and make it easier to use the
   new macros. [Jim]
 - Port more of pmu_event_filter_test.c to pmu.h macros. [Jim, Jinrong]
 - Clean up test comments and error messages. [Jim]
 - Sanity check the value provided to vcpu_set_cpuid_property(). [Jim]

v6:
 - https://lore.kernel.org/all/20231104000239.367005-1-seanjc@google.com
 - Test LLC references/misses with CFLUSH{OPT}. [Jim]
 - Make the tests play nice without PERF_CAPABILITIES. [Mingwei]
 - Don't squash eventsels that happen to match an unsupported arch event. [Kan]
 - Test PMC counters with forced emulation (don't ask how long it took me to
   figure out how to read integer module params).

v5: https://lore.kernel.org/all/20231024002633.2540714-1-seanjc@google.com
v4: https://lore.kernel.org/all/20230911114347.85882-1-cloudliang@tencent.com
v3: https://lore.kernel.org/kvm/20230814115108.45741-1-cloudliang@tencent.com

 
Jinrong Liang (7):
  KVM: selftests: Add vcpu_set_cpuid_property() to set properties
  KVM: selftests: Add pmu.h and lib/pmu.c for common PMU assets
  KVM: selftests: Test Intel PMU architectural events on gp counters
  KVM: selftests: Test Intel PMU architectural events on fixed counters
  KVM: selftests: Test consistency of CPUID with num of gp counters
  KVM: selftests: Test consistency of CPUID with num of fixed counters
  KVM: selftests: Add functional test for Intel's fixed PMU counters

Sean Christopherson (12):
  KVM: x86/pmu: Always treat Fixed counters as available when supported
  KVM: x86/pmu: Allow programming events that match unsupported arch
    events
  KVM: x86/pmu: Remove KVM's enumeration of Intel's architectural
    encodings
  KVM: x86/pmu: Setup fixed counters' eventsel during PMU initialization
  KVM: selftests: Drop the "name" param from KVM_X86_PMU_FEATURE()
  KVM: selftests: Extend {kvm,this}_pmu_has() to support fixed counters
  KVM: selftests: Expand PMU counters test to verify LLC events
  KVM: selftests: Add a helper to query if the PMU module param is
    enabled
  KVM: selftests: Add helpers to read integer module params
  KVM: selftests: Query module param to detect FEP in MSR filtering test
  KVM: selftests: Move KVM_FEP macro into common library header
  KVM: selftests: Test PMC virtualization with forced emulation

 arch/x86/include/asm/kvm-x86-pmu-ops.h        |   1 -
 arch/x86/kvm/pmu.c                            |   1 -
 arch/x86/kvm/pmu.h                            |   1 -
 arch/x86/kvm/svm/pmu.c                        |   6 -
 arch/x86/kvm/vmx/pmu_intel.c                  | 107 +---
 tools/testing/selftests/kvm/Makefile          |   2 +
 .../selftests/kvm/include/kvm_util_base.h     |   4 +
 tools/testing/selftests/kvm/include/pmu.h     |  95 +++
 .../selftests/kvm/include/x86_64/processor.h  |  82 ++-
 tools/testing/selftests/kvm/lib/kvm_util.c    |  62 +-
 tools/testing/selftests/kvm/lib/pmu.c         |  31 +
 .../selftests/kvm/lib/x86_64/processor.c      |  15 +-
 .../selftests/kvm/x86_64/pmu_counters_test.c  | 568 ++++++++++++++++++
 .../kvm/x86_64/pmu_event_filter_test.c        | 143 ++---
 .../smaller_maxphyaddr_emulation_test.c       |   2 +-
 .../kvm/x86_64/userspace_msr_exit_test.c      |  29 +-
 .../selftests/kvm/x86_64/vmx_pmu_caps_test.c  |   2 +-
 17 files changed, 912 insertions(+), 239 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/include/pmu.h
 create mode 100644 tools/testing/selftests/kvm/lib/pmu.c
 create mode 100644 tools/testing/selftests/kvm/x86_64/pmu_counters_test.c


base-commit: 45b890f7689eb0aba454fc5831d2d79763781677
-- 
2.42.0.869.gea05f2083d-goog

[PATCH v7 01/19] KVM: x86/pmu: Always treat Fixed counters as available when supported

[Sean Christopherson]

Treat fixed counters as available when they are supported, i.e. don't
silently ignore an enabled fixed counter just because guest CPUID says the
associated general purpose architectural event is unavailable.

KVM originally treated fixed counters as always available, but that got
changed as part of a fix to avoid confusing REF_CPU_CYCLES, which does NOT
map to an architectural event, with the actual architectural event used
associated with bit 7, TOPDOWN_SLOTS.

The commit justified the change with:

    If the event is marked as unavailable in the Intel guest CPUID
    0AH.EBX leaf, we need to avoid any perf_event creation, whether
    it's a gp or fixed counter.

but that justification doesn't mesh with reality.  The Intel SDM uses
"architectural events" to refer to both general purpose events (the ones
with the reverse polarity mask in CPUID.0xA.EBX) and the events for fixed
counters, e.g. the SDM makes statements like:

  Each of the fixed-function PMC can count only one architectural
  performance event.

but the fact that fixed counter 2 (TSC reference cycles) doesn't have an
associated general purpose architectural makes trying to apply the mask
from CPUID.0xA.EBX impossible.

Furthermore, the lack of enumeration for an architectural event in CPUID
only means the CPU doesn't officially support the architectural encoding,
i.e. it doesn't mean using the architectural encoding _won't_ work, it
sipmly means there are no guarantees that it will work as expected.  E.g.
if KVM is running in a VM that advertises a fixed counters but not the
corresponding architectural event encoding, and perf decides to use a
general purpose counter instead of a fixed counter, odds are very good
that the underlying hardware actually does support the architectrual
encoding, and that programming the encoding will count the right thing.

In other words, asking perf to count the event will probably work, whereas
intentionally doing nothing is obviously guaranteed to fail.

Note, at the time of the change, KVM didn't enforce hardware support, i.e.
didn't prevent userspace from enumerating support in guest CPUID.0xA.EBX
for architectural events that aren't supported in hardware.  I.e. silently
dropping the fixed counter didn't somehow protection against counting the
wrong event, it just enforced guest CPUID.  And practically speaking, this
issue is almost certainly limited to running KVM on a funky virtual CPU
model.  No known real hardware has an asymmetric PMU where a fixed counter
is supported but the associated architectural event is not.

Fixes: a21864486f7e ("KVM: x86/pmu: Fix available_event_types check for REF_CPU_CYCLES event")
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 820d3e1f6b4f..c6e227edcf8e 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -108,11 +108,24 @@ static bool intel_hw_event_available(struct kvm_pmc *pmc)
 	u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
 	int i;
 
+	/*
+	 * Fixed counters are always available if KVM reaches this point.  If a
+	 * fixed counter is unsupported in hardware or guest CPUID, KVM doesn't
+	 * allow the counter's corresponding MSR to be written.  KVM does use
+	 * architectural events to program fixed counters, as the interface to
+	 * perf doesn't allow requesting a specific fixed counter, e.g. perf
+	 * may (sadly) back a guest fixed PMC with a general purposed counter.
+	 * But if _hardware_ doesn't support the associated event, KVM simply
+	 * doesn't enumerate support for the fixed counter.
+	 */
+	if (pmc_is_fixed(pmc))
+		return true;
+
 	BUILD_BUG_ON(ARRAY_SIZE(intel_arch_events) != NR_INTEL_ARCH_EVENTS);
 
 	/*
 	 * Disallow events reported as unavailable in guest CPUID.  Note, this
-	 * doesn't apply to pseudo-architectural events.
+	 * doesn't apply to pseudo-architectural events (see above).
 	 */
 	for (i = 0; i < NR_REAL_INTEL_ARCH_EVENTS; i++) {
 		if (intel_arch_events[i].eventsel != event_select ||
-- 
2.42.0.869.gea05f2083d-goog

[PATCH v7 02/19] KVM: x86/pmu: Allow programming events that match unsupported arch events

[Sean Christopherson]

Remove KVM's bogus restriction that the guest can't program an event whose
encoding matches an unsupported architectural event.  The enumeration of
an architectural event only says that if a CPU supports an architectural
event, then the event can be programmed using the architectural encoding.
The enumeration does NOT say anything about the encoding when the CPU
doesn't report support the architectural event.

Preventing the guest from counting events whose encoding happens to match
an architectural event breaks existing functionality whenever Intel adds
an architectural encoding that was *ever* used for a CPU that doesn't
enumerate support for the architectural event, even if the encoding is for
the exact same event!

E.g. the architectural encoding for Top-Down Slots is 0x01a4.  Broadwell
CPUs, which do not support the Top-Down Slots architectural event, 0x10a4
is a valid, model-specific event.  Denying guest usage of 0x01a4 if/when
KVM adds support for Top-Down slots would break any Broadwell-based guest.

Reported-by: Kan Liang <kan.liang@linux.intel.com>
Closes: https://lore.kernel.org/all/2004baa6-b494-462c-a11f-8104ea152c6a@linux.intel.com
Fixes: a21864486f7e ("KVM: x86/pmu: Fix available_event_types check for REF_CPU_CYCLES event")
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/include/asm/kvm-x86-pmu-ops.h |  1 -
 arch/x86/kvm/pmu.c                     |  1 -
 arch/x86/kvm/pmu.h                     |  1 -
 arch/x86/kvm/svm/pmu.c                 |  6 ----
 arch/x86/kvm/vmx/pmu_intel.c           | 38 --------------------------
 5 files changed, 47 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h
index 6c98f4bb4228..884af8ef7657 100644
--- a/arch/x86/include/asm/kvm-x86-pmu-ops.h
+++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h
@@ -12,7 +12,6 @@ BUILD_BUG_ON(1)
  * a NULL definition, for example if "static_call_cond()" will be used
  * at the call sites.
  */
-KVM_X86_PMU_OP(hw_event_available)
 KVM_X86_PMU_OP(pmc_idx_to_pmc)
 KVM_X86_PMU_OP(rdpmc_ecx_to_pmc)
 KVM_X86_PMU_OP(msr_idx_to_pmc)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 9ae07db6f0f6..99ed72966528 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -374,7 +374,6 @@ static bool check_pmu_event_filter(struct kvm_pmc *pmc)
 static bool pmc_event_is_allowed(struct kvm_pmc *pmc)
 {
 	return pmc_is_globally_enabled(pmc) && pmc_speculative_in_use(pmc) &&
-	       static_call(kvm_x86_pmu_hw_event_available)(pmc) &&
 	       check_pmu_event_filter(pmc);
 }
 
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 1d64113de488..10fe5bf02705 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -19,7 +19,6 @@
 #define VMWARE_BACKDOOR_PMC_APPARENT_TIME	0x10002
 
 struct kvm_pmu_ops {
-	bool (*hw_event_available)(struct kvm_pmc *pmc);
 	struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx);
 	struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu,
 		unsigned int idx, u64 *mask);
diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index 373ff6a6687b..5596fe816ea8 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -73,11 +73,6 @@ static inline struct kvm_pmc *get_gp_pmc_amd(struct kvm_pmu *pmu, u32 msr,
 	return amd_pmc_idx_to_pmc(pmu, idx);
 }
 
-static bool amd_hw_event_available(struct kvm_pmc *pmc)
-{
-	return true;
-}
-
 static bool amd_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -249,7 +244,6 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu)
 }
 
 struct kvm_pmu_ops amd_pmu_ops __initdata = {
-	.hw_event_available = amd_hw_event_available,
 	.pmc_idx_to_pmc = amd_pmc_idx_to_pmc,
 	.rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc,
 	.msr_idx_to_pmc = amd_msr_idx_to_pmc,
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index c6e227edcf8e..7737ee2fc62f 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -101,43 +101,6 @@ static struct kvm_pmc *intel_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx)
 	}
 }
 
-static bool intel_hw_event_available(struct kvm_pmc *pmc)
-{
-	struct kvm_pmu *pmu = pmc_to_pmu(pmc);
-	u8 event_select = pmc->eventsel & ARCH_PERFMON_EVENTSEL_EVENT;
-	u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
-	int i;
-
-	/*
-	 * Fixed counters are always available if KVM reaches this point.  If a
-	 * fixed counter is unsupported in hardware or guest CPUID, KVM doesn't
-	 * allow the counter's corresponding MSR to be written.  KVM does use
-	 * architectural events to program fixed counters, as the interface to
-	 * perf doesn't allow requesting a specific fixed counter, e.g. perf
-	 * may (sadly) back a guest fixed PMC with a general purposed counter.
-	 * But if _hardware_ doesn't support the associated event, KVM simply
-	 * doesn't enumerate support for the fixed counter.
-	 */
-	if (pmc_is_fixed(pmc))
-		return true;
-
-	BUILD_BUG_ON(ARRAY_SIZE(intel_arch_events) != NR_INTEL_ARCH_EVENTS);
-
-	/*
-	 * Disallow events reported as unavailable in guest CPUID.  Note, this
-	 * doesn't apply to pseudo-architectural events (see above).
-	 */
-	for (i = 0; i < NR_REAL_INTEL_ARCH_EVENTS; i++) {
-		if (intel_arch_events[i].eventsel != event_select ||
-		    intel_arch_events[i].unit_mask != unit_mask)
-			continue;
-
-		return pmu->available_event_types & BIT(i);
-	}
-
-	return true;
-}
-
 static bool intel_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -802,7 +765,6 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu)
 }
 
 struct kvm_pmu_ops intel_pmu_ops __initdata = {
-	.hw_event_available = intel_hw_event_available,
 	.pmc_idx_to_pmc = intel_pmc_idx_to_pmc,
 	.rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc,
 	.msr_idx_to_pmc = intel_msr_idx_to_pmc,
-- 
2.42.0.869.gea05f2083d-goog

Re: [PATCH v7 02/19] KVM: x86/pmu: Allow programming events that match unsupported arch events

[Jim Mattson]

On Tue, Nov 7, 2023 at 4:31 PM Sean Christopherson <seanjc@google.com> wrote:
>
> Remove KVM's bogus restriction that the guest can't program an event whose
> encoding matches an unsupported architectural event.  The enumeration of
> an architectural event only says that if a CPU supports an architectural
> event, then the event can be programmed using the architectural encoding.
> The enumeration does NOT say anything about the encoding when the CPU
> doesn't report support the architectural event.
>
> Preventing the guest from counting events whose encoding happens to match
> an architectural event breaks existing functionality whenever Intel adds
> an architectural encoding that was *ever* used for a CPU that doesn't
> enumerate support for the architectural event, even if the encoding is for
> the exact same event!
>
> E.g. the architectural encoding for Top-Down Slots is 0x01a4.  Broadwell
> CPUs, which do not support the Top-Down Slots architectural event, 0x10a4

Nit: 0x01a4

> is a valid, model-specific event.  Denying guest usage of 0x01a4 if/when
> KVM adds support for Top-Down slots would break any Broadwell-based guest.
>
> Reported-by: Kan Liang <kan.liang@linux.intel.com>
> Closes: https://lore.kernel.org/all/2004baa6-b494-462c-a11f-8104ea152c6a@linux.intel.com
> Fixes: a21864486f7e ("KVM: x86/pmu: Fix available_event_types check for REF_CPU_CYCLES event")
> Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
> Reviewed-by: Jim Mattson <jmattson@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>  arch/x86/include/asm/kvm-x86-pmu-ops.h |  1 -
>  arch/x86/kvm/pmu.c                     |  1 -
>  arch/x86/kvm/pmu.h                     |  1 -
>  arch/x86/kvm/svm/pmu.c                 |  6 ----
>  arch/x86/kvm/vmx/pmu_intel.c           | 38 --------------------------
>  5 files changed, 47 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h
> index 6c98f4bb4228..884af8ef7657 100644
> --- a/arch/x86/include/asm/kvm-x86-pmu-ops.h
> +++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h
> @@ -12,7 +12,6 @@ BUILD_BUG_ON(1)
>   * a NULL definition, for example if "static_call_cond()" will be used
>   * at the call sites.
>   */
> -KVM_X86_PMU_OP(hw_event_available)
>  KVM_X86_PMU_OP(pmc_idx_to_pmc)
>  KVM_X86_PMU_OP(rdpmc_ecx_to_pmc)
>  KVM_X86_PMU_OP(msr_idx_to_pmc)
> diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
> index 9ae07db6f0f6..99ed72966528 100644
> --- a/arch/x86/kvm/pmu.c
> +++ b/arch/x86/kvm/pmu.c
> @@ -374,7 +374,6 @@ static bool check_pmu_event_filter(struct kvm_pmc *pmc)
>  static bool pmc_event_is_allowed(struct kvm_pmc *pmc)
>  {
>         return pmc_is_globally_enabled(pmc) && pmc_speculative_in_use(pmc) &&
> -              static_call(kvm_x86_pmu_hw_event_available)(pmc) &&
>                check_pmu_event_filter(pmc);
>  }
>
> diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
> index 1d64113de488..10fe5bf02705 100644
> --- a/arch/x86/kvm/pmu.h
> +++ b/arch/x86/kvm/pmu.h
> @@ -19,7 +19,6 @@
>  #define VMWARE_BACKDOOR_PMC_APPARENT_TIME      0x10002
>
>  struct kvm_pmu_ops {
> -       bool (*hw_event_available)(struct kvm_pmc *pmc);
>         struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx);
>         struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu,
>                 unsigned int idx, u64 *mask);
> diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
> index 373ff6a6687b..5596fe816ea8 100644
> --- a/arch/x86/kvm/svm/pmu.c
> +++ b/arch/x86/kvm/svm/pmu.c
> @@ -73,11 +73,6 @@ static inline struct kvm_pmc *get_gp_pmc_amd(struct kvm_pmu *pmu, u32 msr,
>         return amd_pmc_idx_to_pmc(pmu, idx);
>  }
>
> -static bool amd_hw_event_available(struct kvm_pmc *pmc)
> -{
> -       return true;
> -}
> -
>  static bool amd_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
>  {
>         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
> @@ -249,7 +244,6 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu)
>  }
>
>  struct kvm_pmu_ops amd_pmu_ops __initdata = {
> -       .hw_event_available = amd_hw_event_available,
>         .pmc_idx_to_pmc = amd_pmc_idx_to_pmc,
>         .rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc,
>         .msr_idx_to_pmc = amd_msr_idx_to_pmc,
> diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> index c6e227edcf8e..7737ee2fc62f 100644
> --- a/arch/x86/kvm/vmx/pmu_intel.c
> +++ b/arch/x86/kvm/vmx/pmu_intel.c
> @@ -101,43 +101,6 @@ static struct kvm_pmc *intel_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx)
>         }
>  }
>
> -static bool intel_hw_event_available(struct kvm_pmc *pmc)
> -{
> -       struct kvm_pmu *pmu = pmc_to_pmu(pmc);
> -       u8 event_select = pmc->eventsel & ARCH_PERFMON_EVENTSEL_EVENT;
> -       u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
> -       int i;
> -
> -       /*
> -        * Fixed counters are always available if KVM reaches this point.  If a
> -        * fixed counter is unsupported in hardware or guest CPUID, KVM doesn't
> -        * allow the counter's corresponding MSR to be written.  KVM does use
> -        * architectural events to program fixed counters, as the interface to
> -        * perf doesn't allow requesting a specific fixed counter, e.g. perf
> -        * may (sadly) back a guest fixed PMC with a general purposed counter.
> -        * But if _hardware_ doesn't support the associated event, KVM simply
> -        * doesn't enumerate support for the fixed counter.
> -        */
> -       if (pmc_is_fixed(pmc))
> -               return true;
> -
> -       BUILD_BUG_ON(ARRAY_SIZE(intel_arch_events) != NR_INTEL_ARCH_EVENTS);
> -
> -       /*
> -        * Disallow events reported as unavailable in guest CPUID.  Note, this
> -        * doesn't apply to pseudo-architectural events (see above).
> -        */
> -       for (i = 0; i < NR_REAL_INTEL_ARCH_EVENTS; i++) {
> -               if (intel_arch_events[i].eventsel != event_select ||
> -                   intel_arch_events[i].unit_mask != unit_mask)
> -                       continue;
> -
> -               return pmu->available_event_types & BIT(i);
> -       }
> -
> -       return true;
> -}
> -
>  static bool intel_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
>  {
>         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
> @@ -802,7 +765,6 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu)
>  }
>
>  struct kvm_pmu_ops intel_pmu_ops __initdata = {
> -       .hw_event_available = intel_hw_event_available,
>         .pmc_idx_to_pmc = intel_pmc_idx_to_pmc,
>         .rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc,
>         .msr_idx_to_pmc = intel_msr_idx_to_pmc,
> --
> 2.42.0.869.gea05f2083d-goog
>

Re: [PATCH v7 02/19] KVM: x86/pmu: Allow programming events that match unsupported arch events

[Liang, Kan]

On 2023-11-07 7:31 p.m., Sean Christopherson wrote:
> Remove KVM's bogus restriction that the guest can't program an event whose
> encoding matches an unsupported architectural event.  The enumeration of
> an architectural event only says that if a CPU supports an architectural
> event, then the event can be programmed using the architectural encoding.
> The enumeration does NOT say anything about the encoding when the CPU
> doesn't report support the architectural event.
> 
> Preventing the guest from counting events whose encoding happens to match
> an architectural event breaks existing functionality whenever Intel adds
> an architectural encoding that was *ever* used for a CPU that doesn't
> enumerate support for the architectural event, even if the encoding is for
> the exact same event!
> 
> E.g. the architectural encoding for Top-Down Slots is 0x01a4.  Broadwell
> CPUs, which do not support the Top-Down Slots architectural event, 0x10a4
> is a valid, model-specific event.  Denying guest usage of 0x01a4 if/when
> KVM adds support for Top-Down slots would break any Broadwell-based guest.
> 
> Reported-by: Kan Liang <kan.liang@linux.intel.com>
> Closes: https://lore.kernel.org/all/2004baa6-b494-462c-a11f-8104ea152c6a@linux.intel.com
> Fixes: a21864486f7e ("KVM: x86/pmu: Fix available_event_types check for REF_CPU_CYCLES event")
> Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
> Reviewed-by: Jim Mattson <jmattson@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---


Reviewed-by: Kan Liang <kan.liang@linux.intel.com>

Thanks,
Kan

>  arch/x86/include/asm/kvm-x86-pmu-ops.h |  1 -
>  arch/x86/kvm/pmu.c                     |  1 -
>  arch/x86/kvm/pmu.h                     |  1 -
>  arch/x86/kvm/svm/pmu.c                 |  6 ----
>  arch/x86/kvm/vmx/pmu_intel.c           | 38 --------------------------
>  5 files changed, 47 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h
> index 6c98f4bb4228..884af8ef7657 100644
> --- a/arch/x86/include/asm/kvm-x86-pmu-ops.h
> +++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h
> @@ -12,7 +12,6 @@ BUILD_BUG_ON(1)
>   * a NULL definition, for example if "static_call_cond()" will be used
>   * at the call sites.
>   */
> -KVM_X86_PMU_OP(hw_event_available)
>  KVM_X86_PMU_OP(pmc_idx_to_pmc)
>  KVM_X86_PMU_OP(rdpmc_ecx_to_pmc)
>  KVM_X86_PMU_OP(msr_idx_to_pmc)
> diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
> index 9ae07db6f0f6..99ed72966528 100644
> --- a/arch/x86/kvm/pmu.c
> +++ b/arch/x86/kvm/pmu.c
> @@ -374,7 +374,6 @@ static bool check_pmu_event_filter(struct kvm_pmc *pmc)
>  static bool pmc_event_is_allowed(struct kvm_pmc *pmc)
>  {
>  	return pmc_is_globally_enabled(pmc) && pmc_speculative_in_use(pmc) &&
> -	       static_call(kvm_x86_pmu_hw_event_available)(pmc) &&
>  	       check_pmu_event_filter(pmc);
>  }
>  
> diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
> index 1d64113de488..10fe5bf02705 100644
> --- a/arch/x86/kvm/pmu.h
> +++ b/arch/x86/kvm/pmu.h
> @@ -19,7 +19,6 @@
>  #define VMWARE_BACKDOOR_PMC_APPARENT_TIME	0x10002
>  
>  struct kvm_pmu_ops {
> -	bool (*hw_event_available)(struct kvm_pmc *pmc);
>  	struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx);
>  	struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu,
>  		unsigned int idx, u64 *mask);
> diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
> index 373ff6a6687b..5596fe816ea8 100644
> --- a/arch/x86/kvm/svm/pmu.c
> +++ b/arch/x86/kvm/svm/pmu.c
> @@ -73,11 +73,6 @@ static inline struct kvm_pmc *get_gp_pmc_amd(struct kvm_pmu *pmu, u32 msr,
>  	return amd_pmc_idx_to_pmc(pmu, idx);
>  }
>  
> -static bool amd_hw_event_available(struct kvm_pmc *pmc)
> -{
> -	return true;
> -}
> -
>  static bool amd_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
>  {
>  	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
> @@ -249,7 +244,6 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu)
>  }
>  
>  struct kvm_pmu_ops amd_pmu_ops __initdata = {
> -	.hw_event_available = amd_hw_event_available,
>  	.pmc_idx_to_pmc = amd_pmc_idx_to_pmc,
>  	.rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc,
>  	.msr_idx_to_pmc = amd_msr_idx_to_pmc,
> diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> index c6e227edcf8e..7737ee2fc62f 100644
> --- a/arch/x86/kvm/vmx/pmu_intel.c
> +++ b/arch/x86/kvm/vmx/pmu_intel.c
> @@ -101,43 +101,6 @@ static struct kvm_pmc *intel_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx)
>  	}
>  }
>  
> -static bool intel_hw_event_available(struct kvm_pmc *pmc)
> -{
> -	struct kvm_pmu *pmu = pmc_to_pmu(pmc);
> -	u8 event_select = pmc->eventsel & ARCH_PERFMON_EVENTSEL_EVENT;
> -	u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
> -	int i;
> -
> -	/*
> -	 * Fixed counters are always available if KVM reaches this point.  If a
> -	 * fixed counter is unsupported in hardware or guest CPUID, KVM doesn't
> -	 * allow the counter's corresponding MSR to be written.  KVM does use
> -	 * architectural events to program fixed counters, as the interface to
> -	 * perf doesn't allow requesting a specific fixed counter, e.g. perf
> -	 * may (sadly) back a guest fixed PMC with a general purposed counter.
> -	 * But if _hardware_ doesn't support the associated event, KVM simply
> -	 * doesn't enumerate support for the fixed counter.
> -	 */
> -	if (pmc_is_fixed(pmc))
> -		return true;
> -
> -	BUILD_BUG_ON(ARRAY_SIZE(intel_arch_events) != NR_INTEL_ARCH_EVENTS);
> -
> -	/*
> -	 * Disallow events reported as unavailable in guest CPUID.  Note, this
> -	 * doesn't apply to pseudo-architectural events (see above).
> -	 */
> -	for (i = 0; i < NR_REAL_INTEL_ARCH_EVENTS; i++) {
> -		if (intel_arch_events[i].eventsel != event_select ||
> -		    intel_arch_events[i].unit_mask != unit_mask)
> -			continue;
> -
> -		return pmu->available_event_types & BIT(i);
> -	}
> -
> -	return true;
> -}
> -
>  static bool intel_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
>  {
>  	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
> @@ -802,7 +765,6 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu)
>  }
>  
>  struct kvm_pmu_ops intel_pmu_ops __initdata = {
> -	.hw_event_available = intel_hw_event_available,
>  	.pmc_idx_to_pmc = intel_pmc_idx_to_pmc,
>  	.rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc,
>  	.msr_idx_to_pmc = intel_msr_idx_to_pmc,

[PATCH v7 03/19] KVM: x86/pmu: Remove KVM's enumeration of Intel's architectural encodings

[Sean Christopherson]

Drop KVM's enumeration of Intel's architectural event encodings, and
instead open code the three encodings (of which only two are real) that
KVM uses to emulate fixed counters.  Now that KVM doesn't incorrectly
enforce the availability of architectural encodings, there is no reason
for KVM to ever care about the encodings themselves, at least not in the
current format of an array indexed by the encoding's position in CPUID.

Opportunistically add a comment to explain why KVM cares about eventsel
values for fixed counters.

Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 72 ++++++++++++------------------------
 1 file changed, 23 insertions(+), 49 deletions(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 7737ee2fc62f..c4f2c6a268e7 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -22,52 +22,6 @@
 
 #define MSR_PMC_FULL_WIDTH_BIT      (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0)
 
-enum intel_pmu_architectural_events {
-	/*
-	 * The order of the architectural events matters as support for each
-	 * event is enumerated via CPUID using the index of the event.
-	 */
-	INTEL_ARCH_CPU_CYCLES,
-	INTEL_ARCH_INSTRUCTIONS_RETIRED,
-	INTEL_ARCH_REFERENCE_CYCLES,
-	INTEL_ARCH_LLC_REFERENCES,
-	INTEL_ARCH_LLC_MISSES,
-	INTEL_ARCH_BRANCHES_RETIRED,
-	INTEL_ARCH_BRANCHES_MISPREDICTED,
-
-	NR_REAL_INTEL_ARCH_EVENTS,
-
-	/*
-	 * Pseudo-architectural event used to implement IA32_FIXED_CTR2, a.k.a.
-	 * TSC reference cycles.  The architectural reference cycles event may
-	 * or may not actually use the TSC as the reference, e.g. might use the
-	 * core crystal clock or the bus clock (yeah, "architectural").
-	 */
-	PSEUDO_ARCH_REFERENCE_CYCLES = NR_REAL_INTEL_ARCH_EVENTS,
-	NR_INTEL_ARCH_EVENTS,
-};
-
-static struct {
-	u8 eventsel;
-	u8 unit_mask;
-} const intel_arch_events[] = {
-	[INTEL_ARCH_CPU_CYCLES]			= { 0x3c, 0x00 },
-	[INTEL_ARCH_INSTRUCTIONS_RETIRED]	= { 0xc0, 0x00 },
-	[INTEL_ARCH_REFERENCE_CYCLES]		= { 0x3c, 0x01 },
-	[INTEL_ARCH_LLC_REFERENCES]		= { 0x2e, 0x4f },
-	[INTEL_ARCH_LLC_MISSES]			= { 0x2e, 0x41 },
-	[INTEL_ARCH_BRANCHES_RETIRED]		= { 0xc4, 0x00 },
-	[INTEL_ARCH_BRANCHES_MISPREDICTED]	= { 0xc5, 0x00 },
-	[PSEUDO_ARCH_REFERENCE_CYCLES]		= { 0x00, 0x03 },
-};
-
-/* mapping between fixed pmc index and intel_arch_events array */
-static int fixed_pmc_events[] = {
-	[0] = INTEL_ARCH_INSTRUCTIONS_RETIRED,
-	[1] = INTEL_ARCH_CPU_CYCLES,
-	[2] = PSEUDO_ARCH_REFERENCE_CYCLES,
-};
-
 static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data)
 {
 	struct kvm_pmc *pmc;
@@ -442,8 +396,29 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	return 0;
 }
 
+/*
+ * Map fixed counter events to architectural general purpose event encodings.
+ * Perf doesn't provide APIs to allow KVM to directly program a fixed counter,
+ * and so KVM instead programs the architectural event to effectively request
+ * the fixed counter.  Perf isn't guaranteed to use a fixed counter and may
+ * instead program the encoding into a general purpose counter, e.g. if a
+ * different perf_event is already utilizing the requested counter, but the end
+ * result is the same (ignoring the fact that using a general purpose counter
+ * will likely exacerbate counter contention).
+ *
+ * Note, reference cycles is counted using a perf-defined "psuedo-encoding",
+ * as there is no architectural general purpose encoding for reference cycles.
+ */
 static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
 {
+	const struct {
+		u8 eventsel;
+		u8 unit_mask;
+	} fixed_pmc_events[] = {
+		[0] = { 0xc0, 0x00 }, /* Instruction Retired / PERF_COUNT_HW_INSTRUCTIONS. */
+		[1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */
+		[2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/
+	};
 	int i;
 
 	BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED);
@@ -451,10 +426,9 @@ static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
 	for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
 		int index = array_index_nospec(i, KVM_PMC_MAX_FIXED);
 		struct kvm_pmc *pmc = &pmu->fixed_counters[index];
-		u32 event = fixed_pmc_events[index];
 
-		pmc->eventsel = (intel_arch_events[event].unit_mask << 8) |
-				 intel_arch_events[event].eventsel;
+		pmc->eventsel = (fixed_pmc_events[index].unit_mask << 8) |
+				 fixed_pmc_events[index].eventsel;
 	}
 }
 
-- 
2.42.0.869.gea05f2083d-goog

Re: [PATCH v7 03/19] KVM: x86/pmu: Remove KVM's enumeration of Intel's architectural encodings

[Liang, Kan]

On 2023-11-07 7:31 p.m., Sean Christopherson wrote:
> Drop KVM's enumeration of Intel's architectural event encodings, and
> instead open code the three encodings (of which only two are real) that
> KVM uses to emulate fixed counters.  Now that KVM doesn't incorrectly
> enforce the availability of architectural encodings, there is no reason
> for KVM to ever care about the encodings themselves, at least not in the
> current format of an array indexed by the encoding's position in CPUID.
> 
> Opportunistically add a comment to explain why KVM cares about eventsel
> values for fixed counters.
> 
> Suggested-by: Jim Mattson <jmattson@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>  arch/x86/kvm/vmx/pmu_intel.c | 72 ++++++++++++------------------------
>  1 file changed, 23 insertions(+), 49 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> index 7737ee2fc62f..c4f2c6a268e7 100644
> --- a/arch/x86/kvm/vmx/pmu_intel.c
> +++ b/arch/x86/kvm/vmx/pmu_intel.c
> @@ -22,52 +22,6 @@
>  
>  #define MSR_PMC_FULL_WIDTH_BIT      (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0)
>  
> -enum intel_pmu_architectural_events {
> -	/*
> -	 * The order of the architectural events matters as support for each
> -	 * event is enumerated via CPUID using the index of the event.
> -	 */
> -	INTEL_ARCH_CPU_CYCLES,
> -	INTEL_ARCH_INSTRUCTIONS_RETIRED,
> -	INTEL_ARCH_REFERENCE_CYCLES,
> -	INTEL_ARCH_LLC_REFERENCES,
> -	INTEL_ARCH_LLC_MISSES,
> -	INTEL_ARCH_BRANCHES_RETIRED,
> -	INTEL_ARCH_BRANCHES_MISPREDICTED,
> -
> -	NR_REAL_INTEL_ARCH_EVENTS,
> -
> -	/*
> -	 * Pseudo-architectural event used to implement IA32_FIXED_CTR2, a.k.a.
> -	 * TSC reference cycles.  The architectural reference cycles event may
> -	 * or may not actually use the TSC as the reference, e.g. might use the
> -	 * core crystal clock or the bus clock (yeah, "architectural").
> -	 */
> -	PSEUDO_ARCH_REFERENCE_CYCLES = NR_REAL_INTEL_ARCH_EVENTS,
> -	NR_INTEL_ARCH_EVENTS,
> -};
> -
> -static struct {
> -	u8 eventsel;
> -	u8 unit_mask;
> -} const intel_arch_events[] = {
> -	[INTEL_ARCH_CPU_CYCLES]			= { 0x3c, 0x00 },
> -	[INTEL_ARCH_INSTRUCTIONS_RETIRED]	= { 0xc0, 0x00 },
> -	[INTEL_ARCH_REFERENCE_CYCLES]		= { 0x3c, 0x01 },
> -	[INTEL_ARCH_LLC_REFERENCES]		= { 0x2e, 0x4f },
> -	[INTEL_ARCH_LLC_MISSES]			= { 0x2e, 0x41 },
> -	[INTEL_ARCH_BRANCHES_RETIRED]		= { 0xc4, 0x00 },
> -	[INTEL_ARCH_BRANCHES_MISPREDICTED]	= { 0xc5, 0x00 },
> -	[PSEUDO_ARCH_REFERENCE_CYCLES]		= { 0x00, 0x03 },
> -};
> -
> -/* mapping between fixed pmc index and intel_arch_events array */
> -static int fixed_pmc_events[] = {
> -	[0] = INTEL_ARCH_INSTRUCTIONS_RETIRED,
> -	[1] = INTEL_ARCH_CPU_CYCLES,
> -	[2] = PSEUDO_ARCH_REFERENCE_CYCLES,
> -};
> -
>  static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data)
>  {
>  	struct kvm_pmc *pmc;
> @@ -442,8 +396,29 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>  	return 0;
>  }
>  
> +/*
> + * Map fixed counter events to architectural general purpose event encodings.
> + * Perf doesn't provide APIs to allow KVM to directly program a fixed counter,
> + * and so KVM instead programs the architectural event to effectively request
> + * the fixed counter.  Perf isn't guaranteed to use a fixed counter and may
> + * instead program the encoding into a general purpose counter, e.g. if a
> + * different perf_event is already utilizing the requested counter, but the end
> + * result is the same (ignoring the fact that using a general purpose counter
> + * will likely exacerbate counter contention).
> + *
> + * Note, reference cycles is counted using a perf-defined "psuedo-encoding",
> + * as there is no architectural general purpose encoding for reference cycles.

It's not the case for the latest Intel platforms anymore. Please see
ffbe4ab0beda ("perf/x86/intel: Extend the ref-cycles event to GP counters").

Maybe perf should export .event_map to KVM somehow.

Thanks,
Kan
> + */
>  static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
>  {
> +	const struct {
> +		u8 eventsel;
> +		u8 unit_mask;
> +	} fixed_pmc_events[] = {
> +		[0] = { 0xc0, 0x00 }, /* Instruction Retired / PERF_COUNT_HW_INSTRUCTIONS. */
> +		[1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */
> +		[2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/
> +	};
>  	int i;
>  
>  	BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED);
> @@ -451,10 +426,9 @@ static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
>  	for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
>  		int index = array_index_nospec(i, KVM_PMC_MAX_FIXED);
>  		struct kvm_pmc *pmc = &pmu->fixed_counters[index];
> -		u32 event = fixed_pmc_events[index];
>  
> -		pmc->eventsel = (intel_arch_events[event].unit_mask << 8) |
> -				 intel_arch_events[event].eventsel;
> +		pmc->eventsel = (fixed_pmc_events[index].unit_mask << 8) |
> +				 fixed_pmc_events[index].eventsel;
>  	}
>  }
>  

Re: [PATCH v7 03/19] KVM: x86/pmu: Remove KVM's enumeration of Intel's architectural encodings

[Sean Christopherson]

On Wed, Nov 08, 2023, Kan Liang wrote:
> On 2023-11-07 7:31 p.m., Sean Christopherson wrote:
> > @@ -442,8 +396,29 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> >  	return 0;
> >  }
> >  
> > +/*
> > + * Map fixed counter events to architectural general purpose event encodings.
> > + * Perf doesn't provide APIs to allow KVM to directly program a fixed counter,
> > + * and so KVM instead programs the architectural event to effectively request
> > + * the fixed counter.  Perf isn't guaranteed to use a fixed counter and may
> > + * instead program the encoding into a general purpose counter, e.g. if a
> > + * different perf_event is already utilizing the requested counter, but the end
> > + * result is the same (ignoring the fact that using a general purpose counter
> > + * will likely exacerbate counter contention).
> > + *
> > + * Note, reference cycles is counted using a perf-defined "psuedo-encoding",
> > + * as there is no architectural general purpose encoding for reference cycles.
> 
> It's not the case for the latest Intel platforms anymore. Please see
> ffbe4ab0beda ("perf/x86/intel: Extend the ref-cycles event to GP counters").

Ugh, yeah.  But that and should actually be easier to do on top.

> Maybe perf should export .event_map to KVM somehow.

Oh for ***** sake, perf already does export this for KVM.  Untested, but the below
should do the trick.  If I need to spin another version of this series then I'll
fold it in, otherwise I'll post it as something on top.

There's also an optimization to be had for kvm_pmu_trigger_event(), which incurs
an indirect branch not only every invocation, but on every iteration.  I'll post
this one separately.

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 5fc5a62af428..a02e13c2e5e6 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -405,25 +405,32 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
  * different perf_event is already utilizing the requested counter, but the end
  * result is the same (ignoring the fact that using a general purpose counter
  * will likely exacerbate counter contention).
- *
- * Note, reference cycles is counted using a perf-defined "psuedo-encoding",
- * as there is no architectural general purpose encoding for reference cycles.
  */
 static u64 intel_get_fixed_pmc_eventsel(int index)
 {
-       const struct {
-               u8 eventsel;
-               u8 unit_mask;
-       } fixed_pmc_events[] = {
-               [0] = { 0xc0, 0x00 }, /* Instruction Retired / PERF_COUNT_HW_INSTRUCTIONS. */
-               [1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */
-               [2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/
+       enum perf_hw_id perf_id;
+       u64 eventsel;
+
+       BUILD_BUG_ON(KVM_PMC_MAX_FIXED != 3);
+
+       switch (index) {
+       case 0:
+               perf_id = PERF_COUNT_HW_INSTRUCTIONS;
+               break;
+       case 1:
+               perf_id = PERF_COUNT_HW_CPU_CYCLES;
+               break;
+       case 2:
+               perf_id = PERF_COUNT_HW_REF_CPU_CYCLES;
+               break;
+       default:
+               WARN_ON_ONCE(1);
+               return 0;
        };
 
-       BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED);
-
-       return (fixed_pmc_events[index].unit_mask << 8) |
-               fixed_pmc_events[index].eventsel;
+       eventsel = perf_get_hw_event_config(perf_id);
+       WARN_ON_ONCE(!eventsel && index < kvm_pmu_cap.num_counters_fixed);
+       return eventsel;
 }
 
 static void intel_pmu_refresh(struct kvm_vcpu *vcpu)

Re: [PATCH v7 03/19] KVM: x86/pmu: Remove KVM's enumeration of Intel's architectural encodings

[Liang, Kan]

On 2023-11-08 2:35 p.m., Sean Christopherson wrote:
> On Wed, Nov 08, 2023, Kan Liang wrote:
>> On 2023-11-07 7:31 p.m., Sean Christopherson wrote:
>>> @@ -442,8 +396,29 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>>>  	return 0;
>>>  }
>>>  
>>> +/*
>>> + * Map fixed counter events to architectural general purpose event encodings.
>>> + * Perf doesn't provide APIs to allow KVM to directly program a fixed counter,
>>> + * and so KVM instead programs the architectural event to effectively request
>>> + * the fixed counter.  Perf isn't guaranteed to use a fixed counter and may
>>> + * instead program the encoding into a general purpose counter, e.g. if a
>>> + * different perf_event is already utilizing the requested counter, but the end
>>> + * result is the same (ignoring the fact that using a general purpose counter
>>> + * will likely exacerbate counter contention).
>>> + *
>>> + * Note, reference cycles is counted using a perf-defined "psuedo-encoding",
>>> + * as there is no architectural general purpose encoding for reference cycles.
>>
>> It's not the case for the latest Intel platforms anymore. Please see
>> ffbe4ab0beda ("perf/x86/intel: Extend the ref-cycles event to GP counters").
> 
> Ugh, yeah.  But that and should actually be easier to do on top.
> 
>> Maybe perf should export .event_map to KVM somehow.
> 
> Oh for ***** sake, perf already does export this for KVM.  Untested, but the below
> should do the trick.  If I need to spin another version of this series then I'll
> fold it in, otherwise I'll post it as something on top.
> 
> There's also an optimization to be had for kvm_pmu_trigger_event(), which incurs
> an indirect branch not only every invocation, but on every iteration.  I'll post
> this one separately.
> 
> diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> index 5fc5a62af428..a02e13c2e5e6 100644
> --- a/arch/x86/kvm/vmx/pmu_intel.c
> +++ b/arch/x86/kvm/vmx/pmu_intel.c
> @@ -405,25 +405,32 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>   * different perf_event is already utilizing the requested counter, but the end
>   * result is the same (ignoring the fact that using a general purpose counter
>   * will likely exacerbate counter contention).
> - *
> - * Note, reference cycles is counted using a perf-defined "psuedo-encoding",
> - * as there is no architectural general purpose encoding for reference cycles.
>   */
>  static u64 intel_get_fixed_pmc_eventsel(int index)
>  {
> -       const struct {
> -               u8 eventsel;
> -               u8 unit_mask;
> -       } fixed_pmc_events[] = {
> -               [0] = { 0xc0, 0x00 }, /* Instruction Retired / PERF_COUNT_HW_INSTRUCTIONS. */
> -               [1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */
> -               [2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/
> +       enum perf_hw_id perf_id;
> +       u64 eventsel;
> +
> +       BUILD_BUG_ON(KVM_PMC_MAX_FIXED != 3);
> +
> +       switch (index) {
> +       case 0:
> +               perf_id = PERF_COUNT_HW_INSTRUCTIONS;
> +               break;
> +       case 1:
> +               perf_id = PERF_COUNT_HW_CPU_CYCLES;
> +               break;
> +       case 2:
> +               perf_id = PERF_COUNT_HW_REF_CPU_CYCLES;
> +               break;
> +       default:
> +               WARN_ON_ONCE(1);
> +               return 0;
>         };
>  
> -       BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED);
> -
> -       return (fixed_pmc_events[index].unit_mask << 8) |
> -               fixed_pmc_events[index].eventsel;
> +       eventsel = perf_get_hw_event_config(perf_id);

Yes, the perf_get_hw_event_config() can tell the updated event encoding.

Thanks,
Kan

> +       WARN_ON_ONCE(!eventsel && index < kvm_pmu_cap.num_counters_fixed);
> +       return eventsel;
>  }
>  
>  static void intel_pmu_refresh(struct kvm_vcpu *vcpu)

[PATCH v7 04/19] KVM: x86/pmu: Setup fixed counters' eventsel during PMU initialization

[Sean Christopherson]

Set the eventsel for all fixed counters during PMU initialization, the
eventsel is hardcoded and consumed if and only if the counter is supported,
i.e. there is no reason to redo the setup every time the PMU is refreshed.

Configuring all KVM-supported fixed counter also eliminates a potential
pitfall if/when KVM supports discontiguous fixed counters, in which case
configuring only nr_arch_fixed_counters will be insufficient (ignoring the
fact that KVM will need many other changes to support discontiguous fixed
counters).

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index c4f2c6a268e7..5fc5a62af428 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -409,7 +409,7 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
  * Note, reference cycles is counted using a perf-defined "psuedo-encoding",
  * as there is no architectural general purpose encoding for reference cycles.
  */
-static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
+static u64 intel_get_fixed_pmc_eventsel(int index)
 {
 	const struct {
 		u8 eventsel;
@@ -419,17 +419,11 @@ static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
 		[1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */
 		[2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/
 	};
-	int i;
 
 	BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED);
 
-	for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
-		int index = array_index_nospec(i, KVM_PMC_MAX_FIXED);
-		struct kvm_pmc *pmc = &pmu->fixed_counters[index];
-
-		pmc->eventsel = (fixed_pmc_events[index].unit_mask << 8) |
-				 fixed_pmc_events[index].eventsel;
-	}
+	return (fixed_pmc_events[index].unit_mask << 8) |
+		fixed_pmc_events[index].eventsel;
 }
 
 static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
@@ -495,7 +489,6 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 						  kvm_pmu_cap.bit_width_fixed);
 		pmu->counter_bitmask[KVM_PMC_FIXED] =
 			((u64)1 << edx.split.bit_width_fixed) - 1;
-		setup_fixed_pmc_eventsel(pmu);
 	}
 
 	for (i = 0; i < pmu->nr_arch_fixed_counters; i++)
@@ -573,6 +566,7 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu)
 		pmu->fixed_counters[i].vcpu = vcpu;
 		pmu->fixed_counters[i].idx = i + INTEL_PMC_IDX_FIXED;
 		pmu->fixed_counters[i].current_config = 0;
+		pmu->fixed_counters[i].eventsel = intel_get_fixed_pmc_eventsel(i);
 	}
 
 	lbr_desc->records.nr = 0;
-- 
2.42.0.869.gea05f2083d-goog

Re: [PATCH v7 04/19] KVM: x86/pmu: Setup fixed counters' eventsel during PMU initialization

[Jim Mattson]

On Tue, Nov 7, 2023 at 4:31 PM Sean Christopherson <seanjc@google.com> wrote:
>
> Set the eventsel for all fixed counters during PMU initialization, the
> eventsel is hardcoded and consumed if and only if the counter is supported,
> i.e. there is no reason to redo the setup every time the PMU is refreshed.
>
> Configuring all KVM-supported fixed counter also eliminates a potential
> pitfall if/when KVM supports discontiguous fixed counters, in which case
> configuring only nr_arch_fixed_counters will be insufficient (ignoring the
> fact that KVM will need many other changes to support discontiguous fixed
> counters).
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>  arch/x86/kvm/vmx/pmu_intel.c | 14 ++++----------
>  1 file changed, 4 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> index c4f2c6a268e7..5fc5a62af428 100644
> --- a/arch/x86/kvm/vmx/pmu_intel.c
> +++ b/arch/x86/kvm/vmx/pmu_intel.c
> @@ -409,7 +409,7 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>   * Note, reference cycles is counted using a perf-defined "psuedo-encoding",
>   * as there is no architectural general purpose encoding for reference cycles.
>   */
> -static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
> +static u64 intel_get_fixed_pmc_eventsel(int index)
>  {
>         const struct {
>                 u8 eventsel;
> @@ -419,17 +419,11 @@ static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
>                 [1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */
>                 [2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/
>         };
> -       int i;
>
>         BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED);
>
> -       for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
> -               int index = array_index_nospec(i, KVM_PMC_MAX_FIXED);
> -               struct kvm_pmc *pmc = &pmu->fixed_counters[index];
> -
> -               pmc->eventsel = (fixed_pmc_events[index].unit_mask << 8) |
> -                                fixed_pmc_events[index].eventsel;
> -       }
> +       return (fixed_pmc_events[index].unit_mask << 8) |
> +               fixed_pmc_events[index].eventsel;

Can I just say that it's really confusing that the value returned by
intel_get_fixed_pmc_eventsel() is the concatenation of an 8-bit "unit
mask" and an 8-bit "eventsel"?

Re: [PATCH v7 04/19] KVM: x86/pmu: Setup fixed counters' eventsel during PMU initialization

[Sean Christopherson]

On Tue, Nov 07, 2023, Jim Mattson wrote:
> On Tue, Nov 7, 2023 at 4:31 PM Sean Christopherson <seanjc@google.com> wrote:
> >
> > Set the eventsel for all fixed counters during PMU initialization, the
> > eventsel is hardcoded and consumed if and only if the counter is supported,
> > i.e. there is no reason to redo the setup every time the PMU is refreshed.
> >
> > Configuring all KVM-supported fixed counter also eliminates a potential
> > pitfall if/when KVM supports discontiguous fixed counters, in which case
> > configuring only nr_arch_fixed_counters will be insufficient (ignoring the
> > fact that KVM will need many other changes to support discontiguous fixed
> > counters).
> >
> > Signed-off-by: Sean Christopherson <seanjc@google.com>
> > ---
> >  arch/x86/kvm/vmx/pmu_intel.c | 14 ++++----------
> >  1 file changed, 4 insertions(+), 10 deletions(-)
> >
> > diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> > index c4f2c6a268e7..5fc5a62af428 100644
> > --- a/arch/x86/kvm/vmx/pmu_intel.c
> > +++ b/arch/x86/kvm/vmx/pmu_intel.c
> > @@ -409,7 +409,7 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> >   * Note, reference cycles is counted using a perf-defined "psuedo-encoding",
> >   * as there is no architectural general purpose encoding for reference cycles.
> >   */
> > -static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
> > +static u64 intel_get_fixed_pmc_eventsel(int index)
> >  {
> >         const struct {
> >                 u8 eventsel;
> > @@ -419,17 +419,11 @@ static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
> >                 [1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */
> >                 [2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/
> >         };
> > -       int i;
> >
> >         BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED);
> >
> > -       for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
> > -               int index = array_index_nospec(i, KVM_PMC_MAX_FIXED);
> > -               struct kvm_pmc *pmc = &pmu->fixed_counters[index];
> > -
> > -               pmc->eventsel = (fixed_pmc_events[index].unit_mask << 8) |
> > -                                fixed_pmc_events[index].eventsel;
> > -       }
> > +       return (fixed_pmc_events[index].unit_mask << 8) |
> > +               fixed_pmc_events[index].eventsel;
> 
> Can I just say that it's really confusing that the value returned by
> intel_get_fixed_pmc_eventsel() is the concatenation of an 8-bit "unit
> mask" and an 8-bit "eventsel"?

Heh, blame the SDM for having an "event select" field in "event select" MSRs.

Is this better?

	const struct {
		u8 event;
		u8 unit_mask;
	} fixed_pmc_events[] = {
		[0] = { 0xc0, 0x00 }, /* Instruction Retired / PERF_COUNT_HW_INSTRUCTIONS. */
		[1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */
		[2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/
	};

	BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED);

	return (fixed_pmc_events[index].unit_mask << 8) |
		fixed_pmc_events[index].event;


Or are you complaining about the fact that they're split at all?  I'm open to any
format, though I personally found the seperate umask and event values helpful
when trying to understand what's going on.

Re: [PATCH v7 04/19] KVM: x86/pmu: Setup fixed counters' eventsel during PMU initialization

[Jim Mattson]

On Wed, Nov 8, 2023 at 6:39 AM Sean Christopherson <seanjc@google.com> wrote:
>
> On Tue, Nov 07, 2023, Jim Mattson wrote:
> > On Tue, Nov 7, 2023 at 4:31 PM Sean Christopherson <seanjc@google.com> wrote:
> > >
> > > Set the eventsel for all fixed counters during PMU initialization, the
> > > eventsel is hardcoded and consumed if and only if the counter is supported,
> > > i.e. there is no reason to redo the setup every time the PMU is refreshed.
> > >
> > > Configuring all KVM-supported fixed counter also eliminates a potential
> > > pitfall if/when KVM supports discontiguous fixed counters, in which case
> > > configuring only nr_arch_fixed_counters will be insufficient (ignoring the
> > > fact that KVM will need many other changes to support discontiguous fixed
> > > counters).
> > >
> > > Signed-off-by: Sean Christopherson <seanjc@google.com>
> > > ---
> > >  arch/x86/kvm/vmx/pmu_intel.c | 14 ++++----------
> > >  1 file changed, 4 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> > > index c4f2c6a268e7..5fc5a62af428 100644
> > > --- a/arch/x86/kvm/vmx/pmu_intel.c
> > > +++ b/arch/x86/kvm/vmx/pmu_intel.c
> > > @@ -409,7 +409,7 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> > >   * Note, reference cycles is counted using a perf-defined "psuedo-encoding",
> > >   * as there is no architectural general purpose encoding for reference cycles.
> > >   */
> > > -static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
> > > +static u64 intel_get_fixed_pmc_eventsel(int index)
> > >  {
> > >         const struct {
> > >                 u8 eventsel;
> > > @@ -419,17 +419,11 @@ static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
> > >                 [1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */
> > >                 [2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/
> > >         };
> > > -       int i;
> > >
> > >         BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_events) != KVM_PMC_MAX_FIXED);
> > >
> > > -       for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
> > > -               int index = array_index_nospec(i, KVM_PMC_MAX_FIXED);
> > > -               struct kvm_pmc *pmc = &pmu->fixed_counters[index];
> > > -
> > > -               pmc->eventsel = (fixed_pmc_events[index].unit_mask << 8) |
> > > -                                fixed_pmc_events[index].eventsel;
> > > -       }
> > > +       return (fixed_pmc_events[index].unit_mask << 8) |
> > > +               fixed_pmc_events[index].eventsel;
> >
> > Can I just say that it's really confusing that the value returned by
> > intel_get_fixed_pmc_eventsel() is the concatenation of an 8-bit "unit
> > mask" and an 8-bit "eventsel"?
>
> Heh, blame the SDM for having an "event select" field in "event select" MSRs.
>
> Is this better?
>
>         const struct {
>                 u8 event;
>                 u8 unit_mask;
>         } fixed_pmc_events[] = {
>                 [0] = { 0xc0, 0x00 }, /* Instruction Retired / PERF_COUNT_HW_INSTRUCTIONS. */
>                 [1] = { 0x3c, 0x00 }, /* CPU Cycles/ PERF_COUNT_HW_CPU_CYCLES. */
>                 [2] = { 0x00, 0x03 }, /* Reference Cycles / PERF_COUNT_HW_REF_CPU_CYCLES*/
>         };

Better. Thank you.

[PATCH v7 05/19] KVM: selftests: Add vcpu_set_cpuid_property() to set properties

[Sean Christopherson]

From: Jinrong Liang <cloudliang@tencent.com>

Add vcpu_set_cpuid_property() helper function for setting properties, and
use it instead of open coding an equivalent for MAX_PHY_ADDR.  Future vPMU
testcases will also need to stuff various CPUID properties.

Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/include/x86_64/processor.h      |  4 +++-
 .../testing/selftests/kvm/lib/x86_64/processor.c  | 15 ++++++++++++---
 .../x86_64/smaller_maxphyaddr_emulation_test.c    |  2 +-
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 25bc61dac5fb..a01931f7d954 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -994,7 +994,9 @@ static inline void vcpu_set_cpuid(struct kvm_vcpu *vcpu)
 	vcpu_ioctl(vcpu, KVM_GET_CPUID2, vcpu->cpuid);
 }
 
-void vcpu_set_cpuid_maxphyaddr(struct kvm_vcpu *vcpu, uint8_t maxphyaddr);
+void vcpu_set_cpuid_property(struct kvm_vcpu *vcpu,
+			     struct kvm_x86_cpu_property property,
+			     uint32_t value);
 
 void vcpu_clear_cpuid_entry(struct kvm_vcpu *vcpu, uint32_t function);
 void vcpu_set_or_clear_cpuid_feature(struct kvm_vcpu *vcpu,
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index d8288374078e..67eb82a6c754 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -752,12 +752,21 @@ void vcpu_init_cpuid(struct kvm_vcpu *vcpu, const struct kvm_cpuid2 *cpuid)
 	vcpu_set_cpuid(vcpu);
 }
 
-void vcpu_set_cpuid_maxphyaddr(struct kvm_vcpu *vcpu, uint8_t maxphyaddr)
+void vcpu_set_cpuid_property(struct kvm_vcpu *vcpu,
+			     struct kvm_x86_cpu_property property,
+			     uint32_t value)
 {
-	struct kvm_cpuid_entry2 *entry = vcpu_get_cpuid_entry(vcpu, 0x80000008);
+	struct kvm_cpuid_entry2 *entry;
+
+	entry = __vcpu_get_cpuid_entry(vcpu, property.function, property.index);
+
+	(&entry->eax)[property.reg] &= ~GENMASK(property.hi_bit, property.lo_bit);
+	(&entry->eax)[property.reg] |= value << property.lo_bit;
 
-	entry->eax = (entry->eax & ~0xff) | maxphyaddr;
 	vcpu_set_cpuid(vcpu);
+
+	/* Sanity check that @value doesn't exceed the bounds in any way. */
+	TEST_ASSERT_EQ(kvm_cpuid_property(vcpu->cpuid, property), value);
 }
 
 void vcpu_clear_cpuid_entry(struct kvm_vcpu *vcpu, uint32_t function)
diff --git a/tools/testing/selftests/kvm/x86_64/smaller_maxphyaddr_emulation_test.c b/tools/testing/selftests/kvm/x86_64/smaller_maxphyaddr_emulation_test.c
index 06edf00a97d6..9b89440dff19 100644
--- a/tools/testing/selftests/kvm/x86_64/smaller_maxphyaddr_emulation_test.c
+++ b/tools/testing/selftests/kvm/x86_64/smaller_maxphyaddr_emulation_test.c
@@ -63,7 +63,7 @@ int main(int argc, char *argv[])
 	vm_init_descriptor_tables(vm);
 	vcpu_init_descriptor_tables(vcpu);
 
-	vcpu_set_cpuid_maxphyaddr(vcpu, MAXPHYADDR);
+	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_MAX_PHY_ADDR, MAXPHYADDR);
 
 	rc = kvm_check_cap(KVM_CAP_EXIT_ON_EMULATION_FAILURE);
 	TEST_ASSERT(rc, "KVM_CAP_EXIT_ON_EMULATION_FAILURE is unavailable");
-- 
2.42.0.869.gea05f2083d-goog

Re: [PATCH v7 05/19] KVM: selftests: Add vcpu_set_cpuid_property() to set properties

[Jim Mattson]

On Tue, Nov 7, 2023 at 4:31 PM Sean Christopherson <seanjc@google.com> wrote:
>
> From: Jinrong Liang <cloudliang@tencent.com>
>
> Add vcpu_set_cpuid_property() helper function for setting properties, and
> use it instead of open coding an equivalent for MAX_PHY_ADDR.  Future vPMU
> testcases will also need to stuff various CPUID properties.
>
> Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>

[PATCH v7 06/19] KVM: selftests: Drop the "name" param from KVM_X86_PMU_FEATURE()

[Sean Christopherson]

Drop the "name" parameter from KVM_X86_PMU_FEATURE(), it's unused and
the name is redundant with the macro, i.e. it's truly useless.

Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/include/x86_64/processor.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index a01931f7d954..2d9771151dd9 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -289,7 +289,7 @@ struct kvm_x86_cpu_property {
 struct kvm_x86_pmu_feature {
 	struct kvm_x86_cpu_feature anti_feature;
 };
-#define	KVM_X86_PMU_FEATURE(name, __bit)					\
+#define	KVM_X86_PMU_FEATURE(__bit)						\
 ({										\
 	struct kvm_x86_pmu_feature feature = {					\
 		.anti_feature = KVM_X86_CPU_FEATURE(0xa, 0, EBX, __bit),	\
@@ -298,7 +298,7 @@ struct kvm_x86_pmu_feature {
 	feature;								\
 })
 
-#define X86_PMU_FEATURE_BRANCH_INSNS_RETIRED	KVM_X86_PMU_FEATURE(BRANCH_INSNS_RETIRED, 5)
+#define X86_PMU_FEATURE_BRANCH_INSNS_RETIRED	KVM_X86_PMU_FEATURE(5)
 
 static inline unsigned int x86_family(unsigned int eax)
 {
-- 
2.42.0.869.gea05f2083d-goog

[PATCH v7 07/19] KVM: selftests: Extend {kvm,this}_pmu_has() to support fixed counters

[Sean Christopherson]

Extend the kvm_x86_pmu_feature framework to allow querying for fixed
counters via {kvm,this}_pmu_has().  Like architectural events, checking
for a fixed counter annoyingly requires checking multiple CPUID fields, as
a fixed counter exists if:

  FxCtr[i]_is_supported := ECX[i] || (EDX[4:0] > i);

Note, KVM currently doesn't actually support exposing fixed counters via
the bitmask, but that will hopefully change sooner than later, and Intel's
SDM explicitly "recommends" checking both the number of counters and the
mask.

Rename the intermedate "anti_feature" field to simply 'f' since the fixed
counter bitmask (thankfully) doesn't have reversed polarity like the
architectural events bitmask.

Note, ideally the helpers would use BUILD_BUG_ON() to assert on the
incoming register, but the expected usage in PMU tests can't guarantee the
inputs are compile-time constants.

Opportunistically define macros for all of the known architectural events
and fixed counters.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/include/x86_64/processor.h  | 65 ++++++++++++++-----
 1 file changed, 47 insertions(+), 18 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 2d9771151dd9..64aecb3dcf60 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -281,24 +281,41 @@ struct kvm_x86_cpu_property {
  * that indicates the feature is _not_ supported, and a property that states
  * the length of the bit mask of unsupported features.  A feature is supported
  * if the size of the bit mask is larger than the "unavailable" bit, and said
- * bit is not set.
+ * bit is not set.  Fixed counters also bizarre enumeration, but inverted from
+ * arch events for general purpose counters.  Fixed counters are supported if a
+ * feature flag is set **OR** the total number of fixed counters is greater
+ * than index of the counter.
  *
- * Wrap the "unavailable" feature to simplify checking whether or not a given
- * architectural event is supported.
+ * Wrap the events for general purpose and fixed counters to simplify checking
+ * whether or not a given architectural event is supported.
  */
 struct kvm_x86_pmu_feature {
-	struct kvm_x86_cpu_feature anti_feature;
+	struct kvm_x86_cpu_feature f;
 };
-#define	KVM_X86_PMU_FEATURE(__bit)						\
-({										\
-	struct kvm_x86_pmu_feature feature = {					\
-		.anti_feature = KVM_X86_CPU_FEATURE(0xa, 0, EBX, __bit),	\
-	};									\
-										\
-	feature;								\
+#define	KVM_X86_PMU_FEATURE(__reg, __bit)				\
+({									\
+	struct kvm_x86_pmu_feature feature = {				\
+		.f = KVM_X86_CPU_FEATURE(0xa, 0, __reg, __bit),		\
+	};								\
+									\
+	kvm_static_assert(KVM_CPUID_##__reg == KVM_CPUID_EBX ||		\
+			  KVM_CPUID_##__reg == KVM_CPUID_ECX);		\
+	feature;							\
 })
 
-#define X86_PMU_FEATURE_BRANCH_INSNS_RETIRED	KVM_X86_PMU_FEATURE(5)
+#define X86_PMU_FEATURE_CPU_CYCLES			KVM_X86_PMU_FEATURE(EBX, 0)
+#define X86_PMU_FEATURE_INSNS_RETIRED			KVM_X86_PMU_FEATURE(EBX, 1)
+#define X86_PMU_FEATURE_REFERENCE_CYCLES		KVM_X86_PMU_FEATURE(EBX, 2)
+#define X86_PMU_FEATURE_LLC_REFERENCES			KVM_X86_PMU_FEATURE(EBX, 3)
+#define X86_PMU_FEATURE_LLC_MISSES			KVM_X86_PMU_FEATURE(EBX, 4)
+#define X86_PMU_FEATURE_BRANCH_INSNS_RETIRED		KVM_X86_PMU_FEATURE(EBX, 5)
+#define X86_PMU_FEATURE_BRANCHES_MISPREDICTED		KVM_X86_PMU_FEATURE(EBX, 6)
+#define X86_PMU_FEATURE_TOPDOWN_SLOTS			KVM_X86_PMU_FEATURE(EBX, 7)
+
+#define X86_PMU_FEATURE_INSNS_RETIRED_FIXED		KVM_X86_PMU_FEATURE(ECX, 0)
+#define X86_PMU_FEATURE_CPU_CYCLES_FIXED		KVM_X86_PMU_FEATURE(ECX, 1)
+#define X86_PMU_FEATURE_REFERENCE_TSC_CYCLES_FIXED	KVM_X86_PMU_FEATURE(ECX, 2)
+#define X86_PMU_FEATURE_TOPDOWN_SLOTS_FIXED		KVM_X86_PMU_FEATURE(ECX, 3)
 
 static inline unsigned int x86_family(unsigned int eax)
 {
@@ -697,10 +714,16 @@ static __always_inline bool this_cpu_has_p(struct kvm_x86_cpu_property property)
 
 static inline bool this_pmu_has(struct kvm_x86_pmu_feature feature)
 {
-	uint32_t nr_bits = this_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH);
+	uint32_t nr_bits;
 
-	return nr_bits > feature.anti_feature.bit &&
-	       !this_cpu_has(feature.anti_feature);
+	if (feature.f.reg == KVM_CPUID_EBX) {
+		nr_bits = this_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH);
+		return nr_bits > feature.f.bit && !this_cpu_has(feature.f);
+	}
+
+	GUEST_ASSERT(feature.f.reg == KVM_CPUID_ECX);
+	nr_bits = this_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
+	return nr_bits > feature.f.bit || this_cpu_has(feature.f);
 }
 
 static __always_inline uint64_t this_cpu_supported_xcr0(void)
@@ -916,10 +939,16 @@ static __always_inline bool kvm_cpu_has_p(struct kvm_x86_cpu_property property)
 
 static inline bool kvm_pmu_has(struct kvm_x86_pmu_feature feature)
 {
-	uint32_t nr_bits = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH);
+	uint32_t nr_bits;
 
-	return nr_bits > feature.anti_feature.bit &&
-	       !kvm_cpu_has(feature.anti_feature);
+	if (feature.f.reg == KVM_CPUID_EBX) {
+		nr_bits = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH);
+		return nr_bits > feature.f.bit && !kvm_cpu_has(feature.f);
+	}
+
+	TEST_ASSERT_EQ(feature.f.reg, KVM_CPUID_ECX);
+	nr_bits = kvm_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
+	return nr_bits > feature.f.bit || kvm_cpu_has(feature.f);
 }
 
 static __always_inline uint64_t kvm_cpu_supported_xcr0(void)
-- 
2.42.0.869.gea05f2083d-goog

[PATCH v7 08/19] KVM: selftests: Add pmu.h and lib/pmu.c for common PMU assets

[Sean Christopherson]

From: Jinrong Liang <cloudliang@tencent.com>

Add a PMU library for x86 selftests to help eliminate open-coded event
encodings, and to reduce the amount of copy+paste between PMU selftests.

Use the new common macro definitions in the existing PMU event filter test.

Cc: Aaron Lewis <aaronlewis@google.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/Makefile          |   1 +
 tools/testing/selftests/kvm/include/pmu.h     |  95 ++++++++++++
 tools/testing/selftests/kvm/lib/pmu.c         |  31 ++++
 .../kvm/x86_64/pmu_event_filter_test.c        | 141 ++++++------------
 4 files changed, 171 insertions(+), 97 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/include/pmu.h
 create mode 100644 tools/testing/selftests/kvm/lib/pmu.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index a5963ab9215b..44d8d022b023 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -32,6 +32,7 @@ LIBKVM += lib/guest_modes.c
 LIBKVM += lib/io.c
 LIBKVM += lib/kvm_util.c
 LIBKVM += lib/memstress.c
+LIBKVM += lib/pmu.c
 LIBKVM += lib/guest_sprintf.c
 LIBKVM += lib/rbtree.c
 LIBKVM += lib/sparsebit.c
diff --git a/tools/testing/selftests/kvm/include/pmu.h b/tools/testing/selftests/kvm/include/pmu.h
new file mode 100644
index 000000000000..2da59a9d98b3
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/pmu.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023, Tencent, Inc.
+ */
+#ifndef SELFTEST_KVM_PMU_H
+#define SELFTEST_KVM_PMU_H
+
+#include <stdint.h>
+
+#define KVM_PMU_EVENT_FILTER_MAX_EVENTS			300
+
+/*
+ * Encode an eventsel+umask pair into event-select MSR format.  Note, this is
+ * technically AMD's format, as Intel's format only supports 8 bits for the
+ * event selector, i.e. doesn't use bits 24:16 for the selector.  But, OR-ing
+ * in '0' is a nop and won't clobber the CMASK.
+ */
+#define RAW_EVENT(eventsel, umask) (((eventsel & 0xf00UL) << 24) |	\
+				    ((eventsel) & 0xff) |		\
+				    ((umask) & 0xff) << 8)
+
+/*
+ * These are technically Intel's definitions, but except for CMASK (see above),
+ * AMD's layout is compatible with Intel's.
+ */
+#define ARCH_PERFMON_EVENTSEL_EVENT		GENMASK_ULL(7, 0)
+#define ARCH_PERFMON_EVENTSEL_UMASK		GENMASK_ULL(15, 8)
+#define ARCH_PERFMON_EVENTSEL_USR		BIT_ULL(16)
+#define ARCH_PERFMON_EVENTSEL_OS		BIT_ULL(17)
+#define ARCH_PERFMON_EVENTSEL_EDGE		BIT_ULL(18)
+#define ARCH_PERFMON_EVENTSEL_PIN_CONTROL	BIT_ULL(19)
+#define ARCH_PERFMON_EVENTSEL_INT		BIT_ULL(20)
+#define ARCH_PERFMON_EVENTSEL_ANY		BIT_ULL(21)
+#define ARCH_PERFMON_EVENTSEL_ENABLE		BIT_ULL(22)
+#define ARCH_PERFMON_EVENTSEL_INV		BIT_ULL(23)
+#define ARCH_PERFMON_EVENTSEL_CMASK		GENMASK_ULL(31, 24)
+
+/* RDPMC offset for Fixed PMCs */
+#define FIXED_PMC_RDPMC_METRICS			BIT_ULL(29)
+#define FIXED_PMC_RDPMC_BASE			BIT_ULL(30)
+
+#define FIXED_PMC_GLOBAL_CTRL_ENABLE(_idx)	BIT_ULL((32 + (_idx)))
+
+#define FIXED_PMC_KERNEL			BIT_ULL(0)
+#define FIXED_PMC_USER				BIT_ULL(1)
+#define FIXED_PMC_ANYTHREAD			BIT_ULL(2)
+#define FIXED_PMC_ENABLE_PMI			BIT_ULL(3)
+#define FIXED_PMC_NR_BITS			4
+#define FIXED_PMC_CTRL(_idx, _val)		((_val) << ((_idx) * FIXED_PMC_NR_BITS))
+
+#define PMU_CAP_FW_WRITES			BIT_ULL(13)
+#define PMU_CAP_LBR_FMT				0x3f
+
+#define	INTEL_ARCH_CPU_CYCLES			RAW_EVENT(0x3c, 0x00)
+#define	INTEL_ARCH_INSTRUCTIONS_RETIRED		RAW_EVENT(0xc0, 0x00)
+#define	INTEL_ARCH_REFERENCE_CYCLES		RAW_EVENT(0x3c, 0x01)
+#define	INTEL_ARCH_LLC_REFERENCES		RAW_EVENT(0x2e, 0x4f)
+#define	INTEL_ARCH_LLC_MISSES			RAW_EVENT(0x2e, 0x41)
+#define	INTEL_ARCH_BRANCHES_RETIRED		RAW_EVENT(0xc4, 0x00)
+#define	INTEL_ARCH_BRANCHES_MISPREDICTED	RAW_EVENT(0xc5, 0x00)
+#define	INTEL_ARCH_TOPDOWN_SLOTS		RAW_EVENT(0xa4, 0x01)
+
+#define	AMD_ZEN_CORE_CYCLES			RAW_EVENT(0x76, 0x00)
+#define	AMD_ZEN_INSTRUCTIONS_RETIRED		RAW_EVENT(0xc0, 0x00)
+#define	AMD_ZEN_BRANCHES_RETIRED		RAW_EVENT(0xc2, 0x00)
+#define	AMD_ZEN_BRANCHES_MISPREDICTED		RAW_EVENT(0xc3, 0x00)
+
+/*
+ * Note!  The order and thus the index of the architectural events matters as
+ * support for each event is enumerated via CPUID using the index of the event.
+ */
+enum intel_pmu_architectural_events {
+	INTEL_ARCH_CPU_CYCLES_INDEX,
+	INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX,
+	INTEL_ARCH_REFERENCE_CYCLES_INDEX,
+	INTEL_ARCH_LLC_REFERENCES_INDEX,
+	INTEL_ARCH_LLC_MISSES_INDEX,
+	INTEL_ARCH_BRANCHES_RETIRED_INDEX,
+	INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX,
+	INTEL_ARCH_TOPDOWN_SLOTS_INDEX,
+	NR_INTEL_ARCH_EVENTS,
+};
+
+enum amd_pmu_zen_events {
+	AMD_ZEN_CORE_CYCLES_INDEX,
+	AMD_ZEN_INSTRUCTIONS_INDEX,
+	AMD_ZEN_BRANCHES_INDEX,
+	AMD_ZEN_BRANCH_MISSES_INDEX,
+	NR_AMD_ZEN_EVENTS,
+};
+
+extern const uint64_t intel_pmu_arch_events[];
+extern const uint64_t amd_pmu_zen_events[];
+
+#endif /* SELFTEST_KVM_PMU_H */
diff --git a/tools/testing/selftests/kvm/lib/pmu.c b/tools/testing/selftests/kvm/lib/pmu.c
new file mode 100644
index 000000000000..f31f0427c17c
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/pmu.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023, Tencent, Inc.
+ */
+
+#include <stdint.h>
+
+#include <linux/kernel.h>
+
+#include "kvm_util.h"
+#include "pmu.h"
+
+const uint64_t intel_pmu_arch_events[] = {
+	INTEL_ARCH_CPU_CYCLES,
+	INTEL_ARCH_INSTRUCTIONS_RETIRED,
+	INTEL_ARCH_REFERENCE_CYCLES,
+	INTEL_ARCH_LLC_REFERENCES,
+	INTEL_ARCH_LLC_MISSES,
+	INTEL_ARCH_BRANCHES_RETIRED,
+	INTEL_ARCH_BRANCHES_MISPREDICTED,
+	INTEL_ARCH_TOPDOWN_SLOTS,
+};
+kvm_static_assert(ARRAY_SIZE(intel_pmu_arch_events) == NR_INTEL_ARCH_EVENTS);
+
+const uint64_t amd_pmu_zen_events[] = {
+	AMD_ZEN_CORE_CYCLES,
+	AMD_ZEN_INSTRUCTIONS_RETIRED,
+	AMD_ZEN_BRANCHES_RETIRED,
+	AMD_ZEN_BRANCHES_MISPREDICTED,
+};
+kvm_static_assert(ARRAY_SIZE(amd_pmu_zen_events) == NR_AMD_ZEN_EVENTS);
diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
index 283cc55597a4..7ec9fbed92e0 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
@@ -11,72 +11,18 @@
  */
 
 #define _GNU_SOURCE /* for program_invocation_short_name */
-#include "test_util.h"
+
 #include "kvm_util.h"
+#include "pmu.h"
 #include "processor.h"
-
-/*
- * In lieu of copying perf_event.h into tools...
- */
-#define ARCH_PERFMON_EVENTSEL_OS			(1ULL << 17)
-#define ARCH_PERFMON_EVENTSEL_ENABLE			(1ULL << 22)
-
-/* End of stuff taken from perf_event.h. */
-
-/* Oddly, this isn't in perf_event.h. */
-#define ARCH_PERFMON_BRANCHES_RETIRED		5
+#include "test_util.h"
 
 #define NUM_BRANCHES 42
-#define INTEL_PMC_IDX_FIXED		32
-
-/* Matches KVM_PMU_EVENT_FILTER_MAX_EVENTS in pmu.c */
-#define MAX_FILTER_EVENTS		300
 #define MAX_TEST_EVENTS		10
 
 #define PMU_EVENT_FILTER_INVALID_ACTION		(KVM_PMU_EVENT_DENY + 1)
 #define PMU_EVENT_FILTER_INVALID_FLAGS			(KVM_PMU_EVENT_FLAGS_VALID_MASK << 1)
-#define PMU_EVENT_FILTER_INVALID_NEVENTS		(MAX_FILTER_EVENTS + 1)
-
-/*
- * This is how the event selector and unit mask are stored in an AMD
- * core performance event-select register. Intel's format is similar,
- * but the event selector is only 8 bits.
- */
-#define EVENT(select, umask) ((select & 0xf00UL) << 24 | (select & 0xff) | \
-			      (umask & 0xff) << 8)
-
-/*
- * "Branch instructions retired", from the Intel SDM, volume 3,
- * "Pre-defined Architectural Performance Events."
- */
-
-#define INTEL_BR_RETIRED EVENT(0xc4, 0)
-
-/*
- * "Retired branch instructions", from Processor Programming Reference
- * (PPR) for AMD Family 17h Model 01h, Revision B1 Processors,
- * Preliminary Processor Programming Reference (PPR) for AMD Family
- * 17h Model 31h, Revision B0 Processors, and Preliminary Processor
- * Programming Reference (PPR) for AMD Family 19h Model 01h, Revision
- * B1 Processors Volume 1 of 2.
- */
-
-#define AMD_ZEN_BR_RETIRED EVENT(0xc2, 0)
-
-
-/*
- * "Retired instructions", from Processor Programming Reference
- * (PPR) for AMD Family 17h Model 01h, Revision B1 Processors,
- * Preliminary Processor Programming Reference (PPR) for AMD Family
- * 17h Model 31h, Revision B0 Processors, and Preliminary Processor
- * Programming Reference (PPR) for AMD Family 19h Model 01h, Revision
- * B1 Processors Volume 1 of 2.
- *                      --- and ---
- * "Instructions retired", from the Intel SDM, volume 3,
- * "Pre-defined Architectural Performance Events."
- */
-
-#define INST_RETIRED EVENT(0xc0, 0)
+#define PMU_EVENT_FILTER_INVALID_NEVENTS		(KVM_PMU_EVENT_FILTER_MAX_EVENTS + 1)
 
 struct __kvm_pmu_event_filter {
 	__u32 action;
@@ -84,26 +30,28 @@ struct __kvm_pmu_event_filter {
 	__u32 fixed_counter_bitmap;
 	__u32 flags;
 	__u32 pad[4];
-	__u64 events[MAX_FILTER_EVENTS];
+	__u64 events[KVM_PMU_EVENT_FILTER_MAX_EVENTS];
 };
 
 /*
- * This event list comprises Intel's eight architectural events plus
- * AMD's "retired branch instructions" for Zen[123] (and possibly
- * other AMD CPUs).
+ * This event list comprises Intel's known architectural events, plus AMD's
+ * "retired branch instructions" for Zen1-Zen3 (and* possibly other AMD CPUs).
+ * Note, AMD and Intel use the same encoding for instructions retired.
  */
+kvm_static_assert(INTEL_ARCH_INSTRUCTIONS_RETIRED == AMD_ZEN_INSTRUCTIONS_RETIRED);
+
 static const struct __kvm_pmu_event_filter base_event_filter = {
 	.nevents = ARRAY_SIZE(base_event_filter.events),
 	.events = {
-		EVENT(0x3c, 0),
-		INST_RETIRED,
-		EVENT(0x3c, 1),
-		EVENT(0x2e, 0x4f),
-		EVENT(0x2e, 0x41),
-		EVENT(0xc4, 0),
-		EVENT(0xc5, 0),
-		EVENT(0xa4, 1),
-		AMD_ZEN_BR_RETIRED,
+		INTEL_ARCH_CPU_CYCLES,
+		INTEL_ARCH_INSTRUCTIONS_RETIRED,
+		INTEL_ARCH_REFERENCE_CYCLES,
+		INTEL_ARCH_LLC_REFERENCES,
+		INTEL_ARCH_LLC_MISSES,
+		INTEL_ARCH_BRANCHES_RETIRED,
+		INTEL_ARCH_BRANCHES_MISPREDICTED,
+		INTEL_ARCH_TOPDOWN_SLOTS,
+		AMD_ZEN_BRANCHES_RETIRED,
 	},
 };
 
@@ -165,9 +113,9 @@ static void intel_guest_code(void)
 	for (;;) {
 		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
 		wrmsr(MSR_P6_EVNTSEL0, ARCH_PERFMON_EVENTSEL_ENABLE |
-		      ARCH_PERFMON_EVENTSEL_OS | INTEL_BR_RETIRED);
+		      ARCH_PERFMON_EVENTSEL_OS | INTEL_ARCH_BRANCHES_RETIRED);
 		wrmsr(MSR_P6_EVNTSEL1, ARCH_PERFMON_EVENTSEL_ENABLE |
-		      ARCH_PERFMON_EVENTSEL_OS | INST_RETIRED);
+		      ARCH_PERFMON_EVENTSEL_OS | INTEL_ARCH_INSTRUCTIONS_RETIRED);
 		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0x3);
 
 		run_and_measure_loop(MSR_IA32_PMC0);
@@ -189,9 +137,9 @@ static void amd_guest_code(void)
 	for (;;) {
 		wrmsr(MSR_K7_EVNTSEL0, 0);
 		wrmsr(MSR_K7_EVNTSEL0, ARCH_PERFMON_EVENTSEL_ENABLE |
-		      ARCH_PERFMON_EVENTSEL_OS | AMD_ZEN_BR_RETIRED);
+		      ARCH_PERFMON_EVENTSEL_OS | AMD_ZEN_BRANCHES_RETIRED);
 		wrmsr(MSR_K7_EVNTSEL1, ARCH_PERFMON_EVENTSEL_ENABLE |
-		      ARCH_PERFMON_EVENTSEL_OS | INST_RETIRED);
+		      ARCH_PERFMON_EVENTSEL_OS | AMD_ZEN_INSTRUCTIONS_RETIRED);
 
 		run_and_measure_loop(MSR_K7_PERFCTR0);
 		GUEST_SYNC(0);
@@ -312,7 +260,7 @@ static void test_amd_deny_list(struct kvm_vcpu *vcpu)
 		.action = KVM_PMU_EVENT_DENY,
 		.nevents = 1,
 		.events = {
-			EVENT(0x1C2, 0),
+			RAW_EVENT(0x1C2, 0),
 		},
 	};
 
@@ -347,9 +295,9 @@ static void test_not_member_deny_list(struct kvm_vcpu *vcpu)
 
 	f.action = KVM_PMU_EVENT_DENY;
 
-	remove_event(&f, INST_RETIRED);
-	remove_event(&f, INTEL_BR_RETIRED);
-	remove_event(&f, AMD_ZEN_BR_RETIRED);
+	remove_event(&f, INTEL_ARCH_INSTRUCTIONS_RETIRED);
+	remove_event(&f, INTEL_ARCH_BRANCHES_RETIRED);
+	remove_event(&f, AMD_ZEN_BRANCHES_RETIRED);
 	test_with_filter(vcpu, &f);
 
 	ASSERT_PMC_COUNTING_INSTRUCTIONS();
@@ -361,9 +309,9 @@ static void test_not_member_allow_list(struct kvm_vcpu *vcpu)
 
 	f.action = KVM_PMU_EVENT_ALLOW;
 
-	remove_event(&f, INST_RETIRED);
-	remove_event(&f, INTEL_BR_RETIRED);
-	remove_event(&f, AMD_ZEN_BR_RETIRED);
+	remove_event(&f, INTEL_ARCH_INSTRUCTIONS_RETIRED);
+	remove_event(&f, INTEL_ARCH_BRANCHES_RETIRED);
+	remove_event(&f, AMD_ZEN_BRANCHES_RETIRED);
 	test_with_filter(vcpu, &f);
 
 	ASSERT_PMC_NOT_COUNTING_INSTRUCTIONS();
@@ -452,9 +400,9 @@ static bool use_amd_pmu(void)
  *  - Sapphire Rapids, Ice Lake, Cascade Lake, Skylake.
  */
 #define MEM_INST_RETIRED		0xD0
-#define MEM_INST_RETIRED_LOAD		EVENT(MEM_INST_RETIRED, 0x81)
-#define MEM_INST_RETIRED_STORE		EVENT(MEM_INST_RETIRED, 0x82)
-#define MEM_INST_RETIRED_LOAD_STORE	EVENT(MEM_INST_RETIRED, 0x83)
+#define MEM_INST_RETIRED_LOAD		RAW_EVENT(MEM_INST_RETIRED, 0x81)
+#define MEM_INST_RETIRED_STORE		RAW_EVENT(MEM_INST_RETIRED, 0x82)
+#define MEM_INST_RETIRED_LOAD_STORE	RAW_EVENT(MEM_INST_RETIRED, 0x83)
 
 static bool supports_event_mem_inst_retired(void)
 {
@@ -486,9 +434,9 @@ static bool supports_event_mem_inst_retired(void)
  * B1 Processors Volume 1 of 2.
  */
 #define LS_DISPATCH		0x29
-#define LS_DISPATCH_LOAD	EVENT(LS_DISPATCH, BIT(0))
-#define LS_DISPATCH_STORE	EVENT(LS_DISPATCH, BIT(1))
-#define LS_DISPATCH_LOAD_STORE	EVENT(LS_DISPATCH, BIT(2))
+#define LS_DISPATCH_LOAD	RAW_EVENT(LS_DISPATCH, BIT(0))
+#define LS_DISPATCH_STORE	RAW_EVENT(LS_DISPATCH, BIT(1))
+#define LS_DISPATCH_LOAD_STORE	RAW_EVENT(LS_DISPATCH, BIT(2))
 
 #define INCLUDE_MASKED_ENTRY(event_select, mask, match) \
 	KVM_PMU_ENCODE_MASKED_ENTRY(event_select, mask, match, false)
@@ -729,14 +677,14 @@ static void add_dummy_events(uint64_t *events, int nevents)
 
 static void test_masked_events(struct kvm_vcpu *vcpu)
 {
-	int nevents = MAX_FILTER_EVENTS - MAX_TEST_EVENTS;
-	uint64_t events[MAX_FILTER_EVENTS];
+	int nevents = KVM_PMU_EVENT_FILTER_MAX_EVENTS - MAX_TEST_EVENTS;
+	uint64_t events[KVM_PMU_EVENT_FILTER_MAX_EVENTS];
 
 	/* Run the test cases against a sparse PMU event filter. */
 	run_masked_events_tests(vcpu, events, 0);
 
 	/* Run the test cases against a dense PMU event filter. */
-	add_dummy_events(events, MAX_FILTER_EVENTS);
+	add_dummy_events(events, KVM_PMU_EVENT_FILTER_MAX_EVENTS);
 	run_masked_events_tests(vcpu, events, nevents);
 }
 
@@ -809,20 +757,19 @@ static void test_filter_ioctl(struct kvm_vcpu *vcpu)
 	TEST_ASSERT(!r, "Masking non-existent fixed counters should be allowed");
 }
 
-static void intel_run_fixed_counter_guest_code(uint8_t fixed_ctr_idx)
+static void intel_run_fixed_counter_guest_code(uint8_t idx)
 {
 	for (;;) {
 		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
-		wrmsr(MSR_CORE_PERF_FIXED_CTR0 + fixed_ctr_idx, 0);
+		wrmsr(MSR_CORE_PERF_FIXED_CTR0 + idx, 0);
 
 		/* Only OS_EN bit is enabled for fixed counter[idx]. */
-		wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, BIT_ULL(4 * fixed_ctr_idx));
-		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL,
-		      BIT_ULL(INTEL_PMC_IDX_FIXED + fixed_ctr_idx));
+		wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, FIXED_PMC_CTRL(idx, FIXED_PMC_KERNEL));
+		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, FIXED_PMC_GLOBAL_CTRL_ENABLE(idx));
 		__asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
 		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
 
-		GUEST_SYNC(rdmsr(MSR_CORE_PERF_FIXED_CTR0 + fixed_ctr_idx));
+		GUEST_SYNC(rdmsr(MSR_CORE_PERF_FIXED_CTR0 + idx));
 	}
 }
 
-- 
2.42.0.869.gea05f2083d-goog

[PATCH v7 09/19] KVM: selftests: Test Intel PMU architectural events on gp counters

[Sean Christopherson]

From: Jinrong Liang <cloudliang@tencent.com>

Add test cases to verify that Intel's Architectural PMU events work as
expected when the are (un)available according to guest CPUID.  Iterate
over a range of sane PMU versions, with and without full-width writes
enabled, and over interesting combinations of lengths/masks for the bit
vector that enumerates unavailable events.

Test up to vPMU version 5, i.e. the current architectural max.  KVM only
officially supports up to version 2, but the behavior of the counters is
backwards compatible, i.e. KVM shouldn't do something completely different
for a higher, architecturally-defined vPMU version.  Verify KVM behavior
against the effective vPMU version, e.g. advertising vPMU 5 when KVM only
supports vPMU 2 shouldn't magically unlock vPMU 5 features.

According to Intel SDM, the number of architectural events is reported
through CPUID.0AH:EAX[31:24] and the architectural event x is supported
if EBX[x]=0 && EAX[31:24]>x.

Handcode the entirety of the measured section so that the test can
precisely assert on the number of instructions and branches retired.

Co-developed-by: Like Xu <likexu@tencent.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../selftests/kvm/x86_64/pmu_counters_test.c  | 321 ++++++++++++++++++
 2 files changed, 322 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/x86_64/pmu_counters_test.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 44d8d022b023..09f5d6fe84de 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -91,6 +91,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test
 TEST_GEN_PROGS_x86_64 += x86_64/monitor_mwait_test
 TEST_GEN_PROGS_x86_64 += x86_64/nested_exceptions_test
 TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test
+TEST_GEN_PROGS_x86_64 += x86_64/pmu_counters_test
 TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test
 TEST_GEN_PROGS_x86_64 += x86_64/set_boot_cpu_id
 TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test
diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
new file mode 100644
index 000000000000..5b8687bb4639
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -0,0 +1,321 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023, Tencent, Inc.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <x86intrin.h>
+
+#include "pmu.h"
+#include "processor.h"
+
+/* Number of LOOP instructions for the guest measurement payload. */
+#define NUM_BRANCHES		10
+/*
+ * Number of "extra" instructions that will be counted, i.e. the number of
+ * instructions that are needed to set up the loop and then disabled the
+ * counter.  2 MOV, 2 XOR, 1 WRMSR.
+ */
+#define NUM_EXTRA_INSNS		5
+#define NUM_INSNS_RETIRED	(NUM_BRANCHES + NUM_EXTRA_INSNS)
+
+static uint8_t kvm_pmu_version;
+static bool kvm_has_perf_caps;
+
+static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu,
+						  void *guest_code,
+						  uint8_t pmu_version,
+						  uint64_t perf_capabilities)
+{
+	struct kvm_vm *vm;
+
+	vm = vm_create_with_one_vcpu(vcpu, guest_code);
+	vm_init_descriptor_tables(vm);
+	vcpu_init_descriptor_tables(*vcpu);
+
+	sync_global_to_guest(vm, kvm_pmu_version);
+
+	/*
+	 * Set PERF_CAPABILITIES before PMU version as KVM disallows enabling
+	 * features via PERF_CAPABILITIES if the guest doesn't have a vPMU.
+	 */
+	if (kvm_has_perf_caps)
+		vcpu_set_msr(*vcpu, MSR_IA32_PERF_CAPABILITIES, perf_capabilities);
+
+	vcpu_set_cpuid_property(*vcpu, X86_PROPERTY_PMU_VERSION, pmu_version);
+	return vm;
+}
+
+static void run_vcpu(struct kvm_vcpu *vcpu)
+{
+	struct ucall uc;
+
+	do {
+		vcpu_run(vcpu);
+		switch (get_ucall(vcpu, &uc)) {
+		case UCALL_SYNC:
+			break;
+		case UCALL_ABORT:
+			REPORT_GUEST_ASSERT(uc);
+			break;
+		case UCALL_PRINTF:
+			pr_info("%s", uc.buffer);
+			break;
+		case UCALL_DONE:
+			break;
+		default:
+			TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
+		}
+	} while (uc.cmd != UCALL_DONE);
+}
+
+static uint8_t guest_get_pmu_version(void)
+{
+	/*
+	 * Return the effective PMU version, i.e. the minimum between what KVM
+	 * supports and what is enumerated to the guest.  The host deliberately
+	 * advertises a PMU version to the guest beyond what is actually
+	 * supported by KVM to verify KVM doesn't freak out and do something
+	 * bizarre with an architecturally valid, but unsupported, version.
+	 */
+	return min_t(uint8_t, kvm_pmu_version, this_cpu_property(X86_PROPERTY_PMU_VERSION));
+}
+
+/*
+ * If an architectural event is supported and guaranteed to generate at least
+ * one "hit, assert that its count is non-zero.  If an event isn't supported or
+ * the test can't guarantee the associated action will occur, then all bets are
+ * off regarding the count, i.e. no checks can be done.
+ *
+ * Sanity check that in all cases, the event doesn't count when it's disabled,
+ * and that KVM correctly emulates the write of an arbitrary value.
+ */
+static void guest_assert_event_count(uint8_t idx,
+				     struct kvm_x86_pmu_feature event,
+				     uint32_t pmc, uint32_t pmc_msr)
+{
+	uint64_t count;
+
+	count = _rdpmc(pmc);
+	if (!this_pmu_has(event))
+		goto sanity_checks;
+
+	switch (idx) {
+	case INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX:
+		GUEST_ASSERT_EQ(count, NUM_INSNS_RETIRED);
+		break;
+	case INTEL_ARCH_BRANCHES_RETIRED_INDEX:
+		GUEST_ASSERT_EQ(count, NUM_BRANCHES);
+		break;
+	case INTEL_ARCH_CPU_CYCLES_INDEX:
+	case INTEL_ARCH_REFERENCE_CYCLES_INDEX:
+		GUEST_ASSERT_NE(count, 0);
+		break;
+	default:
+		break;
+	}
+
+sanity_checks:
+	__asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
+	GUEST_ASSERT_EQ(_rdpmc(pmc), count);
+
+	wrmsr(pmc_msr, 0xdead);
+	GUEST_ASSERT_EQ(_rdpmc(pmc), 0xdead);
+}
+
+static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature event,
+				    uint32_t pmc, uint32_t pmc_msr,
+				    uint32_t ctrl_msr, uint64_t ctrl_msr_value)
+{
+	wrmsr(pmc_msr, 0);
+
+	/*
+	 * Enable and disable the PMC in a monolithic asm blob to ensure that
+	 * the compiler can't insert _any_ code into the measured sequence.
+	 * Note, ECX doesn't need to be clobbered as the input value, @pmc_msr,
+	 * is restored before the end of the sequence.
+	 */
+	__asm__ __volatile__("wrmsr\n\t"
+			     "mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t"
+			     "loop .\n\t"
+			     "mov %%edi, %%ecx\n\t"
+			     "xor %%eax, %%eax\n\t"
+			     "xor %%edx, %%edx\n\t"
+			     "wrmsr\n\t"
+			     :: "a"((uint32_t)ctrl_msr_value),
+				"d"(ctrl_msr_value >> 32),
+				"c"(ctrl_msr), "D"(ctrl_msr)
+			     );
+
+	guest_assert_event_count(idx, event, pmc, pmc_msr);
+}
+
+static void guest_test_arch_event(uint8_t idx)
+{
+	const struct {
+		struct kvm_x86_pmu_feature gp_event;
+	} intel_event_to_feature[] = {
+		[INTEL_ARCH_CPU_CYCLES_INDEX]		 = { X86_PMU_FEATURE_CPU_CYCLES },
+		[INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX]	 = { X86_PMU_FEATURE_INSNS_RETIRED },
+		[INTEL_ARCH_REFERENCE_CYCLES_INDEX]	 = { X86_PMU_FEATURE_REFERENCE_CYCLES },
+		[INTEL_ARCH_LLC_REFERENCES_INDEX]	 = { X86_PMU_FEATURE_LLC_REFERENCES },
+		[INTEL_ARCH_LLC_MISSES_INDEX]		 = { X86_PMU_FEATURE_LLC_MISSES },
+		[INTEL_ARCH_BRANCHES_RETIRED_INDEX]	 = { X86_PMU_FEATURE_BRANCH_INSNS_RETIRED },
+		[INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX] = { X86_PMU_FEATURE_BRANCHES_MISPREDICTED },
+		[INTEL_ARCH_TOPDOWN_SLOTS_INDEX]	 = { X86_PMU_FEATURE_TOPDOWN_SLOTS },
+	};
+
+	uint32_t nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS);
+	uint32_t pmu_version = guest_get_pmu_version();
+	/* PERF_GLOBAL_CTRL exists only for Architectural PMU Version 2+. */
+	bool guest_has_perf_global_ctrl = pmu_version >= 2;
+	struct kvm_x86_pmu_feature gp_event;
+	uint32_t base_pmc_msr;
+	unsigned int i;
+
+	/* The host side shouldn't invoke this without a guest PMU. */
+	GUEST_ASSERT(pmu_version);
+
+	if (this_cpu_has(X86_FEATURE_PDCM) &&
+	    rdmsr(MSR_IA32_PERF_CAPABILITIES) & PMU_CAP_FW_WRITES)
+		base_pmc_msr = MSR_IA32_PMC0;
+	else
+		base_pmc_msr = MSR_IA32_PERFCTR0;
+
+	gp_event = intel_event_to_feature[idx].gp_event;
+	GUEST_ASSERT_EQ(idx, gp_event.f.bit);
+
+	GUEST_ASSERT(nr_gp_counters);
+
+	for (i = 0; i < nr_gp_counters; i++) {
+		uint64_t eventsel = ARCH_PERFMON_EVENTSEL_OS |
+				    ARCH_PERFMON_EVENTSEL_ENABLE |
+				    intel_pmu_arch_events[idx];
+
+		wrmsr(MSR_P6_EVNTSEL0 + i, 0);
+		if (guest_has_perf_global_ctrl)
+			wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, BIT_ULL(i));
+
+		__guest_test_arch_event(idx, gp_event, i, base_pmc_msr + i,
+					MSR_P6_EVNTSEL0 + i, eventsel);
+	}
+}
+
+static void guest_test_arch_events(void)
+{
+	uint8_t i;
+
+	for (i = 0; i < NR_INTEL_ARCH_EVENTS; i++)
+		guest_test_arch_event(i);
+
+	GUEST_DONE();
+}
+
+static void test_arch_events(uint8_t pmu_version, uint64_t perf_capabilities,
+			     uint8_t length, uint8_t unavailable_mask)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+
+	/* Testing arch events requires a vPMU (there are no negative tests). */
+	if (!pmu_version)
+		return;
+
+	vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_test_arch_events,
+					 pmu_version, perf_capabilities);
+
+	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH,
+				length);
+	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_EVENTS_MASK,
+				unavailable_mask);
+
+	run_vcpu(vcpu);
+
+	kvm_vm_free(vm);
+}
+
+static void test_intel_counters(void)
+{
+	uint8_t nr_arch_events = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH);
+	uint8_t pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION);
+	unsigned int i;
+	uint8_t v, j;
+	uint32_t k;
+
+	const uint64_t perf_caps[] = {
+		0,
+		PMU_CAP_FW_WRITES,
+	};
+
+	/*
+	 * Test up to PMU v5, which is the current maximum version defined by
+	 * Intel, i.e. is the last version that is guaranteed to be backwards
+	 * compatible with KVM's existing behavior.
+	 */
+	uint8_t max_pmu_version = max_t(typeof(pmu_version), pmu_version, 5);
+
+	/*
+	 * Detect the existence of events that aren't supported by selftests.
+	 * This will (obviously) fail any time the kernel adds support for a
+	 * new event, but it's worth paying that price to keep the test fresh.
+	 */
+	TEST_ASSERT(nr_arch_events <= NR_INTEL_ARCH_EVENTS,
+		    "New architectural event(s) detected; please update this test (length = %u, mask = %x)",
+		    nr_arch_events, kvm_cpu_property(X86_PROPERTY_PMU_EVENTS_MASK));
+
+	/*
+	 * Force iterating over known arch events regardless of whether or not
+	 * KVM/hardware supports a given event.
+	 */
+	nr_arch_events = max_t(typeof(nr_arch_events), nr_arch_events, NR_INTEL_ARCH_EVENTS);
+
+	for (v = 0; v <= max_pmu_version; v++) {
+		for (i = 0; i < ARRAY_SIZE(perf_caps); i++) {
+			if (!kvm_has_perf_caps && perf_caps[i])
+				continue;
+
+			pr_info("Testing arch events, PMU version %u, perf_caps = %lx\n",
+				v, perf_caps[i]);
+			/*
+			 * To keep the total runtime reasonable, test every
+			 * possible non-zero, non-reserved bitmap combination
+			 * only with the native PMU version and the full bit
+			 * vector length.
+			 */
+			if (v == pmu_version) {
+				for (k = 1; k < (BIT(nr_arch_events) - 1); k++)
+					test_arch_events(v, perf_caps[i], nr_arch_events, k);
+			}
+			/*
+			 * Test single bits for all PMU version and lengths up
+			 * the number of events +1 (to verify KVM doesn't do
+			 * weird things if the guest length is greater than the
+			 * host length).  Explicitly test a mask of '0' and all
+			 * ones i.e. all events being available and unavailable.
+			 */
+			for (j = 0; j <= nr_arch_events + 1; j++) {
+				test_arch_events(v, perf_caps[i], j, 0);
+				test_arch_events(v, perf_caps[i], j, 0xff);
+
+				for (k = 0; k < nr_arch_events; k++)
+					test_arch_events(v, perf_caps[i], j, BIT(k));
+			}
+		}
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
+
+	TEST_REQUIRE(host_cpu_is_intel);
+	TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
+	TEST_REQUIRE(kvm_cpu_property(X86_PROPERTY_PMU_VERSION) > 0);
+
+	kvm_pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION);
+	kvm_has_perf_caps = kvm_cpu_has(X86_FEATURE_PDCM);
+
+	test_intel_counters();
+
+	return 0;
+}
-- 
2.42.0.869.gea05f2083d-goog

Re: [PATCH v7 09/19] KVM: selftests: Test Intel PMU architectural events on gp counters

[Mi, Dapeng]

On 11/8/2023 8:31 AM, Sean Christopherson wrote:
> From: Jinrong Liang <cloudliang@tencent.com>
>
> Add test cases to verify that Intel's Architectural PMU events work as
> expected when the are (un)available according to guest CPUID.  Iterate


Typo: 'the' are -> 'they' are

Reviewed by: Dapeng Mi <dapeng1.mi@linux.intel.com>


> over a range of sane PMU versions, with and without full-width writes
> enabled, and over interesting combinations of lengths/masks for the bit
> vector that enumerates unavailable events.
>
> Test up to vPMU version 5, i.e. the current architectural max.  KVM only
> officially supports up to version 2, but the behavior of the counters is
> backwards compatible, i.e. KVM shouldn't do something completely different
> for a higher, architecturally-defined vPMU version.  Verify KVM behavior
> against the effective vPMU version, e.g. advertising vPMU 5 when KVM only
> supports vPMU 2 shouldn't magically unlock vPMU 5 features.
>
> According to Intel SDM, the number of architectural events is reported
> through CPUID.0AH:EAX[31:24] and the architectural event x is supported
> if EBX[x]=0 && EAX[31:24]>x.
>
> Handcode the entirety of the measured section so that the test can
> precisely assert on the number of instructions and branches retired.
>
> Co-developed-by: Like Xu <likexu@tencent.com>
> Signed-off-by: Like Xu <likexu@tencent.com>
> Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>   tools/testing/selftests/kvm/Makefile          |   1 +
>   .../selftests/kvm/x86_64/pmu_counters_test.c  | 321 ++++++++++++++++++
>   2 files changed, 322 insertions(+)
>   create mode 100644 tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
>
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index 44d8d022b023..09f5d6fe84de 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -91,6 +91,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test
>   TEST_GEN_PROGS_x86_64 += x86_64/monitor_mwait_test
>   TEST_GEN_PROGS_x86_64 += x86_64/nested_exceptions_test
>   TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test
> +TEST_GEN_PROGS_x86_64 += x86_64/pmu_counters_test
>   TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test
>   TEST_GEN_PROGS_x86_64 += x86_64/set_boot_cpu_id
>   TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test
> diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> new file mode 100644
> index 000000000000..5b8687bb4639
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> @@ -0,0 +1,321 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2023, Tencent, Inc.
> + */
> +
> +#define _GNU_SOURCE /* for program_invocation_short_name */
> +#include <x86intrin.h>
> +
> +#include "pmu.h"
> +#include "processor.h"
> +
> +/* Number of LOOP instructions for the guest measurement payload. */
> +#define NUM_BRANCHES		10
> +/*
> + * Number of "extra" instructions that will be counted, i.e. the number of
> + * instructions that are needed to set up the loop and then disabled the
> + * counter.  2 MOV, 2 XOR, 1 WRMSR.
> + */
> +#define NUM_EXTRA_INSNS		5
> +#define NUM_INSNS_RETIRED	(NUM_BRANCHES + NUM_EXTRA_INSNS)
> +
> +static uint8_t kvm_pmu_version;
> +static bool kvm_has_perf_caps;
> +
> +static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu,
> +						  void *guest_code,
> +						  uint8_t pmu_version,
> +						  uint64_t perf_capabilities)
> +{
> +	struct kvm_vm *vm;
> +
> +	vm = vm_create_with_one_vcpu(vcpu, guest_code);
> +	vm_init_descriptor_tables(vm);
> +	vcpu_init_descriptor_tables(*vcpu);
> +
> +	sync_global_to_guest(vm, kvm_pmu_version);
> +
> +	/*
> +	 * Set PERF_CAPABILITIES before PMU version as KVM disallows enabling
> +	 * features via PERF_CAPABILITIES if the guest doesn't have a vPMU.
> +	 */
> +	if (kvm_has_perf_caps)
> +		vcpu_set_msr(*vcpu, MSR_IA32_PERF_CAPABILITIES, perf_capabilities);
> +
> +	vcpu_set_cpuid_property(*vcpu, X86_PROPERTY_PMU_VERSION, pmu_version);
> +	return vm;
> +}
> +
> +static void run_vcpu(struct kvm_vcpu *vcpu)
> +{
> +	struct ucall uc;
> +
> +	do {
> +		vcpu_run(vcpu);
> +		switch (get_ucall(vcpu, &uc)) {
> +		case UCALL_SYNC:
> +			break;
> +		case UCALL_ABORT:
> +			REPORT_GUEST_ASSERT(uc);
> +			break;
> +		case UCALL_PRINTF:
> +			pr_info("%s", uc.buffer);
> +			break;
> +		case UCALL_DONE:
> +			break;
> +		default:
> +			TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
> +		}
> +	} while (uc.cmd != UCALL_DONE);
> +}
> +
> +static uint8_t guest_get_pmu_version(void)
> +{
> +	/*
> +	 * Return the effective PMU version, i.e. the minimum between what KVM
> +	 * supports and what is enumerated to the guest.  The host deliberately
> +	 * advertises a PMU version to the guest beyond what is actually
> +	 * supported by KVM to verify KVM doesn't freak out and do something
> +	 * bizarre with an architecturally valid, but unsupported, version.
> +	 */
> +	return min_t(uint8_t, kvm_pmu_version, this_cpu_property(X86_PROPERTY_PMU_VERSION));
> +}
> +
> +/*
> + * If an architectural event is supported and guaranteed to generate at least
> + * one "hit, assert that its count is non-zero.  If an event isn't supported or
> + * the test can't guarantee the associated action will occur, then all bets are
> + * off regarding the count, i.e. no checks can be done.
> + *
> + * Sanity check that in all cases, the event doesn't count when it's disabled,
> + * and that KVM correctly emulates the write of an arbitrary value.
> + */
> +static void guest_assert_event_count(uint8_t idx,
> +				     struct kvm_x86_pmu_feature event,
> +				     uint32_t pmc, uint32_t pmc_msr)
> +{
> +	uint64_t count;
> +
> +	count = _rdpmc(pmc);
> +	if (!this_pmu_has(event))
> +		goto sanity_checks;
> +
> +	switch (idx) {
> +	case INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX:
> +		GUEST_ASSERT_EQ(count, NUM_INSNS_RETIRED);
> +		break;
> +	case INTEL_ARCH_BRANCHES_RETIRED_INDEX:
> +		GUEST_ASSERT_EQ(count, NUM_BRANCHES);
> +		break;
> +	case INTEL_ARCH_CPU_CYCLES_INDEX:
> +	case INTEL_ARCH_REFERENCE_CYCLES_INDEX:
> +		GUEST_ASSERT_NE(count, 0);
> +		break;
> +	default:
> +		break;
> +	}
> +
> +sanity_checks:
> +	__asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
> +	GUEST_ASSERT_EQ(_rdpmc(pmc), count);
> +
> +	wrmsr(pmc_msr, 0xdead);
> +	GUEST_ASSERT_EQ(_rdpmc(pmc), 0xdead);
> +}
> +
> +static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature event,
> +				    uint32_t pmc, uint32_t pmc_msr,
> +				    uint32_t ctrl_msr, uint64_t ctrl_msr_value)
> +{
> +	wrmsr(pmc_msr, 0);
> +
> +	/*
> +	 * Enable and disable the PMC in a monolithic asm blob to ensure that
> +	 * the compiler can't insert _any_ code into the measured sequence.
> +	 * Note, ECX doesn't need to be clobbered as the input value, @pmc_msr,
> +	 * is restored before the end of the sequence.
> +	 */
> +	__asm__ __volatile__("wrmsr\n\t"
> +			     "mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t"
> +			     "loop .\n\t"
> +			     "mov %%edi, %%ecx\n\t"
> +			     "xor %%eax, %%eax\n\t"
> +			     "xor %%edx, %%edx\n\t"
> +			     "wrmsr\n\t"
> +			     :: "a"((uint32_t)ctrl_msr_value),
> +				"d"(ctrl_msr_value >> 32),
> +				"c"(ctrl_msr), "D"(ctrl_msr)
> +			     );
> +
> +	guest_assert_event_count(idx, event, pmc, pmc_msr);
> +}
> +
> +static void guest_test_arch_event(uint8_t idx)
> +{
> +	const struct {
> +		struct kvm_x86_pmu_feature gp_event;
> +	} intel_event_to_feature[] = {
> +		[INTEL_ARCH_CPU_CYCLES_INDEX]		 = { X86_PMU_FEATURE_CPU_CYCLES },
> +		[INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX]	 = { X86_PMU_FEATURE_INSNS_RETIRED },
> +		[INTEL_ARCH_REFERENCE_CYCLES_INDEX]	 = { X86_PMU_FEATURE_REFERENCE_CYCLES },
> +		[INTEL_ARCH_LLC_REFERENCES_INDEX]	 = { X86_PMU_FEATURE_LLC_REFERENCES },
> +		[INTEL_ARCH_LLC_MISSES_INDEX]		 = { X86_PMU_FEATURE_LLC_MISSES },
> +		[INTEL_ARCH_BRANCHES_RETIRED_INDEX]	 = { X86_PMU_FEATURE_BRANCH_INSNS_RETIRED },
> +		[INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX] = { X86_PMU_FEATURE_BRANCHES_MISPREDICTED },
> +		[INTEL_ARCH_TOPDOWN_SLOTS_INDEX]	 = { X86_PMU_FEATURE_TOPDOWN_SLOTS },
> +	};
> +
> +	uint32_t nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS);
> +	uint32_t pmu_version = guest_get_pmu_version();
> +	/* PERF_GLOBAL_CTRL exists only for Architectural PMU Version 2+. */
> +	bool guest_has_perf_global_ctrl = pmu_version >= 2;
> +	struct kvm_x86_pmu_feature gp_event;
> +	uint32_t base_pmc_msr;
> +	unsigned int i;
> +
> +	/* The host side shouldn't invoke this without a guest PMU. */
> +	GUEST_ASSERT(pmu_version);
> +
> +	if (this_cpu_has(X86_FEATURE_PDCM) &&
> +	    rdmsr(MSR_IA32_PERF_CAPABILITIES) & PMU_CAP_FW_WRITES)
> +		base_pmc_msr = MSR_IA32_PMC0;
> +	else
> +		base_pmc_msr = MSR_IA32_PERFCTR0;
> +
> +	gp_event = intel_event_to_feature[idx].gp_event;
> +	GUEST_ASSERT_EQ(idx, gp_event.f.bit);
> +
> +	GUEST_ASSERT(nr_gp_counters);
> +
> +	for (i = 0; i < nr_gp_counters; i++) {
> +		uint64_t eventsel = ARCH_PERFMON_EVENTSEL_OS |
> +				    ARCH_PERFMON_EVENTSEL_ENABLE |
> +				    intel_pmu_arch_events[idx];
> +
> +		wrmsr(MSR_P6_EVNTSEL0 + i, 0);
> +		if (guest_has_perf_global_ctrl)
> +			wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, BIT_ULL(i));
> +
> +		__guest_test_arch_event(idx, gp_event, i, base_pmc_msr + i,
> +					MSR_P6_EVNTSEL0 + i, eventsel);
> +	}
> +}
> +
> +static void guest_test_arch_events(void)
> +{
> +	uint8_t i;
> +
> +	for (i = 0; i < NR_INTEL_ARCH_EVENTS; i++)
> +		guest_test_arch_event(i);
> +
> +	GUEST_DONE();
> +}
> +
> +static void test_arch_events(uint8_t pmu_version, uint64_t perf_capabilities,
> +			     uint8_t length, uint8_t unavailable_mask)
> +{
> +	struct kvm_vcpu *vcpu;
> +	struct kvm_vm *vm;
> +
> +	/* Testing arch events requires a vPMU (there are no negative tests). */
> +	if (!pmu_version)
> +		return;
> +
> +	vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_test_arch_events,
> +					 pmu_version, perf_capabilities);
> +
> +	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH,
> +				length);
> +	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_EVENTS_MASK,
> +				unavailable_mask);
> +
> +	run_vcpu(vcpu);
> +
> +	kvm_vm_free(vm);
> +}
> +
> +static void test_intel_counters(void)
> +{
> +	uint8_t nr_arch_events = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH);
> +	uint8_t pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION);
> +	unsigned int i;
> +	uint8_t v, j;
> +	uint32_t k;
> +
> +	const uint64_t perf_caps[] = {
> +		0,
> +		PMU_CAP_FW_WRITES,
> +	};
> +
> +	/*
> +	 * Test up to PMU v5, which is the current maximum version defined by
> +	 * Intel, i.e. is the last version that is guaranteed to be backwards
> +	 * compatible with KVM's existing behavior.
> +	 */
> +	uint8_t max_pmu_version = max_t(typeof(pmu_version), pmu_version, 5);
> +
> +	/*
> +	 * Detect the existence of events that aren't supported by selftests.
> +	 * This will (obviously) fail any time the kernel adds support for a
> +	 * new event, but it's worth paying that price to keep the test fresh.
> +	 */
> +	TEST_ASSERT(nr_arch_events <= NR_INTEL_ARCH_EVENTS,
> +		    "New architectural event(s) detected; please update this test (length = %u, mask = %x)",
> +		    nr_arch_events, kvm_cpu_property(X86_PROPERTY_PMU_EVENTS_MASK));
> +
> +	/*
> +	 * Force iterating over known arch events regardless of whether or not
> +	 * KVM/hardware supports a given event.
> +	 */
> +	nr_arch_events = max_t(typeof(nr_arch_events), nr_arch_events, NR_INTEL_ARCH_EVENTS);
> +
> +	for (v = 0; v <= max_pmu_version; v++) {
> +		for (i = 0; i < ARRAY_SIZE(perf_caps); i++) {
> +			if (!kvm_has_perf_caps && perf_caps[i])
> +				continue;
> +
> +			pr_info("Testing arch events, PMU version %u, perf_caps = %lx\n",
> +				v, perf_caps[i]);
> +			/*
> +			 * To keep the total runtime reasonable, test every
> +			 * possible non-zero, non-reserved bitmap combination
> +			 * only with the native PMU version and the full bit
> +			 * vector length.
> +			 */
> +			if (v == pmu_version) {
> +				for (k = 1; k < (BIT(nr_arch_events) - 1); k++)
> +					test_arch_events(v, perf_caps[i], nr_arch_events, k);
> +			}
> +			/*
> +			 * Test single bits for all PMU version and lengths up
> +			 * the number of events +1 (to verify KVM doesn't do
> +			 * weird things if the guest length is greater than the
> +			 * host length).  Explicitly test a mask of '0' and all
> +			 * ones i.e. all events being available and unavailable.
> +			 */
> +			for (j = 0; j <= nr_arch_events + 1; j++) {
> +				test_arch_events(v, perf_caps[i], j, 0);
> +				test_arch_events(v, perf_caps[i], j, 0xff);
> +
> +				for (k = 0; k < nr_arch_events; k++)
> +					test_arch_events(v, perf_caps[i], j, BIT(k));
> +			}
> +		}
> +	}
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
> +
> +	TEST_REQUIRE(host_cpu_is_intel);
> +	TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
> +	TEST_REQUIRE(kvm_cpu_property(X86_PROPERTY_PMU_VERSION) > 0);
> +
> +	kvm_pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION);
> +	kvm_has_perf_caps = kvm_cpu_has(X86_FEATURE_PDCM);
> +
> +	test_intel_counters();
> +
> +	return 0;
> +}

[PATCH v7 10/19] KVM: selftests: Test Intel PMU architectural events on fixed counters

[Sean Christopherson]

From: Jinrong Liang <cloudliang@tencent.com>

Extend the PMU counters test to validate architectural events using fixed
counters.  The core logic is largely the same, the biggest difference
being that if a fixed counter exists, its associated event is available
(the SDM doesn't explicitly state this to be true, but it's KVM's ABI and
letting software program a fixed counter that doesn't actually count would
be quite bizarre).

Note, fixed counters rely on PERF_GLOBAL_CTRL.

Reviewed-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Like Xu <likexu@tencent.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/x86_64/pmu_counters_test.c  | 54 +++++++++++++++----
 1 file changed, 45 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
index 5b8687bb4639..9cd308417aeb 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -150,26 +150,46 @@ static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature even
 	guest_assert_event_count(idx, event, pmc, pmc_msr);
 }
 
+#define X86_PMU_FEATURE_NULL						\
+({									\
+	struct kvm_x86_pmu_feature feature = {};			\
+									\
+	feature;							\
+})
+
+static bool pmu_is_null_feature(struct kvm_x86_pmu_feature event)
+{
+	return !(*(u64 *)&event);
+}
+
 static void guest_test_arch_event(uint8_t idx)
 {
 	const struct {
 		struct kvm_x86_pmu_feature gp_event;
+		struct kvm_x86_pmu_feature fixed_event;
 	} intel_event_to_feature[] = {
-		[INTEL_ARCH_CPU_CYCLES_INDEX]		 = { X86_PMU_FEATURE_CPU_CYCLES },
-		[INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX]	 = { X86_PMU_FEATURE_INSNS_RETIRED },
-		[INTEL_ARCH_REFERENCE_CYCLES_INDEX]	 = { X86_PMU_FEATURE_REFERENCE_CYCLES },
-		[INTEL_ARCH_LLC_REFERENCES_INDEX]	 = { X86_PMU_FEATURE_LLC_REFERENCES },
-		[INTEL_ARCH_LLC_MISSES_INDEX]		 = { X86_PMU_FEATURE_LLC_MISSES },
-		[INTEL_ARCH_BRANCHES_RETIRED_INDEX]	 = { X86_PMU_FEATURE_BRANCH_INSNS_RETIRED },
-		[INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX] = { X86_PMU_FEATURE_BRANCHES_MISPREDICTED },
-		[INTEL_ARCH_TOPDOWN_SLOTS_INDEX]	 = { X86_PMU_FEATURE_TOPDOWN_SLOTS },
+		[INTEL_ARCH_CPU_CYCLES_INDEX]		 = { X86_PMU_FEATURE_CPU_CYCLES, X86_PMU_FEATURE_CPU_CYCLES_FIXED },
+		[INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX]	 = { X86_PMU_FEATURE_INSNS_RETIRED, X86_PMU_FEATURE_INSNS_RETIRED_FIXED },
+		/*
+		 * Note, the fixed counter for reference cycles is NOT the same
+		 * as the general purpose architectural event.  The fixed counter
+		 * explicitly counts at the same frequency as the TSC, whereas
+		 * the GP event counts at a fixed, but uarch specific, frequency.
+		 * Bundle them here for simplicity.
+		 */
+		[INTEL_ARCH_REFERENCE_CYCLES_INDEX]	 = { X86_PMU_FEATURE_REFERENCE_CYCLES, X86_PMU_FEATURE_REFERENCE_TSC_CYCLES_FIXED },
+		[INTEL_ARCH_LLC_REFERENCES_INDEX]	 = { X86_PMU_FEATURE_LLC_REFERENCES, X86_PMU_FEATURE_NULL },
+		[INTEL_ARCH_LLC_MISSES_INDEX]		 = { X86_PMU_FEATURE_LLC_MISSES, X86_PMU_FEATURE_NULL },
+		[INTEL_ARCH_BRANCHES_RETIRED_INDEX]	 = { X86_PMU_FEATURE_BRANCH_INSNS_RETIRED, X86_PMU_FEATURE_NULL },
+		[INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX] = { X86_PMU_FEATURE_BRANCHES_MISPREDICTED, X86_PMU_FEATURE_NULL },
+		[INTEL_ARCH_TOPDOWN_SLOTS_INDEX]	 = { X86_PMU_FEATURE_TOPDOWN_SLOTS, X86_PMU_FEATURE_TOPDOWN_SLOTS_FIXED },
 	};
 
 	uint32_t nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS);
 	uint32_t pmu_version = guest_get_pmu_version();
 	/* PERF_GLOBAL_CTRL exists only for Architectural PMU Version 2+. */
 	bool guest_has_perf_global_ctrl = pmu_version >= 2;
-	struct kvm_x86_pmu_feature gp_event;
+	struct kvm_x86_pmu_feature gp_event, fixed_event;
 	uint32_t base_pmc_msr;
 	unsigned int i;
 
@@ -199,6 +219,22 @@ static void guest_test_arch_event(uint8_t idx)
 		__guest_test_arch_event(idx, gp_event, i, base_pmc_msr + i,
 					MSR_P6_EVNTSEL0 + i, eventsel);
 	}
+
+	if (!guest_has_perf_global_ctrl)
+		return;
+
+	fixed_event = intel_event_to_feature[idx].fixed_event;
+	if (pmu_is_null_feature(fixed_event) || !this_pmu_has(fixed_event))
+		return;
+
+	i = fixed_event.f.bit;
+
+	wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL));
+
+	__guest_test_arch_event(idx, fixed_event, FIXED_PMC_RDPMC_BASE + i,
+				MSR_CORE_PERF_FIXED_CTR0 + i,
+				MSR_CORE_PERF_GLOBAL_CTRL,
+				FIXED_PMC_GLOBAL_CTRL_ENABLE(i));
 }
 
 static void guest_test_arch_events(void)
-- 
2.42.0.869.gea05f2083d-goog

Re: [PATCH v7 10/19] KVM: selftests: Test Intel PMU architectural events on fixed counters

[Mi, Dapeng]

On 11/8/2023 8:31 AM, Sean Christopherson wrote:
> From: Jinrong Liang <cloudliang@tencent.com>
>
> Extend the PMU counters test to validate architectural events using fixed
> counters.  The core logic is largely the same, the biggest difference
> being that if a fixed counter exists, its associated event is available
> (the SDM doesn't explicitly state this to be true, but it's KVM's ABI and
> letting software program a fixed counter that doesn't actually count would
> be quite bizarre).
>
> Note, fixed counters rely on PERF_GLOBAL_CTRL.
>
> Reviewed-by: Jim Mattson <jmattson@google.com>
> Co-developed-by: Like Xu <likexu@tencent.com>
> Signed-off-by: Like Xu <likexu@tencent.com>
> Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>   .../selftests/kvm/x86_64/pmu_counters_test.c  | 54 +++++++++++++++----
>   1 file changed, 45 insertions(+), 9 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> index 5b8687bb4639..9cd308417aeb 100644
> --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> @@ -150,26 +150,46 @@ static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature even
>   	guest_assert_event_count(idx, event, pmc, pmc_msr);
>   }
>   
> +#define X86_PMU_FEATURE_NULL						\
> +({									\
> +	struct kvm_x86_pmu_feature feature = {};			\
> +									\
> +	feature;							\
> +})
> +
> +static bool pmu_is_null_feature(struct kvm_x86_pmu_feature event)
> +{
> +	return !(*(u64 *)&event);
> +}
> +
>   static void guest_test_arch_event(uint8_t idx)
>   {
>   	const struct {
>   		struct kvm_x86_pmu_feature gp_event;
> +		struct kvm_x86_pmu_feature fixed_event;
>   	} intel_event_to_feature[] = {
> -		[INTEL_ARCH_CPU_CYCLES_INDEX]		 = { X86_PMU_FEATURE_CPU_CYCLES },
> -		[INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX]	 = { X86_PMU_FEATURE_INSNS_RETIRED },
> -		[INTEL_ARCH_REFERENCE_CYCLES_INDEX]	 = { X86_PMU_FEATURE_REFERENCE_CYCLES },
> -		[INTEL_ARCH_LLC_REFERENCES_INDEX]	 = { X86_PMU_FEATURE_LLC_REFERENCES },
> -		[INTEL_ARCH_LLC_MISSES_INDEX]		 = { X86_PMU_FEATURE_LLC_MISSES },
> -		[INTEL_ARCH_BRANCHES_RETIRED_INDEX]	 = { X86_PMU_FEATURE_BRANCH_INSNS_RETIRED },
> -		[INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX] = { X86_PMU_FEATURE_BRANCHES_MISPREDICTED },
> -		[INTEL_ARCH_TOPDOWN_SLOTS_INDEX]	 = { X86_PMU_FEATURE_TOPDOWN_SLOTS },
> +		[INTEL_ARCH_CPU_CYCLES_INDEX]		 = { X86_PMU_FEATURE_CPU_CYCLES, X86_PMU_FEATURE_CPU_CYCLES_FIXED },
> +		[INTEL_ARCH_INSTRUCTIONS_RETIRED_INDEX]	 = { X86_PMU_FEATURE_INSNS_RETIRED, X86_PMU_FEATURE_INSNS_RETIRED_FIXED },
> +		/*
> +		 * Note, the fixed counter for reference cycles is NOT the same
> +		 * as the general purpose architectural event.  The fixed counter
> +		 * explicitly counts at the same frequency as the TSC, whereas
> +		 * the GP event counts at a fixed, but uarch specific, frequency.
> +		 * Bundle them here for simplicity.
> +		 */
> +		[INTEL_ARCH_REFERENCE_CYCLES_INDEX]	 = { X86_PMU_FEATURE_REFERENCE_CYCLES, X86_PMU_FEATURE_REFERENCE_TSC_CYCLES_FIXED },
> +		[INTEL_ARCH_LLC_REFERENCES_INDEX]	 = { X86_PMU_FEATURE_LLC_REFERENCES, X86_PMU_FEATURE_NULL },
> +		[INTEL_ARCH_LLC_MISSES_INDEX]		 = { X86_PMU_FEATURE_LLC_MISSES, X86_PMU_FEATURE_NULL },
> +		[INTEL_ARCH_BRANCHES_RETIRED_INDEX]	 = { X86_PMU_FEATURE_BRANCH_INSNS_RETIRED, X86_PMU_FEATURE_NULL },
> +		[INTEL_ARCH_BRANCHES_MISPREDICTED_INDEX] = { X86_PMU_FEATURE_BRANCHES_MISPREDICTED, X86_PMU_FEATURE_NULL },
> +		[INTEL_ARCH_TOPDOWN_SLOTS_INDEX]	 = { X86_PMU_FEATURE_TOPDOWN_SLOTS, X86_PMU_FEATURE_TOPDOWN_SLOTS_FIXED },
>   	};
>   
>   	uint32_t nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS);
>   	uint32_t pmu_version = guest_get_pmu_version();
>   	/* PERF_GLOBAL_CTRL exists only for Architectural PMU Version 2+. */
>   	bool guest_has_perf_global_ctrl = pmu_version >= 2;
> -	struct kvm_x86_pmu_feature gp_event;
> +	struct kvm_x86_pmu_feature gp_event, fixed_event;
>   	uint32_t base_pmc_msr;
>   	unsigned int i;
>   
> @@ -199,6 +219,22 @@ static void guest_test_arch_event(uint8_t idx)
>   		__guest_test_arch_event(idx, gp_event, i, base_pmc_msr + i,
>   					MSR_P6_EVNTSEL0 + i, eventsel);
>   	}
> +
> +	if (!guest_has_perf_global_ctrl)
> +		return;
> +
> +	fixed_event = intel_event_to_feature[idx].fixed_event;
> +	if (pmu_is_null_feature(fixed_event) || !this_pmu_has(fixed_event))
> +		return;
> +
> +	i = fixed_event.f.bit;
> +
> +	wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL));
> +
> +	__guest_test_arch_event(idx, fixed_event, FIXED_PMC_RDPMC_BASE + i,
> +				MSR_CORE_PERF_FIXED_CTR0 + i,
> +				MSR_CORE_PERF_GLOBAL_CTRL,
> +				FIXED_PMC_GLOBAL_CTRL_ENABLE(i));
>   }
>   
>   static void guest_test_arch_events(void)

Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>

Re: [PATCH v7 10/19] KVM: selftests: Test Intel PMU architectural events on fixed counters

[Sean Christopherson]

On Tue, Nov 07, 2023, Sean Christopherson wrote:
> @@ -199,6 +219,22 @@ static void guest_test_arch_event(uint8_t idx)
>  		__guest_test_arch_event(idx, gp_event, i, base_pmc_msr + i,
>  					MSR_P6_EVNTSEL0 + i, eventsel);
>  	}
> +
> +	if (!guest_has_perf_global_ctrl)
> +		return;
> +
> +	fixed_event = intel_event_to_feature[idx].fixed_event;
> +	if (pmu_is_null_feature(fixed_event) || !this_pmu_has(fixed_event))
> +		return;
> +
> +	i = fixed_event.f.bit;
> +
> +	wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL));
> +
> +	__guest_test_arch_event(idx, fixed_event, FIXED_PMC_RDPMC_BASE + i,

Grr, this should be an OR, not a SUM, i.e. "FIXED_PMC_RDPMC_BASE | i".  That's
how Like/Jinrong originally had things, but I got confused by the BASE terminology
and "fixed" it.  The end result is the name, but the PMU code is hard enough to
follow as it is.

I'm also going to rename FIXED_PMC_RDPMC_BASE, that is a terrible name that got
copy+pasted from perf.  It's not a base value, it's a single flag that says "read
fixed counters".

[PATCH v7 11/19] KVM: selftests: Test consistency of CPUID with num of gp counters

[Sean Christopherson]

From: Jinrong Liang <cloudliang@tencent.com>

Add a test to verify that KVM correctly emulates MSR-based accesses to
general purpose counters based on guest CPUID, e.g. that accesses to
non-existent counters #GP and accesses to existent counters succeed.

Note, for compatibility reasons, KVM does not emulate #GP when
MSR_P6_PERFCTR[0|1] is not present (writes should be dropped).

Co-developed-by: Like Xu <likexu@tencent.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/x86_64/pmu_counters_test.c  | 91 +++++++++++++++++++
 1 file changed, 91 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
index 9cd308417aeb..6f2d3a64a118 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -270,9 +270,95 @@ static void test_arch_events(uint8_t pmu_version, uint64_t perf_capabilities,
 	kvm_vm_free(vm);
 }
 
+/*
+ * Limit testing to MSRs that are actually defined by Intel (in the SDM).  MSRs
+ * that aren't defined counter MSRs *probably* don't exist, but there's no
+ * guarantee that currently undefined MSR indices won't be used for something
+ * other than PMCs in the future.
+ */
+#define MAX_NR_GP_COUNTERS	8
+#define MAX_NR_FIXED_COUNTERS	3
+
+#define GUEST_ASSERT_PMC_MSR_ACCESS(insn, msr, expect_gp, vector)		\
+__GUEST_ASSERT(expect_gp ? vector == GP_VECTOR : !vector,			\
+	       "Expected %s on " #insn "(0x%x), got vector %u",			\
+	       expect_gp ? "#GP" : "no fault", msr, vector)			\
+
+static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters,
+				 uint8_t nr_counters)
+{
+	uint8_t i;
+
+	for (i = 0; i < nr_possible_counters; i++) {
+		const uint32_t msr = base_msr + i;
+		const bool expect_success = i < nr_counters;
+
+		/*
+		 * KVM drops writes to MSR_P6_PERFCTR[0|1] if the counters are
+		 * unsupported, i.e. doesn't #GP and reads back '0'.
+		 */
+		const uint64_t expected_val = expect_success ? 0xffff : 0;
+		const bool expect_gp = !expect_success && msr != MSR_P6_PERFCTR0 &&
+				       msr != MSR_P6_PERFCTR1;
+		uint8_t vector;
+		uint64_t val;
+
+		vector = wrmsr_safe(msr, 0xffff);
+		GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector);
+
+		vector = rdmsr_safe(msr, &val);
+		GUEST_ASSERT_PMC_MSR_ACCESS(RDMSR, msr, expect_gp, vector);
+
+		/* On #GP, the result of RDMSR is undefined. */
+		if (!expect_gp)
+			__GUEST_ASSERT(val == expected_val,
+				       "Expected RDMSR(0x%x) to yield 0x%lx, got 0x%lx",
+				       msr, expected_val, val);
+
+		vector = wrmsr_safe(msr, 0);
+		GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector);
+	}
+	GUEST_DONE();
+}
+
+static void guest_test_gp_counters(void)
+{
+	uint8_t nr_gp_counters = 0;
+	uint32_t base_msr;
+
+	if (guest_get_pmu_version())
+		nr_gp_counters = this_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS);
+
+	if (this_cpu_has(X86_FEATURE_PDCM) &&
+	    rdmsr(MSR_IA32_PERF_CAPABILITIES) & PMU_CAP_FW_WRITES)
+		base_msr = MSR_IA32_PMC0;
+	else
+		base_msr = MSR_IA32_PERFCTR0;
+
+	guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters);
+}
+
+static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities,
+			     uint8_t nr_gp_counters)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+
+	vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_test_gp_counters,
+					 pmu_version, perf_capabilities);
+
+	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_NR_GP_COUNTERS,
+				nr_gp_counters);
+
+	run_vcpu(vcpu);
+
+	kvm_vm_free(vm);
+}
+
 static void test_intel_counters(void)
 {
 	uint8_t nr_arch_events = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH);
+	uint8_t nr_gp_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS);
 	uint8_t pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION);
 	unsigned int i;
 	uint8_t v, j;
@@ -336,6 +422,11 @@ static void test_intel_counters(void)
 				for (k = 0; k < nr_arch_events; k++)
 					test_arch_events(v, perf_caps[i], j, BIT(k));
 			}
+
+			pr_info("Testing GP counters, PMU version %u, perf_caps = %lx\n",
+				v, perf_caps[i]);
+			for (j = 0; j <= nr_gp_counters; j++)
+				test_gp_counters(v, perf_caps[i], j);
 		}
 	}
 }
-- 
2.42.0.869.gea05f2083d-goog

[PATCH v7 12/19] KVM: selftests: Test consistency of CPUID with num of fixed counters

[Sean Christopherson]

From: Jinrong Liang <cloudliang@tencent.com>

Extend the PMU counters test to verify KVM emulation of fixed counters in
addition to general purpose counters.  Fixed counters add an extra wrinkle
in the form of an extra supported bitmask.  Thus quoth the SDM:

  fixed-function performance counter 'i' is supported if ECX[i] || (EDX[4:0] > i)

Test that KVM handles a counter being available through either method.

Co-developed-by: Like Xu <likexu@tencent.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/x86_64/pmu_counters_test.c  | 60 ++++++++++++++++++-
 1 file changed, 57 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
index 6f2d3a64a118..8c934e261f2d 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -285,13 +285,19 @@ __GUEST_ASSERT(expect_gp ? vector == GP_VECTOR : !vector,			\
 	       expect_gp ? "#GP" : "no fault", msr, vector)			\
 
 static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters,
-				 uint8_t nr_counters)
+				 uint8_t nr_counters, uint32_t or_mask)
 {
 	uint8_t i;
 
 	for (i = 0; i < nr_possible_counters; i++) {
 		const uint32_t msr = base_msr + i;
-		const bool expect_success = i < nr_counters;
+
+		/*
+		 * Fixed counters are supported if the counter is less than the
+		 * number of enumerated contiguous counters *or* the counter is
+		 * explicitly enumerated in the supported counters mask.
+		 */
+		const bool expect_success = i < nr_counters || (or_mask & BIT(i));
 
 		/*
 		 * KVM drops writes to MSR_P6_PERFCTR[0|1] if the counters are
@@ -335,7 +341,7 @@ static void guest_test_gp_counters(void)
 	else
 		base_msr = MSR_IA32_PERFCTR0;
 
-	guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters);
+	guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters, 0);
 }
 
 static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities,
@@ -355,9 +361,50 @@ static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities,
 	kvm_vm_free(vm);
 }
 
+static void guest_test_fixed_counters(void)
+{
+	uint64_t supported_bitmask = 0;
+	uint8_t nr_fixed_counters = 0;
+
+	/* Fixed counters require Architectural vPMU Version 2+. */
+	if (guest_get_pmu_version() >= 2)
+		nr_fixed_counters = this_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
+
+	/*
+	 * The supported bitmask for fixed counters was introduced in PMU
+	 * version 5.
+	 */
+	if (guest_get_pmu_version() >= 5)
+		supported_bitmask = this_cpu_property(X86_PROPERTY_PMU_FIXED_COUNTERS_BITMASK);
+
+	guest_rd_wr_counters(MSR_CORE_PERF_FIXED_CTR0, MAX_NR_FIXED_COUNTERS,
+			     nr_fixed_counters, supported_bitmask);
+}
+
+static void test_fixed_counters(uint8_t pmu_version, uint64_t perf_capabilities,
+				uint8_t nr_fixed_counters,
+				uint32_t supported_bitmask)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+
+	vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_test_fixed_counters,
+					 pmu_version, perf_capabilities);
+
+	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_FIXED_COUNTERS_BITMASK,
+				supported_bitmask);
+	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_NR_FIXED_COUNTERS,
+				nr_fixed_counters);
+
+	run_vcpu(vcpu);
+
+	kvm_vm_free(vm);
+}
+
 static void test_intel_counters(void)
 {
 	uint8_t nr_arch_events = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH);
+	uint8_t nr_fixed_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
 	uint8_t nr_gp_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS);
 	uint8_t pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION);
 	unsigned int i;
@@ -427,6 +474,13 @@ static void test_intel_counters(void)
 				v, perf_caps[i]);
 			for (j = 0; j <= nr_gp_counters; j++)
 				test_gp_counters(v, perf_caps[i], j);
+
+			pr_info("Testing fixed counters, PMU version %u, perf_caps = %lx\n",
+				v, perf_caps[i]);
+			for (j = 0; j <= nr_fixed_counters; j++) {
+				for (k = 0; k <= (BIT(nr_fixed_counters) - 1); k++)
+					test_fixed_counters(v, perf_caps[i], j, k);
+			}
 		}
 	}
 }
-- 
2.42.0.869.gea05f2083d-goog

Re: [PATCH v7 12/19] KVM: selftests: Test consistency of CPUID with num of fixed counters

[Mi, Dapeng]

On 11/8/2023 8:31 AM, Sean Christopherson wrote:
> From: Jinrong Liang <cloudliang@tencent.com>
>
> Extend the PMU counters test to verify KVM emulation of fixed counters in
> addition to general purpose counters.  Fixed counters add an extra wrinkle
> in the form of an extra supported bitmask.  Thus quoth the SDM:
>
>    fixed-function performance counter 'i' is supported if ECX[i] || (EDX[4:0] > i)
>
> Test that KVM handles a counter being available through either method.
>
> Co-developed-by: Like Xu <likexu@tencent.com>
> Signed-off-by: Like Xu <likexu@tencent.com>
> Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>   .../selftests/kvm/x86_64/pmu_counters_test.c  | 60 ++++++++++++++++++-
>   1 file changed, 57 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> index 6f2d3a64a118..8c934e261f2d 100644
> --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> @@ -285,13 +285,19 @@ __GUEST_ASSERT(expect_gp ? vector == GP_VECTOR : !vector,			\
>   	       expect_gp ? "#GP" : "no fault", msr, vector)			\
>   
>   static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters,
> -				 uint8_t nr_counters)
> +				 uint8_t nr_counters, uint32_t or_mask)


'or_mask' doesn't show a clear meaning, "counters_bitmap" may be a 
better name.

Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>


>   {
>   	uint8_t i;
>   
>   	for (i = 0; i < nr_possible_counters; i++) {
>   		const uint32_t msr = base_msr + i;
> -		const bool expect_success = i < nr_counters;
> +
> +		/*
> +		 * Fixed counters are supported if the counter is less than the
> +		 * number of enumerated contiguous counters *or* the counter is
> +		 * explicitly enumerated in the supported counters mask.
> +		 */
> +		const bool expect_success = i < nr_counters || (or_mask & BIT(i));
>   
>   		/*
>   		 * KVM drops writes to MSR_P6_PERFCTR[0|1] if the counters are
> @@ -335,7 +341,7 @@ static void guest_test_gp_counters(void)
>   	else
>   		base_msr = MSR_IA32_PERFCTR0;
>   
> -	guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters);
> +	guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters, 0);
>   }
>   
>   static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities,
> @@ -355,9 +361,50 @@ static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities,
>   	kvm_vm_free(vm);
>   }
>   
> +static void guest_test_fixed_counters(void)
> +{
> +	uint64_t supported_bitmask = 0;
> +	uint8_t nr_fixed_counters = 0;
> +
> +	/* Fixed counters require Architectural vPMU Version 2+. */
> +	if (guest_get_pmu_version() >= 2)
> +		nr_fixed_counters = this_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
> +
> +	/*
> +	 * The supported bitmask for fixed counters was introduced in PMU
> +	 * version 5.
> +	 */
> +	if (guest_get_pmu_version() >= 5)
> +		supported_bitmask = this_cpu_property(X86_PROPERTY_PMU_FIXED_COUNTERS_BITMASK);
> +
> +	guest_rd_wr_counters(MSR_CORE_PERF_FIXED_CTR0, MAX_NR_FIXED_COUNTERS,
> +			     nr_fixed_counters, supported_bitmask);
> +}
> +
> +static void test_fixed_counters(uint8_t pmu_version, uint64_t perf_capabilities,
> +				uint8_t nr_fixed_counters,
> +				uint32_t supported_bitmask)
> +{
> +	struct kvm_vcpu *vcpu;
> +	struct kvm_vm *vm;
> +
> +	vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_test_fixed_counters,
> +					 pmu_version, perf_capabilities);
> +
> +	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_FIXED_COUNTERS_BITMASK,
> +				supported_bitmask);
> +	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_PMU_NR_FIXED_COUNTERS,
> +				nr_fixed_counters);
> +
> +	run_vcpu(vcpu);
> +
> +	kvm_vm_free(vm);
> +}
> +
>   static void test_intel_counters(void)
>   {
>   	uint8_t nr_arch_events = kvm_cpu_property(X86_PROPERTY_PMU_EBX_BIT_VECTOR_LENGTH);
> +	uint8_t nr_fixed_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_FIXED_COUNTERS);
>   	uint8_t nr_gp_counters = kvm_cpu_property(X86_PROPERTY_PMU_NR_GP_COUNTERS);
>   	uint8_t pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION);
>   	unsigned int i;
> @@ -427,6 +474,13 @@ static void test_intel_counters(void)
>   				v, perf_caps[i]);
>   			for (j = 0; j <= nr_gp_counters; j++)
>   				test_gp_counters(v, perf_caps[i], j);
> +
> +			pr_info("Testing fixed counters, PMU version %u, perf_caps = %lx\n",
> +				v, perf_caps[i]);
> +			for (j = 0; j <= nr_fixed_counters; j++) {
> +				for (k = 0; k <= (BIT(nr_fixed_counters) - 1); k++)
> +					test_fixed_counters(v, perf_caps[i], j, k);
> +			}
>   		}
>   	}
>   }

Re: [PATCH v7 12/19] KVM: selftests: Test consistency of CPUID with num of fixed counters

[Sean Christopherson]

On Thu, Nov 09, 2023, Dapeng Mi wrote:
> 
> On 11/8/2023 8:31 AM, Sean Christopherson wrote:
> > From: Jinrong Liang <cloudliang@tencent.com>
> > 
> > Extend the PMU counters test to verify KVM emulation of fixed counters in
> > addition to general purpose counters.  Fixed counters add an extra wrinkle
> > in the form of an extra supported bitmask.  Thus quoth the SDM:
> > 
> >    fixed-function performance counter 'i' is supported if ECX[i] || (EDX[4:0] > i)
> > 
> > Test that KVM handles a counter being available through either method.
> > 
> > Co-developed-by: Like Xu <likexu@tencent.com>
> > Signed-off-by: Like Xu <likexu@tencent.com>
> > Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
> > Co-developed-by: Sean Christopherson <seanjc@google.com>
> > Signed-off-by: Sean Christopherson <seanjc@google.com>
> > ---
> >   .../selftests/kvm/x86_64/pmu_counters_test.c  | 60 ++++++++++++++++++-
> >   1 file changed, 57 insertions(+), 3 deletions(-)
> > 
> > diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> > index 6f2d3a64a118..8c934e261f2d 100644
> > --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> > +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> > @@ -285,13 +285,19 @@ __GUEST_ASSERT(expect_gp ? vector == GP_VECTOR : !vector,			\
> >   	       expect_gp ? "#GP" : "no fault", msr, vector)			\
> >   static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters,
> > -				 uint8_t nr_counters)
> > +				 uint8_t nr_counters, uint32_t or_mask)
> 
> 
> 'or_mask' doesn't show a clear meaning, "counters_bitmap" may be a better
> name.

I don't love "or_mask" either, but I like "counters_bitmap" far less, as it doesn't
provide any hint as to the polarity or behavior.  Readers that aren't familiar with
the kludgy enumeration of PMCs in CPUID won't already know that it's a mask that's
OR-d in, e.g. counters_bitmap could be a replacement, it could be an AND-mask, it
could be something entirely unrelated.  I opted for a name that describe the behavior
because I don't see a way to succintly capture the (IMO) weird enumeration.

[PATCH v7 13/19] KVM: selftests: Add functional test for Intel's fixed PMU counters

[Sean Christopherson]

From: Jinrong Liang <cloudliang@tencent.com>

Extend the fixed counters test to verify that supported counters can
actually be enabled in the control MSRs, that unsupported counters cannot,
and that enabled counters actually count.

Co-developed-by: Like Xu <likexu@tencent.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
[sean: fold into the rd/wr access test, massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/x86_64/pmu_counters_test.c  | 31 ++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
index 8c934e261f2d..b9c073d3ade9 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -324,7 +324,6 @@ static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters
 		vector = wrmsr_safe(msr, 0);
 		GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector);
 	}
-	GUEST_DONE();
 }
 
 static void guest_test_gp_counters(void)
@@ -342,6 +341,7 @@ static void guest_test_gp_counters(void)
 		base_msr = MSR_IA32_PERFCTR0;
 
 	guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters, 0);
+	GUEST_DONE();
 }
 
 static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities,
@@ -365,6 +365,7 @@ static void guest_test_fixed_counters(void)
 {
 	uint64_t supported_bitmask = 0;
 	uint8_t nr_fixed_counters = 0;
+	uint8_t i;
 
 	/* Fixed counters require Architectural vPMU Version 2+. */
 	if (guest_get_pmu_version() >= 2)
@@ -379,6 +380,34 @@ static void guest_test_fixed_counters(void)
 
 	guest_rd_wr_counters(MSR_CORE_PERF_FIXED_CTR0, MAX_NR_FIXED_COUNTERS,
 			     nr_fixed_counters, supported_bitmask);
+
+	for (i = 0; i < MAX_NR_FIXED_COUNTERS; i++) {
+		uint8_t vector;
+		uint64_t val;
+
+		if (i >= nr_fixed_counters && !(supported_bitmask & BIT_ULL(i))) {
+			vector = wrmsr_safe(MSR_CORE_PERF_FIXED_CTR_CTRL,
+					    FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL));
+			__GUEST_ASSERT(vector == GP_VECTOR,
+				       "Expected #GP for counter %u in FIXED_CTR_CTRL", i);
+
+			vector = wrmsr_safe(MSR_CORE_PERF_GLOBAL_CTRL,
+					    FIXED_PMC_GLOBAL_CTRL_ENABLE(i));
+			__GUEST_ASSERT(vector == GP_VECTOR,
+				       "Expected #GP for counter %u in PERF_GLOBAL_CTRL", i);
+			continue;
+		}
+
+		wrmsr(MSR_CORE_PERF_FIXED_CTR0 + i, 0);
+		wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL));
+		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, FIXED_PMC_GLOBAL_CTRL_ENABLE(i));
+		__asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
+		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
+		val = rdmsr(MSR_CORE_PERF_FIXED_CTR0 + i);
+
+		GUEST_ASSERT_NE(val, 0);
+	}
+	GUEST_DONE();
 }
 
 static void test_fixed_counters(uint8_t pmu_version, uint64_t perf_capabilities,
-- 
2.42.0.869.gea05f2083d-goog

Re: [PATCH v7 13/19] KVM: selftests: Add functional test for Intel's fixed PMU counters

[Mi, Dapeng]

On 11/8/2023 8:31 AM, Sean Christopherson wrote:
> From: Jinrong Liang <cloudliang@tencent.com>
>
> Extend the fixed counters test to verify that supported counters can
> actually be enabled in the control MSRs, that unsupported counters cannot,
> and that enabled counters actually count.
>
> Co-developed-by: Like Xu <likexu@tencent.com>
> Signed-off-by: Like Xu <likexu@tencent.com>
> Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
> [sean: fold into the rd/wr access test, massage changelog]
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>   .../selftests/kvm/x86_64/pmu_counters_test.c  | 31 ++++++++++++++++++-
>   1 file changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> index 8c934e261f2d..b9c073d3ade9 100644
> --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> @@ -324,7 +324,6 @@ static void guest_rd_wr_counters(uint32_t base_msr, uint8_t nr_possible_counters
>   		vector = wrmsr_safe(msr, 0);
>   		GUEST_ASSERT_PMC_MSR_ACCESS(WRMSR, msr, expect_gp, vector);
>   	}
> -	GUEST_DONE();
>   }
>   
>   static void guest_test_gp_counters(void)
> @@ -342,6 +341,7 @@ static void guest_test_gp_counters(void)
>   		base_msr = MSR_IA32_PERFCTR0;
>   
>   	guest_rd_wr_counters(base_msr, MAX_NR_GP_COUNTERS, nr_gp_counters, 0);
> +	GUEST_DONE();
>   }
>   
>   static void test_gp_counters(uint8_t pmu_version, uint64_t perf_capabilities,
> @@ -365,6 +365,7 @@ static void guest_test_fixed_counters(void)
>   {
>   	uint64_t supported_bitmask = 0;
>   	uint8_t nr_fixed_counters = 0;
> +	uint8_t i;
>   
>   	/* Fixed counters require Architectural vPMU Version 2+. */
>   	if (guest_get_pmu_version() >= 2)
> @@ -379,6 +380,34 @@ static void guest_test_fixed_counters(void)
>   
>   	guest_rd_wr_counters(MSR_CORE_PERF_FIXED_CTR0, MAX_NR_FIXED_COUNTERS,
>   			     nr_fixed_counters, supported_bitmask);
> +
> +	for (i = 0; i < MAX_NR_FIXED_COUNTERS; i++) {
> +		uint8_t vector;
> +		uint64_t val;
> +
> +		if (i >= nr_fixed_counters && !(supported_bitmask & BIT_ULL(i))) {
> +			vector = wrmsr_safe(MSR_CORE_PERF_FIXED_CTR_CTRL,
> +					    FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL));
> +			__GUEST_ASSERT(vector == GP_VECTOR,
> +				       "Expected #GP for counter %u in FIXED_CTR_CTRL", i);
> +
> +			vector = wrmsr_safe(MSR_CORE_PERF_GLOBAL_CTRL,
> +					    FIXED_PMC_GLOBAL_CTRL_ENABLE(i));
> +			__GUEST_ASSERT(vector == GP_VECTOR,
> +				       "Expected #GP for counter %u in PERF_GLOBAL_CTRL", i);
> +			continue;
> +		}
> +
> +		wrmsr(MSR_CORE_PERF_FIXED_CTR0 + i, 0);
> +		wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, FIXED_PMC_CTRL(i, FIXED_PMC_KERNEL));
> +		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, FIXED_PMC_GLOBAL_CTRL_ENABLE(i));
> +		__asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));

This assembly code seems to be called many times, we may wrap it into a 
macro or function.

Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>


> +		wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
> +		val = rdmsr(MSR_CORE_PERF_FIXED_CTR0 + i);
> +
> +		GUEST_ASSERT_NE(val, 0);
> +	}
> +	GUEST_DONE();
>   }
>   
>   static void test_fixed_counters(uint8_t pmu_version, uint64_t perf_capabilities,

[PATCH v7 14/19] KVM: selftests: Expand PMU counters test to verify LLC events

[Sean Christopherson]

Expand the PMU counters test to verify that LLC references and misses have
non-zero counts when the code being executed while the LLC event(s) is
active is evicted via CFLUSH{,OPT}.  Note, CLFLUSH{,OPT} requires a fence
of some kind to ensure the cache lines are flushed before execution
continues.  Use MFENCE for simplicity (performance is not a concern).

Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/x86_64/pmu_counters_test.c  | 59 +++++++++++++------
 1 file changed, 40 insertions(+), 19 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
index b9c073d3ade9..90381382c51f 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -14,9 +14,9 @@
 /*
  * Number of "extra" instructions that will be counted, i.e. the number of
  * instructions that are needed to set up the loop and then disabled the
- * counter.  2 MOV, 2 XOR, 1 WRMSR.
+ * counter.  1 CLFLUSH/CLFLUSHOPT/NOP, 1 MFENCE, 2 MOV, 2 XOR, 1 WRMSR.
  */
-#define NUM_EXTRA_INSNS		5
+#define NUM_EXTRA_INSNS		7
 #define NUM_INSNS_RETIRED	(NUM_BRANCHES + NUM_EXTRA_INSNS)
 
 static uint8_t kvm_pmu_version;
@@ -107,6 +107,12 @@ static void guest_assert_event_count(uint8_t idx,
 	case INTEL_ARCH_BRANCHES_RETIRED_INDEX:
 		GUEST_ASSERT_EQ(count, NUM_BRANCHES);
 		break;
+	case INTEL_ARCH_LLC_REFERENCES_INDEX:
+	case INTEL_ARCH_LLC_MISSES_INDEX:
+		if (!this_cpu_has(X86_FEATURE_CLFLUSHOPT) &&
+		    !this_cpu_has(X86_FEATURE_CLFLUSH))
+			break;
+		fallthrough;
 	case INTEL_ARCH_CPU_CYCLES_INDEX:
 	case INTEL_ARCH_REFERENCE_CYCLES_INDEX:
 		GUEST_ASSERT_NE(count, 0);
@@ -123,29 +129,44 @@ static void guest_assert_event_count(uint8_t idx,
 	GUEST_ASSERT_EQ(_rdpmc(pmc), 0xdead);
 }
 
+/*
+ * Enable and disable the PMC in a monolithic asm blob to ensure that the
+ * compiler can't insert _any_ code into the measured sequence.  Note, ECX
+ * doesn't need to be clobbered as the input value, @pmc_msr, is restored
+ * before the end of the sequence.
+ *
+ * If CLFUSH{,OPT} is supported, flush the cacheline containing (at least) the
+ * start of the loop to force LLC references and misses, i.e. to allow testing
+ * that those events actually count.
+ */
+#define GUEST_MEASURE_EVENT(_msr, _value, clflush)				\
+do {										\
+	__asm__ __volatile__("wrmsr\n\t"					\
+			     clflush "\n\t"					\
+			     "mfence\n\t"					\
+			     "1: mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t"	\
+			     "loop .\n\t"					\
+			     "mov %%edi, %%ecx\n\t"				\
+			     "xor %%eax, %%eax\n\t"				\
+			     "xor %%edx, %%edx\n\t"				\
+			     "wrmsr\n\t"					\
+			     :: "a"((uint32_t)_value), "d"(_value >> 32),	\
+				"c"(_msr), "D"(_msr)				\
+	);									\
+} while (0)
+
 static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature event,
 				    uint32_t pmc, uint32_t pmc_msr,
 				    uint32_t ctrl_msr, uint64_t ctrl_msr_value)
 {
 	wrmsr(pmc_msr, 0);
 
-	/*
-	 * Enable and disable the PMC in a monolithic asm blob to ensure that
-	 * the compiler can't insert _any_ code into the measured sequence.
-	 * Note, ECX doesn't need to be clobbered as the input value, @pmc_msr,
-	 * is restored before the end of the sequence.
-	 */
-	__asm__ __volatile__("wrmsr\n\t"
-			     "mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t"
-			     "loop .\n\t"
-			     "mov %%edi, %%ecx\n\t"
-			     "xor %%eax, %%eax\n\t"
-			     "xor %%edx, %%edx\n\t"
-			     "wrmsr\n\t"
-			     :: "a"((uint32_t)ctrl_msr_value),
-				"d"(ctrl_msr_value >> 32),
-				"c"(ctrl_msr), "D"(ctrl_msr)
-			     );
+	if (this_cpu_has(X86_FEATURE_CLFLUSHOPT))
+		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflushopt 1f");
+	else if (this_cpu_has(X86_FEATURE_CLFLUSH))
+		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflush 1f");
+	else
+		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "nop");
 
 	guest_assert_event_count(idx, event, pmc, pmc_msr);
 }
-- 
2.42.0.869.gea05f2083d-goog

Re: [PATCH v7 14/19] KVM: selftests: Expand PMU counters test to verify LLC events

[Mi, Dapeng]

On 11/8/2023 8:31 AM, Sean Christopherson wrote:
> Expand the PMU counters test to verify that LLC references and misses have
> non-zero counts when the code being executed while the LLC event(s) is
> active is evicted via CFLUSH{,OPT}.  Note, CLFLUSH{,OPT} requires a fence
> of some kind to ensure the cache lines are flushed before execution
> continues.  Use MFENCE for simplicity (performance is not a concern).
>
> Suggested-by: Jim Mattson <jmattson@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>   .../selftests/kvm/x86_64/pmu_counters_test.c  | 59 +++++++++++++------
>   1 file changed, 40 insertions(+), 19 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> index b9c073d3ade9..90381382c51f 100644
> --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> @@ -14,9 +14,9 @@
>   /*
>    * Number of "extra" instructions that will be counted, i.e. the number of
>    * instructions that are needed to set up the loop and then disabled the
> - * counter.  2 MOV, 2 XOR, 1 WRMSR.
> + * counter.  1 CLFLUSH/CLFLUSHOPT/NOP, 1 MFENCE, 2 MOV, 2 XOR, 1 WRMSR.
>    */
> -#define NUM_EXTRA_INSNS		5
> +#define NUM_EXTRA_INSNS		7
>   #define NUM_INSNS_RETIRED	(NUM_BRANCHES + NUM_EXTRA_INSNS)
>   
>   static uint8_t kvm_pmu_version;
> @@ -107,6 +107,12 @@ static void guest_assert_event_count(uint8_t idx,
>   	case INTEL_ARCH_BRANCHES_RETIRED_INDEX:
>   		GUEST_ASSERT_EQ(count, NUM_BRANCHES);
>   		break;
> +	case INTEL_ARCH_LLC_REFERENCES_INDEX:
> +	case INTEL_ARCH_LLC_MISSES_INDEX:
> +		if (!this_cpu_has(X86_FEATURE_CLFLUSHOPT) &&
> +		    !this_cpu_has(X86_FEATURE_CLFLUSH))
> +			break;
> +		fallthrough;
>   	case INTEL_ARCH_CPU_CYCLES_INDEX:
>   	case INTEL_ARCH_REFERENCE_CYCLES_INDEX:
>   		GUEST_ASSERT_NE(count, 0);
> @@ -123,29 +129,44 @@ static void guest_assert_event_count(uint8_t idx,
>   	GUEST_ASSERT_EQ(_rdpmc(pmc), 0xdead);
>   }
>   
> +/*
> + * Enable and disable the PMC in a monolithic asm blob to ensure that the
> + * compiler can't insert _any_ code into the measured sequence.  Note, ECX
> + * doesn't need to be clobbered as the input value, @pmc_msr, is restored
> + * before the end of the sequence.
> + *
> + * If CLFUSH{,OPT} is supported, flush the cacheline containing (at least) the
> + * start of the loop to force LLC references and misses, i.e. to allow testing
> + * that those events actually count.
> + */
> +#define GUEST_MEASURE_EVENT(_msr, _value, clflush)				\
> +do {										\
> +	__asm__ __volatile__("wrmsr\n\t"					\
> +			     clflush "\n\t"					\
> +			     "mfence\n\t"					\
> +			     "1: mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t"	\
> +			     "loop .\n\t"					\
> +			     "mov %%edi, %%ecx\n\t"				\
> +			     "xor %%eax, %%eax\n\t"				\
> +			     "xor %%edx, %%edx\n\t"				\
> +			     "wrmsr\n\t"					\
> +			     :: "a"((uint32_t)_value), "d"(_value >> 32),	\
> +				"c"(_msr), "D"(_msr)				\
> +	);									\
> +} while (0)
> +
>   static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature event,
>   				    uint32_t pmc, uint32_t pmc_msr,
>   				    uint32_t ctrl_msr, uint64_t ctrl_msr_value)
>   {
>   	wrmsr(pmc_msr, 0);
>   
> -	/*
> -	 * Enable and disable the PMC in a monolithic asm blob to ensure that
> -	 * the compiler can't insert _any_ code into the measured sequence.
> -	 * Note, ECX doesn't need to be clobbered as the input value, @pmc_msr,
> -	 * is restored before the end of the sequence.
> -	 */
> -	__asm__ __volatile__("wrmsr\n\t"
> -			     "mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t"
> -			     "loop .\n\t"
> -			     "mov %%edi, %%ecx\n\t"
> -			     "xor %%eax, %%eax\n\t"
> -			     "xor %%edx, %%edx\n\t"
> -			     "wrmsr\n\t"
> -			     :: "a"((uint32_t)ctrl_msr_value),
> -				"d"(ctrl_msr_value >> 32),
> -				"c"(ctrl_msr), "D"(ctrl_msr)
> -			     );
> +	if (this_cpu_has(X86_FEATURE_CLFLUSHOPT))
> +		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflushopt 1f");
> +	else if (this_cpu_has(X86_FEATURE_CLFLUSH))
> +		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflush 1f");
> +	else
> +		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "nop");
>   
>   	guest_assert_event_count(idx, event, pmc, pmc_msr);
>   }


Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>

[PATCH v7 15/19] KVM: selftests: Add a helper to query if the PMU module param is enabled

[Sean Christopherson]

Add a helper to problem KVM's "enable_pmu" param, open coding strings in
multiple places is just asking for a false negatives and/or runtime errors
due to typos.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/include/x86_64/processor.h     | 5 +++++
 tools/testing/selftests/kvm/x86_64/pmu_counters_test.c     | 2 +-
 tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c | 2 +-
 tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c     | 2 +-
 4 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 64aecb3dcf60..c261e0941dfe 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -1216,6 +1216,11 @@ static inline uint8_t xsetbv_safe(uint32_t index, uint64_t value)
 
 bool kvm_is_tdp_enabled(void);
 
+static inline bool kvm_is_pmu_enabled(void)
+{
+	return get_kvm_param_bool("enable_pmu");
+}
+
 uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr,
 				    int *level);
 uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr);
diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
index 90381382c51f..d775cc7e8fab 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -537,7 +537,7 @@ static void test_intel_counters(void)
 
 int main(int argc, char *argv[])
 {
-	TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
+	TEST_REQUIRE(kvm_is_pmu_enabled());
 
 	TEST_REQUIRE(host_cpu_is_intel);
 	TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
index 7ec9fbed92e0..fa407e2ccb2f 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
@@ -867,7 +867,7 @@ int main(int argc, char *argv[])
 	struct kvm_vcpu *vcpu, *vcpu2 = NULL;
 	struct kvm_vm *vm;
 
-	TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
+	TEST_REQUIRE(kvm_is_pmu_enabled());
 	TEST_REQUIRE(kvm_has_cap(KVM_CAP_PMU_EVENT_FILTER));
 	TEST_REQUIRE(kvm_has_cap(KVM_CAP_PMU_EVENT_MASKED_EVENTS));
 
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c b/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
index ebbcb0a3f743..562b0152a122 100644
--- a/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
+++ b/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
@@ -237,7 +237,7 @@ int main(int argc, char *argv[])
 {
 	union perf_capabilities host_cap;
 
-	TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
+	TEST_REQUIRE(kvm_is_pmu_enabled());
 	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_PDCM));
 
 	TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
-- 
2.42.0.869.gea05f2083d-goog

Re: [PATCH v7 15/19] KVM: selftests: Add a helper to query if the PMU module param is enabled

[Mi, Dapeng]

On 11/8/2023 8:31 AM, Sean Christopherson wrote:
> Add a helper to problem KVM's "enable_pmu" param, open coding strings in
> multiple places is just asking for a false negatives and/or runtime errors
> due to typos.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>   tools/testing/selftests/kvm/include/x86_64/processor.h     | 5 +++++
>   tools/testing/selftests/kvm/x86_64/pmu_counters_test.c     | 2 +-
>   tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c | 2 +-
>   tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c     | 2 +-
>   4 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
> index 64aecb3dcf60..c261e0941dfe 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/processor.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
> @@ -1216,6 +1216,11 @@ static inline uint8_t xsetbv_safe(uint32_t index, uint64_t value)
>   
>   bool kvm_is_tdp_enabled(void);
>   
> +static inline bool kvm_is_pmu_enabled(void)
> +{
> +	return get_kvm_param_bool("enable_pmu");
> +}
> +
>   uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr,
>   				    int *level);
>   uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr);
> diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> index 90381382c51f..d775cc7e8fab 100644
> --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> @@ -537,7 +537,7 @@ static void test_intel_counters(void)
>   
>   int main(int argc, char *argv[])
>   {
> -	TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
> +	TEST_REQUIRE(kvm_is_pmu_enabled());
>   
>   	TEST_REQUIRE(host_cpu_is_intel);
>   	TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
> diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
> index 7ec9fbed92e0..fa407e2ccb2f 100644
> --- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
> @@ -867,7 +867,7 @@ int main(int argc, char *argv[])
>   	struct kvm_vcpu *vcpu, *vcpu2 = NULL;
>   	struct kvm_vm *vm;
>   
> -	TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
> +	TEST_REQUIRE(kvm_is_pmu_enabled());
>   	TEST_REQUIRE(kvm_has_cap(KVM_CAP_PMU_EVENT_FILTER));
>   	TEST_REQUIRE(kvm_has_cap(KVM_CAP_PMU_EVENT_MASKED_EVENTS));
>   
> diff --git a/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c b/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
> index ebbcb0a3f743..562b0152a122 100644
> --- a/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
> @@ -237,7 +237,7 @@ int main(int argc, char *argv[])
>   {
>   	union perf_capabilities host_cap;
>   
> -	TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
> +	TEST_REQUIRE(kvm_is_pmu_enabled());
>   	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_PDCM));
>   
>   	TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>

[PATCH v7 16/19] KVM: selftests: Add helpers to read integer module params

[Sean Christopherson]

Add helpers to read integer module params, which is painfully non-trivial
because the pain of dealing with strings in C is exacerbated by the kernel
inserting a newline.

Don't bother differentiating between int, uint, short, etc.  They all fit
in an int, and KVM (thankfully) doesn't have any integer params larger
than an int.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/include/kvm_util_base.h     |  4 ++
 tools/testing/selftests/kvm/lib/kvm_util.c    | 62 +++++++++++++++++--
 2 files changed, 60 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index a18db6a7b3cf..46b71241216e 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -238,6 +238,10 @@ bool get_kvm_param_bool(const char *param);
 bool get_kvm_intel_param_bool(const char *param);
 bool get_kvm_amd_param_bool(const char *param);
 
+int get_kvm_param_integer(const char *param);
+int get_kvm_intel_param_integer(const char *param);
+int get_kvm_amd_param_integer(const char *param);
+
 unsigned int kvm_check_cap(long cap);
 
 static inline bool kvm_has_cap(long cap)
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 7a8af1821f5d..65101c7d1a1a 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -51,13 +51,13 @@ int open_kvm_dev_path_or_exit(void)
 	return _open_kvm_dev_path_or_exit(O_RDONLY);
 }
 
-static bool get_module_param_bool(const char *module_name, const char *param)
+static ssize_t get_module_param(const char *module_name, const char *param,
+				void *buffer, size_t buffer_size)
 {
 	const int path_size = 128;
 	char path[path_size];
-	char value;
-	ssize_t r;
-	int fd;
+	ssize_t bytes_read;
+	int fd, r;
 
 	r = snprintf(path, path_size, "/sys/module/%s/parameters/%s",
 		     module_name, param);
@@ -66,11 +66,46 @@ static bool get_module_param_bool(const char *module_name, const char *param)
 
 	fd = open_path_or_exit(path, O_RDONLY);
 
-	r = read(fd, &value, 1);
-	TEST_ASSERT(r == 1, "read(%s) failed", path);
+	bytes_read = read(fd, buffer, buffer_size);
+	TEST_ASSERT(bytes_read > 0, "read(%s) returned %ld, wanted %ld bytes",
+		    path, bytes_read, buffer_size);
 
 	r = close(fd);
 	TEST_ASSERT(!r, "close(%s) failed", path);
+	return bytes_read;
+}
+
+static int get_module_param_integer(const char *module_name, const char *param)
+{
+	/*
+	 * 16 bytes to hold a 64-bit value (1 byte per char), 1 byte for the
+	 * NUL char, and 1 byte because the kernel sucks and inserts a newline
+	 * at the end.
+	 */
+	char value[16 + 1 + 1];
+	ssize_t r;
+
+	memset(value, '\0', sizeof(value));
+
+	r = get_module_param(module_name, param, value, sizeof(value));
+	TEST_ASSERT(value[r - 1] == '\n',
+		    "Expected trailing newline, got char '%c'", value[r - 1]);
+
+	/*
+	 * Squash the newline, otherwise atoi_paranoid() will complain about
+	 * trailing non-NUL characters in the string.
+	 */
+	value[r - 1] = '\0';
+	return atoi_paranoid(value);
+}
+
+static bool get_module_param_bool(const char *module_name, const char *param)
+{
+	char value;
+	ssize_t r;
+
+	r = get_module_param(module_name, param, &value, sizeof(value));
+	TEST_ASSERT_EQ(r, 1);
 
 	if (value == 'Y')
 		return true;
@@ -95,6 +130,21 @@ bool get_kvm_amd_param_bool(const char *param)
 	return get_module_param_bool("kvm_amd", param);
 }
 
+int get_kvm_param_integer(const char *param)
+{
+	return get_module_param_integer("kvm", param);
+}
+
+int get_kvm_intel_param_integer(const char *param)
+{
+	return get_module_param_integer("kvm_intel", param);
+}
+
+int get_kvm_amd_param_integer(const char *param)
+{
+	return get_module_param_integer("kvm_amd", param);
+}
+
 /*
  * Capability
  *
-- 
2.42.0.869.gea05f2083d-goog

[PATCH v7 17/19] KVM: selftests: Query module param to detect FEP in MSR filtering test

[Sean Christopherson]

Add a helper to detect KVM support for forced emulation by querying the
module param, and use the helper to detect support for the MSR filtering
test instead of throwing a noodle/NOP at KVM to see if it sticks.

Cc: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/include/x86_64/processor.h  |  5 ++++
 .../kvm/x86_64/userspace_msr_exit_test.c      | 27 +++++++------------
 2 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index c261e0941dfe..8a404faafb21 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -1221,6 +1221,11 @@ static inline bool kvm_is_pmu_enabled(void)
 	return get_kvm_param_bool("enable_pmu");
 }
 
+static inline bool kvm_is_forced_emulation_enabled(void)
+{
+	return !!get_kvm_param_integer("force_emulation_prefix");
+}
+
 uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr,
 				    int *level);
 uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr);
diff --git a/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c b/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c
index 3533dc2fbfee..9e12dbc47a72 100644
--- a/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c
+++ b/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c
@@ -14,8 +14,7 @@
 
 /* Forced emulation prefix, used to invoke the emulator unconditionally. */
 #define KVM_FEP "ud2; .byte 'k', 'v', 'm';"
-#define KVM_FEP_LENGTH 5
-static int fep_available = 1;
+static bool fep_available;
 
 #define MSR_NON_EXISTENT 0x474f4f00
 
@@ -260,13 +259,6 @@ static void guest_code_filter_allow(void)
 	GUEST_ASSERT(data == 2);
 	GUEST_ASSERT(guest_exception_count == 0);
 
-	/*
-	 * Test to see if the instruction emulator is available (ie: the module
-	 * parameter 'kvm.force_emulation_prefix=1' is set).  This instruction
-	 * will #UD if it isn't available.
-	 */
-	__asm__ __volatile__(KVM_FEP "nop");
-
 	if (fep_available) {
 		/* Let userspace know we aren't done. */
 		GUEST_SYNC(0);
@@ -388,12 +380,6 @@ static void guest_fep_gp_handler(struct ex_regs *regs)
 			   &em_wrmsr_start, &em_wrmsr_end);
 }
 
-static void guest_ud_handler(struct ex_regs *regs)
-{
-	fep_available = 0;
-	regs->rip += KVM_FEP_LENGTH;
-}
-
 static void check_for_guest_assert(struct kvm_vcpu *vcpu)
 {
 	struct ucall uc;
@@ -531,9 +517,11 @@ static void test_msr_filter_allow(void)
 {
 	struct kvm_vcpu *vcpu;
 	struct kvm_vm *vm;
+	uint64_t cmd;
 	int rc;
 
 	vm = vm_create_with_one_vcpu(&vcpu, guest_code_filter_allow);
+	sync_global_to_guest(vm, fep_available);
 
 	rc = kvm_check_cap(KVM_CAP_X86_USER_SPACE_MSR);
 	TEST_ASSERT(rc, "KVM_CAP_X86_USER_SPACE_MSR is available");
@@ -561,11 +549,11 @@ static void test_msr_filter_allow(void)
 	run_guest_then_process_wrmsr(vcpu, MSR_NON_EXISTENT);
 	run_guest_then_process_rdmsr(vcpu, MSR_NON_EXISTENT);
 
-	vm_install_exception_handler(vm, UD_VECTOR, guest_ud_handler);
 	vcpu_run(vcpu);
-	vm_install_exception_handler(vm, UD_VECTOR, NULL);
+	cmd = process_ucall(vcpu);
 
-	if (process_ucall(vcpu) != UCALL_DONE) {
+	if (fep_available) {
+		TEST_ASSERT_EQ(cmd, UCALL_SYNC);
 		vm_install_exception_handler(vm, GP_VECTOR, guest_fep_gp_handler);
 
 		/* Process emulated rdmsr and wrmsr instructions. */
@@ -583,6 +571,7 @@ static void test_msr_filter_allow(void)
 		/* Confirm the guest completed without issues. */
 		run_guest_then_process_ucall_done(vcpu);
 	} else {
+		TEST_ASSERT_EQ(cmd, UCALL_DONE);
 		printf("To run the instruction emulated tests set the module parameter 'kvm.force_emulation_prefix=1'\n");
 	}
 
@@ -804,6 +793,8 @@ static void test_user_exit_msr_flags(void)
 
 int main(int argc, char *argv[])
 {
+	fep_available = kvm_is_forced_emulation_enabled();
+
 	test_msr_filter_allow();
 
 	test_msr_filter_deny();
-- 
2.42.0.869.gea05f2083d-goog

[PATCH v7 18/19] KVM: selftests: Move KVM_FEP macro into common library header

[Sean Christopherson]

Move the KVM_FEP definition, a.k.a. the KVM force emulation prefix, into
processor.h so that it can be used for other tests besides the MSR filter
test.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/include/x86_64/processor.h       | 3 +++
 tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c | 2 --
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 8a404faafb21..e5c383bd313b 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -22,6 +22,9 @@
 extern bool host_cpu_is_intel;
 extern bool host_cpu_is_amd;
 
+/* Forced emulation prefix, used to invoke the emulator unconditionally. */
+#define KVM_FEP "ud2; .byte 'k', 'v', 'm';"
+
 #define NMI_VECTOR		0x02
 
 #define X86_EFLAGS_FIXED	 (1u << 1)
diff --git a/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c b/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c
index 9e12dbc47a72..ab3a8c4f0b86 100644
--- a/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c
+++ b/tools/testing/selftests/kvm/x86_64/userspace_msr_exit_test.c
@@ -12,8 +12,6 @@
 #include "kvm_util.h"
 #include "vmx.h"
 
-/* Forced emulation prefix, used to invoke the emulator unconditionally. */
-#define KVM_FEP "ud2; .byte 'k', 'v', 'm';"
 static bool fep_available;
 
 #define MSR_NON_EXISTENT 0x474f4f00
-- 
2.42.0.869.gea05f2083d-goog

[PATCH v7 19/19] KVM: selftests: Test PMC virtualization with forced emulation

[Sean Christopherson]

Extend the PMC counters test to use forced emulation to verify that KVM
emulates counter events for instructions retired and branches retired.
Force emulation for only a subset of the measured code to test that KVM
does the right thing when mixing perf events with emulated events.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 .../selftests/kvm/x86_64/pmu_counters_test.c  | 44 +++++++++++++------
 1 file changed, 30 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
index d775cc7e8fab..09332b3c0a69 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
@@ -21,6 +21,7 @@
 
 static uint8_t kvm_pmu_version;
 static bool kvm_has_perf_caps;
+static bool is_forced_emulation_enabled;
 
 static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu,
 						  void *guest_code,
@@ -34,6 +35,7 @@ static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu,
 	vcpu_init_descriptor_tables(*vcpu);
 
 	sync_global_to_guest(vm, kvm_pmu_version);
+	sync_global_to_guest(vm, is_forced_emulation_enabled);
 
 	/*
 	 * Set PERF_CAPABILITIES before PMU version as KVM disallows enabling
@@ -138,37 +140,50 @@ static void guest_assert_event_count(uint8_t idx,
  * If CLFUSH{,OPT} is supported, flush the cacheline containing (at least) the
  * start of the loop to force LLC references and misses, i.e. to allow testing
  * that those events actually count.
+ *
+ * If forced emulation is enabled (and specified), force emulation on a subset
+ * of the measured code to verify that KVM correctly emulates instructions and
+ * branches retired events in conjunction with hardware also counting said
+ * events.
  */
-#define GUEST_MEASURE_EVENT(_msr, _value, clflush)				\
+#define GUEST_MEASURE_EVENT(_msr, _value, clflush, FEP)				\
 do {										\
 	__asm__ __volatile__("wrmsr\n\t"					\
 			     clflush "\n\t"					\
 			     "mfence\n\t"					\
 			     "1: mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t"	\
-			     "loop .\n\t"					\
-			     "mov %%edi, %%ecx\n\t"				\
-			     "xor %%eax, %%eax\n\t"				\
-			     "xor %%edx, %%edx\n\t"				\
+			     FEP "loop .\n\t"					\
+			     FEP "mov %%edi, %%ecx\n\t"				\
+			     FEP "xor %%eax, %%eax\n\t"				\
+			     FEP "xor %%edx, %%edx\n\t"				\
 			     "wrmsr\n\t"					\
 			     :: "a"((uint32_t)_value), "d"(_value >> 32),	\
 				"c"(_msr), "D"(_msr)				\
 	);									\
 } while (0)
 
+#define GUEST_TEST_EVENT(_idx, _event, _pmc, _pmc_msr, _ctrl_msr, _value, FEP)	\
+do {										\
+	wrmsr(pmc_msr, 0);							\
+										\
+	if (this_cpu_has(X86_FEATURE_CLFLUSHOPT))				\
+		GUEST_MEASURE_EVENT(_ctrl_msr, _value, "clflushopt 1f", FEP);	\
+	else if (this_cpu_has(X86_FEATURE_CLFLUSH))				\
+		GUEST_MEASURE_EVENT(_ctrl_msr, _value, "clflush 1f", FEP);	\
+	else									\
+		GUEST_MEASURE_EVENT(_ctrl_msr, _value, "nop", FEP);		\
+										\
+	guest_assert_event_count(_idx, _event, _pmc, _pmc_msr);			\
+} while (0)
+
 static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature event,
 				    uint32_t pmc, uint32_t pmc_msr,
 				    uint32_t ctrl_msr, uint64_t ctrl_msr_value)
 {
-	wrmsr(pmc_msr, 0);
+	GUEST_TEST_EVENT(idx, event, pmc, pmc_msr, ctrl_msr, ctrl_msr_value, "");
 
-	if (this_cpu_has(X86_FEATURE_CLFLUSHOPT))
-		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflushopt 1f");
-	else if (this_cpu_has(X86_FEATURE_CLFLUSH))
-		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflush 1f");
-	else
-		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "nop");
-
-	guest_assert_event_count(idx, event, pmc, pmc_msr);
+	if (is_forced_emulation_enabled)
+		GUEST_TEST_EVENT(idx, event, pmc, pmc_msr, ctrl_msr, ctrl_msr_value, KVM_FEP);
 }
 
 #define X86_PMU_FEATURE_NULL						\
@@ -545,6 +560,7 @@ int main(int argc, char *argv[])
 
 	kvm_pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION);
 	kvm_has_perf_caps = kvm_cpu_has(X86_FEATURE_PDCM);
+	is_forced_emulation_enabled = kvm_is_forced_emulation_enabled();
 
 	test_intel_counters();
 
-- 
2.42.0.869.gea05f2083d-goog

Re: [PATCH v7 19/19] KVM: selftests: Test PMC virtualization with forced emulation

[Mi, Dapeng]

On 11/8/2023 8:31 AM, Sean Christopherson wrote:
> Extend the PMC counters test to use forced emulation to verify that KVM
> emulates counter events for instructions retired and branches retired.
> Force emulation for only a subset of the measured code to test that KVM
> does the right thing when mixing perf events with emulated events.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>   .../selftests/kvm/x86_64/pmu_counters_test.c  | 44 +++++++++++++------
>   1 file changed, 30 insertions(+), 14 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> index d775cc7e8fab..09332b3c0a69 100644
> --- a/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/pmu_counters_test.c
> @@ -21,6 +21,7 @@
>   
>   static uint8_t kvm_pmu_version;
>   static bool kvm_has_perf_caps;
> +static bool is_forced_emulation_enabled;
>   
>   static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu,
>   						  void *guest_code,
> @@ -34,6 +35,7 @@ static struct kvm_vm *pmu_vm_create_with_one_vcpu(struct kvm_vcpu **vcpu,
>   	vcpu_init_descriptor_tables(*vcpu);
>   
>   	sync_global_to_guest(vm, kvm_pmu_version);
> +	sync_global_to_guest(vm, is_forced_emulation_enabled);
>   
>   	/*
>   	 * Set PERF_CAPABILITIES before PMU version as KVM disallows enabling
> @@ -138,37 +140,50 @@ static void guest_assert_event_count(uint8_t idx,
>    * If CLFUSH{,OPT} is supported, flush the cacheline containing (at least) the
>    * start of the loop to force LLC references and misses, i.e. to allow testing
>    * that those events actually count.
> + *
> + * If forced emulation is enabled (and specified), force emulation on a subset
> + * of the measured code to verify that KVM correctly emulates instructions and
> + * branches retired events in conjunction with hardware also counting said
> + * events.
>    */
> -#define GUEST_MEASURE_EVENT(_msr, _value, clflush)				\
> +#define GUEST_MEASURE_EVENT(_msr, _value, clflush, FEP)				\
>   do {										\
>   	__asm__ __volatile__("wrmsr\n\t"					\
>   			     clflush "\n\t"					\
>   			     "mfence\n\t"					\
>   			     "1: mov $" __stringify(NUM_BRANCHES) ", %%ecx\n\t"	\
> -			     "loop .\n\t"					\
> -			     "mov %%edi, %%ecx\n\t"				\
> -			     "xor %%eax, %%eax\n\t"				\
> -			     "xor %%edx, %%edx\n\t"				\
> +			     FEP "loop .\n\t"					\
> +			     FEP "mov %%edi, %%ecx\n\t"				\
> +			     FEP "xor %%eax, %%eax\n\t"				\
> +			     FEP "xor %%edx, %%edx\n\t"				\
>   			     "wrmsr\n\t"					\
>   			     :: "a"((uint32_t)_value), "d"(_value >> 32),	\
>   				"c"(_msr), "D"(_msr)				\
>   	);									\
>   } while (0)
>   
> +#define GUEST_TEST_EVENT(_idx, _event, _pmc, _pmc_msr, _ctrl_msr, _value, FEP)	\
> +do {										\
> +	wrmsr(pmc_msr, 0);							\
> +										\
> +	if (this_cpu_has(X86_FEATURE_CLFLUSHOPT))				\
> +		GUEST_MEASURE_EVENT(_ctrl_msr, _value, "clflushopt 1f", FEP);	\
> +	else if (this_cpu_has(X86_FEATURE_CLFLUSH))				\
> +		GUEST_MEASURE_EVENT(_ctrl_msr, _value, "clflush 1f", FEP);	\
> +	else									\
> +		GUEST_MEASURE_EVENT(_ctrl_msr, _value, "nop", FEP);		\
> +										\
> +	guest_assert_event_count(_idx, _event, _pmc, _pmc_msr);			\
> +} while (0)
> +
>   static void __guest_test_arch_event(uint8_t idx, struct kvm_x86_pmu_feature event,
>   				    uint32_t pmc, uint32_t pmc_msr,
>   				    uint32_t ctrl_msr, uint64_t ctrl_msr_value)
>   {
> -	wrmsr(pmc_msr, 0);
> +	GUEST_TEST_EVENT(idx, event, pmc, pmc_msr, ctrl_msr, ctrl_msr_value, "");
>   
> -	if (this_cpu_has(X86_FEATURE_CLFLUSHOPT))
> -		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflushopt 1f");
> -	else if (this_cpu_has(X86_FEATURE_CLFLUSH))
> -		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "clflush 1f");
> -	else
> -		GUEST_MEASURE_EVENT(ctrl_msr, ctrl_msr_value, "nop");
> -
> -	guest_assert_event_count(idx, event, pmc, pmc_msr);
> +	if (is_forced_emulation_enabled)
> +		GUEST_TEST_EVENT(idx, event, pmc, pmc_msr, ctrl_msr, ctrl_msr_value, KVM_FEP);
>   }
>   
>   #define X86_PMU_FEATURE_NULL						\
> @@ -545,6 +560,7 @@ int main(int argc, char *argv[])
>   
>   	kvm_pmu_version = kvm_cpu_property(X86_PROPERTY_PMU_VERSION);
>   	kvm_has_perf_caps = kvm_cpu_has(X86_FEATURE_PDCM);
> +	is_forced_emulation_enabled = kvm_is_forced_emulation_enabled();
>   
>   	test_intel_counters();
>   

Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>