[Patch v2 1/2] KVM: x86/pmu: Introduce distinct macros for GP/fixed counter max number

[Patch v2 1/2] KVM: x86/pmu: Introduce distinct macros for GP/fixed counter max number

[Dapeng Mi]

Refine the macros which define maximum General Purpose (GP) and fixed
counter numbers.

Currently the macro KVM_INTEL_PMC_MAX_GENERIC is used to represent the
maximum supported General Purpose (GP) counter number ambiguously across
Intel and AMD platforms. This would cause issues if AMD begins to support
more GP counters than Intel.

Thus a bunch of new macros including vendor specific and vendor
independent are introduced to replace the old macros. The vendor
independent macros are used in x86 common code to hide vendor difference
and eliminate the ambiguity.

No logic changes are introduced in this patch.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
 arch/x86/include/asm/kvm_host.h | 20 ++++++++++++--------
 arch/x86/kvm/pmu.c              |  2 +-
 arch/x86/kvm/pmu.h              |  2 +-
 arch/x86/kvm/svm/pmu.c          |  7 +++----
 arch/x86/kvm/vmx/pmu_intel.c    | 10 +++++-----
 arch/x86/kvm/x86.c              | 15 +++++++++------
 6 files changed, 31 insertions(+), 25 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 57440bda4dc4..d565c6f11fdf 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -533,12 +533,16 @@ struct kvm_pmc {
 };
 
 /* More counters may conflict with other existing Architectural MSRs */
-#define KVM_INTEL_PMC_MAX_GENERIC	8
-#define MSR_ARCH_PERFMON_PERFCTR_MAX	(MSR_ARCH_PERFMON_PERFCTR0 + KVM_INTEL_PMC_MAX_GENERIC - 1)
-#define MSR_ARCH_PERFMON_EVENTSEL_MAX	(MSR_ARCH_PERFMON_EVENTSEL0 + KVM_INTEL_PMC_MAX_GENERIC - 1)
-#define KVM_PMC_MAX_FIXED	3
-#define MSR_ARCH_PERFMON_FIXED_CTR_MAX	(MSR_ARCH_PERFMON_FIXED_CTR0 + KVM_PMC_MAX_FIXED - 1)
-#define KVM_AMD_PMC_MAX_GENERIC	6
+#define KVM_MAX(a, b)	((a) >= (b) ? (a) : (b))
+#define KVM_MAX_NR_INTEL_GP_COUNTERS	8
+#define KVM_MAX_NR_AMD_GP_COUNTERS	6
+#define KVM_MAX_NR_GP_COUNTERS		KVM_MAX(KVM_MAX_NR_INTEL_GP_COUNTERS, \
+						KVM_MAX_NR_AMD_GP_COUNTERS)
+
+#define KVM_MAX_NR_INTEL_FIXED_COUTNERS	3
+#define KVM_MAX_NR_AMD_FIXED_COUTNERS	0
+#define KVM_MAX_NR_FIXED_COUNTERS	KVM_MAX(KVM_MAX_NR_INTEL_FIXED_COUTNERS, \
+						KVM_MAX_NR_AMD_FIXED_COUTNERS)
 
 struct kvm_pmu {
 	u8 version;
@@ -554,8 +558,8 @@ struct kvm_pmu {
 	u64 global_status_rsvd;
 	u64 reserved_bits;
 	u64 raw_event_mask;
-	struct kvm_pmc gp_counters[KVM_INTEL_PMC_MAX_GENERIC];
-	struct kvm_pmc fixed_counters[KVM_PMC_MAX_FIXED];
+	struct kvm_pmc gp_counters[KVM_MAX_NR_GP_COUNTERS];
+	struct kvm_pmc fixed_counters[KVM_MAX_NR_FIXED_COUNTERS];
 
 	/*
 	 * Overlay the bitmap with a 64-bit atomic so that all bits can be
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 42422a73a348..47a46283c866 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -69,7 +69,7 @@ static const struct x86_cpu_id vmx_pebs_pdist_cpu[] = {
  *        code. Each pmc, stored in kvm_pmc.idx field, is unique across
  *        all perf counters (both gp and fixed). The mapping relationship
  *        between pmc and perf counters is as the following:
- *        * Intel: [0 .. KVM_INTEL_PMC_MAX_GENERIC-1] <=> gp counters
+ *        * Intel: [0 .. KVM_MAX_NR_INTEL_GP_COUNTERS-1] <=> gp counters
  *                 [KVM_FIXED_PMC_BASE_IDX .. KVM_FIXED_PMC_BASE_IDX + 2] <=> fixed
  *        * AMD:   [0 .. AMD64_NUM_COUNTERS-1] and, for families 15H
  *          and later, [0 .. AMD64_NUM_COUNTERS_CORE-1] <=> gp counters
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index d54741fe4bdd..ad89d0bd6005 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -219,7 +219,7 @@ static inline void kvm_init_pmu_capability(const struct kvm_pmu_ops *pmu_ops)
 	kvm_pmu_cap.num_counters_gp = min(kvm_pmu_cap.num_counters_gp,
 					  pmu_ops->MAX_NR_GP_COUNTERS);
 	kvm_pmu_cap.num_counters_fixed = min(kvm_pmu_cap.num_counters_fixed,
-					     KVM_PMC_MAX_FIXED);
+					     KVM_MAX_NR_FIXED_COUNTERS);
 
 	kvm_pmu_eventsel.INSTRUCTIONS_RETIRED =
 		perf_get_hw_event_config(PERF_COUNT_HW_INSTRUCTIONS);
diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index 6e908bdc3310..22d5a65b410c 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -217,10 +217,9 @@ static void amd_pmu_init(struct kvm_vcpu *vcpu)
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 	int i;
 
-	BUILD_BUG_ON(KVM_AMD_PMC_MAX_GENERIC > AMD64_NUM_COUNTERS_CORE);
-	BUILD_BUG_ON(KVM_AMD_PMC_MAX_GENERIC > INTEL_PMC_MAX_GENERIC);
+	BUILD_BUG_ON(KVM_MAX_NR_AMD_GP_COUNTERS > AMD64_NUM_COUNTERS_CORE);
 
-	for (i = 0; i < KVM_AMD_PMC_MAX_GENERIC ; i++) {
+	for (i = 0; i < KVM_MAX_NR_AMD_GP_COUNTERS; i++) {
 		pmu->gp_counters[i].type = KVM_PMC_GP;
 		pmu->gp_counters[i].vcpu = vcpu;
 		pmu->gp_counters[i].idx = i;
@@ -238,6 +237,6 @@ struct kvm_pmu_ops amd_pmu_ops __initdata = {
 	.refresh = amd_pmu_refresh,
 	.init = amd_pmu_init,
 	.EVENTSEL_EVENT = AMD64_EVENTSEL_EVENT,
-	.MAX_NR_GP_COUNTERS = KVM_AMD_PMC_MAX_GENERIC,
+	.MAX_NR_GP_COUNTERS = KVM_MAX_NR_AMD_GP_COUNTERS,
 	.MIN_NR_GP_COUNTERS = AMD64_NUM_COUNTERS,
 };
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index fb5cbd6cbeff..83382a4d1d66 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -436,8 +436,8 @@ static __always_inline u64 intel_get_fixed_pmc_eventsel(unsigned int index)
 	};
 	u64 eventsel;
 
-	BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_perf_ids) != KVM_PMC_MAX_FIXED);
-	BUILD_BUG_ON(index >= KVM_PMC_MAX_FIXED);
+	BUILD_BUG_ON(ARRAY_SIZE(fixed_pmc_perf_ids) != KVM_MAX_NR_INTEL_FIXED_COUTNERS);
+	BUILD_BUG_ON(index >= KVM_MAX_NR_INTEL_FIXED_COUTNERS);
 
 	/*
 	 * Yell if perf reports support for a fixed counter but perf doesn't
@@ -570,14 +570,14 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu)
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 	struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
 
-	for (i = 0; i < KVM_INTEL_PMC_MAX_GENERIC; i++) {
+	for (i = 0; i < KVM_MAX_NR_INTEL_GP_COUNTERS; i++) {
 		pmu->gp_counters[i].type = KVM_PMC_GP;
 		pmu->gp_counters[i].vcpu = vcpu;
 		pmu->gp_counters[i].idx = i;
 		pmu->gp_counters[i].current_config = 0;
 	}
 
-	for (i = 0; i < KVM_PMC_MAX_FIXED; i++) {
+	for (i = 0; i < KVM_MAX_NR_INTEL_FIXED_COUTNERS; i++) {
 		pmu->fixed_counters[i].type = KVM_PMC_FIXED;
 		pmu->fixed_counters[i].vcpu = vcpu;
 		pmu->fixed_counters[i].idx = i + KVM_FIXED_PMC_BASE_IDX;
@@ -737,6 +737,6 @@ struct kvm_pmu_ops intel_pmu_ops __initdata = {
 	.deliver_pmi = intel_pmu_deliver_pmi,
 	.cleanup = intel_pmu_cleanup,
 	.EVENTSEL_EVENT = ARCH_PERFMON_EVENTSEL_EVENT,
-	.MAX_NR_GP_COUNTERS = KVM_INTEL_PMC_MAX_GENERIC,
+	.MAX_NR_GP_COUNTERS = KVM_MAX_NR_INTEL_GP_COUNTERS,
 	.MIN_NR_GP_COUNTERS = 1,
 };
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6ad19d913d31..dea7058ebdd0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1451,7 +1451,7 @@ static const u32 msrs_to_save_pmu[] = {
 	MSR_CORE_PERF_GLOBAL_CTRL,
 	MSR_IA32_PEBS_ENABLE, MSR_IA32_DS_AREA, MSR_PEBS_DATA_CFG,
 
-	/* This part of MSRs should match KVM_INTEL_PMC_MAX_GENERIC. */
+	/* This part of MSRs should match KVM_MAX_NR_INTEL_GP_COUNTERS. */
 	MSR_ARCH_PERFMON_PERFCTR0, MSR_ARCH_PERFMON_PERFCTR1,
 	MSR_ARCH_PERFMON_PERFCTR0 + 2, MSR_ARCH_PERFMON_PERFCTR0 + 3,
 	MSR_ARCH_PERFMON_PERFCTR0 + 4, MSR_ARCH_PERFMON_PERFCTR0 + 5,
@@ -1464,7 +1464,7 @@ static const u32 msrs_to_save_pmu[] = {
 	MSR_K7_EVNTSEL0, MSR_K7_EVNTSEL1, MSR_K7_EVNTSEL2, MSR_K7_EVNTSEL3,
 	MSR_K7_PERFCTR0, MSR_K7_PERFCTR1, MSR_K7_PERFCTR2, MSR_K7_PERFCTR3,
 
-	/* This part of MSRs should match KVM_AMD_PMC_MAX_GENERIC. */
+	/* This part of MSRs should match KVM_MAX_NR_AMD_GP_COUNTERS. */
 	MSR_F15H_PERF_CTL0, MSR_F15H_PERF_CTL1, MSR_F15H_PERF_CTL2,
 	MSR_F15H_PERF_CTL3, MSR_F15H_PERF_CTL4, MSR_F15H_PERF_CTL5,
 	MSR_F15H_PERF_CTR0, MSR_F15H_PERF_CTR1, MSR_F15H_PERF_CTR2,
@@ -7432,17 +7432,20 @@ static void kvm_probe_msr_to_save(u32 msr_index)
 		     intel_pt_validate_hw_cap(PT_CAP_num_address_ranges) * 2))
 			return;
 		break;
-	case MSR_ARCH_PERFMON_PERFCTR0 ... MSR_ARCH_PERFMON_PERFCTR_MAX:
+	case MSR_ARCH_PERFMON_PERFCTR0 ...
+	     MSR_ARCH_PERFMON_PERFCTR0 + KVM_MAX_NR_GP_COUNTERS - 1:
 		if (msr_index - MSR_ARCH_PERFMON_PERFCTR0 >=
 		    kvm_pmu_cap.num_counters_gp)
 			return;
 		break;
-	case MSR_ARCH_PERFMON_EVENTSEL0 ... MSR_ARCH_PERFMON_EVENTSEL_MAX:
+	case MSR_ARCH_PERFMON_EVENTSEL0 ...
+	     MSR_ARCH_PERFMON_EVENTSEL0 + KVM_MAX_NR_GP_COUNTERS - 1:
 		if (msr_index - MSR_ARCH_PERFMON_EVENTSEL0 >=
 		    kvm_pmu_cap.num_counters_gp)
 			return;
 		break;
-	case MSR_ARCH_PERFMON_FIXED_CTR0 ... MSR_ARCH_PERFMON_FIXED_CTR_MAX:
+	case MSR_ARCH_PERFMON_FIXED_CTR0 ...
+	     MSR_ARCH_PERFMON_FIXED_CTR0 + KVM_MAX_NR_FIXED_COUNTERS - 1:
 		if (msr_index - MSR_ARCH_PERFMON_FIXED_CTR0 >=
 		    kvm_pmu_cap.num_counters_fixed)
 			return;
@@ -7473,7 +7476,7 @@ static void kvm_init_msr_lists(void)
 {
 	unsigned i;
 
-	BUILD_BUG_ON_MSG(KVM_PMC_MAX_FIXED != 3,
+	BUILD_BUG_ON_MSG(KVM_MAX_NR_FIXED_COUNTERS != 3,
 			 "Please update the fixed PMCs in msrs_to_save_pmu[]");
 
 	num_msrs_to_save = 0;

base-commit: 0ce958282e66b3d1882e2bb2f503a5e2cebcc3ef
-- 
2.34.1

[Patch v2 2/2] KVM: selftests: Print the seed for the guest pRNG iff it has changed

[Dapeng Mi]

From: Sean Christopherson <seanjc@google.com>

Print the guest's random seed during VM creation if and only if the seed
has changed since the seed was last printed.  The vast majority of tests,
if not all tests at this point, set the seed during test initialization
and never change the seed, i.e. printing it every time a VM is created is
useless noise.

Snapshot and print the seed during early selftest init to play nice with
tests that use the kselftests harness, at the cost of printing an unused
seed for tests that change the seed during test-specific initialization,
e.g. dirty_log_perf_test.  The kselftests harness runs each testcase in a
separate process that is forked from the original process before creating
each testcase's VM, i.e. waiting until first VM creation will result in
the seed being printed by each testcase despite it never changing.  And
long term, the hope/goal is that setting the seed will be handled by the
core framework, i.e. that the dirty_log_perf_test wart will naturally go
away.

Reported-by: Yi Lai <yi1.lai@intel.com>
Reported-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/lib/kvm_util.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index ad00e4761886..56b170b725b3 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -21,6 +21,7 @@
 
 uint32_t guest_random_seed;
 struct guest_random_state guest_rng;
+static uint32_t last_guest_seed;
 
 static int vcpu_mmap_sz(void);
 
@@ -434,7 +435,10 @@ struct kvm_vm *__vm_create(struct vm_shape shape, uint32_t nr_runnable_vcpus,
 	slot0 = memslot2region(vm, 0);
 	ucall_init(vm, slot0->region.guest_phys_addr + slot0->region.memory_size);
 
-	pr_info("Random seed: 0x%x\n", guest_random_seed);
+	if (guest_random_seed != last_guest_seed) {
+		pr_info("Random seed: 0x%x\n", guest_random_seed);
+		last_guest_seed = guest_random_seed;
+	}
 	guest_rng = new_guest_random_state(guest_random_seed);
 	sync_global_to_guest(vm, guest_rng);
 
@@ -2319,7 +2323,8 @@ void __attribute((constructor)) kvm_selftest_init(void)
 	/* Tell stdout not to buffer its content. */
 	setbuf(stdout, NULL);
 
-	guest_random_seed = random();
+	guest_random_seed = last_guest_seed = random();
+	pr_info("Random seed: 0x%x\n", guest_random_seed);
 
 	kvm_selftest_arch_init();
 }
-- 
2.34.1

Re: [Patch v2 1/2] KVM: x86/pmu: Introduce distinct macros for GP/fixed counter max number

[Sean Christopherson]

On Thu, 27 Jun 2024 10:17:55 +0800, Dapeng Mi wrote:
> Refine the macros which define maximum General Purpose (GP) and fixed
> counter numbers.
> 
> Currently the macro KVM_INTEL_PMC_MAX_GENERIC is used to represent the
> maximum supported General Purpose (GP) counter number ambiguously across
> Intel and AMD platforms. This would cause issues if AMD begins to support
> more GP counters than Intel.
> 
> [...]

Applied 1 to kvm-x86 pmu, and 2 to selftests.  Thanks!

[1/2] KVM: x86/pmu: Introduce distinct macros for GP/fixed counter max number
      https://github.com/kvm-x86/linux/commit/f287bef6ddc2
[2/2] KVM: selftests: Print the seed for the guest pRNG iff it has changed
      https://github.com/kvm-x86/linux/commit/ea09ace3f8f3

--
https://github.com/kvm-x86/linux/tree/next