linux-kernel - [PATCH v5 31/44] KVM: x86/pmu: Restrict GLOBAL_{CTRL,STATUS}, fixed PMCs, and PEBS to PMU v2+

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250806195706.1650976-32-seanjc@google.com>
Date: Wed,  6 Aug 2025 12:56:53 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
	Tianrui Zhao <zhaotianrui@...ngson.cn>, Bibo Mao <maobibo@...ngson.cn>, 
	Huacai Chen <chenhuacai@...nel.org>, Anup Patel <anup@...infault.org>, 
	Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>, 
	Albert Ou <aou@...s.berkeley.edu>, Xin Li <xin@...or.com>, "H. Peter Anvin" <hpa@...or.com>, 
	Andy Lutomirski <luto@...nel.org>, Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev, 
	kvm@...r.kernel.org, loongarch@...ts.linux.dev, kvm-riscv@...ts.infradead.org, 
	linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-perf-users@...r.kernel.org, Kan Liang <kan.liang@...ux.intel.com>, 
	Yongwei Ma <yongwei.ma@...el.com>, Mingwei Zhang <mizhang@...gle.com>, 
	Xiong Zhang <xiong.y.zhang@...ux.intel.com>, Sandipan Das <sandipan.das@....com>, 
	Dapeng Mi <dapeng1.mi@...ux.intel.com>
Subject: [PATCH v5 31/44] KVM: x86/pmu: Restrict GLOBAL_{CTRL,STATUS}, fixed
 PMCs, and PEBS to PMU v2+

Restrict support for GLOBAL_CTRL, GLOBAL_STATUS, fixed PMCs, and PEBS to
v2 or later vPMUs.  The SDM explicitly states that GLOBAL_{CTRL,STATUS} and
fixed counters were introduced with PMU v2, and PEBS has hard dependencies
on fixed counters and the bitmap MSR layouts established by PMU v2.

Reported-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 51 ++++++++++++++++++------------------
 1 file changed, 25 insertions(+), 26 deletions(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 1de94a39ca18..779b4e64acac 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -541,16 +541,33 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 				      kvm_pmu_cap.events_mask_len);
 	pmu->available_event_types = ~entry->ebx & (BIT_ULL(eax.split.mask_length) - 1);
 
-	if (pmu->version == 1) {
-		pmu->nr_arch_fixed_counters = 0;
-	} else {
-		pmu->nr_arch_fixed_counters = min_t(int, edx.split.num_counters_fixed,
-						    kvm_pmu_cap.num_counters_fixed);
-		edx.split.bit_width_fixed = min_t(int, edx.split.bit_width_fixed,
-						  kvm_pmu_cap.bit_width_fixed);
-		pmu->counter_bitmask[KVM_PMC_FIXED] = BIT_ULL(edx.split.bit_width_fixed) - 1;
+	entry = kvm_find_cpuid_entry_index(vcpu, 7, 0);
+	if (entry &&
+	    (boot_cpu_has(X86_FEATURE_HLE) || boot_cpu_has(X86_FEATURE_RTM)) &&
+	    (entry->ebx & (X86_FEATURE_HLE|X86_FEATURE_RTM))) {
+		pmu->reserved_bits ^= HSW_IN_TX;
+		pmu->raw_event_mask |= (HSW_IN_TX|HSW_IN_TX_CHECKPOINTED);
 	}
 
+	perf_capabilities = vcpu_get_perf_capabilities(vcpu);
+	if (intel_pmu_lbr_is_compatible(vcpu) &&
+	    (perf_capabilities & PERF_CAP_LBR_FMT))
+		memcpy(&lbr_desc->records, &vmx_lbr_caps, sizeof(vmx_lbr_caps));
+	else
+		lbr_desc->records.nr = 0;
+
+	if (lbr_desc->records.nr)
+		bitmap_set(pmu->all_valid_pmc_idx, INTEL_PMC_IDX_FIXED_VLBR, 1);
+
+	if (pmu->version == 1)
+		return;
+
+	pmu->nr_arch_fixed_counters = min_t(int, edx.split.num_counters_fixed,
+					    kvm_pmu_cap.num_counters_fixed);
+	edx.split.bit_width_fixed = min_t(int, edx.split.bit_width_fixed,
+					  kvm_pmu_cap.bit_width_fixed);
+	pmu->counter_bitmask[KVM_PMC_FIXED] = BIT_ULL(edx.split.bit_width_fixed) - 1;
+
 	intel_pmu_enable_fixed_counter_bits(pmu, INTEL_FIXED_0_KERNEL |
 						 INTEL_FIXED_0_USER |
 						 INTEL_FIXED_0_ENABLE_PMI);
@@ -571,24 +588,6 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 		pmu->global_status_rsvd &=
 				~MSR_CORE_PERF_GLOBAL_OVF_CTRL_TRACE_TOPA_PMI;
 
-	entry = kvm_find_cpuid_entry_index(vcpu, 7, 0);
-	if (entry &&
-	    (boot_cpu_has(X86_FEATURE_HLE) || boot_cpu_has(X86_FEATURE_RTM)) &&
-	    (entry->ebx & (X86_FEATURE_HLE|X86_FEATURE_RTM))) {
-		pmu->reserved_bits ^= HSW_IN_TX;
-		pmu->raw_event_mask |= (HSW_IN_TX|HSW_IN_TX_CHECKPOINTED);
-	}
-
-	perf_capabilities = vcpu_get_perf_capabilities(vcpu);
-	if (intel_pmu_lbr_is_compatible(vcpu) &&
-	    (perf_capabilities & PERF_CAP_LBR_FMT))
-		memcpy(&lbr_desc->records, &vmx_lbr_caps, sizeof(vmx_lbr_caps));
-	else
-		lbr_desc->records.nr = 0;
-
-	if (lbr_desc->records.nr)
-		bitmap_set(pmu->all_valid_pmc_idx, INTEL_PMC_IDX_FIXED_VLBR, 1);
-
 	if (perf_capabilities & PERF_CAP_PEBS_FORMAT) {
 		if (perf_capabilities & PERF_CAP_PEBS_BASELINE) {
 			pmu->pebs_enable_rsvd = counter_rsvd;
-- 
2.50.1.565.gc32cd1483b-goog