Merge tag 'kvm-x86-pmu-6.9' of https://github.com/kvm-x86/linux into HEAD

KVM x86 PMU changes for 6.9:

 - Fix several bugs where KVM speciously prevents the guest from utilizing
   fixed counters and architectural event encodings based on whether or not
   guest CPUID reports support for the _architectural_ encoding.

 - Fix a variety of bugs in KVM's emulation of RDPMC, e.g. for "fast" reads,
   priority of VMX interception vs #GP, PMC types in architectural PMUs, etc.

 - Add a selftest to verify KVM correctly emulates RDMPC, counter availability,
   and a variety of other PMC-related behaviors that depend on guest CPUID,
   i.e. are difficult to validate via KVM-Unit-Tests.

 - Zero out PMU metadata on AMD if the virtual PMU is disabled to avoid wasting
   cycles, e.g. when checking if a PMC event needs to be synthesized when
   skipping an instruction.

 - Optimize triggering of emulated events, e.g. for "count instructions" events
   when skipping an instruction, which yields a ~10% performance improvement in
   VM-Exit microbenchmarks when a vPMU is exposed to the guest.

 - Tighten the check for "PMI in guest" to reduce false positives if an NMI
   arrives in the host while KVM is handling an IRQ VM-Exit.

2 files changed, 213 insertions, 32 deletions

diff --git a/tools/testing/selftests/kvm/include/x86_64/pmu.h b/tools/testing/selftests/kvm/include/x86_64/pmu.h
new file mode 100644
index 000000000000..3c10c4dc0ae8
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/x86_64/pmu.h
@@ -0,0 +1,97 @@
+/* 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 control flags, Intel only. */
+#define INTEL_RDPMC_METRICS			BIT_ULL(29)
+#define INTEL_RDPMC_FIXED			BIT_ULL(30)
+#define INTEL_RDPMC_FAST			BIT_ULL(31)
+
+/* Fixed PMC controls, Intel only. */
+#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/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index d2534a4a077b..3bd03b088dda 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -29,6 +29,9 @@ enum vm_guest_x86_subtype {
 	VM_SUBTYPE_SEV_ES,
 };
 
+/* 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)
@@ -289,24 +292,41 @@ 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(name, __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(BRANCH_INSNS_RETIRED, 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)
 {
@@ -705,10 +725,16 @@ 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;
+
+	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);
+	}
 
-	return nr_bits > feature.anti_feature.bit &&
-	       !this_cpu_has(feature.anti_feature);
+	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)
@@ -924,10 +950,16 @@ 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;
+
+	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);
+	}
 
-	return nr_bits > feature.anti_feature.bit &&
-	       !kvm_cpu_has(feature.anti_feature);
+	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)
@@ -1002,7 +1034,9 @@ 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,
@@ -1128,16 +1162,19 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
  * r9  = exception vector (non-zero)
  * r10 = error code
  */
-#define KVM_ASM_SAFE(insn)					\
+#define __KVM_ASM_SAFE(insn, fep)				\
 	"mov $" __stringify(KVM_EXCEPTION_MAGIC) ", %%r9\n\t"	\
 	"lea 1f(%%rip), %%r10\n\t"				\
 	"lea 2f(%%rip), %%r11\n\t"				\
-	"1: " insn "\n\t"					\
+	fep "1: " insn "\n\t"					\
 	"xor %%r9, %%r9\n\t"					\
 	"2:\n\t"						\
 	"mov  %%r9b, %[vector]\n\t"				\
 	"mov  %%r10, %[error_code]\n\t"
 
+#define KVM_ASM_SAFE(insn) __KVM_ASM_SAFE(insn, "")
+#define KVM_ASM_SAFE_FEP(insn) __KVM_ASM_SAFE(insn, KVM_FEP)
+
 #define KVM_ASM_SAFE_OUTPUTS(v, ec)	[vector] "=qm"(v), [error_code] "=rm"(ec)
 #define KVM_ASM_SAFE_CLOBBERS	"r9", "r10", "r11"
 
@@ -1164,21 +1201,58 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
 	vector;								\
 })
 
-static inline uint8_t rdmsr_safe(uint32_t msr, uint64_t *val)
-{
-	uint64_t error_code;
-	uint8_t vector;
-	uint32_t a, d;
+#define kvm_asm_safe_fep(insn, inputs...)				\
+({									\
+	uint64_t ign_error_code;					\
+	uint8_t vector;							\
+									\
+	asm volatile(KVM_ASM_SAFE(insn)					\
+		     : KVM_ASM_SAFE_OUTPUTS(vector, ign_error_code)	\
+		     : inputs						\
+		     : KVM_ASM_SAFE_CLOBBERS);				\
+	vector;								\
+})
 
-	asm volatile(KVM_ASM_SAFE("rdmsr")
-		     : "=a"(a), "=d"(d), KVM_ASM_SAFE_OUTPUTS(vector, error_code)
-		     : "c"(msr)
-		     : KVM_ASM_SAFE_CLOBBERS);
+#define kvm_asm_safe_ec_fep(insn, error_code, inputs...)		\
+({									\
+	uint8_t vector;							\
+									\
+	asm volatile(KVM_ASM_SAFE_FEP(insn)				\
+		     : KVM_ASM_SAFE_OUTPUTS(vector, error_code)		\
+		     : inputs						\
+		     : KVM_ASM_SAFE_CLOBBERS);				\
+	vector;								\
+})
 
-	*val = (uint64_t)a | ((uint64_t)d << 32);
-	return vector;
+#define BUILD_READ_U64_SAFE_HELPER(insn, _fep, _FEP)			\
+static inline uint8_t insn##_safe ##_fep(uint32_t idx, uint64_t *val)	\
+{									\
+	uint64_t error_code;						\
+	uint8_t vector;							\
+	uint32_t a, d;							\
+									\
+	asm volatile(KVM_ASM_SAFE##_FEP(#insn)				\
+		     : "=a"(a), "=d"(d),				\
+		       KVM_ASM_SAFE_OUTPUTS(vector, error_code)		\
+		     : "c"(idx)						\
+		     : KVM_ASM_SAFE_CLOBBERS);				\
+									\
+	*val = (uint64_t)a | ((uint64_t)d << 32);			\
+	return vector;							\
 }
 
+/*
+ * Generate {insn}_safe() and {insn}_safe_fep() helpers for instructions that
+ * use ECX as in input index, and EDX:EAX as a 64-bit output.
+ */
+#define BUILD_READ_U64_SAFE_HELPERS(insn)				\
+	BUILD_READ_U64_SAFE_HELPER(insn, , )				\
+	BUILD_READ_U64_SAFE_HELPER(insn, _fep, _FEP)			\
+
+BUILD_READ_U64_SAFE_HELPERS(rdmsr)
+BUILD_READ_U64_SAFE_HELPERS(rdpmc)
+BUILD_READ_U64_SAFE_HELPERS(xgetbv)
+
 static inline uint8_t wrmsr_safe(uint32_t msr, uint64_t val)
 {
 	return kvm_asm_safe("wrmsr", "a"(val & -1u), "d"(val >> 32), "c"(msr));
@@ -1194,6 +1268,16 @@ 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");
+}
+
+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);