linux-kernel - [PATCH v2 26/49] KVM: x86: Add a macro to init CPUID features that KVM emulates in software

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Message-ID: <20240517173926.965351-27-seanjc@google.com>
Date: Fri, 17 May 2024 10:39:03 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Sean Christopherson <seanjc@...gle.com>, 
	Vitaly Kuznetsov <vkuznets@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Hou Wenlong <houwenlong.hwl@...group.com>, Kechen Lu <kechenl@...dia.com>, 
	Oliver Upton <oliver.upton@...ux.dev>, Maxim Levitsky <mlevitsk@...hat.com>, 
	Binbin Wu <binbin.wu@...ux.intel.com>, Yang Weijiang <weijiang.yang@...el.com>, 
	Robert Hoo <robert.hoo.linux@...il.com>
Subject: [PATCH v2 26/49] KVM: x86: Add a macro to init CPUID features that
 KVM emulates in software

Now that kvm_cpu_cap_init() is a macro with its own scope, add EMUL_F() to
OR-in features that KVM emulates in software, i.e. that don't depend on
the feature being available in hardware.  The contained scope
of kvm_cpu_cap_init() allows using a local variable to track the set of
emulated leaves, which in addition to avoiding confusing and/or
unnecessary variables, helps prevent misuse of EMUL_F().

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/cpuid.c | 36 +++++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 1064e4d68718..33e3e77de1b7 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -94,6 +94,16 @@ u32 xstate_required_size(u64 xstate_bv, bool compacted)
 	F(name);						\
 })
 
+/*
+ * Emulated Feature - For features that KVM emulates in software irrespective
+ * of host CPU/kernel support.
+ */
+#define EMUL_F(name)						\
+({								\
+	kvm_cpu_cap_emulated |= F(name);			\
+	F(name);						\
+})
+
 /*
  * Aliased Features - For features in 0x8000_0001.EDX that are duplicates of
  * identical 0x1.EDX features, and thus are aliased from 0x1 to 0x8000_0001.
@@ -649,6 +659,7 @@ do {									\
 do {									\
 	const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32);	\
 	const u32 __maybe_unused kvm_cpu_cap_init_in_progress = leaf;	\
+	u32 kvm_cpu_cap_emulated = 0;					\
 									\
 	if (leaf < NCAPINTS)						\
 		kvm_cpu_caps[leaf] &= (mask);				\
@@ -656,6 +667,7 @@ do {									\
 		kvm_cpu_caps[leaf] = (mask);				\
 									\
 	kvm_cpu_caps[leaf] &= raw_cpuid_get(cpuid);			\
+	kvm_cpu_caps[leaf] |= kvm_cpu_cap_emulated;			\
 } while (0)
 
 /*
@@ -684,12 +696,10 @@ void kvm_set_cpu_caps(void)
 		0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
 		F(FMA) | F(CX16) | 0 /* xTPR Update */ | F(PDCM) |
 		F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
-		F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
+		F(XMM4_2) | EMUL_F(X2APIC) | F(MOVBE) | F(POPCNT) |
 		0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
 		F(F16C) | F(RDRAND)
 	);
-	/* KVM emulates x2apic in software irrespective of host support. */
-	kvm_cpu_cap_set(X86_FEATURE_X2APIC);
 
 	kvm_cpu_cap_init(CPUID_1_EDX,
 		F(FPU) | F(VME) | F(DE) | F(PSE) |
@@ -703,13 +713,13 @@ void kvm_set_cpu_caps(void)
 	);
 
 	kvm_cpu_cap_init(CPUID_7_0_EBX,
-		F(FSGSBASE) | F(SGX) | F(BMI1) | F(HLE) | F(AVX2) |
-		F(FDP_EXCPTN_ONLY) | F(SMEP) | F(BMI2) | F(ERMS) | F(INVPCID) |
-		F(RTM) | F(ZERO_FCS_FDS) | 0 /*MPX*/ | F(AVX512F) |
-		F(AVX512DQ) | F(RDSEED) | F(ADX) | F(SMAP) | F(AVX512IFMA) |
-		F(CLFLUSHOPT) | F(CLWB) | 0 /*INTEL_PT*/ | F(AVX512PF) |
-		F(AVX512ER) | F(AVX512CD) | F(SHA_NI) | F(AVX512BW) |
-		F(AVX512VL));
+		F(FSGSBASE) | EMUL_F(TSC_ADJUST) | F(SGX) | F(BMI1) | F(HLE) |
+		F(AVX2) | F(FDP_EXCPTN_ONLY) | F(SMEP) | F(BMI2) | F(ERMS) |
+		F(INVPCID) | F(RTM) | F(ZERO_FCS_FDS) | 0 /*MPX*/ |
+		F(AVX512F) | F(AVX512DQ) | F(RDSEED) | F(ADX) | F(SMAP) |
+		F(AVX512IFMA) | F(CLFLUSHOPT) | F(CLWB) | 0 /*INTEL_PT*/ |
+		F(AVX512PF) | F(AVX512ER) | F(AVX512CD) | F(SHA_NI) |
+		F(AVX512BW) | F(AVX512VL));
 
 	kvm_cpu_cap_init(CPUID_7_ECX,
 		F(AVX512VBMI) | RAW_F(LA57) | F(PKU) | 0 /*OSPKE*/ | F(RDPID) |
@@ -728,16 +738,12 @@ void kvm_set_cpu_caps(void)
 
 	kvm_cpu_cap_init(CPUID_7_EDX,
 		F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
-		F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | F(INTEL_STIBP) |
+		F(SPEC_CTRL_SSBD) | EMUL_F(ARCH_CAPABILITIES) | F(INTEL_STIBP) |
 		F(MD_CLEAR) | F(AVX512_VP2INTERSECT) | F(FSRM) |
 		F(SERIALIZE) | F(TSXLDTRK) | F(AVX512_FP16) |
 		F(AMX_TILE) | F(AMX_INT8) | F(AMX_BF16) | F(FLUSH_L1D)
 	);
 
-	/* TSC_ADJUST and ARCH_CAPABILITIES are emulated in software. */
-	kvm_cpu_cap_set(X86_FEATURE_TSC_ADJUST);
-	kvm_cpu_cap_set(X86_FEATURE_ARCH_CAPABILITIES);
-
 	if (boot_cpu_has(X86_FEATURE_IBPB) && boot_cpu_has(X86_FEATURE_IBRS))
 		kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL);
 	if (boot_cpu_has(X86_FEATURE_STIBP))
-- 
2.45.0.215.g3402c0e53f-goog