linux-kernel - [PATCH v3 30/57] KVM: x86: Add a macro to init CPUID features that KVM emulates in software

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Message-ID: <20241128013424.4096668-31-seanjc@google.com>
Date: Wed, 27 Nov 2024 17:33:57 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Sean Christopherson <seanjc@...gle.com>, 
	Vitaly Kuznetsov <vkuznets@...hat.com>, Jarkko Sakkinen <jarkko@...nel.org>
Cc: kvm@...r.kernel.org, linux-sgx@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Maxim Levitsky <mlevitsk@...hat.com>, 
	Hou Wenlong <houwenlong.hwl@...group.com>, Xiaoyao Li <xiaoyao.li@...el.com>, 
	Kechen Lu <kechenl@...dia.com>, Oliver Upton <oliver.upton@...ux.dev>, 
	Binbin Wu <binbin.wu@...ux.intel.com>, Yang Weijiang <weijiang.yang@...el.com>, 
	Robert Hoo <robert.hoo.linux@...il.com>
Subject: [PATCH v3 30/57] 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 | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 9bf324aa5fae..83b29c5a0498 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -611,6 +611,7 @@ 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_passthrough = 0;				\
+	u32 kvm_cpu_cap_emulated = 0;					\
 									\
 	if (leaf < NCAPINTS)						\
 		kvm_cpu_caps[leaf] &= (mask);				\
@@ -619,6 +620,7 @@ do {									\
 									\
 	kvm_cpu_caps[leaf] |= kvm_cpu_cap_passthrough;			\
 	kvm_cpu_caps[leaf] &= raw_cpuid_get(cpuid);			\
+	kvm_cpu_caps[leaf] |= kvm_cpu_cap_emulated;			\
 } while (0)
 
 /*
@@ -654,6 +656,16 @@ do {									\
 	(IS_ENABLED(CONFIG_X86_64) ? F(name) : 0);		\
 })
 
+/*
+ * Emulated Feature - For features that KVM emulates in software irrespective
+ * of host CPU/kernel support.
+ */
+#define EMULATED_F(name)					\
+({								\
+	kvm_cpu_cap_emulated |= F(name);			\
+	F(name);						\
+})
+
 /*
  * Passthrough Feature - For features that KVM supports based purely on raw
  * hardware CPUID, i.e. that KVM virtualizes even if the host kernel doesn't
@@ -715,7 +727,7 @@ void kvm_set_cpu_caps(void)
 		0 /* Reserved, DCA */ |
 		F(XMM4_1) |
 		F(XMM4_2) |
-		F(X2APIC) |
+		EMULATED_F(X2APIC) |
 		F(MOVBE) |
 		F(POPCNT) |
 		0 /* Reserved*/ |
@@ -726,8 +738,6 @@ void kvm_set_cpu_caps(void)
 		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) |
@@ -761,6 +771,7 @@ void kvm_set_cpu_caps(void)
 
 	kvm_cpu_cap_init(CPUID_7_0_EBX,
 		F(FSGSBASE) |
+		EMULATED_F(TSC_ADJUST) |
 		F(SGX) |
 		F(BMI1) |
 		F(HLE) |
@@ -823,7 +834,7 @@ void kvm_set_cpu_caps(void)
 		F(AVX512_4FMAPS) |
 		F(SPEC_CTRL) |
 		F(SPEC_CTRL_SSBD) |
-		F(ARCH_CAPABILITIES) |
+		EMULATED_F(ARCH_CAPABILITIES) |
 		F(INTEL_STIBP) |
 		F(MD_CLEAR) |
 		F(AVX512_VP2INTERSECT) |
@@ -837,10 +848,6 @@ void kvm_set_cpu_caps(void)
 		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_AMD_IBPB_RET) &&
 	    boot_cpu_has(X86_FEATURE_AMD_IBPB) &&
 	    boot_cpu_has(X86_FEATURE_AMD_IBRS))
@@ -1026,6 +1033,7 @@ void kvm_set_cpu_caps(void)
 		0 /* SmmPgCfgLock */ |
 		F(NULL_SEL_CLR_BASE) |
 		F(AUTOIBRS) |
+		EMULATED_F(NO_SMM_CTL_MSR) |
 		0 /* PrefetchCtlMsr */ |
 		F(WRMSR_XX_BASE_NS)
 	);
@@ -1052,7 +1060,6 @@ void kvm_set_cpu_caps(void)
 		kvm_cpu_cap_set(X86_FEATURE_LFENCE_RDTSC);
 	if (!static_cpu_has_bug(X86_BUG_NULL_SEG))
 		kvm_cpu_cap_set(X86_FEATURE_NULL_SEL_CLR_BASE);
-	kvm_cpu_cap_set(X86_FEATURE_NO_SMM_CTL_MSR);
 
 	kvm_cpu_cap_init(CPUID_C000_0001_EDX,
 		F(XSTORE) |
@@ -1087,6 +1094,7 @@ EXPORT_SYMBOL_GPL(kvm_set_cpu_caps);
 #undef F
 #undef SF
 #undef X86_64_F
+#undef EMULATED_F
 #undef PASSTHROUGH_F
 #undef ALIASED_1_EDX_F
 
-- 
2.47.0.338.g60cca15819-goog