linux-kernel - [PATCH v3 55/57] KVM: x86: Explicitly track feature flags that require vendor enabling

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Message-ID: <20241128013424.4096668-56-seanjc@google.com>
Date: Wed, 27 Nov 2024 17:34:22 -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 55/57] KVM: x86: Explicitly track feature flags that
 require vendor enabling

Add another CPUID feature macro, VENDOR_F(), and use it to track features
that KVM supports, but that need additional vendor support and so are
conditionally enabled in vendor code.

Currently, VENDOR_F() is mostly just documentation, but tracking all
KVM-supported features will allow for asserting, at build time, take),
that all features that are set, cleared, *or* checked by KVM are known to
kvm_set_cpu_caps().

To fudge around a macro collision on 32-bit kernels, #undef DS to be able
to get at X86_FEATURE_DS.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/cpuid.c | 59 ++++++++++++++++++++++++++++++++------------
 1 file changed, 43 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index a1a80f1f10ec..5ac5fe2febf7 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -758,12 +758,25 @@ do {									\
 	feature_bit(name);							\
 })
 
+/*
+ * Vendor Features - For features that KVM supports, but are added in later
+ * because they require additional vendor enabling.
+ */
+#define VENDOR_F(name)						\
+({								\
+	KVM_VALIDATE_CPU_CAP_USAGE(name);			\
+	0;							\
+})
+
 /*
  * Undefine the MSR bit macro to avoid token concatenation issues when
  * processing X86_FEATURE_SPEC_CTRL_SSBD.
  */
 #undef SPEC_CTRL_SSBD
 
+/* DS is defined by ptrace-abi.h on 32-bit builds. */
+#undef DS
+
 void kvm_set_cpu_caps(void)
 {
 	memset(kvm_cpu_caps, 0, sizeof(kvm_cpu_caps));
@@ -774,13 +787,14 @@ void kvm_set_cpu_caps(void)
 	kvm_cpu_cap_init(CPUID_1_ECX,
 		F(XMM3) |
 		F(PCLMULQDQ) |
-		0 /* DTES64 */ |
+		VENDOR_F(DTES64) |
 		/*
 		 * NOTE: MONITOR (and MWAIT) are emulated as NOP, but *not*
 		 * advertised to guests via CPUID!
 		 */
 		0 /* MONITOR */ |
-		0 /* DS-CPL, VMX, SMX, EST */ |
+		VENDOR_F(VMX) |
+		0 /* DS-CPL, SMX, EST */ |
 		0 /* TM2 */ |
 		F(SSSE3) |
 		0 /* CNXT-ID */ |
@@ -827,7 +841,9 @@ void kvm_set_cpu_caps(void)
 		F(PSE36) |
 		0 /* PSN */ |
 		F(CLFLUSH) |
-		0 /* Reserved, DS, ACPI */ |
+		0 /* Reserved */ |
+		VENDOR_F(DS) |
+		0 /* ACPI */ |
 		F(MMX) |
 		F(FXSR) |
 		F(XMM) |
@@ -850,7 +866,7 @@ void kvm_set_cpu_caps(void)
 		F(INVPCID) |
 		F(RTM) |
 		F(ZERO_FCS_FDS) |
-		0 /*MPX*/ |
+		VENDOR_F(MPX) |
 		F(AVX512F) |
 		F(AVX512DQ) |
 		F(RDSEED) |
@@ -859,7 +875,7 @@ void kvm_set_cpu_caps(void)
 		F(AVX512IFMA) |
 		F(CLFLUSHOPT) |
 		F(CLWB) |
-		0 /*INTEL_PT*/ |
+		VENDOR_F(INTEL_PT) |
 		F(AVX512PF) |
 		F(AVX512ER) |
 		F(AVX512CD) |
@@ -884,7 +900,7 @@ void kvm_set_cpu_caps(void)
 		F(CLDEMOTE) |
 		F(MOVDIRI) |
 		F(MOVDIR64B) |
-		0 /*WAITPKG*/ |
+		VENDOR_F(WAITPKG) |
 		F(SGX_LC) |
 		F(BUS_LOCK_DETECT)
 	);
@@ -980,7 +996,7 @@ void kvm_set_cpu_caps(void)
 	kvm_cpu_cap_init(CPUID_8000_0001_ECX,
 		F(LAHF_LM) |
 		F(CMP_LEGACY) |
-		0 /*SVM*/ |
+		VENDOR_F(SVM) |
 		0 /* ExtApicSpace */ |
 		F(CR8_LEGACY) |
 		F(ABM) |
@@ -994,7 +1010,7 @@ void kvm_set_cpu_caps(void)
 		F(FMA4) |
 		F(TBM) |
 		F(TOPOEXT) |
-		0 /* PERFCTR_CORE */
+		VENDOR_F(PERFCTR_CORE)
 	);
 
 	kvm_cpu_cap_init(CPUID_8000_0001_EDX,
@@ -1080,17 +1096,27 @@ void kvm_set_cpu_caps(void)
 	    !boot_cpu_has(X86_FEATURE_AMD_SSBD))
 		kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD);
 
-	/*
-	 * Hide all SVM features by default, SVM will set the cap bits for
-	 * features it emulates and/or exposes for L1.
-	 */
-	kvm_cpu_cap_init(CPUID_8000_000A_EDX, 0);
+	/* All SVM features required additional vendor module enabling. */
+	kvm_cpu_cap_init(CPUID_8000_000A_EDX,
+		VENDOR_F(NPT) |
+		VENDOR_F(VMCBCLEAN) |
+		VENDOR_F(FLUSHBYASID) |
+		VENDOR_F(NRIPS) |
+		VENDOR_F(TSCRATEMSR) |
+		VENDOR_F(V_VMSAVE_VMLOAD) |
+		VENDOR_F(LBRV) |
+		VENDOR_F(PAUSEFILTER) |
+		VENDOR_F(PFTHRESHOLD) |
+		VENDOR_F(VGIF) |
+		VENDOR_F(VNMI) |
+		VENDOR_F(SVME_ADDR_CHK)
+	);
 
 	kvm_cpu_cap_init(CPUID_8000_001F_EAX,
-		0 /* SME */ |
-		0 /* SEV */ |
+		VENDOR_F(SME) |
+		VENDOR_F(SEV) |
 		0 /* VM_PAGE_FLUSH */ |
-		0 /* SEV_ES */ |
+		VENDOR_F(SEV_ES) |
 		F(SME_COHERENT)
 	);
 
@@ -1162,6 +1188,7 @@ EXPORT_SYMBOL_GPL(kvm_set_cpu_caps);
 #undef SYNTHESIZED_F
 #undef PASSTHROUGH_F
 #undef ALIASED_1_EDX_F
+#undef VENDOR_F
 
 struct kvm_cpuid_array {
 	struct kvm_cpuid_entry2 *entries;
-- 
2.47.0.338.g60cca15819-goog