Commit 0fea7aa2 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

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.

Link: https://lore.kernel.org/r/20241128013424.4096668-56-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 9b2776c7

arch/x86/kvm/cpuid.c

+43 −16
Original line number Diff line number Diff line
@@ -779,12 +779,25 @@ 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));
@@ -795,13 +808,14 @@ 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 */ |
@@ -848,7 +862,9 @@ 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) |
@@ -871,7 +887,7 @@ 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) |
@@ -880,7 +896,7 @@ 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) |
@@ -905,7 +921,7 @@ void kvm_set_cpu_caps(void) 
		F(CLDEMOTE) |

		F(MOVDIRI) |

		F(MOVDIR64B) |

		0 /*WAITPKG*/ |

		VENDOR_F(WAITPKG) |

		F(SGX_LC) |

		F(BUS_LOCK_DETECT)

	);
@@ -1001,7 +1017,7 @@ 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) |
@@ -1015,7 +1031,7 @@ 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,
@@ -1101,17 +1117,27 @@ 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)

	);
@@ -1183,6 +1209,7 @@ 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;