[PATCH 2/5] KVM: cpuid: extract do_cpuid_7_mask and support multiple subleafs

[Paolo Bonzini]

CPUID function 7 has multiple subleafs.  Instead of having nested
switch statements, move the logic to filter supported features to
a separate function, and call it for each subleaf.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
	Here you would have something like entry->eax = min(entry->eax, 1)
	when adding subleaf 1.

 arch/x86/kvm/cpuid.c | 128 +++++++++++++++++++++++++++----------------
 1 file changed, 81 insertions(+), 47 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index ddffc56c39b4..1c6b9a4a74de 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -328,6 +328,71 @@ static int __do_cpuid_func_emulated(struct kvm_cpuid_entry2 *entry,
 	return 0;
 }
 
+static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry, int index)
+{
+	unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
+	unsigned f_mpx = kvm_mpx_supported() ? F(MPX) : 0;
+	unsigned f_umip = kvm_x86_ops->umip_emulated() ? F(UMIP) : 0;
+	unsigned f_intel_pt = kvm_x86_ops->pt_supported() ? F(INTEL_PT) : 0;
+	unsigned f_la57;
+
+	/* cpuid 7.0.ebx */
+	const u32 kvm_cpuid_7_0_ebx_x86_features =
+		F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
+		F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
+		F(ADX) | F(SMAP) | F(AVX512IFMA) | F(AVX512F) | F(AVX512PF) |
+		F(AVX512ER) | F(AVX512CD) | F(CLFLUSHOPT) | F(CLWB) | F(AVX512DQ) |
+		F(SHA_NI) | F(AVX512BW) | F(AVX512VL) | f_intel_pt;
+
+	/* cpuid 7.0.ecx*/
+	const u32 kvm_cpuid_7_0_ecx_x86_features =
+		F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ |
+		F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) |
+		F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) |
+		F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B);
+
+	/* cpuid 7.0.edx*/
+	const u32 kvm_cpuid_7_0_edx_x86_features =
+		F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
+		F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | F(INTEL_STIBP) |
+		F(MD_CLEAR);
+
+	switch (index) {
+	case 0:
+		entry->eax = 0;
+		entry->ebx &= kvm_cpuid_7_0_ebx_x86_features;
+		cpuid_mask(&entry->ebx, CPUID_7_0_EBX);
+		/* TSC_ADJUST is emulated */
+		entry->ebx |= F(TSC_ADJUST);
+
+		entry->ecx &= kvm_cpuid_7_0_ecx_x86_features;
+		f_la57 = entry->ecx & F(LA57);
+		cpuid_mask(&entry->ecx, CPUID_7_ECX);
+		/* Set LA57 based on hardware capability. */
+		entry->ecx |= f_la57;
+		entry->ecx |= f_umip;
+		/* PKU is not yet implemented for shadow paging. */
+		if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE))
+			entry->ecx &= ~F(PKU);
+
+		entry->edx &= kvm_cpuid_7_0_edx_x86_features;
+		cpuid_mask(&entry->edx, CPUID_7_EDX);
+		/*
+		 * We emulate ARCH_CAPABILITIES in software even
+		 * if the host doesn't support it.
+		 */
+		entry->edx |= F(ARCH_CAPABILITIES);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		entry->eax = 0;
+		entry->ebx = 0;
+		entry->ecx = 0;
+		entry->edx = 0;
+		break;
+	}
+}
+
 static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
 				  int *nent, int maxnent)
 {
@@ -342,12 +407,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
 	unsigned f_lm = 0;
 #endif
 	unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
-	unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
-	unsigned f_mpx = kvm_mpx_supported() ? F(MPX) : 0;
 	unsigned f_xsaves = kvm_x86_ops->xsaves_supported() ? F(XSAVES) : 0;
-	unsigned f_umip = kvm_x86_ops->umip_emulated() ? F(UMIP) : 0;
 	unsigned f_intel_pt = kvm_x86_ops->pt_supported() ? F(INTEL_PT) : 0;
-	unsigned f_la57 = 0;
 
 	/* cpuid 1.edx */
 	const u32 kvm_cpuid_1_edx_x86_features =
@@ -400,31 +461,10 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
 		F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
 		F(PMM) | F(PMM_EN);
 
-	/* cpuid 7.0.ebx */
-	const u32 kvm_cpuid_7_0_ebx_x86_features =
-		F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
-		F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
-		F(ADX) | F(SMAP) | F(AVX512IFMA) | F(AVX512F) | F(AVX512PF) |
-		F(AVX512ER) | F(AVX512CD) | F(CLFLUSHOPT) | F(CLWB) | F(AVX512DQ) |
-		F(SHA_NI) | F(AVX512BW) | F(AVX512VL) | f_intel_pt;
-
 	/* cpuid 0xD.1.eax */
 	const u32 kvm_cpuid_D_1_eax_x86_features =
 		F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | f_xsaves;
 
-	/* cpuid 7.0.ecx*/
-	const u32 kvm_cpuid_7_0_ecx_x86_features =
-		F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ |
-		F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) |
-		F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) |
-		F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B);
-
-	/* cpuid 7.0.edx*/
-	const u32 kvm_cpuid_7_0_edx_x86_features =
-		F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
-		F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | F(INTEL_STIBP) |
-		F(MD_CLEAR);
-
 	/* all calls to cpuid_count() should be made on the same cpu */
 	get_cpu();
 
@@ -496,30 +536,24 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
 		entry->ecx = 0;
 		entry->edx = 0;
 		break;
+	/* function 7 has additional index. */
 	case 7: {
+		int i;
+
 		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
-		entry->eax = 0;
-		/* Mask ebx against host capability word 9 */
-		entry->ebx &= kvm_cpuid_7_0_ebx_x86_features;
-		cpuid_mask(&entry->ebx, CPUID_7_0_EBX);
-		// TSC_ADJUST is emulated
-		entry->ebx |= F(TSC_ADJUST);
-		entry->ecx &= kvm_cpuid_7_0_ecx_x86_features;
-		f_la57 = entry->ecx & F(LA57);
-		cpuid_mask(&entry->ecx, CPUID_7_ECX);
-		/* Set LA57 based on hardware capability. */
-		entry->ecx |= f_la57;
-		entry->ecx |= f_umip;
-		/* PKU is not yet implemented for shadow paging. */
-		if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE))
-			entry->ecx &= ~F(PKU);
-		entry->edx &= kvm_cpuid_7_0_edx_x86_features;
-		cpuid_mask(&entry->edx, CPUID_7_EDX);
-		/*
-		 * We emulate ARCH_CAPABILITIES in software even
-		 * if the host doesn't support it.
-		 */
-		entry->edx |= F(ARCH_CAPABILITIES);
+		for (i = 0; ; ) {
+			do_cpuid_7_mask(&entry[i], i);
+			if (i == entry->eax)
+				break;
+			if (*nent >= maxnent)
+				goto out;
+
+			++i;
+			do_cpuid_1_ent(&entry[i], function, i);
+			entry[i].flags |=
+			       KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
+			++*nent;
+		}
 		break;
 	}
 	case 9:
-- 
2.21.0