KVM: x86: Replace (almost) all guest CPUID feature queries with cpu_caps

Switch all queries (except XSAVES) of guest features from guest CPUID to
guest capabilities, i.e. replace all calls to guest_cpuid_has() with calls
to guest_cpu_cap_has().

Keep guest_cpuid_has() around for XSAVES, but subsume its helper
guest_cpuid_get_register() and add a compile-time assertion to prevent
using guest_cpuid_has() for any other feature.  Add yet another comment
for XSAVE to explain why KVM is allowed to query its raw guest CPUID.

Opportunistically drop the unused guest_cpuid_clear(), as there should be
no circumstance in which KVM needs to _clear_ a guest CPUID feature now
that everything is tracked via cpu_caps.  E.g. KVM may need to _change_
a feature to emulate dynamic CPUID flags, but KVM should never need to
clear a feature in guest CPUID to prevent it from being used by the guest.

Delete the last remnants of the governed features framework, as the lone
holdout was vmx_adjust_secondary_exec_control()'s divergent behavior for
governed vs. ungoverned features.

Note, replacing guest_cpuid_has() checks with guest_cpu_cap_has() when
computing reserved CR4 bits is a nop when viewed as a whole, as KVM's
capabilities are already incorporated into the calculation, i.e. if a
feature is present in guest CPUID but unsupported by KVM, its CR4 bit
was already being marked as reserved, checking guest_cpu_cap_has() simply
double-stamps that it's a reserved bit.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20241128013424.4096668-51-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 10 insertions, 10 deletions

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 0045fe474023..734b3ca40311 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1187,14 +1187,14 @@ static void svm_recalc_instruction_intercepts(struct kvm_vcpu *vcpu,
 	 */
 	if (kvm_cpu_cap_has(X86_FEATURE_INVPCID)) {
 		if (!npt_enabled ||
-		    !guest_cpuid_has(&svm->vcpu, X86_FEATURE_INVPCID))
+		    !guest_cpu_cap_has(&svm->vcpu, X86_FEATURE_INVPCID))
 			svm_set_intercept(svm, INTERCEPT_INVPCID);
 		else
 			svm_clr_intercept(svm, INTERCEPT_INVPCID);
 	}
 
 	if (kvm_cpu_cap_has(X86_FEATURE_RDTSCP)) {
-		if (guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))
+		if (guest_cpu_cap_has(vcpu, X86_FEATURE_RDTSCP))
 			svm_clr_intercept(svm, INTERCEPT_RDTSCP);
 		else
 			svm_set_intercept(svm, INTERCEPT_RDTSCP);
@@ -2940,7 +2940,7 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		break;
 	case MSR_AMD64_VIRT_SPEC_CTRL:
 		if (!msr_info->host_initiated &&
-		    !guest_cpuid_has(vcpu, X86_FEATURE_VIRT_SSBD))
+		    !guest_cpu_cap_has(vcpu, X86_FEATURE_VIRT_SSBD))
 			return 1;
 
 		msr_info->data = svm->virt_spec_ctrl;
@@ -3091,7 +3091,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
 		break;
 	case MSR_AMD64_VIRT_SPEC_CTRL:
 		if (!msr->host_initiated &&
-		    !guest_cpuid_has(vcpu, X86_FEATURE_VIRT_SSBD))
+		    !guest_cpu_cap_has(vcpu, X86_FEATURE_VIRT_SSBD))
 			return 1;
 
 		if (data & ~SPEC_CTRL_SSBD)
@@ -3272,7 +3272,7 @@ static int invpcid_interception(struct kvm_vcpu *vcpu)
 	unsigned long type;
 	gva_t gva;
 
-	if (!guest_cpuid_has(vcpu, X86_FEATURE_INVPCID)) {
+	if (!guest_cpu_cap_has(vcpu, X86_FEATURE_INVPCID)) {
 		kvm_queue_exception(vcpu, UD_VECTOR);
 		return 1;
 	}
@@ -4404,7 +4404,7 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 	guest_cpu_cap_change(vcpu, X86_FEATURE_XSAVES,
 			     boot_cpu_has(X86_FEATURE_XSAVE) &&
 			     boot_cpu_has(X86_FEATURE_XSAVES) &&
-			     guest_cpuid_has(vcpu, X86_FEATURE_XSAVE));
+			     guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVE));
 
 	/*
 	 * Intercept VMLOAD if the vCPU model is Intel in order to emulate that
@@ -4422,7 +4422,7 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 
 	if (boot_cpu_has(X86_FEATURE_FLUSH_L1D))
 		set_msr_interception(vcpu, svm->msrpm, MSR_IA32_FLUSH_CMD, 0,
-				     !!guest_cpuid_has(vcpu, X86_FEATURE_FLUSH_L1D));
+				     !!guest_cpu_cap_has(vcpu, X86_FEATURE_FLUSH_L1D));
 
 	if (sev_guest(vcpu->kvm))
 		sev_vcpu_after_set_cpuid(svm);
@@ -4673,7 +4673,7 @@ static int svm_enter_smm(struct kvm_vcpu *vcpu, union kvm_smram *smram)
 	 * responsible for ensuring nested SVM and SMIs are mutually exclusive.
 	 */
 
-	if (!guest_cpuid_has(vcpu, X86_FEATURE_LM))
+	if (!guest_cpu_cap_has(vcpu, X86_FEATURE_LM))
 		return 1;
 
 	smram->smram64.svm_guest_flag = 1;
@@ -4720,14 +4720,14 @@ static int svm_leave_smm(struct kvm_vcpu *vcpu, const union kvm_smram *smram)
 
 	const struct kvm_smram_state_64 *smram64 = &smram->smram64;
 
-	if (!guest_cpuid_has(vcpu, X86_FEATURE_LM))
+	if (!guest_cpu_cap_has(vcpu, X86_FEATURE_LM))
 		return 0;
 
 	/* Non-zero if SMI arrived while vCPU was in guest mode. */
 	if (!smram64->svm_guest_flag)
 		return 0;
 
-	if (!guest_cpuid_has(vcpu, X86_FEATURE_SVM))
+	if (!guest_cpu_cap_has(vcpu, X86_FEATURE_SVM))
 		return 1;
 
 	if (!(smram64->efer & EFER_SVME))