KVM: x86: Use KVM_REQ_RECALC_INTERCEPTS to react to CPUID updates

Defer recalculating MSR and instruction intercepts after a CPUID update
via RECALC_INTERCEPTS to converge on RECALC_INTERCEPTS as the "official"
mechanism for triggering recalcs.  As a bonus, because KVM does a "recalc"
during vCPU creation, and every functional VMM sets CPUID at least once,
for all intents and purposes this saves at least one recalc.

Tested-by: Xudong Hao <xudong.hao@intel.com>
Link: https://lore.kernel.org/r/20250806195706.1650976-26-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/kvm/cpuid.c

@@ -448,6 +448,8 @@ void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 	 * adjustments to the reserved GPA bits.
 	 */
 	kvm_mmu_after_set_cpuid(vcpu);
+
+	kvm_make_request(KVM_REQ_RECALC_INTERCEPTS, vcpu);
 }
 
 int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu)

arch/x86/kvm/svm/svm.c

@@ -1225,7 +1225,7 @@ static void init_vmcb(struct kvm_vcpu *vcpu)
 
 	svm_hv_init_vmcb(vmcb);
 
-	svm_recalc_intercepts(vcpu);
+	kvm_make_request(KVM_REQ_RECALC_INTERCEPTS, vcpu);
 
 	vmcb_mark_all_dirty(vmcb);
 
@@ -4478,8 +4478,6 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 
 	if (sev_guest(vcpu->kvm))
 		sev_vcpu_after_set_cpuid(svm);
-
-	svm_recalc_intercepts(vcpu);
 }
 
 static bool svm_has_wbinvd_exit(void)

arch/x86/kvm/vmx/vmx.c

@@ -7806,9 +7806,6 @@ void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 		vmx->msr_ia32_feature_control_valid_bits &=
 			~FEAT_CTL_SGX_LC_ENABLED;
 
-	/* Recalc MSR interception to account for feature changes. */
-	vmx_recalc_intercepts(vcpu);
-
 	/* Refresh #PF interception to account for MAXPHYADDR changes. */
 	vmx_update_exception_bitmap(vcpu);
 }