KVM: x86: Move EDX initialization at vCPU RESET to common code

Move the EDX initialization at vCPU RESET, which is now identical between
VMX and SVM, into common code.

No functional change intended.
Reviewed-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210713163324.627647-20-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -1773,11 +1773,6 @@ static inline unsigned long read_msr(unsigned long msr)
 }
 #endif
 
-static inline u32 get_rdx_init_val(void)
-{
-	return 0x600; /* P6 family */
-}
-
 static inline void kvm_inject_gp(struct kvm_vcpu *vcpu, u32 error_code)
 {
 	kvm_queue_exception_e(vcpu, GP_VECTOR, error_code);

arch/x86/kvm/svm/svm.c

@@ -1330,25 +1330,12 @@ static void init_vmcb(struct kvm_vcpu *vcpu)
 static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
-	u32 dummy;
-	u32 eax = 1;
 
 	svm->spec_ctrl = 0;
 	svm->virt_spec_ctrl = 0;
 
 	init_vmcb(vcpu);
 
-	/*
-	 * Fall back to KVM's default Family/Model/Stepping if no CPUID match
-	 * is found.  Note, it's impossible to get a match at RESET since KVM
-	 * emulates RESET before exposing the vCPU to userspace, i.e. it's
-	 * impossible for kvm_cpuid() to find a valid entry on RESET.  But, go
-	 * through the motions in case that's ever remedied, and to be pedantic.
-	 */
-	if (!kvm_cpuid(vcpu, &eax, &dummy, &dummy, &dummy, true))
-		eax = get_rdx_init_val();
-	kvm_rdx_write(vcpu, eax);
-
 	if (kvm_vcpu_apicv_active(vcpu) && !init_event)
 		avic_update_vapic_bar(svm, APIC_DEFAULT_PHYS_BASE);
 }

arch/x86/kvm/vmx/vmx.c

@@ -4391,7 +4391,6 @@ static void init_vmcs(struct vcpu_vmx *vmx)
 static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	u32 eax, dummy;
 	u64 cr0;
 
 	vmx->rmode.vm86_active = 0;
@@ -4399,11 +4398,6 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 
 	vmx->msr_ia32_umwait_control = 0;
 
-	eax = 1;
-	if (!kvm_cpuid(vcpu, &eax, &dummy, &dummy, &dummy, true))
-		eax = get_rdx_init_val();
-	kvm_rdx_write(vcpu, eax);
-
 	vmx->hv_deadline_tsc = -1;
 	kvm_set_cr8(vcpu, 0);
 

arch/x86/kvm/x86.c

@@ -10792,6 +10792,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 {
 	unsigned long old_cr0 = kvm_read_cr0(vcpu);
+	u32 eax, dummy;
 
 	kvm_lapic_reset(vcpu, init_event);
 
@@ -10858,6 +10859,18 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 	vcpu->arch.regs_avail = ~0;
 	vcpu->arch.regs_dirty = ~0;
 
+	/*
+	 * Fall back to KVM's default Family/Model/Stepping of 0x600 (P6/Athlon)
+	 * if no CPUID match is found.  Note, it's impossible to get a match at
+	 * RESET since KVM emulates RESET before exposing the vCPU to userspace,
+	 * i.e. it'simpossible for kvm_cpuid() to find a valid entry on RESET.
+	 * But, go through the motions in case that's ever remedied.
+	 */
+	eax = 1;
+	if (!kvm_cpuid(vcpu, &eax, &dummy, &dummy, &dummy, true))
+		eax = 0x600;
+	kvm_rdx_write(vcpu, eax);
+
 	vcpu->arch.ia32_xss = 0;
 
 	static_call(kvm_x86_vcpu_reset)(vcpu, init_event);