KVM: SVM/SEV/SEV-ES: Rework intercepts

Currently SVM setup is done sequentially in
init_vmcb() -> sev_init_vmcb() -> sev_es_init_vmcb()
and tries keeping SVM/SEV/SEV-ES bits separated. One of the exceptions
is DR intercepts which is for SEV-ES before sev_es_init_vmcb() runs.

Move the SEV-ES intercept setup to sev_es_init_vmcb(). From now on
set_dr_intercepts()/clr_dr_intercepts() handle SVM/SEV only.

No functional change intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Reviewed-by: Santosh Shukla <santosh.shukla@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-6-aik@amd.com
[sean: drop comment about intercepting DR7]
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: aik

arch/x86/kvm/svm/sev.c

@@ -2951,6 +2951,7 @@ int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in)
 
 static void sev_es_init_vmcb(struct vcpu_svm *svm)
 {
+	struct vmcb *vmcb = svm->vmcb01.ptr;
 	struct kvm_vcpu *vcpu = &svm->vcpu;
 
 	svm->vmcb->control.nested_ctl |= SVM_NESTED_CTL_SEV_ES_ENABLE;
@@ -2979,6 +2980,11 @@ static void sev_es_init_vmcb(struct vcpu_svm *svm)
 	svm_set_intercept(svm, TRAP_CR4_WRITE);
 	svm_set_intercept(svm, TRAP_CR8_WRITE);
 
+	vmcb->control.intercepts[INTERCEPT_DR] = 0;
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_READ);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_WRITE);
+	recalc_intercepts(svm);
+
 	/* Can't intercept XSETBV, HV can't modify XCR0 directly */
 	svm_clr_intercept(svm, INTERCEPT_XSETBV);
 

arch/x86/kvm/svm/svm.c

@@ -681,23 +681,20 @@ static void set_dr_intercepts(struct vcpu_svm *svm)
 {
 	struct vmcb *vmcb = svm->vmcb01.ptr;
 
-	if (!sev_es_guest(svm->vcpu.kvm)) {
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR0_READ);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR1_READ);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR2_READ);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR3_READ);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR4_READ);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR5_READ);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR6_READ);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR0_WRITE);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR1_WRITE);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR2_WRITE);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR3_WRITE);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR4_WRITE);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR5_WRITE);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR6_WRITE);
-	}
-
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR0_READ);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR1_READ);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR2_READ);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR3_READ);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR4_READ);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR5_READ);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR6_READ);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR0_WRITE);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR1_WRITE);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR2_WRITE);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR3_WRITE);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR4_WRITE);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR5_WRITE);
+	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR6_WRITE);
 	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_READ);
 	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_WRITE);
 
@@ -710,12 +707,6 @@ static void clr_dr_intercepts(struct vcpu_svm *svm)
 
 	vmcb->control.intercepts[INTERCEPT_DR] = 0;
 
-	/* DR7 access must remain intercepted for an SEV-ES guest */
-	if (sev_es_guest(svm->vcpu.kvm)) {
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_READ);
-		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_WRITE);
-	}
-
 	recalc_intercepts(svm);
 }