[RFC PATCH v2 07/25] KVM: SVM: Duplicate pre-run ASID check for SEV and non-SEV guests

[Yosry Ahmed]

In preparation for dropping the check for non-SEV VMs, duplicate the
check between pre_sev_run() and pre_svm_run() (for the non-SEV code
path).

Opportunistically drop the unconditional dirtying of VMCB_ASID, as it's
only needed when the ASID is actually updated in the VMCB, not when
TLB_CONTROL is updated (as the code currently reads).

No functional change intended.

Signed-off-by: Yosry Ahmed <yosry@xxxxxxxxxx>
---
 arch/x86/kvm/svm/sev.c | 6 +++++-
 arch/x86/kvm/svm/svm.c | 9 +++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 026b070522dac..3c873c88894b3 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3558,6 +3558,11 @@ int pre_sev_run(struct vcpu_svm *svm, int cpu)
 	/* Assign the asid allocated with this SEV guest */
 	svm->asid = asid;
 
+	if (unlikely(svm->asid != svm->vmcb->control.asid)) {
+		svm->vmcb->control.asid = asid;
+		vmcb_mark_dirty(svm->vmcb, VMCB_ASID);
+	}
+
 	/*
 	 * Flush guest TLB:
 	 *
@@ -3570,7 +3575,6 @@ int pre_sev_run(struct vcpu_svm *svm, int cpu)
 
 	sd->sev_vmcbs[asid] = svm->vmcb;
 	vmcb_set_flush_asid(svm->vmcb);
-	vmcb_mark_dirty(svm->vmcb, VMCB_ASID);
 	return 0;
 }
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 159abf841738f..5d4c45d788b54 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3766,6 +3766,11 @@ static int pre_svm_run(struct kvm_vcpu *vcpu)
 	if (svm->current_vmcb->asid_generation != sd->asid_generation)
 		new_asid(svm, sd);
 
+	if (unlikely(svm->asid != svm->vmcb->control.asid)) {
+		svm->vmcb->control.asid = svm->asid;
+		vmcb_mark_dirty(svm->vmcb, VMCB_ASID);
+	}
+
 	return 0;
 }
 
@@ -4502,10 +4507,6 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags)
 
 	sync_lapic_to_cr8(vcpu);
 
-	if (unlikely(svm->asid != svm->vmcb->control.asid)) {
-		svm->vmcb->control.asid = svm->asid;
-		vmcb_mark_dirty(svm->vmcb, VMCB_ASID);
-	}
 	svm->vmcb->save.cr2 = vcpu->arch.cr2;
 
 	if (guest_cpu_cap_has(vcpu, X86_FEATURE_ERAPS) &&
-- 
2.54.0.1136.gdb2ca164c4-goog