[RFC PATCH 02/13] KVM: nSVM: Rework svm_flush_tlb_asid() to operate on a given VMCB

[Yosry Ahmed <yosry.ahmed@linux.dev>]

svm_flush_tlb_asid() currently operates on the current VMCB. In
preparation for properly tracking TLB flushes for L1 and L2 ASIDs,
refactor it to work on a given VMCB. All existing callers pass the
current VMCB.

Create a svm_flush_tlb_guest() wrapper to use as the flush_tlb_guest()
callback.

kvm_hv_vcpu_purge_flush_tlb() is only called when the current VMCB is
passed to maintain current behavior.

No functional change intended.

Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
---
 arch/x86/kvm/svm/svm.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 08340ae57777b..2108b48ba4959 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3954,7 +3954,7 @@ static void svm_enable_nmi_window(struct kvm_vcpu *vcpu)
 	svm->vmcb->save.rflags |= (X86_EFLAGS_TF | X86_EFLAGS_RF);
 }
 
-static void svm_flush_tlb_asid(struct kvm_vcpu *vcpu)
+static void svm_flush_tlb_asid(struct kvm_vcpu *vcpu, struct kvm_vmcb_info *vmcb)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 
@@ -3963,7 +3963,8 @@ static void svm_flush_tlb_asid(struct kvm_vcpu *vcpu)
 	 * A TLB flush for the current ASID flushes both "host" and "guest" TLB
 	 * entries, and thus is a superset of Hyper-V's fine grained flushing.
 	 */
-	kvm_hv_vcpu_purge_flush_tlb(vcpu);
+	if (vmcb == svm->current_vmcb)
+		kvm_hv_vcpu_purge_flush_tlb(vcpu);
 
 	/*
 	 * Flush only the current ASID even if the TLB flush was invoked via
@@ -3973,14 +3974,15 @@ static void svm_flush_tlb_asid(struct kvm_vcpu *vcpu)
 	 * VM-Exit (via kvm_mmu_reset_context()).
 	 */
 	if (static_cpu_has(X86_FEATURE_FLUSHBYASID))
-		svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ASID;
+		vmcb->ptr->control.tlb_ctl = TLB_CONTROL_FLUSH_ASID;
 	else
-		svm->current_vmcb->asid_generation--;
+		vmcb->asid_generation--;
 }
 
 static void svm_flush_tlb_current(struct kvm_vcpu *vcpu)
 {
 	hpa_t root_tdp = vcpu->arch.mmu->root.hpa;
+	struct vcpu_svm *svm = to_svm(vcpu);
 
 	/*
 	 * When running on Hyper-V with EnlightenedNptTlb enabled, explicitly
@@ -3991,11 +3993,13 @@ static void svm_flush_tlb_current(struct kvm_vcpu *vcpu)
 	if (svm_hv_is_enlightened_tlb_enabled(vcpu) && VALID_PAGE(root_tdp))
 		hyperv_flush_guest_mapping(root_tdp);
 
-	svm_flush_tlb_asid(vcpu);
+	svm_flush_tlb_asid(vcpu, svm->current_vmcb);
 }
 
 static void svm_flush_tlb_all(struct kvm_vcpu *vcpu)
 {
+	struct vcpu_svm *svm = to_svm(vcpu);
+
 	/*
 	 * When running on Hyper-V with EnlightenedNptTlb enabled, remote TLB
 	 * flushes should be routed to hv_flush_remote_tlbs() without requesting
@@ -4006,7 +4010,7 @@ static void svm_flush_tlb_all(struct kvm_vcpu *vcpu)
 	if (WARN_ON_ONCE(svm_hv_is_enlightened_tlb_enabled(vcpu)))
 		hv_flush_remote_tlbs(vcpu->kvm);
 
-	svm_flush_tlb_asid(vcpu);
+	svm_flush_tlb_asid(vcpu, svm->current_vmcb);
 }
 
 static void svm_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t gva)
@@ -4016,6 +4020,13 @@ static void svm_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t gva)
 	invlpga(gva, svm->vmcb->control.asid);
 }
 
+static void svm_flush_tlb_guest(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	svm_flush_tlb_asid(vcpu, svm->current_vmcb);
+}
+
 static inline void sync_cr8_to_lapic(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -5055,7 +5066,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.flush_tlb_all = svm_flush_tlb_all,
 	.flush_tlb_current = svm_flush_tlb_current,
 	.flush_tlb_gva = svm_flush_tlb_gva,
-	.flush_tlb_guest = svm_flush_tlb_asid,
+	.flush_tlb_guest = svm_flush_tlb_guest,
 
 	.vcpu_pre_run = svm_vcpu_pre_run,
 	.vcpu_run = svm_vcpu_run,
-- 
2.48.1.362.g079036d154-goog