[PATCH] KVM: SVM: handle wraparound of asid_generation

[suryasaimadhu]

If asid_generation wraps around to 0, it matches the initial
value of svm->current_vmcb->asid_generation (0), causing KVM
to skip calling new_asid() and potentially reuse stale ASIDs.

Fix this by skipping 0 when incrementing asid_generation.

Signed-off-by: suryasaimadhu <suryasaimadhu369@xxxxxxxxx>
---
 arch/x86/kvm/svm/svm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 9658ce4e0..fafd0af5d 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1900,7 +1900,8 @@ static void svm_update_exception_bitmap(struct kvm_vcpu *vcpu)
 static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *sd)
 {
 	if (sd->next_asid > sd->max_asid) {
-		++sd->asid_generation;
+		if (!++sd->asid_generation)
+			sd->asid_generation = 1;
 		sd->next_asid = sd->min_asid;
 		svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ALL_ASID;
 		vmcb_mark_dirty(svm->vmcb, VMCB_ASID);
-- 
2.47.3