Flush only the current context, as opposed to all contexts, when
requesting a TLB flush to handle the scenario where a L1 does not expect
a TLB flush, but one is required because L1 and L2 shared an ASID. This
occurs if EPT is disabled (no per-EPTP tag), VPID is enabled (hardware
doesn't flush unconditionally) and vmcs02 does not have its own VPID due
to exhaustion of available VPIDs.
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/kvm/vmx/nested.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index b9fa2f89b564..e630d656b211 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1174,8 +1174,8 @@ static void nested_vmx_transition_tlb_flush(struct kvm_vcpu *vcpu,
*
* If VPID is enabled and used by vmc12, but L2 does not have a unique
* TLB tag (ASID), i.e. EPT is disabled and KVM was unable to allocate
- * a VPID for L2, flush the TLB as the effective ASID is common to both
- * L1 and L2.
+ * a VPID for L2, flush the current context as the effective ASID is
+ * common to both L1 and L2.
*
* Defer the flush so that it runs after vmcs02.EPTP has been set by
* KVM_REQ_LOAD_MMU_PGD (if nested EPT is enabled) and to avoid
@@ -1187,8 +1187,10 @@ static void nested_vmx_transition_tlb_flush(struct kvm_vcpu *vcpu,
* mapping between vpid02 and vpid12, vpid02 is per-vCPU and reused for
* all nested vCPUs.
*/
- if (!nested_cpu_has_vpid(vmcs12) || !nested_has_guest_tlb_tag(vcpu)) {
+ if (!nested_cpu_has_vpid(vmcs12)) {
kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
+ } else if (!nested_has_guest_tlb_tag(vcpu)) {
+ kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu);
} else if (is_vmenter &&
vmcs12->virtual_processor_id != vmx->nested.last_vpid) {
vmx->nested.last_vpid = vmcs12->virtual_processor_id;
--
2.24.1
