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[4/4] KVM: nVMX: Do not flush TLB on L1->L2 VMEntry if L1 uses EPT

Message ID 20180906133228.118282-5-liran.alon@oracle.com (mailing list archive)
State New, archived
Headers show
Series : KVM: nVMX: Consider TLB are tagged with different EPTP if L1 uses EPT | expand

Commit Message

Liran Alon Sept. 6, 2018, 1:32 p.m. UTC 
If L1 uses EPT and VPID, vmcs02->vpid is set to vmcs12->vpid because
L2 TLB entries are separated from L1 TLB entries by having different
EPTP tags and therefore we don't need a special vpid02 to separate them.

Thus, we can avoid flush TLB on L1->L2 VMEntry if L1 uses VPID and EPT.

Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Nikita Leshchenko <nikita.leshchenko@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
---
 arch/x86/kvm/vmx.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 98faba65c24a..bf25317495da 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -12241,18 +12241,16 @@  static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 		decache_tsc_multiplier(vmx);
 
 	if (enable_vpid) {
-		/*
-		 * There is no direct mapping between vpid02 and vpid12, the
-		 * vpid02 is per-vCPU for L0 and reused while the value of
-		 * vpid12 is changed w/ one invvpid during nested vmentry.
-		 * The vpid12 is allocated by L1 for L2, so it will not
-		 * influence global bitmap(for vpid01 and vpid02 allocation)
-		 * even if spawn a lot of nested vCPUs.
-		 */
-		if (nested_cpu_has_vpid(vmcs12) && vmx->nested.vpid02) {
-			if (vmcs12->virtual_processor_id != vmx->nested.last_vpid) {
-				vmx->nested.last_vpid = vmcs12->virtual_processor_id;
-				__vmx_flush_tlb(vcpu, vmx->nested.vpid02, true);
+		if (nested_cpu_has_vpid(vmcs12)) {
+			if (!nested_cpu_has_ept(vmcs12)) {
+				if (vmx->nested.vpid02) {
+					if (vmcs12->virtual_processor_id != vmx->nested.last_vpid) {
+						vmx->nested.last_vpid = vmcs12->virtual_processor_id;
+						__vmx_flush_tlb(vcpu, vmx->nested.vpid02, true);
+					}
+				} else {
+					vmx_flush_tlb(vcpu, true);
+				}
 			}
 		} else {
 			/*