[PATCH 12/13] KVM/VMX: Change hv flush logic when ept tables are mismatched.

From: Tianyu Lan
Date: Mon Sep 10 2018 - 04:39:50 EST


If ept table pointers are mismatched, flushing tlb for each vcpus via
hv flush interface still helps to reduce vmexits which are triggered
by IPI and INEPT emulation.

Signed-off-by: Lan Tianyu <Tianyu.Lan@xxxxxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f910d33858d9..3f9ccbafd0d8 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1557,7 +1557,8 @@ static void check_ept_pointer_match(struct kvm *kvm)

static int vmx_hv_remote_flush_tlb(struct kvm *kvm)
{
- int ret;
+ struct kvm_vcpu *vcpu;
+ int ret = -ENOTSUPP, i;

spin_lock(&to_kvm_vmx(kvm)->ept_pointer_lock);

@@ -1565,14 +1566,14 @@ static int vmx_hv_remote_flush_tlb(struct kvm *kvm)
check_ept_pointer_match(kvm);

if (to_kvm_vmx(kvm)->ept_pointers_match != EPT_POINTERS_MATCH) {
- ret = -ENOTSUPP;
- goto out;
+ kvm_for_each_vcpu(i, vcpu, kvm)
+ ret |= hyperv_flush_guest_mapping(
+ to_vmx(kvm_get_vcpu(kvm, i))->ept_pointer);
+ } else {
+ ret = hyperv_flush_guest_mapping(
+ to_vmx(kvm_get_vcpu(kvm, 0))->ept_pointer);
}

- ret = hyperv_flush_guest_mapping(
- to_vmx(kvm_get_vcpu(kvm, 0))->ept_pointer);
-
-out:
spin_unlock(&to_kvm_vmx(kvm)->ept_pointer_lock);
return ret;
}
--
2.14.4