[PATCH v2 31/32] KVM: nVMX: Don't flush TLB on nested VM transition with EPT enabled

From: Sean Christopherson
Date: Tue Mar 17 2020 - 00:53:35 EST


Don't flush the TLB if a cached EPTP root can be reused for nested
VM-Enter/VM-Exit. Each unique EPTP constitutes a different ASID,
cached roots are invalidated on eviction, and KVM invalidates all EPTP
contexts on global events, e.g. mmu_notifier invalidate or memslot
updates.

Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 2 +-
arch/x86/kvm/vmx/nested.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index b98482b60748..de2bd07bad7f 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5047,7 +5047,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
kvm_calc_shadow_ept_root_page_role(vcpu, accessed_dirty,
execonly, level);

- __kvm_mmu_new_cr3(vcpu, new_eptp, new_role.base, false);
+ __kvm_mmu_new_cr3(vcpu, new_eptp, new_role.base, true);

if (new_role.as_u64 == context->mmu_role.as_u64)
return;
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index d816f1366943..a77eab5b0e8a 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1123,7 +1123,7 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool ne
}

if (!nested_ept)
- kvm_mmu_new_cr3(vcpu, cr3, false);
+ kvm_mmu_new_cr3(vcpu, cr3, enable_ept);

vcpu->arch.cr3 = cr3;
kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);
--
2.24.1