From fa9b4ee318f9a9ede1ada05ae170b500426ce6ec Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 4 Mar 2021 17:10:57 -0800 Subject: [PATCH] KVM: nVMX: Defer the MMU reload to the normal path on an EPTP switch commit c805f5d5585ab5e0cdac6b1ccf7086eb120fb7db upstream. Defer reloading the MMU after a EPTP successful EPTP switch. The VMFUNC instruction itself is executed in the previous EPTP context, any side effects, e.g. updating RIP, should occur in the old context. Practically speaking, this bug is benign as VMX doesn't touch the MMU when skipping an emulated instruction, nor does queuing a single-step #DB. No other post-switch side effects exist. Fixes: 41ab93727467 ("KVM: nVMX: Emulate EPTP switching for the L1 hypervisor") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-Id: <20210305011101.3597423-14-seanjc@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/vmx/nested.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 15532feb19f1..bce4f0cd9511 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -5491,16 +5491,11 @@ static int nested_vmx_eptp_switching(struct kvm_vcpu *vcpu, if (!nested_vmx_check_eptp(vcpu, new_eptp)) return 1; - kvm_mmu_unload(vcpu); mmu->ept_ad = accessed_dirty; mmu->mmu_role.base.ad_disabled = !accessed_dirty; vmcs12->ept_pointer = new_eptp; - /* - * TODO: Check what's the correct approach in case - * mmu reload fails. Currently, we just let the next - * reload potentially fail - */ - kvm_mmu_reload(vcpu); + + kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu); } return 0;