From: Sean Christopherson Date: Fri, 5 Mar 2021 01:10:57 +0000 (-0800) Subject: KVM: nVMX: Defer the MMU reload to the normal path on an EPTP switch X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=c805f5d5585ab5e0cdac6b1ccf7086eb120fb7db;p=linux.git KVM: nVMX: Defer the MMU reload to the normal path on an EPTP switch 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 --- diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index bd1343a0896ec..d74abd7784295 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -5481,16 +5481,11 @@ 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;