| From c805f5d5585ab5e0cdac6b1ccf7086eb120fb7db Mon Sep 17 00:00:00 2001 |
| From: Sean Christopherson <seanjc@google.com> |
| Date: Thu, 4 Mar 2021 17:10:57 -0800 |
| Subject: KVM: nVMX: Defer the MMU reload to the normal path on an EPTP switch |
| |
| From: Sean Christopherson <seanjc@google.com> |
| |
| 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 <seanjc@google.com> |
| Message-Id: <20210305011101.3597423-14-seanjc@google.com> |
| Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| arch/x86/kvm/vmx/nested.c | 9 ++------- |
| 1 file changed, 2 insertions(+), 7 deletions(-) |
| |
| --- a/arch/x86/kvm/vmx/nested.c |
| +++ b/arch/x86/kvm/vmx/nested.c |
| @@ -5517,16 +5517,11 @@ static int nested_vmx_eptp_switching(str |
| 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; |