From 29bf08f12b2fd72b882da0d85b7385e4a438a297 Mon Sep 17 00:00:00 2001 From: Jan Kiszka <jan.kiszka@web.de> Date: Sat, 28 Dec 2013 16:31:52 +0100 Subject: [PATCH] KVM: nVMX: Unconditionally uninit the MMU on nested vmexit Three reasons for doing this: 1. arch.walk_mmu points to arch.mmu anyway in case nested EPT wasn't in use. 2. this aligns VMX with SVM. But 3. is most important: nested_cpu_has_ept(vmcs12) queries the VMCS page, and if one guest VCPU manipulates the page of another VCPU in L2, we may be fooled to skip over the nested_ept_uninit_mmu_context, leaving mmu in nested state. That can crash the host later on if nested_ept_get_cr3 is invoked while L1 already left vmxon and nested.current_vmcs12 became NULL therefore. Cc: stable@kernel.org Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> --- arch/x86/kvm/vmx.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index b2fe1c252f35..da7837e1349d 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -8283,8 +8283,7 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu, vcpu->arch.cr4_guest_owned_bits = ~vmcs_readl(CR4_GUEST_HOST_MASK); kvm_set_cr4(vcpu, vmcs12->host_cr4); - if (nested_cpu_has_ept(vmcs12)) - nested_ept_uninit_mmu_context(vcpu); + nested_ept_uninit_mmu_context(vcpu); kvm_set_cr3(vcpu, vmcs12->host_cr3); kvm_mmu_reset_context(vcpu); -- GitLab