Currently the inject_pending_event() call during guest entry happens after kvm_mmu_reload(). This is for historical reasons - we used to inject_pending_event() in atomic context, while kvm_mmu_reload() needs task context. A problem is that nested vmx can cause the mmu context to be reset, if event injection is intercepted and causes a #VMEXIT instead (the #VMEXIT resets CR0/CR3/CR4). If this happens, we end up with invalid root_hpa, and since kvm_mmu_reload() has already run, no one will fix it and we end up entering the guest this way. Fix by reordering event injection to be before kvm_mmu_reload(). Use ->cancel_injection() to undo if kvm_mmu_reload() fails. https://bugzilla.kernel.org/show_bug.cgi?id=42980 Reported-by: Luke-Jr <luke-jr+linuxbugs@xxxxxxxxxxx> Signed-off-by: Avi Kivity <avi@xxxxxxxxxx> --- arch/x86/kvm/x86.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4de705c..b78f89d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5279,10 +5279,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_deliver_pmi(vcpu); } - r = kvm_mmu_reload(vcpu); - if (unlikely(r)) - goto out; - if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) { inject_pending_event(vcpu); @@ -5298,6 +5294,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) } } + r = kvm_mmu_reload(vcpu); + if (unlikely(r)) { + kvm_x86_ops->cancel_injection(vcpu); + goto out; + } + preempt_disable(); kvm_x86_ops->prepare_guest_switch(vcpu); -- 1.7.10.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
