From: Avi Kivity Date: Mon, 14 May 2012 15:07:56 +0000 (+0300) Subject: KVM: Fix mmu_reload() clash with nested vmx event injection X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d8368af8b46b904def42a0f341d2f4f29001fa77;p=linux-beck.git KVM: Fix mmu_reload() clash with nested vmx event injection 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 Signed-off-by: Avi Kivity Signed-off-by: Marcelo Tosatti --- diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4de705cdcafd..b78f89d34242 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);