From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH] KVM: nVMX: Fix try to emulate "Acknowledge interrupt on exit" for interrupt which belongs to L1 Date: Mon, 31 Jul 2017 14:10:17 +0200 Message-ID: References: <1501399902-7325-1-git-send-email-wanpeng.li@hotmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Wanpeng Li To: Wanpeng Li , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Return-path: In-Reply-To: <1501399902-7325-1-git-send-email-wanpeng.li@hotmail.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 30/07/2017 09:31, Wanpeng Li wrote: > From: Wanpeng Li > > ------------[ cut here ]------------ > WARNING: CPU: 5 PID: 2288 at arch/x86/kvm/vmx.c:11124 nested_vmx_vmexit+0xd64/0xd70 [kvm_intel] > CPU: 5 PID: 2288 Comm: qemu-system-x86 Not tainted 4.13.0-rc2+ #7 > RIP: 0010:nested_vmx_vmexit+0xd64/0xd70 [kvm_intel] > Call Trace: > vmx_check_nested_events+0x131/0x1f0 [kvm_intel] > ? vmx_check_nested_events+0x131/0x1f0 [kvm_intel] > kvm_arch_vcpu_ioctl_run+0x5dd/0x1be0 [kvm] > ? vmx_vcpu_load+0x1be/0x220 [kvm_intel] > ? kvm_arch_vcpu_load+0x62/0x230 [kvm] > kvm_vcpu_ioctl+0x340/0x700 [kvm] > ? kvm_vcpu_ioctl+0x340/0x700 [kvm] > ? __fget+0xfc/0x210 > do_vfs_ioctl+0xa4/0x6a0 > ? __fget+0x11d/0x210 > SyS_ioctl+0x79/0x90 > do_syscall_64+0x8f/0x750 > ? trace_hardirqs_on_thunk+0x1a/0x1c > entry_SYSCALL64_slow_path+0x25/0x25 > > This can be reproduced by booting L1 guest w/ 'noapic' grub parameter, which > means that tells the kernel to not make use of any IOAPICs that may be present > in the system. > > There is a scenario when !kvm_cpu_has_interrupt(vcpu) && external_intr in > vmx_check_nested_events() which means that there is a pending interrupt from > L0's qemu device model which should be injected to L1, we should not try to > emualte "Acknowledge interrupt on exit" for this interrupt. > > This patch fixes it by trying to emulate "Acknowledge interrupt on exit" if L1 > asks us to. The commit message is not clear; can you rephrase? > Cc: Paolo Bonzini > Cc: Radim Krčmář > Signed-off-by: Wanpeng Li > --- > arch/x86/kvm/vmx.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 2737343..92eb0f75 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -11118,8 +11118,9 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, > > vmx_switch_vmcs(vcpu, &vmx->vmcs01); > > - if ((exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT) > - && nested_exit_intr_ack_set(vcpu)) { > + if (exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT && > + kvm_cpu_has_interrupt(vcpu) && > + nested_exit_intr_ack_set(vcpu)) { Maybe check nested_exit_intr_ack_set first. Paolo > int irq = kvm_cpu_get_interrupt(vcpu); > WARN_ON(irq < 0); > vmcs12->vm_exit_intr_info = irq | >