On 30/07/2017 09:31, Wanpeng Li wrote:
> From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
>
> ------------[ 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 <pbonzini@xxxxxxxxxx>
> Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
> ---
> 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 |
>
