Re: [Qemu-devel] [PATCH 1/1 V5] kernel/kvm: introduce KVM_SET_LINT1 and fix improper nmi emulation

[Avi Kivity]

On 10/14/2011 11:03 AM, Lai Jiangshan wrote:
> Currently, NMI interrupt is blindly sent to all the vCPUs when NMI
> button event happens. This doesn't properly emulate real hardware on
> which NMI button event triggers LINT1. Because of this, NMI is sent to
> the processor even when LINT1 is masked in LVT. For example, this
> causes the problem that kdump initiated by NMI sometimes doesn't work
> on KVM, because kdump assumes NMI is masked on CPUs other than CPU0.
>
> With this patch, we introduce introduce KVM_SET_LINT1,
> and we can use KVM_SET_LINT1 to correctly emulate NMI button
> without change the old KVM_NMI behavior.
>  
> @@ -759,6 +762,8 @@ struct kvm_clock_data {
>  #define KVM_CREATE_SPAPR_TCE   _IOW(KVMIO,  0xa8, struct 
> kvm_create_spapr_tce)
>  /* Available with KVM_CAP_RMA */
>  #define KVM_ALLOCATE_RMA       _IOR(KVMIO,  0xa9, struct kvm_allocate_rma)
> +/* Available with KVM_CAP_SET_LINT1 for x86 */
> +#define KVM_SET_LINT1                  _IO(KVMIO,   0xaa)
>  
>

LINT1 may have been programmed as a level -triggered interrupt instead
of edge triggered (NMI or interrupt).  We can use the ioctl argument for
the level (and pressing the NMI button needs to pulse the level to 1 and
back to 0).

-- 
error compiling committee.c: too many arguments to function