Re: [PATCH 4/4] KVM: x86: Add VCPU substate for NMI states

[Avi Kivity <avi@redhat.com>]

On 10/14/2009 01:06 AM, Jan Kiszka wrote:
> This plugs an NMI-related hole in the VCPU synchronization between
> kernel and user space. So far, neither pending NMIs nor the inhibit NMI
> mask was properly read/set which was able to cause problems on
> vmsave/restore, live migration and system reset. Fix it by making use
> of the new VCPU substate interface.
>
>
> +struct kvm_nmi_state {
> +       __u8 pending;
> +       __u8 masked;
> +       __u8 pad1[2];
> +};
>    

Best to be conservative and use 64-bit alignment.  Who knows what we 
might put after this someday.
> @@ -513,6 +513,8 @@ struct kvm_x86_ops {
>   				unsigned char *hypercall_addr);
>   	void (*set_irq)(struct kvm_vcpu *vcpu);
>   	void (*set_nmi)(struct kvm_vcpu *vcpu);
> +	int (*get_nmi_mask)(struct kvm_vcpu *vcpu);
> +	void (*set_nmi_mask)(struct kvm_vcpu *vcpu, int masked);
>    

Prefer bool for booleans, please.

Needs a KVM_CAP as well.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.