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

[Jan Kiszka <jan.kiszka@siemens.com>]

Avi Kivity wrote:
> 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.

OK.

>> @@ -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.

OK.

> 
> Needs a KVM_CAP as well.

KVM_CAP_VCPU_STATE will imply KVM_CAP_NMI_STATE, so I skipped the latter
(user space code would use the former anyway to avoid yet another #ifdef
layer).

Jan

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