On 1/28/2023 6:39 AM, Sean Christopherson wrote:
> On Tue, Nov 29, 2022, Maxim Levitsky wrote:
>> This patch adds two new vendor callbacks:
>
> No "this patch" please, just say what it does.
>
Sure.
>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
>> index 684a5519812fb2..46993ce61c92db 100644
>> --- a/arch/x86/include/asm/kvm_host.h
>> +++ b/arch/x86/include/asm/kvm_host.h
>> @@ -871,8 +871,13 @@ struct kvm_vcpu_arch {
>> u64 tsc_scaling_ratio; /* current scaling ratio */
>>
>> atomic_t nmi_queued; /* unprocessed asynchronous NMIs */
>> - unsigned nmi_pending; /* NMI queued after currently running handler */
>> +
>> + unsigned int nmi_pending; /*
>> + * NMI queued after currently running handler
>> + * (not including a hardware pending NMI (e.g vNMI))
>> + */
>
> Put the block comment above. I'd say collapse all of the comments about NMIs into
> a single big block comment.
>
ok.
>> bool nmi_injected; /* Trying to inject an NMI this entry */
>> +
>> bool smi_pending; /* SMI queued after currently running handler */
>> u8 handling_intr_from_guest;
>>
>> @@ -10015,13 +10022,34 @@ static void process_nmi(struct kvm_vcpu *vcpu)
>> * Otherwise, allow two (and we'll inject the first one immediately).
>> */
>> if (static_call(kvm_x86_get_nmi_mask)(vcpu) || vcpu->arch.nmi_injected)
>> - limit = 1;
>> + limit--;
>> +
>> + /* Also if there is already a NMI hardware queued to be injected,
>> + * decrease the limit again
>> + */
>
> /*
> * Block comment ...
> */
>
ok.
>> + if (static_call(kvm_x86_get_hw_nmi_pending)(vcpu))
>
> I'd prefer "is_hw_nmi_pending()" over "get", even if it means not pairing with
> "set". Though I think that's a good thing since they aren't perfect pairs.
>
Sure thing, will spin in v3.
>> + limit--;
>>
>> - vcpu->arch.nmi_pending += atomic_xchg(&vcpu->arch.nmi_queued, 0);
>> + if (limit <= 0)
>> + return;
>> +
>> + /* Attempt to use hardware NMI queueing */
>> + if (static_call(kvm_x86_set_hw_nmi_pending)(vcpu)) {
>> + limit--;
>> + nmi_to_queue--;
>> + }
>> +
>> + vcpu->arch.nmi_pending += nmi_to_queue;
>> vcpu->arch.nmi_pending = min(vcpu->arch.nmi_pending, limit);
>> kvm_make_request(KVM_REQ_EVENT, vcpu);
>> }
>>
>> +/* Return total number of NMIs pending injection to the VM */
>> +int kvm_get_total_nmi_pending(struct kvm_vcpu *vcpu)
>> +{
>> + return vcpu->arch.nmi_pending + static_call(kvm_x86_get_hw_nmi_pending)(vcpu);
>
> Nothing cares about the total count, this can just be;
>
>
> bool kvm_is_nmi_pending(struct kvm_vcpu *vcpu)
> {
> return vcpu->arch.nmi_pending ||
> static_call(kvm_x86_is_hw_nmi_pending)(vcpu);
> }
>
Yes, this simplifies things.
Thanks,
Santosh
>
>> +}
>> +
>> void kvm_make_scan_ioapic_request_mask(struct kvm *kvm,
>> unsigned long *vcpu_bitmap)
>> {
>> --
>> 2.26.3
>>
