Re: [v2 PATCH 3/4] x86/kvm: Add host side support for virtual suspend time injection

[Vitaly Kuznetsov]

Paolo Bonzini <pbonzini@xxxxxxxxxx> writes:

> On 06/08/21 12:07, Hikaru Nishida wrote:
>> +#if defined(CONFIG_KVM_VIRT_SUSPEND_TIMING) || \
>> +	defined(CONFIG_KVM_VIRT_SUSPEND_TIMING_GUEST)
>> +#define VIRT_SUSPEND_TIMING_VECTOR	0xec
>> +#endif
>
> No need to use a new vector.  You can rename the existing 
> MSR_KVM_ASYNC_PF_INT to MSR_KVM_HYPERVISOR_CALLBACK_INT or something 
> like that, and add the code to sysvec_kvm_asyncpf_interrupt.

On the host side, I'd vote for keeping MSR_KVM_ASYNC_PF_INT for async PF
mechanism only for two reasons:
- We may want to use (currently reserved) upper 56 bits of it for new
asyncPF related features (e.g. flags) and it would be unnatural to add
them to 'MSR_KVM_HYPERVISOR_CALLBACK_INT'
- We should probably leave it to the guest if it wants to share 'suspend
time' notification interrupt with async PF (and if it actually wants to
get one/another).

On the guest side, it is perfectly fine to reuse
HYPERVISOR_CALLBACK_VECTOR for everything.

-- 
Vitaly