Re: [PATCH v5 4/4] KVM: async_pf: Let host know whether the guest support delivery async_pf as #PF vmexit

[Paolo Bonzini]

On 27/06/2017 03:47, Wanpeng Li wrote:
> -             wrmsrl(MSR_KVM_ASYNC_PF_EN, pa | KVM_ASYNC_PF_ENABLED);
> +             pa |= KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT | KVM_ASYNC_PF_ENABLED;
> +             wrmsr_safe(MSR_KVM_ASYNC_PF_EN, pa & 0xffffffff, pa >> 32);
>               __this_cpu_write(apf_reason.enabled, 1);

Better:

        pa |= KVM_ASYNC_PF_ENABLED;

        /* Async page fault support for L1 hypervisor is optional.  */
        if (wrmsr_safe(MSR_KVM_ASYNC_PF_EN,
                       pa | KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT) < 0)
                wrmsrl(MSR_KVM_ASYNC_PF_EN, pa);

Thanks,

Paolo