linux-kernel - Re: [PATCH V3] KVM: x86: Sync the pending Posted-Interrupts

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Date:   Mon, 4 Feb 2019 11:00:41 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     "Kang, Luwei" <luwei.kang@...el.com>,
        "rkrcmar@...hat.com" <rkrcmar@...hat.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "bp@...en8.de" <bp@...en8.de>, "hpa@...or.com" <hpa@...or.com>,
        "x86@...nel.org" <x86@...nel.org>
Cc:     "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V3] KVM: x86: Sync the pending Posted-Interrupts

On 01/02/19 06:44, Kang, Luwei wrote:
> 
> Do you mean remove the blow code in vmx_vcpu_pi_load() function to make the ON can be set if PIR is not zero?
> 
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -1192,21 +1192,6 @@ static void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu)
>         if (!pi_test_sn(pi_desc) && vcpu->cpu == cpu)
>                 return;
> 
> -       /*
> -        * First handle the simple case where no cmpxchg is necessary; just
> -        * allow posting non-urgent interrupts.
> -        *
> -        * If the 'nv' field is POSTED_INTR_WAKEUP_VECTOR, do not change
> -        * PI.NDST: pi_post_block will do it for us and the wakeup_handler
> -        * expects the VCPU to be on the blocked_vcpu_list that matches
> -        * PI.NDST.
> -        */
> -       if (pi_desc->nv == POSTED_INTR_WAKEUP_VECTOR ||
> -           vcpu->cpu == cpu) {
> -               pi_clear_sn(pi_desc);
> -               return;
> -       }

Yes, exactly.

Paolo