RE: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination
From: Wu, Feng
Date: Mon Jan 25 2016 - 07:27:00 EST
> -----Original Message-----
> From: Paolo Bonzini [mailto:paolo.bonzini@xxxxxxxxx] On Behalf Of Paolo
> Sent: Monday, January 25, 2016 8:23 PM
> To: Radim KrcmÃr <rkrcmar@xxxxxxxxxx>; Wu, Feng <feng.wu@xxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the
> interrupt is not single-destination
> On 22/01/2016 14:05, Radim KrcmÃr wrote:
> > > This is a good question. I also thought about this before, but after
> > > thinking it a bit more, seems we don't need to do this.
> > > If we don't do this, the in-flight interrupts will continue to be
> > > delivered in PI mode while we are changing it to remapped
> > > mode in IRTE. Even if we do this, the in-flight interrupts are
> > > also delivered in PI mode before setting 'SN' anyway, so seems
> > > we really don't need this, what is your opinion?
> > I'd remove it.
> It may be necessary because IRTE writes (128 bits) are not atomic.
IRTE is updated atomically, I added the patch to support this. Please
refer to 344cb4e0b6f3a0dbef0643eacb4946338eb228c0.
> If so, no need to send v5, I'll add it back.