> -----Original Message----- > From: iommu-boun...@lists.linux-foundation.org > [mailto:iommu-boun...@lists.linux-foundation.org] On Behalf Of Zhang, Yang Z > Sent: Thursday, December 18, 2014 11:10 PM > To: Paolo Bonzini; k...@vger.kernel.org > Cc: io...@lists.linux-foundation.org; linux-kernel@vger.kernel.org; > k...@vger.kernel.org > Subject: RE: [v3 25/26] KVM: Suppress posted-interrupt when 'SN' is set > > Paolo Bonzini wrote on 2014-12-18: > > > > > > On 18/12/2014 04:14, Wu, Feng wrote: > >> > >> > >> linux-kernel-ow...@vger.kernel.org wrote on > mailto:linux-kernel-ow...@vger.kernel.org] On Behalf Of Paolo: > >>> x...@kernel.org; Gleb Natapov; Paolo Bonzini; dw...@infradead.org; > >>> joro-zlv9swrftaidnm+yrof...@public.gmane.org; Alex Williamson; > >>> joro-zLv9SwRftAIdnm+Jiang > >>> Liu > >>> Cc: io...@lists.linux-foundation.org; > >>> linux-kernel-u79uwxl29ty76z2rm5m...@public.gmane.org; KVM list; > >>> Eric Auger > >>> Subject: Re: [v3 25/26] KVM: Suppress posted-interrupt when 'SN' is > >>> set > >>> > >>> > >>> > >>> On 12/12/2014 16:14, Feng Wu wrote: > >>>> Currently, we don't support urgent interrupt, all interrupts are > >>>> recognized as non-urgent interrupt, so we cannot send > >>>> posted-interrupt when 'SN' is set. > >>> > >>> Can this happen? If the vcpu is in guest mode, it cannot have been > >>> scheduled out, and that's the only case when SN is set. > >>> > >>> Paolo > >> > >> Currently, the only place where SN is set is vCPU is preempted and > > If the vCPU is preempted, shouldn't the subsequent be ignored? What happens > if a PI is occurs when vCPU is preempted?
If a vCPU is preempted, the 'SN' bit is set, the subsequent interrupts are suppressed for posting. Thanks, Feng > > >> waiting for the next scheduling in the runqueue. But I am not sure > >> whether we need to set SN for other purpose in future. Adding SN > >> checking here is just to follow the Spec. non-urgent interrupts are > >> suppressed > > when SN is set. > > > > I would change that to a WARN_ON_ONCE then. > > > Best regards, > Yang > > > _______________________________________________ > iommu mailing list > io...@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
