From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiang Liu Subject: Re: [PATCH 12/13] iommu/vt-d: No need to migrating irq for VT-d Posted-Interrtups Date: Tue, 11 Nov 2014 21:48:44 +0800 Message-ID: <546213BC.1050204@linux.intel.com> References: <1415600812-27773-1-git-send-email-feng.wu@intel.com> <1415600812-27773-13-git-send-email-feng.wu@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1415600812-27773-13-git-send-email-feng.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Feng Wu , gleb-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org, tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org, mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: iommu@lists.linux-foundation.org On 2014/11/10 14:26, Feng Wu wrote: > We don't need to migrate the irqs for VT-d Posted-Interrtups here. > When 'pst' is set in IRTE, the associated irq will be posted to > guests instead of interrupt remapping. The destination of the > interrupt is set in Posted-Interrupts Descriptor, and the migration > happens during VCPU scheduling. > > Signed-off-by: Feng Wu > --- > drivers/iommu/intel_irq_remapping.c | 7 +++++++ > 1 files changed, 7 insertions(+), 0 deletions(-) > > diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c > index 87c02fe..249e2b1 100644 > --- a/drivers/iommu/intel_irq_remapping.c > +++ b/drivers/iommu/intel_irq_remapping.c > @@ -1038,6 +1038,13 @@ intel_ioapic_set_affinity(struct irq_data *data, const struct cpumask *mask, > if (get_irte(irq, &irte)) > return -EBUSY; > > + /* > + * If the interrupt is for posting, it is used by guests, > + * we cannot change IRTE here. > + */ > + if (irte.irq_post_low.pst == 1) > + return 0; Hi Feng, You should return some error code instead of 0, otherwise the irq core will get confused. > + > err = assign_irq_vector(irq, cfg, mask); > if (err) > return err; >