> -----Original Message----- > From: David Woodhouse [mailto:dwmw2@infradead.org] > Sent: Wednesday, January 28, 2015 11:38 PM > To: Wu, Feng > Cc: tglx@linutronix.de; mingo@redhat.com; hpa@zytor.com; x86@kernel.org; > gleb@kernel.org; pbonzini@redhat.com; joro@8bytes.org; > alex.williamson@redhat.com; jiang.liu@linux.intel.com; eric.auger@linaro.org; > linux-kernel@vger.kernel.org; iommu@lists.linux-foundation.org; > kvm@vger.kernel.org > Subject: Re: [v3 08/26] iommu, x86: Add intel_irq_remapping_capability() for > Intel > > On Fri, 2014-12-12 at 23:14 +0800, Feng Wu wrote: > > Add the Intel side implementation for capability in > > struct irq_remap_ops. > > > > Signed-off-by: Feng Wu > > Reviewed-by: Jiang Liu > > > +static bool intel_irq_remapping_capability(enum irq_remap_cap cap) > > +{ > > + struct dmar_drhd_unit *drhd; > > + struct intel_iommu *iommu; > > + > > + switch (cap) { > > + case IRQ_POSTING_CAP: > > + /* > > + * If 1) posted-interrupts is disabled by user > > + * or 2) irq remapping is disabled, posted-interrupts > > + * is not supported. > > + */ > > + if (disable_irq_post || !irq_remapping_enabled) > > + return 0; > > + > > + for_each_iommu(iommu, drhd) > > + if (!cap_pi_support(iommu->cap)) > > + return 0; > > + > > If a new IOMMU is hotplugged now which doesn't support posted > interrupts, what happens? Good question, Just had a offline discussion with Jiang Liu, actually, there is the same question for IR. In the current implementation, If IR is in use and a new IOMMU without IR capability is hotplugged, it will reject this hotplugging. I think I can simple follow the same policy for PI. Thanks, Feng > > -- > David Woodhouse Open Source Technology > Centre > David.Woodhouse@intel.com Intel > Corporation {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I