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From: Will Deacon <will.deacon@arm.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: Christoffer Dall <christoffer.dall@linaro.org>,
	Antonios Motakis <a.motakis@virtualopensystems.com>,
	"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
	"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"tech@virtualopensystems.com" <tech@virtualopensystems.com>,
	"a.rigo@virtualopensystems.com" <a.rigo@virtualopensystems.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"kim.phillips@freescale.com" <kim.phillips@freescale.com>,
	"stuart.yoder@freescale.com" <stuart.yoder@freescale.com>,
	"eric.auger@linaro.org" <eric.auger@linaro.org>,
	"moderated list:ARM SMMU DRIVER" 
	<linux-arm-kernel@lists.infradead.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH v6 04/20] iommu/arm-smmu: add capability IOMMU_CAP_INTR_REMAP
Date: Mon, 16 Jun 2014 16:25:26 +0100	[thread overview]
Message-ID: <20140616152526.GR16758@arm.com> (raw)
In-Reply-To: <20140616152157.GB31771@8bytes.org>

On Mon, Jun 16, 2014 at 04:21:58PM +0100, Joerg Roedel wrote:
> On Mon, Jun 16, 2014 at 04:13:29PM +0100, Will Deacon wrote:
> > MSIs look just like memory accesses made by the device, so the SMMU
> > will translate them to point at the GIC ITS (doorbell). The ITS then
> > has tables to work out how to route the MSI.
> > 
> > So, if IOMMU_CAP_INTR_REMAP is simply supposed to indicate that the
> > SMMU can translate MSIs to point somewhere else, then the ARM SMMU can
> > always do it.  If it's supposed to indicate that the actual MSI
> > payload can be filtered/routed, then that requires the GIC ITS.
> > 
> > The part I'm unsure of is how VFIO knows where to map the MSIs to.
> > That requires knowledge of the physical and virtual doorbell pages --
> > is that discoverable in the API?
> 
> VFIO does not care about the actual routing, it only cares that the
> device can not send interrupts it is not allowed to send (e.g.
> interrupts to vectors used by other devices or, on x86, exception vectors).
> If that is guaranteed by the SMMU or the GIC ITS hardware and driver
> then it is fine to set this flag.

Ok, thanks. In which case, I think this is really a combined property of
the SMMU and the interrupt controller, so we might need some extra code
so that the SMMU can check that the interrupt controller for the device
is also capable of interrupt remapping.

Will

  reply	other threads:[~2014-06-16 15:25 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1401987808-23596-1-git-send-email-a.motakis@virtualopensystems.com>
2014-06-05 17:03 ` [RFC PATCH v6 01/20] iommu/arm-smmu: change IOMMU_EXEC to IOMMU_NOEXEC Antonios Motakis
2014-06-16 15:04   ` Will Deacon
2014-06-05 17:03 ` [RFC PATCH v6 02/20] iommu: add capability IOMMU_CAP_NOEXEC Antonios Motakis
2014-06-05 20:03   ` Alex Williamson
2014-06-05 17:03 ` [RFC PATCH v6 03/20] iommu/arm-smmu: add IOMMU_CAP_NOEXEC to the ARM SMMU driver Antonios Motakis
2014-06-16 15:04   ` Will Deacon
2014-06-16 15:25     ` Alex Williamson
2014-06-16 15:30       ` Will Deacon
2014-06-05 17:03 ` [RFC PATCH v6 04/20] iommu/arm-smmu: add capability IOMMU_CAP_INTR_REMAP Antonios Motakis
2014-06-05 18:31   ` Varun Sethi
2014-06-08 10:31   ` Christoffer Dall
2014-06-16 14:53     ` Joerg Roedel
2014-06-16 15:13       ` Will Deacon
2014-06-16 15:21         ` Joerg Roedel
2014-06-16 15:25           ` Will Deacon [this message]
2014-06-16 15:38             ` Joerg Roedel
2014-06-26 18:08               ` Chalamarla, Tirumalesh
2014-06-26 18:15                 ` Chalamarla, Tirumalesh
2014-06-26 18:41                   ` Chalamarla, Tirumalesh
2014-06-26 19:00                     ` Alex Williamson
2014-06-26 19:10                       ` Chalamarla, Tirumalesh
2014-06-26 19:36                         ` Alex Williamson
2014-06-27  8:47                           ` Will Deacon
2014-06-27 21:57                             ` Chalamarla, Tirumalesh
2014-06-28  7:05                               ` Marc Zyngier
2014-06-16 15:30           ` Alex Williamson
2014-06-05 17:03 ` [RFC PATCH v6 05/20] vfio/iommu_type1: support for platform bus devices on ARM Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 06/20] vfio: introduce the VFIO_DMA_MAP_FLAG_NOEXEC flag Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 07/20] vfio/iommu_type1: implement " Antonios Motakis
2014-06-05 20:48   ` Alex Williamson
2014-06-05 17:03 ` [RFC PATCH v6 08/20] driver core: platform: add device binding path 'driver_override' Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 09/20] vfio/platform: initial skeleton of VFIO support for platform devices Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 10/20] vfio/platform: return info for device and its memory mapped IO regions Antonios Motakis
2014-06-05 21:14   ` Alex Williamson
2014-06-06 16:39     ` Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 11/20] vfio/platform: read and write support for the device fd Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 12/20] vfio/platform: support MMAP of MMIO regions Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 13/20] vfio/platform: return IRQ info Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 14/20] vfio/platform: initial interrupts support Antonios Motakis
2014-06-08 10:09   ` Christoffer Dall
2014-09-02 16:07     ` Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 15/20] vfio/platform: support for maskable and automasked interrupts Antonios Motakis
2014-06-08 10:17   ` Christoffer Dall
2014-09-02 16:06     ` Antonios Motakis
2014-09-10 10:13       ` Christoffer Dall
2014-09-11 17:20         ` Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 16/20] vfio: move eventfd support code for VFIO_PCI to a sepparate file Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 17/20] vfio: add local lock in virqfd instead of depending on VFIO PCI Antonios Motakis
2014-06-05 22:19   ` Alex Williamson
2014-06-06 16:57     ` Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 18/20] vfio: pass an opaque pointer on virqfd initialization Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 19/20] vfio: initialize the virqfd workqueue in VFIO generic code Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 20/20] vfio/platform: implement IRQ masking/unmasking via an eventfd Antonios Motakis

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