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From: Alex Williamson <alex.williamson@redhat.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: Will Deacon <will.deacon@arm.com>,
	Christoffer Dall <christoffer.dall@linaro.org>,
	Antonios Motakis <a.motakis@virtualopensystems.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 09:30:32 -0600	[thread overview]
Message-ID: <1402932632.3707.37.camel@ul30vt.home> (raw)
In-Reply-To: <20140616152157.GB31771@8bytes.org>

On Mon, 2014-06-16 at 17:21 +0200, 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.

Yep, I agree.  Thanks,

Alex


  parent reply	other threads:[~2014-06-16 15:31 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
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 [this message]
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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