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From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Cc: "iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Joerg Roedel <joro@8bytes.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Rafael Wysocki <rafael.j.wysocki@intel.com>,
	"Liu, Yi L" <yi.l.liu@intel.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	Raj Ashok <ashok.raj@intel.com>,
	Jean Delvare <khali@linux-fr.org>,
	Christoph Hellwig <hch@infradead.org>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	"Liu, Yi L" <yi.l.liu@linux.intel.com>,
	"Liu@ostrya.localdomain" <Liu@ostrya.localdomain>,
	jacob.jun.pan@linux.intel.com
Subject: Re: [PATCH v4 05/22] iommu: introduce iommu invalidate API function
Date: Fri, 4 May 2018 11:07:06 -0700	[thread overview]
Message-ID: <20180504110706.3392a98e@jacob-builder> (raw)
In-Reply-To: <20180503214616.51553247@jacob-builder>

On Thu, 3 May 2018 21:46:16 -0700
Jacob Pan <jacob.jun.pan@linux.intel.com> wrote:

> On Wed, 2 May 2018 10:31:50 +0100
> Jean-Philippe Brucker <jean-philippe.brucker@arm.com> wrote:
> 
> > On 01/05/18 23:58, Jacob Pan wrote:  
> > >>>> Maybe this should be called "NG_PAGE_PASID",      
> > >>> Sure. I was thinking page range already implies non-global
> > >>> pages.      
> > >>>> and "DOMAIN_PAGE" should
> > >>>> instead be "PAGE_PASID". If I understood their meaning
> > >>>> correctly, it would be more consistent with the rest.
> > >>>>      
> > >>> I am trying not to mix granu between request w/ PASID and w/o.
> > >>> DOMAIN_PAGE meant to be for request w/o PASID.      
> > >>
> > >> Is the distinction necessary? I understand the IOMMU side might
> > >> offer many possibilities for invalidation, but the user probably
> > >> doesn't need all of them. It might be easier to document,
> > >> upstream and maintain if we only specify what's currently needed
> > >> by users (what does QEMU VT-d use?) Others can always extend it
> > >> by increasing the version.
> > >>
> > >> Do you think that this invalidation message will be used outside
> > >> of BIND_PASID_TABLE context? I can't see an other use but who
> > >> knows. At the moment requests w/o PASID are managed with
> > >> VFIO_IOMMU_MAP/UNMAP_DMA, which doesn't require invalidation. And
> > >> in a BIND_PASID_TABLE context, IOMMUs requests w/o PASID are
> > >> just a special case using PASID 0 (for Arm and AMD) so I suppose
> > >> they'll use the same invalidation commands as requests w/ PASID.
> > >>    
> > > My understanding is that for GIOVA use case, VT-d vIOMMU creates
> > > GIOVA-GPA mapping and the host shadows the 2nd level page tables
> > > to create GIOVA-HPA mapping. So when assigned device in the guest
> > > can do both DMA map/unmap and VFIO map/unmap, VFIO unmap is one
> > > time deal (I guess invalidation can be captured in other code
> > > path), but guest kernel use of DMA unmap could will trigger
> > > invalidation. QEMU needs to trap those invalidation and passdown
> > > to physical IOMMU. So we do need invalidation w/o PASID.    
> > 
> > Hm, isn't this all done by host userspace? Whether guest does DMA
> > map/unmap or VFIO map/unmap, it creates/removes IOVA-GPA mappings in
> > the vIOMMU. QEMU captures invalidation requests for these mappings
> > from the guest, finds GPA-HVA in the shadow map and sends a VFIO
> > map/unmap request for IOVA-HVA.
> >   
> Sorry for the delay but you are right, I have also confirmed with Yi
> that we don't need second level invalidation. I will remove IOTLB
> invalidation w/o PASID case from the API.
> 
Now the passdown invalidation granularities look like:
(sorted by coarseness), will send out in v5 patchset soon if no issues.

/**
 * enum iommu_inv_granularity - Generic invalidation granularity
 *
 * @IOMMU_INV_GRANU_DOMAIN:		Device context cache associated with a
 *					domain ID.
 * @IOMMU_INV_GRANU_DEVICE:		Device context cache associated with a
 *					device ID
 * @IOMMU_INV_GRANU_DOMAIN_ALL_PASID:	TLB entries or PASID caches of all
 *					PASIDs associated with a domain ID
 * @IOMMU_INV_GRANU_PASID_SEL:		TLB entries or PASID cache associated
 *					with a PASID and a domain
 * @IOMMU_INV_GRANU_PAGE_PASID:		TLB entries of selected page range
 *					within a PASID
 *
 * When an invalidation request is passed down to IOMMU to flush translation
 * caches, it may carry different granularity levels, which can be specific
 * to certain types of translation caches. For an example, PASID selective
 * granularity is only applicable PASID cache and IOTLB invalidation but for
 * device context caches.
 * This enum is a collection of granularities for all types of translation
 * caches. The idea is to make it easy for IOMMU model specific driver to
 * convert from generic to model specific value. Not all combinations between
 * translation caches and granularity levels are valid. Each IOMMU driver
 * can enforce check based on its own conversion table. The conversion is
 * based on 2D look-up with inputs as follows:
 * - translation cache types
 * - granularity
 * No global granularity is allowed in that passdown invalidation for an
 * assigned device should only impact the device or domain itself.
 *
 *             type |   DTLB    |    TLB    |   PASID   |  CONTEXT
 *  granule         |           |           |           |
 * -----------------+-----------+-----------+-----------+-----------
 *  DOMAIN          |           |           |           |     Y
 *  DEVICE          |           |           |           |     Y
 *  DN_ALL_PASID    |   Y       |   Y       |   Y       |
 *  PASID_SEL       |   Y       |   Y       |   Y       |
 *  PAGE_PASID      |           |   Y       |           |
 *
 */
enum iommu_inv_granularity {
	IOMMU_INV_GRANU_DOMAIN,
	IOMMU_INV_GRANU_DEVICE,
	IOMMU_INV_GRANU_DOMAIN_ALL_PASID,
	IOMMU_INV_GRANU_PASID_SEL,
	IOMMU_INV_GRANU_PAGE_PASID,
	IOMMU_INV_NR_GRANU,
};


> Thanks,
> 
> > Thanks,
> > Jean
> >   
> 
> [Jacob Pan]

[Jacob Pan]

  reply	other threads:[~2018-05-04 18:07 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-16 21:48 [PATCH v4 00/22] IOMMU and VT-d driver support for Shared Virtual Address (SVA) Jacob Pan
2018-04-16 21:48 ` [PATCH v4 01/22] iommu: introduce bind_pasid_table API function Jacob Pan
2018-04-16 21:48 ` [PATCH v4 02/22] iommu/vt-d: move device_domain_info to header Jacob Pan
2018-04-16 21:48 ` [PATCH v4 03/22] iommu/vt-d: add a flag for pasid table bound status Jacob Pan
2018-04-16 21:48 ` [PATCH v4 04/22] iommu/vt-d: add bind_pasid_table function Jacob Pan
2018-04-17 19:10   ` Alex Williamson
2018-04-20 18:25     ` Jean-Philippe Brucker
2018-04-20 23:42       ` Jacob Pan
2018-05-29 20:09         ` Alex Williamson
2018-05-30  1:41           ` Tian, Kevin
2018-05-30  3:17             ` Alex Williamson
2018-05-30  3:45               ` Tian, Kevin
2018-05-30 11:53                 ` Jean-Philippe Brucker
2018-05-30 19:52                   ` Jacob Pan
2018-05-31  9:09                     ` Jean-Philippe Brucker
2018-06-05 17:32                       ` Jacob Pan
2018-06-06 11:20                         ` Jean-Philippe Brucker
2018-06-06 21:22                           ` Jacob Pan
2018-06-07 13:21                             ` Jean-Philippe Brucker
2018-04-20 23:22     ` Jacob Pan
2018-04-16 21:48 ` [PATCH v4 05/22] iommu: introduce iommu invalidate API function Jacob Pan
2018-04-20 18:19   ` Jean-Philippe Brucker
2018-04-23 20:43     ` Jacob Pan
2018-04-27 18:07       ` Jean-Philippe Brucker
2018-04-28  2:41         ` Tian, Kevin
2018-05-01 22:58         ` Jacob Pan
2018-05-02  9:31           ` Jean-Philippe Brucker
2018-05-04  4:46             ` Jacob Pan
2018-05-04 18:07               ` Jacob Pan [this message]
2018-05-08 10:35                 ` Jean-Philippe Brucker
2018-05-09 12:55                   ` Jacob Pan
2018-05-05 22:19   ` Jerry Snitselaar
2018-05-07 15:41     ` Jacob Pan
2018-04-16 21:48 ` [PATCH v4 06/22] iommu/vt-d: add definitions for PFSID Jacob Pan
2018-04-16 21:48 ` [PATCH v4 07/22] iommu/vt-d: fix dev iotlb pfsid use Jacob Pan
2018-04-16 21:48 ` [PATCH v4 08/22] iommu/vt-d: support flushing more translation cache types Jacob Pan
2018-04-16 21:48 ` [PATCH v4 09/22] iommu/vt-d: add svm/sva invalidate function Jacob Pan
2018-04-17 19:10   ` Alex Williamson
2018-04-20 22:36     ` Jacob Pan
2018-04-16 21:48 ` [PATCH v4 10/22] iommu: introduce device fault data Jacob Pan
2018-04-23 10:11   ` Jean-Philippe Brucker
2018-04-23 11:54     ` Jacob Pan
2018-05-20  8:17   ` Liu, Yi L
2018-05-21 23:16     ` Jacob Pan
2018-04-16 21:49 ` [PATCH v4 11/22] driver core: add per device iommu param Jacob Pan
2018-04-23 10:26   ` Greg Kroah-Hartman
2018-04-16 21:49 ` [PATCH v4 12/22] iommu: introduce device fault report API Jacob Pan
2018-04-23 11:30   ` Jean-Philippe Brucker
2018-04-24 18:29     ` Jacob Pan
2018-04-30 16:53   ` Jean-Philippe Brucker
2018-04-30 18:54     ` Jacob Pan
2018-04-16 21:49 ` [PATCH v4 13/22] iommu: introduce page response function Jacob Pan
2018-04-23 11:47   ` Jean-Philippe Brucker
2018-04-23 12:16     ` Jacob Pan
2018-04-23 15:50       ` Jean-Philippe Brucker
2018-04-16 21:49 ` [PATCH v4 14/22] iommu: handle page response timeout Jacob Pan
2018-04-23 15:36   ` Jean-Philippe Brucker
2018-04-25 15:37     ` Jacob Pan
2018-04-30 10:58       ` Jean-Philippe Brucker
2018-04-30 17:54         ` Jacob Pan
2018-04-16 21:49 ` [PATCH v4 15/22] iommu/config: add build dependency for dmar Jacob Pan
2018-04-16 21:49 ` [PATCH v4 16/22] iommu/vt-d: report non-recoverable faults to device Jacob Pan
2018-04-16 21:49 ` [PATCH v4 17/22] iommu/intel-svm: report device page request Jacob Pan
2018-04-16 21:49 ` [PATCH v4 18/22] iommu/intel-svm: replace dev ops with fault report API Jacob Pan
2018-04-16 21:49 ` [PATCH v4 19/22] iommu/intel-svm: do not flush iotlb for viommu Jacob Pan
2018-04-16 21:49 ` [PATCH v4 20/22] iommu/vt-d: add intel iommu page response function Jacob Pan
2018-04-16 21:49 ` [PATCH v4 21/22] trace/iommu: add sva trace events Jacob Pan
2018-04-16 21:49 ` [PATCH v4 22/22] iommu: use sva invalidate and device fault trace event Jacob Pan
  -- strict thread matches above, loose matches on Subject: below --
2018-03-23  3:11 [PATCH v4 00/22] IOMMU and VT-d driver support for Shared Virtual Address (SVA) Jacob Pan
2018-03-23  3:11 ` [PATCH v4 05/22] iommu: introduce iommu invalidate API function Jacob Pan

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