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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: Wed, 9 May 2018 05:55:30 -0700	[thread overview]
Message-ID: <20180509055530.166ab2a6@jacob-builder> (raw)
In-Reply-To: <ef462e73-01e3-d581-cf91-3e012a337c61@arm.com>

On Tue, 8 May 2018 11:35:00 +0100
Jean-Philippe Brucker <jean-philippe.brucker@arm.com> wrote:

> Hi Jacob,
> 
> Looks mostly good to me, I just have a couple more comments
> 
> On 04/05/18 19:07, Jacob Pan wrote:
> > 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.  
> 
> Should it be "PASID selective granularity is only applicable to PASID
> cache and IOTLB but not device context caches"?
> 
right, thanks!
> >  * 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.  
> 
> That last sentence is a bit confusing, because "global granularity"
> might also refer to the "global" TLB flag which is allowed. In my
> opinion you can leave this rationale out, I doubt userspace will ever
> demand a mechanism for global invalidation.
> 
yes, i can leave the last sentence out.
> >  *
> >  *             type |   DTLB    |    TLB    |   PASID   |  CONTEXT
> >  *  granule         |           |           |           |
> >  * -----------------+-----------+-----------+-----------+-----------
> >  *  DOMAIN          |           |           |           |     Y
> >  *  DEVICE          |           |           |           |     Y  
> 
> I can't really see a use-case for DOMAIN and DEVICE. It might make
> more sense to keep only DN_ALL_PASID, which would then also
> invalidate the device context cache. But since they will be very rare
> events, factoring them doesn't seem important.
> 
ok. we have no use for now either, was there for completeness. i will
remove for now.
> >  *  DN_ALL_PASID    |   Y       |   Y       |   Y       |
> >  *  PASID_SEL       |   Y       |   Y       |   Y       |
> >  *  PAGE_PASID      |           |   Y       |           |  
> 
> Why not allow PAGE_PASID+DTLB? We need a way to invalidate individual
> DTLB entries
> 
I was thinking PAGE_PASID+TLB includes PAGE_PASID+DTLB, but you are
right, DTLB should be a 'Y' here.
> Thanks,
> Jean

[Jacob Pan]

  reply	other threads:[~2018-05-09 12:55 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
2018-05-08 10:35                 ` Jean-Philippe Brucker
2018-05-09 12:55                   ` Jacob Pan [this message]
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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