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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: Thu, 3 May 2018 21:46:16 -0700	[thread overview]
Message-ID: <20180503214616.51553247@jacob-builder> (raw)
In-Reply-To: <b12bcd35-9472-83ed-a26f-e5be3794e2d2@arm.com>

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.

Thanks,

> Thanks,
> Jean
> 

[Jacob Pan]

  reply	other threads:[~2018-05-04  4:46 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 [this message]
2018-05-04 18:07               ` Jacob Pan
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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