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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]
next prev parent 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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