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From: Christoph Hellwig <hch@infradead.org>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	cohuck@redhat.com, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, jgg@nvidia.com, peterx@redhat.com
Subject: Re: [PATCH v1 07/14] vfio: Add a device notifier interface
Date: Mon, 22 Mar 2021 15:16:16 +0000	[thread overview]
Message-ID: <20210322151616.GA2072680@infradead.org> (raw)
In-Reply-To: <20210319162540.0c5fe9dd@omen.home.shazbot.org>

On Fri, Mar 19, 2021 at 04:25:40PM -0600, Alex Williamson wrote:
> I've been trying to figure out how, but I think not.  A user can have
> multiple devices, each with entirely separate IOMMU contexts.  For each
> device, the user can create an mmap of memory to that device and add it
> to every other IOMMU context.  That enables peer to peer DMA between
> all the devices, across all the IOMMU contexts.  But each individual
> device has no direct reference to any IOMMU context other than its own.
> A callback on the IOMMU can't reach those other contexts either, there's
> no guarantee those other contexts are necessarily managed via the same
> vfio IOMMU backend driver.  A notifier is the best I can come up with,
> please suggest if you have other ideas.  Thanks,

Indeed, reviewing the set again it seems like we need the notifier
here.

  reply	other threads:[~2021-03-22 15:18 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-08 21:47 [PATCH v1 00/14] vfio: Device memory DMA mapping improvements Alex Williamson
2021-03-08 21:47 ` [PATCH v1 01/14] vfio: Create vfio_fs_type with inode per device Alex Williamson
2021-03-09  8:36   ` Christoph Hellwig
2021-04-09  4:54   ` 答复: " Zengtao (B)
2021-04-09 14:24     ` Alex Williamson
2021-04-09 17:32       ` Jason Gunthorpe
2021-04-12  4:03         ` 答复: " Zengtao (B)
2021-04-12  4:09       ` Zengtao (B)
2021-03-08 21:47 ` [PATCH v1 02/14] vfio: Update vfio_add_group_dev() API Alex Williamson
2021-03-10  7:48   ` Christoph Hellwig
2021-03-10 12:19     ` Jason Gunthorpe
2021-03-10 15:28       ` Alex Williamson
2021-03-11 11:23         ` Christoph Hellwig
2021-03-08 21:47 ` [PATCH v1 03/14] vfio: Export unmap_mapping_range() wrapper Alex Williamson
2021-03-08 21:48 ` [PATCH v1 04/14] vfio/pci: Use vfio_device_unmap_mapping_range() Alex Williamson
2021-03-08 21:48 ` [PATCH v1 05/14] vfio: Create a vfio_device from vma lookup Alex Williamson
2021-03-08 21:48 ` [PATCH v1 06/14] vfio: Add vma to pfn callback Alex Williamson
2021-03-09  0:33   ` Jason Gunthorpe
2021-03-08 21:48 ` [PATCH v1 07/14] vfio: Add a device notifier interface Alex Williamson
2021-03-09  0:46   ` Jason Gunthorpe
2021-03-09 15:45     ` Alex Williamson
2021-03-09 16:47       ` Jason Gunthorpe
2021-03-10  7:56   ` Christoph Hellwig
2021-03-19 22:25     ` Alex Williamson
2021-03-22 15:16       ` Christoph Hellwig [this message]
2021-03-08 21:48 ` [PATCH v1 08/14] vfio/pci: Notify on device release Alex Williamson
2021-03-08 21:48 ` [PATCH v1 09/14] vfio/type1: Refactor pfn_list clearing Alex Williamson
2021-03-10  8:01   ` Christoph Hellwig
2021-03-08 21:49 ` [PATCH v1 10/14] vfio/type1: Pass iommu and dma objects through to vaddr_get_pfn Alex Williamson
2021-03-08 21:49 ` [PATCH v1 11/14] vfio/type1: Register device notifier Alex Williamson
2021-03-10  8:03   ` Christoph Hellwig
2021-03-08 21:49 ` [PATCH v1 12/14] vfio/type1: Support batching of device mappings Alex Williamson
2021-03-09  1:04   ` Jason Gunthorpe
2021-03-08 21:49 ` [PATCH v1 13/14] vfio: Remove extern from declarations across vfio Alex Williamson
2021-03-09  0:21   ` Halil Pasic
2021-03-09  1:07   ` Jason Gunthorpe
2021-03-08 21:49 ` [PATCH v1 14/14] vfio: Cleanup use of bare unsigned Alex Williamson
2021-03-09  1:07   ` Jason Gunthorpe
2021-03-09  8:31     ` Christoph Hellwig
2021-03-09  1:06 ` [PATCH v1 00/14] vfio: Device memory DMA mapping improvements Jason Gunthorpe

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