All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jason Gunthorpe <jgg@nvidia.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: "Christoph Hellwig" <hch@infradead.org>,
	"Leon Romanovsky" <leon@kernel.org>,
	kvm@vger.kernel.org, linux-rdma@vger.kernel.org,
	"Daniel Vetter" <daniel.vetter@ffwll.ch>,
	"Oded Gabbay" <ogabbay@kernel.org>,
	"Cornelia Huck" <cohuck@redhat.com>,
	dri-devel@lists.freedesktop.org,
	"Sumit Semwal" <sumit.semwal@linaro.org>,
	linaro-mm-sig@lists.linaro.org,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Maor Gottlieb" <maorg@nvidia.com>,
	"Christian König" <christian.koenig@amd.com>,
	linux-media@vger.kernel.org
Subject: Re: [PATCH v2 4/4] vfio/pci: Allow MMIO regions to be exported through dma-buf
Date: Wed, 7 Sep 2022 13:47:24 -0300	[thread overview]
Message-ID: <YxjLHAw6rAcS/ax6@nvidia.com> (raw)
In-Reply-To: <6a42a8bc-4e2e-4502-3e7b-1a616dfee351@arm.com>

On Wed, Sep 07, 2022 at 05:31:14PM +0100, Robin Murphy wrote:

> The only trouble is that it's not geared for *PCI* P2P when that may or may
> not happen entirely upstream of IOMMU translation.

This is why PCI users have to call the pci_distance stuff before using
dma_map_resource(), it ensures the PCI fabric is setup in a way that
is consistent with the iommu. eg if we have IOMMU turned on then the
fabric must have ACS/etc to ensure that all TLPs are translated.

PCI P2P is very complicated and fragile, sadly.

Thanks,
Jason

WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@nvidia.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: linaro-mm-sig@lists.linaro.org,
	"Leon Romanovsky" <leon@kernel.org>,
	kvm@vger.kernel.org, linux-rdma@vger.kernel.org,
	"Daniel Vetter" <daniel.vetter@ffwll.ch>,
	"Oded Gabbay" <ogabbay@kernel.org>,
	"Cornelia Huck" <cohuck@redhat.com>,
	dri-devel@lists.freedesktop.org,
	"Christian König" <christian.koenig@amd.com>,
	"Christoph Hellwig" <hch@infradead.org>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Maor Gottlieb" <maorg@nvidia.com>,
	"Sumit Semwal" <sumit.semwal@linaro.org>,
	linux-media@vger.kernel.org
Subject: Re: [PATCH v2 4/4] vfio/pci: Allow MMIO regions to be exported through dma-buf
Date: Wed, 7 Sep 2022 13:47:24 -0300	[thread overview]
Message-ID: <YxjLHAw6rAcS/ax6@nvidia.com> (raw)
In-Reply-To: <6a42a8bc-4e2e-4502-3e7b-1a616dfee351@arm.com>

On Wed, Sep 07, 2022 at 05:31:14PM +0100, Robin Murphy wrote:

> The only trouble is that it's not geared for *PCI* P2P when that may or may
> not happen entirely upstream of IOMMU translation.

This is why PCI users have to call the pci_distance stuff before using
dma_map_resource(), it ensures the PCI fabric is setup in a way that
is consistent with the iommu. eg if we have IOMMU turned on then the
fabric must have ACS/etc to ensure that all TLPs are translated.

PCI P2P is very complicated and fragile, sadly.

Thanks,
Jason

  reply	other threads:[~2022-09-07 16:48 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-31 23:12 [PATCH v2 0/4] Allow MMIO regions to be exported through dma-buf Jason Gunthorpe
2022-08-31 23:12 ` Jason Gunthorpe
2022-08-31 23:12 ` [PATCH v2 1/4] dma-buf: Add dma_buf_try_get() Jason Gunthorpe
2022-08-31 23:12   ` Jason Gunthorpe
2022-09-01  7:55   ` Christian König
2022-09-01  7:55     ` Christian König
2022-09-06 16:44     ` Jason Gunthorpe
2022-09-06 16:44       ` Jason Gunthorpe
2022-09-06 17:52       ` Christian König
2022-09-06 17:52         ` Christian König
2022-08-31 23:12 ` [PATCH v2 2/4] vfio: Add vfio_device_get() Jason Gunthorpe
2022-08-31 23:12   ` Jason Gunthorpe
2022-08-31 23:12 ` [PATCH v2 3/4] vfio_pci: Do not open code pci_try_reset_function() Jason Gunthorpe
2022-08-31 23:12   ` Jason Gunthorpe
2022-08-31 23:12 ` [PATCH v2 4/4] vfio/pci: Allow MMIO regions to be exported through dma-buf Jason Gunthorpe
2022-08-31 23:12   ` Jason Gunthorpe
2022-09-06  9:51   ` Christoph Hellwig
2022-09-06 10:38     ` Christian König
2022-09-06 10:38       ` Christian König
2022-09-06 11:48       ` Jason Gunthorpe
2022-09-06 11:48         ` Jason Gunthorpe
2022-09-06 12:34         ` Oded Gabbay
2022-09-06 12:34           ` Oded Gabbay
2022-09-06 17:59           ` Jason Gunthorpe
2022-09-06 17:59             ` Jason Gunthorpe
2022-09-06 19:44             ` Oded Gabbay
2022-09-06 19:44               ` Oded Gabbay
2022-09-07 12:07               ` Christoph Hellwig
2022-09-07 12:05         ` Christoph Hellwig
2022-09-07 12:33           ` Jason Gunthorpe
2022-09-07 12:33             ` Jason Gunthorpe
2022-09-07 14:29             ` Christoph Hellwig
2022-09-07 14:46               ` Oded Gabbay
2022-09-07 14:46                 ` Oded Gabbay
2022-09-07 15:23               ` Jason Gunthorpe
2022-09-07 15:23                 ` Jason Gunthorpe
2022-09-07 15:32                 ` Christoph Hellwig
2022-09-07 16:12                   ` Jason Gunthorpe
2022-09-07 16:12                     ` Jason Gunthorpe
2022-09-09 13:24                     ` Christoph Hellwig
2022-09-09 14:09                       ` Jason Gunthorpe
2022-09-09 14:09                         ` Jason Gunthorpe
2022-09-07 16:31                 ` Robin Murphy
2022-09-07 16:31                   ` Robin Murphy
2022-09-07 16:47                   ` Jason Gunthorpe [this message]
2022-09-07 16:47                     ` Jason Gunthorpe
2022-09-07 17:03               ` Dan Williams
2022-09-07 17:03                 ` Dan Williams
2022-09-07 15:01             ` Robin Murphy
2022-09-07 15:01               ` Robin Murphy
2022-09-07 12:03       ` Christoph Hellwig
2022-09-07 15:08         ` Christian König
2022-09-07 15:08           ` Christian König
2022-09-07 15:23           ` Christoph Hellwig

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YxjLHAw6rAcS/ax6@nvidia.com \
    --to=jgg@nvidia.com \
    --cc=alex.williamson@redhat.com \
    --cc=christian.koenig@amd.com \
    --cc=cohuck@redhat.com \
    --cc=dan.j.williams@intel.com \
    --cc=daniel.vetter@ffwll.ch \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=hch@infradead.org \
    --cc=kvm@vger.kernel.org \
    --cc=leon@kernel.org \
    --cc=linaro-mm-sig@lists.linaro.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-rdma@vger.kernel.org \
    --cc=maorg@nvidia.com \
    --cc=ogabbay@kernel.org \
    --cc=robin.murphy@arm.com \
    --cc=sumit.semwal@linaro.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.