From: Christoph Hellwig <hch@infradead.org>
To: "Christian König" <christian.koenig@amd.com>
Cc: "Jason Gunthorpe" <jgg@nvidia.com>,
"Matthew Brost" <matthew.brost@intel.com>,
"Kasireddy, Vivek" <vivek.kasireddy@intel.com>,
"Simona Vetter" <simona.vetter@ffwll.ch>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"intel-xe@lists.freedesktop.org" <intel-xe@lists.freedesktop.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Logan Gunthorpe" <logang@deltatee.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Subject: Re: [PATCH v4 1/5] PCI/P2PDMA: Don't enforce ACS check for device functions of Intel GPUs
Date: Tue, 23 Sep 2025 06:36:29 -0700 [thread overview]
Message-ID: <aNKiXTGs75fldDYS@infradead.org> (raw)
In-Reply-To: <522d3d83-78b5-4682-bb02-d2ae2468d30a@amd.com>
On Tue, Sep 23, 2025 at 02:45:10PM +0200, Christian König wrote:
> On 23.09.25 14:15, Jason Gunthorpe wrote:
> > On Tue, Sep 23, 2025 at 09:52:04AM +0200, Christian König wrote:
> >> For example the ISP driver part of amdgpu provides the V4L2
> >> interface and when we interchange a DMA-buf with it we recognize that
> >> it is actually the same device we work with.
> >
> > One of the issues here is the mis-use of dma_map_resource() to create
> > dma_addr_t for PCI devices. This was never correct.
>
> That is not a mis-use at all but rather exactly what dma_map_resource() was created for.
It isn't. dma_map_resource was not created for PCIe P2P, and does not
work for the general case of PCIe P2P including offsets and switches.
Using it always was a big, and the drm driver maitaintainers were
constanty reminded of that and chose to ignore it with passion.
next prev parent reply other threads:[~2025-09-23 13:36 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-15 7:21 [PATCH v4 0/5] drm/xe/sriov: Don't migrate dmabuf BO to System RAM if P2P check succeeds Vivek Kasireddy
2025-09-15 7:21 ` [PATCH v4 1/5] PCI/P2PDMA: Don't enforce ACS check for device functions of Intel GPUs Vivek Kasireddy
2025-09-15 15:33 ` Logan Gunthorpe
2025-09-16 17:34 ` Bjorn Helgaas
2025-09-16 17:59 ` Jason Gunthorpe
2025-09-16 17:57 ` Jason Gunthorpe
2025-09-18 6:16 ` Kasireddy, Vivek
2025-09-18 12:04 ` Jason Gunthorpe
2025-09-19 6:22 ` Kasireddy, Vivek
2025-09-19 12:29 ` Jason Gunthorpe
2025-09-22 6:59 ` Kasireddy, Vivek
2025-09-22 11:22 ` Christian König
2025-09-22 12:20 ` Jason Gunthorpe
2025-09-22 12:25 ` Christian König
2025-09-22 12:29 ` Jason Gunthorpe
2025-09-22 13:20 ` Christian König
2025-09-22 13:27 ` Jason Gunthorpe
2025-09-22 13:57 ` Christian König
2025-09-22 14:00 ` Jason Gunthorpe
2025-09-23 5:53 ` Kasireddy, Vivek
2025-09-23 6:25 ` Matthew Brost
2025-09-23 6:44 ` Matthew Brost
2025-09-23 7:52 ` Christian König
2025-09-23 12:15 ` Jason Gunthorpe
2025-09-23 12:45 ` Christian König
2025-09-23 13:12 ` Jason Gunthorpe
2025-09-23 13:28 ` Christian König
2025-09-23 13:38 ` Jason Gunthorpe
2025-09-23 13:48 ` Christian König
2025-09-23 23:02 ` Matthew Brost
2025-09-24 8:29 ` Christian König
2025-09-24 6:50 ` Kasireddy, Vivek
2025-09-24 7:21 ` Christian König
2025-09-25 3:56 ` Kasireddy, Vivek
2025-09-25 10:51 ` Thomas Hellström
2025-09-25 11:28 ` Christian König
2025-09-25 13:11 ` Thomas Hellström
2025-09-25 13:33 ` Jason Gunthorpe
2025-09-25 15:40 ` Thomas Hellström
2025-09-25 15:55 ` Jason Gunthorpe
2025-09-26 6:12 ` Kasireddy, Vivek
2025-09-23 13:36 ` Christoph Hellwig [this message]
2025-09-23 6:01 ` Kasireddy, Vivek
2025-09-22 12:12 ` Jason Gunthorpe
2025-09-24 16:13 ` Simon Richter
2025-09-24 17:12 ` Jason Gunthorpe
2025-09-25 4:06 ` Kasireddy, Vivek
2025-09-15 7:21 ` [PATCH v4 2/5] drm/xe/dmabuf: Don't migrate BO to System RAM if P2P check succeeds Vivek Kasireddy
2025-09-16 20:01 ` Thomas Hellström
2025-09-15 7:21 ` [PATCH v4 3/5] drm/xe/pf: Add a helper function to get a VF's backing object in LMEM Vivek Kasireddy
2025-09-16 19:58 ` Matthew Brost
2025-09-16 20:06 ` Thomas Hellström
2025-09-17 7:10 ` Thomas Hellström
2025-09-15 7:21 ` [PATCH v4 4/5] drm/xe/bo: Create new dma_addr array for dmabuf BOs associated with VFs Vivek Kasireddy
2025-09-16 19:08 ` Matthew Brost
2025-09-16 19:44 ` Matthew Brost
2025-09-15 7:21 ` [PATCH v4 5/5] drm/xe/pt: Add an additional check for dmabuf BOs while doing bind Vivek Kasireddy
2025-09-16 19:13 ` Matthew Brost
2025-09-15 7:32 ` ✗ CI.checkpatch: warning for drm/xe/sriov: Don't migrate dmabuf BO to System RAM if P2P check succeeds Patchwork
2025-09-15 7:33 ` ✓ CI.KUnit: success " Patchwork
2025-09-15 8:16 ` ✓ Xe.CI.BAT: " Patchwork
2025-09-15 10:19 ` ✗ Xe.CI.Full: failure " Patchwork
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