From: Jason Gunthorpe <jgg@nvidia.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: "Leon Romanovsky" <leon@kernel.org>,
"Alex Williamson" <alex.williamson@redhat.com>,
"Leon Romanovsky" <leonro@nvidia.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Christian König" <christian.koenig@amd.com>,
dri-devel@lists.freedesktop.org, iommu@lists.linux.dev,
"Jens Axboe" <axboe@kernel.dk>, "Joerg Roedel" <joro@8bytes.org>,
kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-media@vger.kernel.org, linux-mm@kvack.org,
linux-pci@vger.kernel.org,
"Logan Gunthorpe" <logang@deltatee.com>,
"Marek Szyprowski" <m.szyprowski@samsung.com>,
"Robin Murphy" <robin.murphy@arm.com>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Vivek Kasireddy" <vivek.kasireddy@intel.com>,
"Will Deacon" <will@kernel.org>
Subject: Re: [PATCH v5 8/9] vfio/pci: Enable peer-to-peer DMA transactions by default
Date: Fri, 17 Oct 2025 08:55:24 -0300 [thread overview]
Message-ID: <20251017115524.GG3901471@nvidia.com> (raw)
In-Reply-To: <aPHjG2PS5DVgcG93@infradead.org>
On Thu, Oct 16, 2025 at 11:32:59PM -0700, Christoph Hellwig wrote:
> On Mon, Oct 13, 2025 at 06:26:10PM +0300, Leon Romanovsky wrote:
> > From: Leon Romanovsky <leonro@nvidia.com>
> >
> > Make sure that all VFIO PCI devices have peer-to-peer capabilities
> > enables, so we would be able to export their MMIO memory through DMABUF,
>
> How do you know that they are safe to use with P2P?
All PCI devices are "safe" for P2P by spec. I've never heard of a
non-complaint device causing problems in this area.
The issue is always SOC support inside the CPU and that is delt with
inside the P2P subsystem logic.
If we ever see a problem it would be delt with by quirking the broken
device through pci-quirks and having the p2p subsystem refuse any p2p
with that device.
Jason
next prev parent reply other threads:[~2025-10-17 11:55 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-13 15:26 [PATCH v5 0/9] vfio/pci: Allow MMIO regions to be exported through dma-buf Leon Romanovsky
2025-10-13 15:26 ` [PATCH v5 1/9] PCI/P2PDMA: Separate the mmap() support from the core logic Leon Romanovsky
2025-10-17 6:30 ` Christoph Hellwig
2025-10-17 11:53 ` Jason Gunthorpe
2025-10-20 12:27 ` Christoph Hellwig
2025-10-20 12:58 ` Jason Gunthorpe
2025-10-20 15:04 ` Leon Romanovsky
2025-10-22 7:10 ` Christoph Hellwig
2025-10-22 11:43 ` Jason Gunthorpe
2025-10-13 15:26 ` [PATCH v5 2/9] PCI/P2PDMA: Simplify bus address mapping API Leon Romanovsky
2025-10-13 15:26 ` [PATCH v5 3/9] PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation Leon Romanovsky
2025-10-13 15:26 ` [PATCH v5 4/9] PCI/P2PDMA: Export pci_p2pdma_map_type() function Leon Romanovsky
2025-10-17 6:31 ` Christoph Hellwig
2025-10-17 12:14 ` Jason Gunthorpe
2025-10-20 12:29 ` Christoph Hellwig
2025-10-20 13:14 ` Jason Gunthorpe
2025-10-13 15:26 ` [PATCH v5 5/9] types: move phys_vec definition to common header Leon Romanovsky
2025-10-13 15:26 ` [PATCH v5 6/9] vfio: Export vfio device get and put registration helpers Leon Romanovsky
2025-10-13 15:26 ` [PATCH v5 7/9] vfio/pci: Share the core device pointer while invoking feature functions Leon Romanovsky
2025-10-13 15:26 ` [PATCH v5 8/9] vfio/pci: Enable peer-to-peer DMA transactions by default Leon Romanovsky
2025-10-16 4:09 ` Nicolin Chen
2025-10-16 6:10 ` Leon Romanovsky
2025-10-17 6:32 ` Christoph Hellwig
2025-10-17 11:55 ` Jason Gunthorpe [this message]
2025-10-20 12:28 ` Christoph Hellwig
2025-10-20 13:08 ` Jason Gunthorpe
2025-10-22 7:08 ` Christoph Hellwig
2025-10-22 11:38 ` Jason Gunthorpe
2025-10-22 11:54 ` Jason Gunthorpe
2025-10-13 15:26 ` [PATCH v5 9/9] vfio/pci: Add dma-buf export support for MMIO regions Leon Romanovsky
2025-10-16 23:53 ` Jason Gunthorpe
2025-10-17 5:40 ` Leon Romanovsky
2025-10-17 15:58 ` Jason Gunthorpe
2025-10-17 16:01 ` Jason Gunthorpe
2025-10-17 0:01 ` Jason Gunthorpe
2025-10-17 6:33 ` Christoph Hellwig
2025-10-17 12:16 ` Jason Gunthorpe
2025-10-17 13:02 ` Jason Gunthorpe
2025-10-17 16:13 ` Leon Romanovsky
2025-10-20 16:15 ` Jason Gunthorpe
2025-10-20 16:44 ` Leon Romanovsky
2025-10-20 16:51 ` Jason Gunthorpe
2025-10-17 23:40 ` Jason Gunthorpe
2025-10-22 12:50 ` Jason Gunthorpe
2025-10-26 7:55 ` Shuai Xue
2025-10-27 12:09 ` Jason Gunthorpe
2025-10-28 13:46 ` Shuai Xue
2025-10-27 23:13 ` David Matlack
2025-10-28 12:02 ` Leon Romanovsky
2025-10-30 22:28 ` Alex Mastro
2025-10-29 16:50 ` Alex Mastro
2025-10-29 18:21 ` Leon Romanovsky
2025-10-30 0:25 ` Samiullah Khawaja
2025-10-30 6:48 ` Leon Romanovsky
2025-10-30 12:57 ` Jason Gunthorpe
2025-10-30 20:38 ` Alex Williamson
2025-10-31 6:48 ` Leon Romanovsky
2025-10-15 21:15 ` [PATCH v5 0/9] vfio/pci: Allow MMIO regions to be exported through dma-buf shinichiro.kawasaki
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