From: Christoph Hellwig <hch@lst.de>
To: Leon Romanovsky <leon@kernel.org>
Cc: "Christoph Hellwig" <hch@lst.de>,
"Jason Gunthorpe" <jgg@nvidia.com>,
"Alex Williamson" <alex.williamson@redhat.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>,
"Jérôme Glisse" <jglisse@redhat.com>,
"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 02/10] PCI/P2PDMA: Introduce p2pdma_provider structure for cleaner abstraction
Date: Tue, 29 Jul 2025 12:41:00 +0200 [thread overview]
Message-ID: <20250729104100.GA29053@lst.de> (raw)
In-Reply-To: <20250729085336.GG402218@unreal>
On Tue, Jul 29, 2025 at 11:53:36AM +0300, Leon Romanovsky wrote:
> > Because the struct page is the only thing that:
> >
> > a) dma-mapping works on
> > b) is the only place we can discover the routing information, but also
> > more importantly ensure that the underlying page is still present
> > and the device is not hot unplugged, or in a very theoretical worst
> > case replaced by something else.
>
> It is correct in general case, but here we are talking about MMIO
> memory, which is "connected" to device X and routing information is
> stable.
MMIO is literally the only thing we support to P2P to/from as that is
how PCIe P2P is defined. And not, it's not stable - devices can be
unplugged, and BARs can be reenumerated.
next prev parent reply other threads:[~2025-07-29 10:41 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-23 13:00 [PATCH 00/10] vfio/pci: Allow MMIO regions to be exported through dma-buf Leon Romanovsky
2025-07-23 13:00 ` [PATCH 01/10] PCI/P2PDMA: Remove redundant bus_offset from map state Leon Romanovsky
2025-07-24 7:50 ` Christoph Hellwig
2025-07-23 13:00 ` [PATCH 02/10] PCI/P2PDMA: Introduce p2pdma_provider structure for cleaner abstraction Leon Romanovsky
2025-07-24 7:51 ` Christoph Hellwig
2025-07-24 7:55 ` Leon Romanovsky
2025-07-24 7:59 ` Christoph Hellwig
2025-07-24 8:07 ` Leon Romanovsky
2025-07-27 18:51 ` Jason Gunthorpe
2025-07-29 7:52 ` Christoph Hellwig
2025-07-29 8:53 ` Leon Romanovsky
2025-07-29 10:41 ` Christoph Hellwig [this message]
2025-07-29 11:39 ` Leon Romanovsky
2025-07-29 13:15 ` Jason Gunthorpe
2025-07-29 16:12 ` Jason Gunthorpe
2025-07-23 13:00 ` [PATCH 03/10] PCI/P2PDMA: Simplify bus address mapping API Leon Romanovsky
2025-07-24 7:52 ` Christoph Hellwig
2025-07-23 13:00 ` [PATCH 04/10] PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation Leon Romanovsky
2025-07-23 13:00 ` [PATCH 05/10] PCI/P2PDMA: Export pci_p2pdma_map_type() function Leon Romanovsky
2025-07-24 8:03 ` Christoph Hellwig
2025-07-24 8:13 ` Leon Romanovsky
2025-07-25 16:30 ` Logan Gunthorpe
2025-07-25 18:54 ` Leon Romanovsky
2025-07-25 19:12 ` Logan Gunthorpe
2025-07-27 6:01 ` Leon Romanovsky
2025-07-27 19:05 ` Jason Gunthorpe
2025-07-28 16:12 ` Logan Gunthorpe
2025-07-28 16:41 ` Leon Romanovsky
2025-07-28 17:07 ` Logan Gunthorpe
2025-07-28 23:11 ` Jason Gunthorpe
2025-07-29 20:54 ` Logan Gunthorpe
2025-07-29 22:14 ` Jason Gunthorpe
2025-07-30 8:03 ` Leon Romanovsky
2025-07-29 7:52 ` Christoph Hellwig
2025-07-29 8:45 ` Leon Romanovsky
2025-07-27 19:02 ` Jason Gunthorpe
2025-07-23 13:00 ` [PATCH 06/10] types: move phys_vec definition to common header Leon Romanovsky
2025-07-23 13:00 ` [PATCH 07/10] vfio: Export vfio device get and put registration helpers Leon Romanovsky
2025-07-23 13:00 ` [PATCH 08/10] vfio/pci: Enable peer-to-peer DMA transactions by default Leon Romanovsky
2025-07-23 13:00 ` [PATCH 09/10] vfio/pci: Share the core device pointer while invoking feature functions Leon Romanovsky
2025-07-28 20:55 ` Alex Williamson
2025-07-29 8:39 ` Leon Romanovsky
2025-07-23 13:00 ` [PATCH 10/10] vfio/pci: Add dma-buf export support for MMIO regions Leon Romanovsky
2025-07-24 5:13 ` Kasireddy, Vivek
2025-07-24 5:44 ` Leon Romanovsky
2025-07-25 5:34 ` Kasireddy, Vivek
2025-07-27 6:16 ` Leon Romanovsky
2025-07-29 19:44 ` Robin Murphy
2025-07-29 20:13 ` Jason Gunthorpe
2025-07-30 9:32 ` Leon Romanovsky
2025-07-30 14:49 ` Robin Murphy
2025-07-30 16:01 ` Jason Gunthorpe
2025-07-30 19:58 ` [PATCH 00/10] vfio/pci: Allow MMIO regions to be exported through dma-buf Alex Williamson
2025-07-31 0:21 ` Jason Gunthorpe
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