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R. Silva" , Ankit Agrawal , Yishai Hadas , Shameer Kolothum , Kevin Tian , Alex Williamson , Krishnakant Jaju , Matt Ochs , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, iommu@lists.linux.dev, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, kvm@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH v7 05/11] PCI/P2PDMA: Document DMABUF model Message-ID: <20251107202718.GE15456@unreal> References: <20251106-dmabuf-vfio-v7-0-2503bf390699@nvidia.com> <20251106-dmabuf-vfio-v7-5-2503bf390699@nvidia.com> <135df7eb-9291-428b-9c86-d58c2e19e052@infradead.org> <20251107160120.GD15456@unreal> <0c265a9b-fdc5-40d7-845f-30910f1ac6ea@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0c265a9b-fdc5-40d7-845f-30910f1ac6ea@infradead.org> X-Rspamd-Queue-Id: D5533C0011 X-Rspamd-Server: rspam07 X-Stat-Signature: 4j94655ue94k8f1iy9y8uxn5sox1oi4c X-Rspam-User: X-HE-Tag: 1762547245-803133 X-HE-Meta: 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 LB4UeDXR XMiygeJKfIGT2v3pLgZgBxitYgNOQzmNEU5NWY4amW52P/ZmbQ1/NRbVRuANTU5POtCql3FMARfebDxofn8zauIrLDr6lCGdnb9XtLIdYAvRnePLJtfDvMv+qjT/Ni7O+GdX+Qf3GH+erxCrorR0wlKkR75Ku7paMLs7IwikC3j7UN3VbrgsA6oBdRNn8vsHxlU5varaXCB1A3rGOHxs79zDnQN/U78/TnPYJzkNuknwyOVHRDkKXPGf8oKY6d5fgVazmsKubYBvXMTqDS51NpLPwrQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Nov 07, 2025 at 10:58:27AM -0800, Randy Dunlap wrote: > > > On 11/7/25 8:01 AM, Leon Romanovsky wrote: > > On Thu, Nov 06, 2025 at 10:15:07PM -0800, Randy Dunlap wrote: > >> > >> > >> On 11/6/25 6:16 AM, Leon Romanovsky wrote: > >>> From: Jason Gunthorpe > >>> > >>> Reflect latest changes in p2p implementation to support DMABUF lifecycle. > >>> > >>> Signed-off-by: Leon Romanovsky > >>> Signed-off-by: Jason Gunthorpe > >>> --- > >>> Documentation/driver-api/pci/p2pdma.rst | 95 +++++++++++++++++++++++++-------- > >>> 1 file changed, 72 insertions(+), 23 deletions(-) <...> > >>> -The second issue is that to make use of existing interfaces in Linux, > >>> -memory that is used for P2P transactions needs to be backed by struct > >>> -pages. However, PCI BARs are not typically cache coherent so there are > >>> -a few corner case gotchas with these pages so developers need to > >>> -be careful about what they do with them. > >>> +For PCIe the routing of TLPs is well defined up until they reach a host bridge > >> > >> Define what TLP means? > > > > In PCIe "world", TLP is very well-known and well-defined acronym, which > > means Transaction Layer Packet. > > It's your choice (or Bjorn's). I'm just reviewing... Thanks a lot.