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charset=us-ascii Content-Disposition: inline In-Reply-To: <20250729085336.GG402218@unreal> User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspam-User: X-Rspamd-Queue-Id: E1DB9180005 X-Rspamd-Server: rspam06 X-Stat-Signature: 6gzk98zhaozo3crrih164i6fefa4qejb X-HE-Tag: 1753785666-698636 X-HE-Meta: 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 H8S9j6Mp q78A+vDh9tST1YLE9VXrRBvsrLI+KeywiFBJ1JfTkUcnC8dlpP+myEv6fCZRowV3z6nKYOqj+ASHlHotsnSC3zCd9cZ6eYZ0o9Y5r2xJ2tu/IdHa7s0RYvFqDS6vN1N1sExjFcv99bOtzqo4= 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 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.