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Fri, 17 Jul 2026 14:48:46 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Subject: Re: [PATCH v7 05/12] PCI: liveupdate: Keep bus numbers constant during Live Update From: Pasha Tatashin To: David Matlack Cc: kexec@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Adithya Jayachandran , Alexander Graf , Alex Williamson , Bjorn Helgaas , Chris Li , David Rientjes , Jacob Pan , Jason Gunthorpe , Jonathan Corbet , Josh Hilke , Leon Romanovsky , Lukas Wunner , Mike Rapoport , Parav Pandit , Pasha Tatashin , Pranjal Shrivastava , Pratyush Yadav , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Vipin Sharma , William Tu , Yi Liu In-Reply-To: <20260710212616.1351130-6-dmatlack@google.com> References: <20260710212616.1351130-1-dmatlack@google.com> <20260710212616.1351130-6-dmatlack@google.com> Date: Fri, 17 Jul 2026 21:48:42 +0000 Message-Id: <178432492211.189683.10563224295975168718.b4-review@b4> X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; 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a=openpgp; fpr=CAAAB722DD22A081F0D49F35633A6A993D43B569 On Fri, 10 Jul 2026 21:26:08 +0000, David Matlack wrote: > During a Live Update, preserved devices must be allowed to continue > performing memory transactions so the kernel cannot change the fabric > topology, including bus numbers, since that would require disabling > and flushing any memory transactions first. > > To keep bus numbers constant, always inherit the secondary and > subordinate bus numbers assigned to bridges during scanning, instead of > assigning new ones, if any PCI devices are being preserved. Note that > the kernel inherits bus numbers even on bridges without any downstream > endpoints that were preserved. This avoids accidentally assigning a > bridge a new window that overlaps with a preserved device that is > downstream of a different bridge. > > [...] Reviewed-by: Pasha Tatashin -- Pasha Tatashin