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[34.145.75.25]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3b0fc27e829sm775868a91.0.2026.11.06.14.29.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 Nov 2026 14:29:09 -0800 (PST) Date: Fri, 6 Nov 2026 22:29:06 +0000 From: Samiullah Khawaja To: Vipin Sharma Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-pci@vger.kernel.org, ajayachandra@nvidia.com, alex@shazbot.org, amastro@fb.com, ankita@nvidia.com, apopple@nvidia.com, bhelgaas@google.com, chrisl@kernel.org, christian.koenig@amd.com, corbet@lwn.net, dmatlack@google.com, graf@amazon.com, jacob.pan@linux.microsoft.com, jgg@nvidia.com, jgg@ziepe.ca, jrhilke@google.com, julianr@linux.ibm.com, kees@kernel.org, kevin.tian@intel.com, leon@kernel.org, leonro@nvidia.com, lukas@wunner.de, mattev@meta.com, michal.winiarski@intel.com, parav@nvidia.com, pasha.tatashin@soleen.com, praan@google.com, pratyush@kernel.org, rananta@google.com, rdunlap@infradead.org, rientjes@google.com, rodrigo.vivi@intel.com, rppt@kernel.org, saeedm@nvidia.com, schnelle@linux.ibm.com, skhan@linuxfoundation.org, vivek.kasireddy@intel.com, witu@nvidia.com, yanjun.zhu@linux.dev, yi.l.liu@intel.com Subject: Re: [PATCH v6 04/27] vfio/pci: Register a file handler with Live Update Orchestrator Message-ID: References: <20261102153656.1431701-1-vipinsh@google.com> <20261102153656.1431701-5-vipinsh@google.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20261102153656.1431701-5-vipinsh@google.com> X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 84BF4140005 X-Spam-Status: No, score=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=4.0.1 X-Stat-Signature: 6qtsteumh48xgk5sm5dqaitbd5uahhy5 X-Rspam-User: X-HE-Tag: 1794004152-970786 X-HE-Meta: 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 x+VMsjS8 TDYVaWoj5HmUKevKLj9OVTIS04gvduNiilFuK3Z9gzVj5+yObuaBk6xT3E+6+HmdqxkftrjiZMNZseu8ZXozJbXognxlTJwBno5WPbDQuwMmMt77q3YUWSFIZS34nFw0kAo627KcWqyZqoauRevk3Hyy5/1vrCMVWka6RvZOOdxilqzSH3HhePD/+W1E75OuhK3MNqzhfVkD81wBUX5nvoUz6KpoylPbSuqzZiTzaCMtqx1uMzG5aYnOYIbiAUllwt0ytKa//jVP9V0lIp8mJQ7D59SenHeIKHUa/ConUE44odMcYW71g66eERvz1FBRZVdrM/RASpOjmbVVfCpo98zwddoZRKO+lYJPY Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Mon, Nov 02, 2026 at 07:36:33AM -0800, Vipin Sharma wrote: >Register a live update file handler for vfio-pci device files. Add stub >implementations of all required callbacks so that registration does not >fail. Register it with both live update framework and PCI subsystem. > >This file handler will be extended in subsequent commits to enable a >device bound to vfio-pci to run without interruption while the host is >going through a kexec Live Update. > >Put this support behind a new Kconfig VFIO_PCI_LIVEUPDATE. Initial >support is added for no-iommu model vfio-pci devices. > >Co-developed-by: David Matlack >Signed-off-by: David Matlack >Signed-off-by: Vipin Sharma >--- > MAINTAINERS | 1 + > drivers/vfio/pci/Kconfig | 11 ++++ > drivers/vfio/pci/Makefile | 1 + > drivers/vfio/pci/vfio_pci.c | 11 +++- > drivers/vfio/pci/vfio_pci_liveupdate.c | 75 ++++++++++++++++++++++++++ > drivers/vfio/pci/vfio_pci_priv.h | 14 +++++ > include/linux/kho/abi/vfio_pci.h | 28 ++++++++++ > 7 files changed, 140 insertions(+), 1 deletion(-) > create mode 100644 drivers/vfio/pci/vfio_pci_liveupdate.c > create mode 100644 include/linux/kho/abi/vfio_pci.h > >diff --git a/MAINTAINERS b/MAINTAINERS >index 5d1b58271989..167aa9d66ce8 100644 >--- a/MAINTAINERS >+++ b/MAINTAINERS >@@ -28662,6 +28662,7 @@ F: Documentation/ABI/testing/debugfs-vfio > F: Documentation/ABI/testing/sysfs-devices-vfio-dev > F: Documentation/driver-api/vfio.rst > F: drivers/vfio/ >+F: include/linux/kho/abi/vfio_pci.h > F: include/linux/vfio.h > F: include/linux/vfio_pci_core.h > F: include/uapi/linux/vfio.h >diff --git a/drivers/vfio/pci/Kconfig b/drivers/vfio/pci/Kconfig >index 296bf01e185e..e8285ad93a69 100644 >--- a/drivers/vfio/pci/Kconfig >+++ b/drivers/vfio/pci/Kconfig >@@ -42,6 +42,17 @@ config VFIO_PCI_IGD > and LPC bridge config space. > > To enable Intel IGD assignment through vfio-pci, say Y. >+ >+config VFIO_PCI_LIVEUPDATE >+ bool "VFIO PCI support for Live Update in no-iommu mode" >+ depends on PCI_LIVEUPDATE && VFIO_NOIOMMU Can we handle this dependency in code instead of doing through configs? Are there any build dependencies on noiommu? >+ help >+ Support for preserving devices bound to vfio-pci in no-iommu mode >+ across a Live Update. It enables a device to continue working (DMA) >+ while host kernel is going through a kexec live update. >+ >+ If you don't know what to do here, say N. >+ > endif > Thanks, Sami