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Sat, 18 Oct 2025 16:06:43 -0700 (PDT) Received: from ziepe.ca ([130.41.10.202]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-7c28879e8d5sm1168286a34.5.2025.10.18.16.06.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 18 Oct 2025 16:06:43 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1vAG0X-00000001ddh-3262; Sat, 18 Oct 2025 20:06:41 -0300 Date: Sat, 18 Oct 2025 20:06:41 -0300 From: Jason Gunthorpe To: Vipin Sharma Cc: bhelgaas@google.com, alex.williamson@redhat.com, pasha.tatashin@soleen.com, dmatlack@google.com, graf@amazon.com, pratyush@kernel.org, gregkh@linuxfoundation.org, chrisl@kernel.org, rppt@kernel.org, skhawaja@google.com, parav@nvidia.com, saeedm@nvidia.com, kevin.tian@intel.com, jrhilke@google.com, david@redhat.com, jgowans@amazon.com, dwmw2@infradead.org, epetron@amazon.de, junaids@google.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [RFC PATCH 00/21] VFIO live update support Message-ID: <20251018230641.GR3938986@ziepe.ca> References: <20251018000713.677779-1-vipinsh@google.com> <20251018172130.GQ3938986@ziepe.ca> <20251018225309.GF1034710.vipinsh@google.com> 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=us-ascii Content-Disposition: inline In-Reply-To: <20251018225309.GF1034710.vipinsh@google.com> On Sat, Oct 18, 2025 at 03:53:09PM -0700, Vipin Sharma wrote: > On 2025-10-18 14:21:30, Jason Gunthorpe wrote: > > On Fri, Oct 17, 2025 at 05:06:52PM -0700, Vipin Sharma wrote: > > > 2. Integration with IOMMUFD and PCI series for complete workflow where a > > > device continues a DMA while undergoing through live update. > > > > It is a bit confusing, this series has PCI components so how does it > > relate the PCI series? Is this self contained for at least limited PCI > > topologies? > > This series has very minimal PCI support. For example, it is skipping > DMA disable on the VFIO PCI device during kexec reboot and saving initial PCI > state during first open (bind) of the device. > > We do need proper PCI support, few examples: > > - Not disabling DMA bit on bridges upstream of the leaf VFIO PCI device node. So limited to topology without bridges > - Not writing to PCI config during device enumeration. I think this should be included here > - Not autobinding devices to their default driver. My testing works on > devices which don't have driver bulit in the kernel so there is no > probing by other drivers. Good enough for now, easy to not build in such drivers. > - PCI enable and disable calls support. ?? Shouldn't vfio restore skip calling pci enable? Seems like there should be some solution here. Jason