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[47.55.120.4]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4e8ab0ee857sm97295781cf.31.2025.10.22.10.51.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Oct 2025 10:51:52 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1vBd04-00000002rPt-1SQi; Wed, 22 Oct 2025 14:51:52 -0300 Date: Wed, 22 Oct 2025 14:51:52 -0300 From: Jason Gunthorpe To: David Matlack Cc: Vipin Sharma , Lukas Wunner , bhelgaas@google.com, alex.williamson@redhat.com, pasha.tatashin@soleen.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 15/21] PCI: Make PCI saved state and capability structs public Message-ID: <20251022175152.GE21554@ziepe.ca> References: <20251018000713.677779-1-vipinsh@google.com> <20251018000713.677779-16-vipinsh@google.com> <20251018223620.GD1034710.vipinsh@google.com> <20251018231126.GS3938986@ziepe.ca> <20251020234934.GB648579.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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Wed, Oct 22, 2025 at 10:45:31AM -0700, David Matlack wrote: > On Mon, Oct 20, 2025 at 4:49 PM Vipin Sharma wrote: > > > > On 2025-10-18 20:11:26, Jason Gunthorpe wrote: > > > On Sat, Oct 18, 2025 at 03:36:20PM -0700, Vipin Sharma wrote: > > > > > > > Having __packed in my version of struct, I can build validation like > > > > hardcoded offset of members. I can add version number (not added in this > > > > series) for checking compatbility in the struct for serialization and > > > > deserialization. Overall, it is providing some freedom to how to pass > > > > data to next kernel without changing or modifying the PCI state > > > > structs. > > > > > > I keep saying this, and this series really strongly shows why, we need > > > to have a dedicated header directroy for LUO "ABI" structs. Putting > > > this random struct in some random header and then declaring it is part > > > of the luo ABI is really bad. > > > > Now that we have PCI, IOMMU, and VFIO series out. What should be the > > strategy for LUO "ABI" structs? I would like some more clarity on how > > you are visioning this. > > > > Are you suggesting that each subsystem create a separate header file for > > their serialization structs or we can have one common header file used > > by all subsystems as dumping ground for their structs? > > I think we should have multiple header files in one directory, that > way we can assign separate MAINTAINERS for each file as needed. > > Jason Miu proposed the first such header for KHO in > https://lore.kernel.org/lkml/CALzav=eqwTdzFhZLi_mWWXGuDBRwWQdBxQrzr4tN28ag8Zr_8Q@mail.gmail.com/. > > Following that example we can add vfio_pci.h and pci.h to that > directory for VFIO and PCI ABI structs respectively. Seems like a good idea to me. Jason