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[34.105.23.239]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2adfb6a03fbsm48080705ad.43.2026.02.26.15.27.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Feb 2026 15:27:51 -0800 (PST) Date: Thu, 26 Feb 2026 23:27:47 +0000 From: David Matlack To: Alex Williamson Cc: Adithya Jayachandran , Alexander Graf , Alex Mastro , Alistair Popple , Andrew Morton , Ankit Agrawal , Bjorn Helgaas , Chris Li , David Rientjes , Jacob Pan , Jason Gunthorpe , Jason Gunthorpe , Jonathan Corbet , Josh Hilke , Kevin Tian , kexec@lists.infradead.org, kvm@vger.kernel.org, Leon Romanovsky , Leon Romanovsky , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Lukas Wunner , =?utf-8?Q?Micha=C5=82?= Winiarski , Mike Rapoport , Parav Pandit , Pasha Tatashin , Pranjal Shrivastava , Pratyush Yadav , Raghavendra Rao Ananta , Rodrigo Vivi , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Thomas =?iso-8859-1?Q?Hellstr=F6m?= , Tomita Moeko , Vipin Sharma , Vivek Kasireddy , William Tu , Yi Liu , Zhu Yanjun Subject: Re: [PATCH v2 08/22] vfio: Enforce preserved devices are retrieved via LIVEUPDATE_SESSION_RETRIEVE_FD Message-ID: References: <20260129212510.967611-1-dmatlack@google.com> <20260129212510.967611-9-dmatlack@google.com> <20260226161512.532609ec@shazbot.org> Precedence: bulk X-Mailing-List: linux-doc@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: <20260226161512.532609ec@shazbot.org> On 2026-02-26 04:15 PM, Alex Williamson wrote: > On Thu, 29 Jan 2026 21:24:55 +0000 David Matlack wrote: > > + /* > > + * This device was preserved across a Live Update. Accessing it via > > + * VFIO_GROUP_GET_DEVICE_FD is not allowed. > > + */ > > + if (vfio_liveupdate_incoming_is_preserved(device)) { > > + vfio_device_put_registration(device); > > + return -EBUSY; > > Is this an EPERM issue then? I was thinking EBUSY in the sense that the device is only temporarily inaccesible through this interface due it being in a preserved state as part of a Live Update. Once the preserved device file is retreived and closed, the device can be accessed again through VFIO_GROUP_GET_DEVICE_FD. EPERM might lead to confusion that there is a filesystem permission issue? > > +#ifdef CONFIG_LIVEUPDATE > > +static inline bool vfio_liveupdate_incoming_is_preserved(struct vfio_device *device) > > +{ > > + struct device *d = device->dev; > > + > > + if (dev_is_pci(d)) > > + return to_pci_dev(d)->liveupdate_incoming; > > + > > + return false; > > +} > > +#else > > +static inline bool vfio_liveupdate_incoming_is_preserved(struct vfio_device *device) > > +{ > > + return false; > > +} > > +#endif > > Why does this need to be in the public header versus > drivers/vfio/vfio.h? No good reason. I'll make it private.