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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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260226161512.532609ec@shazbot.org> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 5A5F2180009 X-Stat-Signature: h9ha14db45f1g5c78yz3imzoxc6t4wuz X-HE-Tag: 1772148474-237353 X-HE-Meta: U2FsdGVkX1/UVJYeWoBVdvbmkcuWbK7p0Xh2w7F79dKJErhA23/bp3il99WQq1s+qKfS3pBI49TBupNLfIdyPHSyBr5ctKfRcFuNFnQO5P14nmXhTClpiHbEvv0uzayAUJbHJvUqzlVAT57mTnsQlaQSkA0vnovbzHYmv/rTw+x7c1PEiQMgowCjWkpghAgIAEmnkAlIHkZ0Tm/iWeDmEo54paJxBm33h5NUiStWOLWVYnx0TdnesK6FGynRb2QF5jAjLSC5zH1ToQR9WzZ5AU/F15f+IT18FLiotK+gp+Bc/B8923h474tdgAmvrq6BaDkYh3w6cqJa2omFiMKYoXI6RQtsYgqmDeHWIMb6CJwpAXt3lVaNScT1FK0kdhxrEj4GuBsoDrsVyqZ0KB9EgPKbC64pbQ7oCPgzCFsKh2Z8Kpah34yhltZuqaI+aozYCBWuTjNgaERgpX88x96Kp99ypFNpGuVEqnEtYg+3Yd9GTJ8aQWbV3yuX9O4S/8tceo9NcOq9exu7uwgZDJUe7psJ7bqaxxwyDj1Y+GQqMGnxiTXntF8foEFT2GNZ2CPN34DPbb7T2ZVASXrUX7iWtUG4VV/0A/EAcK4L1fMLjkKeRGdWH14GsPyDnZZaSTOUmDbTwLpducGZzHDJsoqn9R/tptmwGbWdQo5gFgk8+QoF5CEM4S0d2huJWPpuI3z6zhSRnzadKk5lRnlSd9K8T/Pob+zvhqObNP3hrsy9yxeGEnN/wQKVcR4SpZZyiEAeYxVliRZ6FHre7jFfC9wpaVKjpYr3Du/yEJ12b0gqJqikLORgFI+RqKlc8C3M2sCSD3iqwOyjRhgKWUW8kVl8TZxa5vjq4jlE+57BH66PMHcwodyoa2JD3//wESWsS1Lm/4WdBwHoz26goQQKsKcHB/wdU2WbQvL1dhZcZ6IWS/5Kw0zLfE2atHf6hFD6Fl7o5exvd3o0b+5rqWqYrqJ nsXAnSXQ 4JaSIpauA+/mx81XkLFETx23jDvHYnIyRk+A0+P4ehG6kNAHCcOBtUj0zZhcCsenvqqsLGQNs8FFfCCCbaeZBTnXzsSE/5SS+jvxyXK3+Zwihpf4cZOsloLfFM3E6s80gSEWeyohZCv5nh+8AeEB7rJKQwXukF78yA0y4XUvH+t09kcDL6ML1eSbbTMTJOsZ6WSjP+dLwaCBjDyWJ9npzhuMdIQdMVyvKguM4oGXzG1C4+kdchqiAV6dgZd+COyYWlO23hoKZD48rkpthZ9KWl+TWAyb0jjGA7S+nTo7yHTOMCSdLaJwIF+B7TfcIKmEBVRZKixAdw3osh4/u3E9ym8kQgDrr8MqUoauzpb4Pb3hhWzrt8L1XFN5TM9WWP6t+URMu6/h/cDlRnmV4RhLuOphcxCnfYkt8wfuq8mNf25dgCgre2HgADk1bN8/brFVR5vEUhWUoMp+tMVF5zbl+wgQm1nVzz//uMjGYE7cHzOM03XA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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.