From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4620637CD55 for ; Mon, 23 Mar 2026 23:58:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774310321; cv=none; b=uvzDpHVdABmNdqqC1aehorl/3nu+ExTi7jUFUF4OMc0T38XvJYP+TqMepcOkvca4WFzroECKC6jBwaIGzf5yAZtGTtIlQlFitbtrkPKF1VoLpnTyh3vNbHzSKjrhucn4CHziHfYCIG9jQrR2lbICnvEL+IAIzFJMpD8vLP+DzpY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774310321; c=relaxed/simple; bh=tXyttGLXqscxYZmJh0xeJd4JydsEtFrt6SPzWqZzSwc=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=RhmrHGU92LdQ1w7dJnPvpOXgi2k+U/qDeMap864U/5fmdTU5o+lekITy1pNRlqwzTcNKySOYydQGdJZNkb83Mge6EpoASimSq4j1GDmWsq5u88uMoaMZ0jNCDSGI2n1PsJZfOGNIFte+6HY6lopGjJOZ/v0gH4TyNdBSoEY9G80= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--dmatlack.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=WU3gkSR2; arc=none smtp.client-ip=209.85.214.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--dmatlack.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="WU3gkSR2" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2b064884a7cso335537525ad.3 for ; Mon, 23 Mar 2026 16:58:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1774310318; x=1774915118; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=ZJphTQtAwt37fyli6EqFM5TvIsP7A+bmY4QV1yw4cuY=; b=WU3gkSR2LZda8YvJmHBsWXsgYJacGg2rDAeTh+pFzAeiFwl8Gf9p52vJllshJ16OvN XgwANOILhPeQM7dLKab9AVtxZlLIenGKI+xXMfRkYGMqJPpfcOpQeUpICGwBTrXIup72 ofnEraZDXv5GpCr1tkzT2U5y86oibxC+DQV1v4OXBOFu/j45sm/evWsXPPIthE1pkdeB Cl0FPuqoBm7j7rHaZVMmP1F/Y7gsTYDmoLxLJQGdMWEntkQ9nUxuEHZflWmIl9SuNriT x9HJKjciyzml53Pv30Q/J/3haB+roK1MRJ+9PYQnPU5t2beu5aAxnbtE83g0FDWTmXTB q9Ig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774310318; x=1774915118; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=ZJphTQtAwt37fyli6EqFM5TvIsP7A+bmY4QV1yw4cuY=; b=gmJvZ8sbqhTxdDO76jv/h8hgkST8vK0oq5ASwKsrepR428vq4BoSp9+TwFk6BjczYs H+Y21xj0od/G04c0M/R09+knDK+s4eOkegOChqKu3diQzIJXBe4seC9qry9NvKATbpCl q7GoLBaudUuNlcwLhDMjoVS1RpW2iK2MBp/fkOrxbkS4cQXykL9dX4OCZtGk0dBAq4H7 u/iLzN9shBsh2LrN3CrF1ipUap3vhKkGwulpAri5NtOwwn7yLRlGF604DPMlzj8eu8vO cpDYRY1WPYeU2LZdCdSLFZI42OQlRoqZbB5IZj/i+xi5XjIcDEIZJxNM6AESIBB6A1V3 +s9g== X-Forwarded-Encrypted: i=1; AJvYcCUQ4cN4fQpeTzFBGiMmsIbCza0WDdZgScRfKt8JhRri02EPqDCHLVNP2MMCPoxj2QmjYL0Qtxp+x/I=@vger.kernel.org X-Gm-Message-State: AOJu0YztptaTzugjzL/GaTV402E+t9QlfVivpvpd98LsRnR5iFV/yAUK E4nzKCPVblIzns0Mzxa6Yd2NciHxsYd6dR39/NaIEW1/NvUky3+nvRo6Lg/POR1l0fCG8pQFvHz lLeXv6jOj8lWAng== X-Received: from plfu18.prod.google.com ([2002:a17:902:e5d2:b0:2b0:6cdd:87e2]) (user=dmatlack job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:e850:b0:2ae:7fbd:3dcd with SMTP id d9443c01a7336-2b0827e30f8mr133238585ad.52.1774310317408; Mon, 23 Mar 2026 16:58:37 -0700 (PDT) Date: Mon, 23 Mar 2026 23:57:52 +0000 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.53.0.983.g0bb29b3bc5-goog Message-ID: <20260323235817.1960573-1-dmatlack@google.com> Subject: [PATCH v3 00/24] vfio/pci: Base Live Update support for VFIO device files From: David Matlack To: Alex Williamson , Bjorn Helgaas Cc: Adithya Jayachandran , Alexander Graf , Alex Mastro , Andrew Morton , Ankit Agrawal , Arnd Bergmann , Askar Safin , "Borislav Petkov (AMD)" , Chris Li , Dapeng Mi , David Matlack , David Rientjes , Feng Tang , Jacob Pan , Jason Gunthorpe , Jason Gunthorpe , Jonathan Corbet , Josh Hilke , Kees Cook , 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, Li RongQing , Lukas Wunner , Marco Elver , "=?UTF-8?q?Micha=C5=82=20Winiarski?=" , Mike Rapoport , Parav Pandit , Pasha Tatashin , "Paul E. McKenney" , Pawan Gupta , "Peter Zijlstra (Intel)" , Pranjal Shrivastava , Pratyush Yadav , Raghavendra Rao Ananta , Randy Dunlap , Rodrigo Vivi , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Vipin Sharma , Vivek Kasireddy , William Tu , Yi Liu , Zhu Yanjun Content-Type: text/plain; charset="UTF-8" This series can be found on GitHub: https://github.com/dmatlack/linux/tree/liveupdate/vfio/cdev/v3 This series adds the base support to preserve a VFIO device file across a Live Update. "Base support" means that this allows userspace to safely preserve a VFIO device file with LIVEUPDATE_SESSION_PRESERVE_FD and retrieve it with LIVEUPDATE_SESSION_RETRIEVE_FD, but the device itself is not preserved in a fully running state across Live Update. This series aims to provide a foundation on which to build the rest of the device preservation infrastructure, including: 1. Preservation of iommufd files [1] 2. Preservation of IOMMU driver state 3. Preservation of PCI state (BAR resources, device state, bridge state, ...) 4. Preservation of vfio-pci driver state Steps 1 and 2 are already in-progress on the mailing list. We are working on a detailed roadmap for steps 3 and 4. Testing ------- The patches at the end of this series provide comprehensive selftests for the new code added by this series. The selftests have been validated in both a VM environment using a virtio-net PCIe device, and in a baremetal environment on an Intel EMR server with an Intel DSA PCIe device. Here is an example of how to run the new selftests: vfio_pci_liveupdate_uapi_test: $ tools/testing/selftests/vfio/scripts/setup.sh 0000:00:04.0 $ tools/testing/selftests/vfio/vfio_pci_liveupdate_uapi_test 0000:00:04.0 $ tools/testing/selftests/vfio/scripts/cleanup.sh vfio_pci_liveupdate_kexec_test: $ tools/testing/selftests/vfio/scripts/setup.sh 0000:00:04.0 $ tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test --stage 1 0000:00:04.0 $ kexec ... $ tools/testing/selftests/vfio/scripts/setup.sh 0000:00:04.0 $ tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test --stage 2 0000:00:04.0 $ tools/testing/selftests/vfio/scripts/cleanup.sh It is also possible to run vfio_pci_liveupdate_kexec_test multiple times to preserve multiple devices simultaneously across a Live Update. This series has been tested with up to 8 devices concurrently preserved. Dependencies ------------ This series is built on top of v7.0-rc4 plus a series from Pasha Tatashin to fix the module refcounting in FLB: https://lore.kernel.org/lkml/20260318141637.1870220-10-pasha.tatashin@soleen.com/ Changelog --------- v3: - Add logging & documentation for pci=assign-busses overrides (Pranjal) - Use 2026 in drivers/pci/liveupdate.c (Pranjal) - Use 2026 in drivers/vfio/pci/vfio_pci_liveupdate.c (Pranjal) - Drop incoming/outgoing from PCI APIs (Sami) - Eliminate duplicate extern declarations for vfio_device_fops (Pranjal) - Keep struct vfio_device_file private (Pranjal) - Add comment about not supporting hot-plug (Pranjal) - Add comment about not supporting VFs (Sami) - Better error handling for liveupdate_flb_get_incoming() (Pranjal) - Remove liveupdate_enabled() checks (Zhu) - Remove liveupdate_enabled() checks in vfio_pci_liveupdate_init() (Pranjal) - Drop IOMMU reference from bus number commit message (Bjorn) - Add fabric rationale to commit message (Jason) - Swap incoming ... outgoing ordering in commit message (Bjorn) - Use vfio_device_cdev_opened() instead of df->group (Alex) - Add comments for CONFIG_VFIO_PCI_ZDEV_KVM (Alex) - Add comments for vfio_pci_is_intel_display() (Alex) - Use pci_dev_try_lock() in freeze (Alex) - Fix device reset locking in freeze() (me) - Use u32 for domain in PCI (Bjorn) - Use u32 for domain in VFIO (Bjorn) - Make pci_liveupdate_incoming_nr_devices() private to drivers/pci/ (Bjorn) - Fix dev->liveupdate_incoming readability (Bjorn) - Take pci_ser_delete() out of WARN_ON_ONCE() (Bjorn) - Drop reference to userspace & files from PCI commit message (Bjorn) - Rename __vfio_device_fops_cdev_open() to vfio_device_cdev_open_file() (Alex) - Fix NULL pointer dereference in release() (Alex) - Handle return value of pci_liveupdate_outgoing_preserve() (Alex) - Make pci_liveupdate_unregister_fh() unabe to fail. (Alex) - Move vfio_liveupdate_incoming_is_preserved() to drivers/vfio/vfio.h (Alex) - Add vfio_pci_core_probe_reset() (Alex) - Forward declare ser struct in include/linux/vfio_pci_core.h (Alex) - Bump compatibility string when adding reset_works (Alex) - How will userspace detect partial preservation? (Alex) - Require single device per iommu_group (Jason) - Rename pci_liveupdate_register_fh() to pci_liveupdate_register_flb() (Vipin) - Use ksft_exit_skip() and SKIP() (Vipin) - Move documentation to code (Vipin) - Use __u64 instead of int for token in Live Update selftest helpers (Gemini) - Add documentation for drivers/pci/liveupdate.c (me) v2: https://lore.kernel.org/kvm/20260129212510.967611-1-dmatlack@google.com/ v1: https://lore.kernel.org/kvm/20251126193608.2678510-1-dmatlack@google.com/ rfc: https://lore.kernel.org/kvm/20251018000713.677779-1-vipinsh@google.com/ Cc: Pranjal Shrivastava Cc: Saeed Mahameed Cc: Adithya Jayachandran Cc: Jason Gunthorpe Cc: Parav Pandit Cc: Leon Romanovsky Cc: William Tu Cc: Jacob Pan Cc: Lukas Wunner Cc: Pasha Tatashin Cc: Mike Rapoport Cc: Pratyush Yadav Cc: Samiullah Khawaja Cc: Chris Li Cc: Josh Hilke Cc: David Rientjes [1] https://lore.kernel.org/linux-iommu/20251202230303.1017519-1-skhawaja@google.com/ David Matlack (15): liveupdate: Export symbols needed by modules PCI: Add API to track PCI devices preserved across Live Update PCI: Require Live Update preserved devices are in singleton iommu_groups PCI: Inherit bus numbers from previous kernel during Live Update docs: liveupdate: Add documentation for PCI vfio/pci: Notify PCI subsystem about devices preserved across Live Update vfio: Enforce preserved devices are retrieved via LIVEUPDATE_SESSION_RETRIEVE_FD vfio/pci: Store incoming Live Update state in struct vfio_pci_core_device docs: liveupdate: Add documentation for VFIO PCI vfio: selftests: Add Makefile support for TEST_GEN_PROGS_EXTENDED vfio: selftests: Add vfio_pci_liveupdate_uapi_test vfio: selftests: Expose iommu_modes to tests vfio: selftests: Expose low-level helper routines for setting up struct vfio_pci_device vfio: selftests: Verify that opening VFIO device fails during Live Update vfio: selftests: Add continuous DMA to vfio_pci_liveupdate_kexec_test Vipin Sharma (9): vfio/pci: Register a file handler with Live Update Orchestrator vfio/pci: Preserve vfio-pci device files across Live Update vfio/pci: Retrieve preserved device files after Live Update vfio/pci: Skip reset of preserved device after Live Update selftests/liveupdate: Move luo_test_utils.* into a reusable library selftests/liveupdate: Add helpers to preserve/retrieve FDs vfio: selftests: Build liveupdate library in VFIO selftests vfio: selftests: Initialize vfio_pci_device using a VFIO cdev FD vfio: selftests: Add vfio_pci_liveupdate_kexec_test Documentation/PCI/liveupdate.rst | 23 + .../admin-guide/kernel-parameters.txt | 6 +- Documentation/core-api/liveupdate.rst | 2 + .../driver-api/vfio_pci_liveupdate.rst | 23 + MAINTAINERS | 2 + drivers/pci/Kconfig | 11 + drivers/pci/Makefile | 1 + drivers/pci/liveupdate.c | 415 ++++++++++++++++++ drivers/pci/pci.h | 14 + drivers/pci/probe.c | 37 +- drivers/vfio/device_cdev.c | 63 ++- drivers/vfio/group.c | 9 + drivers/vfio/pci/Kconfig | 11 + drivers/vfio/pci/Makefile | 1 + drivers/vfio/pci/vfio_pci.c | 14 +- drivers/vfio/pci/vfio_pci_core.c | 90 ++-- drivers/vfio/pci/vfio_pci_liveupdate.c | 328 ++++++++++++++ drivers/vfio/pci/vfio_pci_priv.h | 18 + drivers/vfio/vfio.h | 18 + drivers/vfio/vfio_main.c | 16 +- include/linux/kho/abi/pci.h | 62 +++ include/linux/kho/abi/vfio_pci.h | 45 ++ include/linux/pci.h | 41 ++ include/linux/vfio.h | 13 + include/linux/vfio_pci_core.h | 2 + kernel/liveupdate/luo_core.c | 1 + kernel/liveupdate/luo_file.c | 2 + tools/testing/selftests/liveupdate/.gitignore | 1 + tools/testing/selftests/liveupdate/Makefile | 14 +- .../include/libliveupdate.h} | 11 +- .../selftests/liveupdate/lib/libliveupdate.mk | 20 + .../{luo_test_utils.c => lib/liveupdate.c} | 43 +- .../selftests/liveupdate/luo_kexec_simple.c | 2 +- .../selftests/liveupdate/luo_multi_session.c | 2 +- tools/testing/selftests/vfio/Makefile | 23 +- .../vfio/lib/include/libvfio/iommu.h | 2 + .../lib/include/libvfio/vfio_pci_device.h | 8 + tools/testing/selftests/vfio/lib/iommu.c | 4 +- .../selftests/vfio/lib/vfio_pci_device.c | 60 ++- .../vfio/vfio_pci_liveupdate_kexec_test.c | 256 +++++++++++ .../vfio/vfio_pci_liveupdate_uapi_test.c | 93 ++++ 41 files changed, 1715 insertions(+), 92 deletions(-) create mode 100644 Documentation/PCI/liveupdate.rst create mode 100644 Documentation/driver-api/vfio_pci_liveupdate.rst create mode 100644 drivers/pci/liveupdate.c create mode 100644 drivers/vfio/pci/vfio_pci_liveupdate.c create mode 100644 include/linux/kho/abi/pci.h create mode 100644 include/linux/kho/abi/vfio_pci.h rename tools/testing/selftests/liveupdate/{luo_test_utils.h => lib/include/libliveupdate.h} (80%) create mode 100644 tools/testing/selftests/liveupdate/lib/libliveupdate.mk rename tools/testing/selftests/liveupdate/{luo_test_utils.c => lib/liveupdate.c} (89%) create mode 100644 tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test.c create mode 100644 tools/testing/selftests/vfio/vfio_pci_liveupdate_uapi_test.c base-commit: 3251ac3df4374e4e94e4fbecf49ad1573933018a prerequisite-patch-id: 37ebd38e2247ccb02e6a6c7543a378534d69a038 prerequisite-patch-id: 19c8469a9ae5cd13618481dd75012444330f80f9 prerequisite-patch-id: 2ba04f598993e2c2d941c4cd3f2dc1e98905d68b prerequisite-patch-id: fcab928f6ee32a145667822ceca5e4f1f567d530 prerequisite-patch-id: 6d11347278609426baa9eacc1726b32b48d09a25 prerequisite-patch-id: 94a9e8a8cb6004e12de90fcc0068e8a8b12652de prerequisite-patch-id: d658019a7ac7c82ebe4a6c6086457e27460174d3 prerequisite-patch-id: 41e68c9fc8e8c5e493497e87ca13577b3167cf80 -- 2.53.0.983.g0bb29b3bc5-goog