Register VFIO live update file handler to Live Update Orchestrator. Provide stub implementation of the handler callbacks.
Adding live update support in VFIO will enable a VFIO PCI device to work uninterrupted while the host kernel is being updated through a kexec reboot. Signed-off-by: Vipin Sharma <[email protected]> --- drivers/vfio/pci/Makefile | 1 + drivers/vfio/pci/vfio_pci_core.c | 1 + drivers/vfio/pci/vfio_pci_liveupdate.c | 44 ++++++++++++++++++++++++++ drivers/vfio/pci/vfio_pci_priv.h | 6 ++++ 4 files changed, 52 insertions(+) create mode 100644 drivers/vfio/pci/vfio_pci_liveupdate.c diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile index cf00c0a7e55c..929df22c079b 100644 --- a/drivers/vfio/pci/Makefile +++ b/drivers/vfio/pci/Makefile @@ -2,6 +2,7 @@ vfio-pci-core-y := vfio_pci_core.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o vfio-pci-core-$(CONFIG_VFIO_PCI_ZDEV_KVM) += vfio_pci_zdev.o +vfio-pci-core-$(CONFIG_LIVEUPDATE) += vfio_pci_liveupdate.o obj-$(CONFIG_VFIO_PCI_CORE) += vfio-pci-core.o vfio-pci-y := vfio_pci.o diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index 7dcf5439dedc..0894673a9262 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -2568,6 +2568,7 @@ static void vfio_pci_core_cleanup(void) static int __init vfio_pci_core_init(void) { /* Allocate shared config space permission data used by all devices */ + vfio_pci_liveupdate_init(); return vfio_pci_init_perm_bits(); } diff --git a/drivers/vfio/pci/vfio_pci_liveupdate.c b/drivers/vfio/pci/vfio_pci_liveupdate.c new file mode 100644 index 000000000000..088f7698a72c --- /dev/null +++ b/drivers/vfio/pci/vfio_pci_liveupdate.c @@ -0,0 +1,44 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Liveupdate support for VFIO devices. + * + * Copyright (c) 2025, Google LLC. + * Vipin Sharma <[email protected]> + */ + +#include <linux/liveupdate.h> +#include <linux/errno.h> + +#include "vfio_pci_priv.h" + +static int vfio_pci_liveupdate_retrieve(struct liveupdate_file_handler *handler, + u64 data, struct file **file) +{ + return -EOPNOTSUPP; +} + +static bool vfio_pci_liveupdate_can_preserve(struct liveupdate_file_handler *handler, + struct file *file) +{ + return -EOPNOTSUPP; +} + +static const struct liveupdate_file_ops vfio_pci_luo_fops = { + .retrieve = vfio_pci_liveupdate_retrieve, + .can_preserve = vfio_pci_liveupdate_can_preserve, + .owner = THIS_MODULE, +}; + +static struct liveupdate_file_handler vfio_pci_luo_handler = { + .ops = &vfio_pci_luo_fops, + .compatible = "vfio-v1", +}; + +void __init vfio_pci_liveupdate_init(void) +{ + int err = liveupdate_register_file_handler(&vfio_pci_luo_handler); + + if (err) + pr_err("VFIO PCI liveupdate file handler register failed, error %d.\n", err); +} diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h index a9972eacb293..7779fd744ff5 100644 --- a/drivers/vfio/pci/vfio_pci_priv.h +++ b/drivers/vfio/pci/vfio_pci_priv.h @@ -107,4 +107,10 @@ static inline bool vfio_pci_is_vga(struct pci_dev *pdev) return (pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA; } +#ifdef CONFIG_LIVEUPDATE +void vfio_pci_liveupdate_init(void); +#else +static inline void vfio_pci_liveupdate_init(void) { } +#endif /* CONFIG_LIVEUPDATE */ + #endif -- 2.51.0.858.gf9c4a03a3a-goog
