Stash a pointer to a device's incoming Live Updated state in struct vfio_pci_core_device. This will enable subsequent commits to use the preserved state when initializing the device.
To enable VFIO to safely access this pointer during device enablement, require that the device is fully enabled before returning true from can_finish(). This is synchronized by vfio_pci_core.c setting vdev->liveupdate_incoming_state to NULL under dev_set lock once it's done using it. Signed-off-by: David Matlack <[email protected]> --- drivers/vfio/pci/vfio_pci_core.c | 2 +- drivers/vfio/pci/vfio_pci_liveupdate.c | 17 ++++++++++++++++- include/linux/vfio_pci_core.h | 2 ++ 3 files changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index 81f941323641..d7c472cf4729 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -568,7 +568,7 @@ int vfio_pci_core_enable(struct vfio_pci_core_device *vdev) if (!vfio_vga_disabled() && vfio_pci_is_vga(pdev)) vdev->has_vga = true; - + vdev->liveupdate_incoming_state = NULL; return 0; out_free_zdev: diff --git a/drivers/vfio/pci/vfio_pci_liveupdate.c b/drivers/vfio/pci/vfio_pci_liveupdate.c index 6f760ace7065..8d6681e1d328 100644 --- a/drivers/vfio/pci/vfio_pci_liveupdate.c +++ b/drivers/vfio/pci/vfio_pci_liveupdate.c @@ -226,6 +226,7 @@ static int match_device(struct device *dev, const void *arg) static int vfio_pci_liveupdate_retrieve(struct liveupdate_file_op_args *args) { struct vfio_pci_core_device_ser *ser; + struct vfio_pci_core_device *vdev; struct vfio_device *device; struct file *file; int ret = 0; @@ -246,6 +247,9 @@ static int vfio_pci_liveupdate_retrieve(struct liveupdate_file_op_args *args) goto out; } + vdev = container_of(device, struct vfio_pci_core_device, vdev); + vdev->liveupdate_incoming_state = ser; + args->file = file; out: /* Drop the reference from vfio_find_device() */ @@ -255,7 +259,18 @@ static int vfio_pci_liveupdate_retrieve(struct liveupdate_file_op_args *args) static bool vfio_pci_liveupdate_can_finish(struct liveupdate_file_op_args *args) { - return args->retrieve_status > 0; + struct vfio_pci_core_device *vdev; + struct vfio_device *device; + + if (args->retrieve_status <= 0) + return false; + + device = vfio_device_from_file(args->file); + vdev = container_of(device, struct vfio_pci_core_device, vdev); + + /* Check that vdev->liveupdate_incoming_state is no longer in use. */ + guard(mutex)(&device->dev_set->lock); + return !vdev->liveupdate_incoming_state; } static void vfio_pci_liveupdate_finish(struct liveupdate_file_op_args *args) diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index 2ebba746c18f..0c508dd8d1ac 100644 --- a/include/linux/vfio_pci_core.h +++ b/include/linux/vfio_pci_core.h @@ -26,6 +26,7 @@ #define VFIO_PCI_OFFSET_MASK (((u64)(1) << VFIO_PCI_OFFSET_SHIFT) - 1) struct vfio_pci_core_device; +struct vfio_pci_core_device_ser; struct vfio_pci_region; struct p2pdma_provider; struct dma_buf_attachment; @@ -142,6 +143,7 @@ struct vfio_pci_core_device { struct notifier_block nb; struct rw_semaphore memory_lock; struct list_head dmabufs; + struct vfio_pci_core_device_ser *liveupdate_incoming_state; }; enum vfio_pci_io_width { -- 2.53.0.983.g0bb29b3bc5-goog
