diff options
| author | Yishai Hadas <yishaih@nvidia.com> | 2026-03-17 18:17:49 +0200 |
|---|---|---|
| committer | Alex Williamson <alex@shazbot.org> | 2026-03-19 12:32:08 -0600 |
| commit | 50ff3f404617c5d15832fec3711978104c4c9efd (patch) | |
| tree | 3adf13e6508f71acc707308ae753bfbb785ae08b | |
| parent | d7140b5dde459048da52cfc0494228055f7e2fb8 (diff) | |
vfio: Add support for VFIO_DEVICE_FEATURE_MIG_PRECOPY_INFOv2
Currently, existing VFIO_MIG_GET_PRECOPY_INFO implementations don't
assign info.flags before copy_to_user().
Because they copy the struct in from userspace first, this effectively
echoes userspace-provided flags back as output, preventing the field
from being used to report new reliable data from the drivers.
Add support for a new device feature named
VFIO_DEVICE_FEATURE_MIG_PRECOPY_INFOv2.
On SET, enables the v2 pre_copy_info behaviour, where the
vfio_precopy_info.flags is a valid output field.
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Link: https://lore.kernel.org/r/20260317161753.18964-3-yishaih@nvidia.com
Signed-off-by: Alex Williamson <alex@shazbot.org>
| -rw-r--r-- | drivers/vfio/vfio_main.c | 21 | ||||
| -rw-r--r-- | include/linux/vfio.h | 1 |
2 files changed, 22 insertions, 0 deletions
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index 742477546b15..8666f35fb3f0 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -553,6 +553,7 @@ static void vfio_df_device_last_close(struct vfio_device_file *df) vfio_df_iommufd_unbind(df); else vfio_device_group_unuse_iommu(device); + device->precopy_info_v2 = 0; module_put(device->dev->driver->owner); } @@ -964,6 +965,23 @@ vfio_ioctl_device_feature_migration_data_size(struct vfio_device *device, return 0; } +static int +vfio_ioctl_device_feature_migration_precopy_info_v2(struct vfio_device *device, + u32 flags, size_t argsz) +{ + int ret; + + if (!(device->migration_flags & VFIO_MIGRATION_PRE_COPY)) + return -EINVAL; + + ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET, 0); + if (ret != 1) + return ret; + + device->precopy_info_v2 = 1; + return 0; +} + static int vfio_ioctl_device_feature_migration(struct vfio_device *device, u32 flags, void __user *arg, size_t argsz) @@ -1251,6 +1269,9 @@ static int vfio_ioctl_device_feature(struct vfio_device *device, return vfio_ioctl_device_feature_migration_data_size( device, feature.flags, arg->data, feature.argsz - minsz); + case VFIO_DEVICE_FEATURE_MIG_PRECOPY_INFOv2: + return vfio_ioctl_device_feature_migration_precopy_info_v2( + device, feature.flags, feature.argsz - minsz); default: if (unlikely(!device->ops->device_feature)) return -ENOTTY; diff --git a/include/linux/vfio.h b/include/linux/vfio.h index e90859956514..7c1d33283e04 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -52,6 +52,7 @@ struct vfio_device { struct vfio_device_set *dev_set; struct list_head dev_set_list; unsigned int migration_flags; + u8 precopy_info_v2; struct kvm *kvm; /* Members below here are private, not for driver use */ |