On Sat, 4 Mar 2023 01:43:41 +0000
Joao Martins <joao.m.mart...@oracle.com> wrote:
> Migrating with vIOMMU will require either tracking maximum
> IOMMU supported address space (e.g. 39/48 address width on Intel)
> or range-track current mappings and dirty track the new ones
> post starting dirty tracking. This will be done as a separate
> series, so add a live migration blocker until that is fixed.
>
> Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
> ---
> hw/vfio/common.c | 51 +++++++++++++++++++++++++++++++++++
> hw/vfio/migration.c | 6 +++++
> include/hw/vfio/vfio-common.h | 2 ++
> 3 files changed, 59 insertions(+)
>
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 5b8456975e97..9b909f856722 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -365,6 +365,7 @@ bool vfio_mig_active(void)
> }
>
> static Error *multiple_devices_migration_blocker;
> +static Error *giommu_migration_blocker;
>
> static unsigned int vfio_migratable_device_num(void)
> {
> @@ -416,6 +417,56 @@ void vfio_unblock_multiple_devices_migration(void)
> multiple_devices_migration_blocker = NULL;
> }
>
> +static unsigned int vfio_use_iommu_device_num(void)
> +{
> + VFIOGroup *group;
> + VFIODevice *vbasedev;
> + unsigned int device_num = 0;
> +
> + QLIST_FOREACH(group, &vfio_group_list, next) {
> + QLIST_FOREACH(vbasedev, &group->device_list, next) {
> + if (vbasedev->group->container->space->as !=
> + &address_space_memory) {
> + device_num++;
> + }
> + }
> + }
> +
> + return device_num;
> +}
I'm not sure why we're counting devices since nobody uses that data,
but couldn't this be even more simple and efficient by walking the
vfio_address_spaces list?
static bool vfio_viommu_preset(void)
{
VFIOAddressSpace *space;
QLIST_FOREACH(space, &vfio_address_spaces, list) {
if (space->as != &address_space_memory) {
return true;
}
}
return false;
}
> +
> +int vfio_block_giommu_migration(Error **errp)
> +{
> + int ret;
> +
> + if (giommu_migration_blocker ||
> + !vfio_use_iommu_device_num()) {
> + return 0;
> + }
> +
> + error_setg(&giommu_migration_blocker,
> + "Migration is currently not supported with vIOMMU enabled");
> + ret = migrate_add_blocker(giommu_migration_blocker, errp);
> + if (ret < 0) {
> + error_free(giommu_migration_blocker);
> + giommu_migration_blocker = NULL;
> + }
> +
> + return ret;
> +}
> +
> +void vfio_unblock_giommu_migration(void)
> +{
> + if (!giommu_migration_blocker ||
> + vfio_use_iommu_device_num()) {
> + return;
> + }
> +
> + migrate_del_blocker(giommu_migration_blocker);
> + error_free(giommu_migration_blocker);
> + giommu_migration_blocker = NULL;
> +}
> +
> static void vfio_set_migration_error(int err)
> {
> MigrationState *ms = migrate_get_current();
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index a2c3d9bade7f..3e75868ae7a9 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -634,6 +634,11 @@ int vfio_migration_probe(VFIODevice *vbasedev, Error
> **errp)
> return ret;
> }
>
> + ret = vfio_block_giommu_migration(errp);
> + if (ret) {
> + return ret;
> + }
> +
> trace_vfio_migration_probe(vbasedev->name);
> return 0;
>
> @@ -659,6 +664,7 @@ void vfio_migration_finalize(VFIODevice *vbasedev)
> unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev);
> vfio_migration_exit(vbasedev);
> vfio_unblock_multiple_devices_migration();
> + vfio_unblock_giommu_migration();
Hmm, this actually gets called from vfio_exitfn(), doesn't all the
group, device, address space unlinking happen in
vfio_instance_finalize()? Has this actually been tested to remove the
blocker? And why is this a _finalize() function when it's called from
an exit callback? Thanks,
Alex
> }
>
> if (vbasedev->migration_blocker) {
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 1cbbccd91e11..38e44258925b 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -233,6 +233,8 @@ extern VFIOGroupList vfio_group_list;
> bool vfio_mig_active(void);
> int vfio_block_multiple_devices_migration(Error **errp);
> void vfio_unblock_multiple_devices_migration(void);
> +int vfio_block_giommu_migration(Error **errp);
> +void vfio_unblock_giommu_migration(void);
> int64_t vfio_mig_bytes_transferred(void);
>
> #ifdef CONFIG_LINUX
