On Thu, Feb 16, 2023 at 04:00:03PM +0200, Anton Kuchin wrote: > Now any vhost-user-fs device makes VM unmigratable, that also prevents > qemu update without stopping the VM. In most cases that makes sense > because qemu has no way to transfer FUSE session state. > > But it is good to have an option for orchestrator to tune this according to > backend capabilities and migration configuration. > > This patch adds device property 'migration' that is 'none' by default > to keep old behaviour but can be set to 'external' to explicitly allow > migration with minimal virtio device state in migration stream if daemon > has some way to sync FUSE state on src and dst without help from qemu. > > Signed-off-by: Anton Kuchin <antonkuc...@yandex-team.ru> > --- > hw/core/qdev-properties-system.c | 10 +++++++++ > hw/virtio/vhost-user-fs.c | 34 ++++++++++++++++++++++++++++- > include/hw/qdev-properties-system.h | 1 + > include/hw/virtio/vhost-user-fs.h | 1 + > qapi/migration.json | 16 ++++++++++++++ > 5 files changed, 61 insertions(+), 1 deletion(-)
Looks okay to me. Comments below.
> diff --git a/hw/core/qdev-properties-system.c
> b/hw/core/qdev-properties-system.c
> index d42493f630..d9b1aa2a5d 100644
> --- a/hw/core/qdev-properties-system.c
> +++ b/hw/core/qdev-properties-system.c
> @@ -1143,3 +1143,13 @@ const PropertyInfo qdev_prop_uuid = {
> .set = set_uuid,
> .set_default_value = set_default_uuid_auto,
> };
> +
> +const PropertyInfo qdev_prop_vhost_user_migration_type = {
> + .name = "VhostUserMigrationType",
> + .description = "none/external",
> + .enum_table = &VhostUserMigrationType_lookup,
> + .get = qdev_propinfo_get_enum,
> + .set = qdev_propinfo_set_enum,
> + .set_default_value = qdev_propinfo_set_default_value_enum,
> + .realized_set_allowed = true,
> +};
> diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c
> index 83fc20e49e..e2a5b6cfdf 100644
> --- a/hw/virtio/vhost-user-fs.c
> +++ b/hw/virtio/vhost-user-fs.c
> @@ -24,6 +24,7 @@
> #include "hw/virtio/vhost-user-fs.h"
> #include "monitor/monitor.h"
> #include "sysemu/sysemu.h"
> +#include "qapi/qapi-types-migration.h"
>
> static const int user_feature_bits[] = {
> VIRTIO_F_VERSION_1,
> @@ -298,9 +299,36 @@ static struct vhost_dev *vuf_get_vhost(VirtIODevice
> *vdev)
> return &fs->vhost_dev;
> }
>
> +static int vhost_user_fs_pre_save(void *opaque)
> +{
> + VHostUserFS *fs = (VHostUserFS *)opaque;
> + g_autofree char *path = object_get_canonical_path(OBJECT(fs));
> +
> + switch (fs->migration_type) {
> + case VHOST_USER_MIGRATION_TYPE_NONE:
> + error_report("Migration is blocked by device %s", path);
> + break;
> + case VHOST_USER_MIGRATION_TYPE_EXTERNAL:
> + return 0;
> + default:
> + error_report("Migration type '%s' is not supported by device %s",
> + VhostUserMigrationType_str(fs->migration_type), path);
> + break;
> + }
> +
> + return -1;
> +}
> +
> static const VMStateDescription vuf_vmstate = {
> .name = "vhost-user-fs",
> - .unmigratable = 1,
> + .minimum_version_id = 0,
> + .version_id = 0,
> + .fields = (VMStateField[]) {
> + VMSTATE_VIRTIO_DEVICE,
> + VMSTATE_UINT8(migration_type, VHostUserFS),
Maybe add a comment since Michael asked what the purpose of this field
is:
/* For verifying that source/destination migration= properties match */
VMSTATE_UINT8(migration_type, VHostUserFS),
Come to think of it...where is the code that checks the vmstate
migration_type field matches the destination device's migration=
property?
> + VMSTATE_END_OF_LIST()
> + },
> + .pre_save = vhost_user_fs_pre_save,
> };
>
> static Property vuf_properties[] = {
> @@ -309,6 +337,10 @@ static Property vuf_properties[] = {
> DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
> conf.num_request_queues, 1),
> DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
> + DEFINE_PROP_UNSIGNED("migration", VHostUserFS, migration_type,
> + VHOST_USER_MIGRATION_TYPE_NONE,
> + qdev_prop_vhost_user_migration_type,
> + uint8_t),
> DEFINE_PROP_END_OF_LIST(),
> };
>
> diff --git a/include/hw/qdev-properties-system.h
> b/include/hw/qdev-properties-system.h
> index 0ac327ae60..1a67591590 100644
> --- a/include/hw/qdev-properties-system.h
> +++ b/include/hw/qdev-properties-system.h
> @@ -22,6 +22,7 @@ extern const PropertyInfo qdev_prop_audiodev;
> extern const PropertyInfo qdev_prop_off_auto_pcibar;
> extern const PropertyInfo qdev_prop_pcie_link_speed;
> extern const PropertyInfo qdev_prop_pcie_link_width;
> +extern const PropertyInfo qdev_prop_vhost_user_migration_type;
>
> #define DEFINE_PROP_PCI_DEVFN(_n, _s, _f, _d) \
> DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_pci_devfn, int32_t)
> diff --git a/include/hw/virtio/vhost-user-fs.h
> b/include/hw/virtio/vhost-user-fs.h
> index 94c3aaa84e..3ebce77be5 100644
> --- a/include/hw/virtio/vhost-user-fs.h
> +++ b/include/hw/virtio/vhost-user-fs.h
> @@ -40,6 +40,7 @@ struct VHostUserFS {
> VirtQueue **req_vqs;
> VirtQueue *hiprio_vq;
> int32_t bootindex;
> + uint8_t migration_type;
>
> /*< public >*/
> };
> diff --git a/qapi/migration.json b/qapi/migration.json
> index c84fa10e86..ababd605a2 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -2178,3 +2178,19 @@
> 'data': { 'job-id': 'str',
> 'tag': 'str',
> 'devices': ['str'] } }
> +
> +##
> +# @VhostUserMigrationType:
> +#
> +# Type of vhost-user device migration.
> +#
> +# @none: Migration is not supported, attempts to migrate with this device
> +# will be blocked.
> +#
> +# @external: Migration stream contains only virtio device state,
> +# deamon state should be transfered externally by orchestrator.
s/deamon/daemon/
s/transfered/transferred/
> +#
> +# Since: 8.0
> +##
> +{ 'enum': 'VhostUserMigrationType',
> + 'data': [ 'none', 'external' ] }
> --
> 2.37.2
>
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