Re: [PATCH v8 2/4] virtio-blk: add zoned storage emulation for zoned devices

[Sam Li <faithilikerun@gmail.com>]

Matias Bjørling <m@bjorling.me> 于2023年3月23日周四 21:39写道：
>
> On 23/03/2023 06.28, Sam Li wrote:
> > This patch extends virtio-blk emulation to handle zoned device commands
> > by calling the new block layer APIs to perform zoned device I/O on
> > behalf of the guest. It supports Report Zone, four zone oparations (open,
> > close, finish, reset), and Append Zone.
> >
> > The VIRTIO_BLK_F_ZONED feature bit will only be set if the host does
> > support zoned block devices. Regular block devices(conventional zones)
> > will not be set.
> >
> > The guest os can use blktests, fio to test those commands on zoned devices.
> > Furthermore, using zonefs to test zone append write is also supported.
> >
> > Signed-off-by: Sam Li <faithilikerun@gmail.com>
> > ---
> >   hw/block/virtio-blk-common.c |   2 +
> >   hw/block/virtio-blk.c        | 389 +++++++++++++++++++++++++++++++++++
> >   2 files changed, 391 insertions(+)
> >
> > diff --git a/hw/block/virtio-blk-common.c b/hw/block/virtio-blk-common.c
> > index ac52d7c176..e2f8e2f6da 100644
> > --- a/hw/block/virtio-blk-common.c
> > +++ b/hw/block/virtio-blk-common.c
> > @@ -29,6 +29,8 @@ static const VirtIOFeature feature_sizes[] = {
> >        .end = endof(struct virtio_blk_config, discard_sector_alignment)},
> >       {.flags = 1ULL << VIRTIO_BLK_F_WRITE_ZEROES,
> >        .end = endof(struct virtio_blk_config, write_zeroes_may_unmap)},
> > +    {.flags = 1ULL << VIRTIO_BLK_F_ZONED,
> > +     .end = endof(struct virtio_blk_config, zoned)},
> >       {}
> >   };
>
> I used the qemu monitor to expect the state of the devices, and on the
> zoned block device specific entries, the zoned device feature shows up
> in the "unknown-features" field (info virtio-status <device>)
>
> What is missing is an entry in the blk_feature_map structure within
> hw/virtio/virtio-qmp.c. The below fixes it up.
>
> diff --git i/hw/virtio/virtio-qmp.c w/hw/virtio/virtio-qmp.c
> index b70148aba9..3efa529bab 100644
> --- i/hw/virtio/virtio-qmp.c
> +++ w/hw/virtio/virtio-qmp.c
> @@ -176,6 +176,8 @@ static const qmp_virtio_feature_map_t
> virtio_blk_feature_map[] = {
>               "VIRTIO_BLK_F_DISCARD: Discard command supported"),
>       FEATURE_ENTRY(VIRTIO_BLK_F_WRITE_ZEROES, \
>               "VIRTIO_BLK_F_WRITE_ZEROES: Write zeroes command supported"),
> +    FEATURE_ENTRY(VIRTIO_BLK_F_ZONED, \
> +            "VIRTIO_BLK_F_ZONED: Zoned block device"),
>   #ifndef VIRTIO_BLK_NO_LEGACY
>       FEATURE_ENTRY(VIRTIO_BLK_F_BARRIER, \
>               "VIRTIO_BLK_F_BARRIER: Request barriers supported"),
>
> Which then lets qemu report the support like this:
>
> (qemu) info virtio-status /machine/peripheral/virtblk0/virtio-backend
> /machine/peripheral/virtblk0/virtio-backend:
>    device_name:             virtio-blk
>    device_id:               2
>    vhost_started:           false
>    bus_name:                (null)
>    broken:                  false
>    disabled:                false
>    disable_legacy_check:    false
>    started:                 true
>    use_started:             true
>    start_on_kick:           false
>    use_guest_notifier_mask: true
>    vm_running:              true
>    num_vqs:                 4
>    queue_sel:               3
>    isr:                     1
>    endianness:              little
>    status:
>          VIRTIO_CONFIG_S_ACKNOWLEDGE: Valid virtio device found,
>          VIRTIO_CONFIG_S_DRIVER: Guest OS compatible with device,
>          VIRTIO_CONFIG_S_FEATURES_OK: Feature negotiation complete,
>          VIRTIO_CONFIG_S_DRIVER_OK: Driver setup and ready
>    Guest features:
>          VIRTIO_RING_F_EVENT_IDX: Used & avail. event fields enabled,
>          VIRTIO_RING_F_INDIRECT_DESC: Indirect descriptors supported,
>          VIRTIO_F_VERSION_1: Device compliant for v1 spec (legacy)
>          VIRTIO_BLK_F_CONFIG_WCE: Cache writeback and ...,
>          VIRTIO_BLK_F_FLUSH: Flush command supported,
>          VIRTIO_BLK_F_ZONED: Zoned block device,
>          VIRTIO_BLK_F_WRITE_ZEROES: Write zeroes command supported,
>          VIRTIO_BLK_F_MQ: Multiqueue supported,
>          VIRTIO_BLK_F_TOPOLOGY: Topology information available,
>          VIRTIO_BLK_F_BLK_SIZE: Block size of disk available,
>          VIRTIO_BLK_F_GEOMETRY: Legacy geometry available,
>          VIRTIO_BLK_F_SEG_MAX: Max segments in a request is seg_max
>    unknown-features(0x0000010000000000)
>    Host features:
>          VIRTIO_RING_F_EVENT_IDX: Used & avail. event fields enabled,
>          VIRTIO_RING_F_INDIRECT_DESC: Indirect descriptors supported,
>          VIRTIO_F_VERSION_1: Device compliant for v1 spec (legacy),
>          VIRTIO_F_ANY_LAYOUT: Device accepts arbitrary desc. layouts,
>          VIRTIO_F_NOTIFY_ON_EMPTY: Notify when device ...,
>          VHOST_USER_F_PROTOCOL_FEATURES: Vhost-user protocol ...,
>          VIRTIO_BLK_F_CONFIG_WCE: Cache writeback and w...,
>          VIRTIO_BLK_F_FLUSH: Flush command supported,
>          VIRTIO_BLK_F_ZONED: Zoned block device,
>          VIRTIO_BLK_F_WRITE_ZEROES: Write zeroes command supported,
>          VIRTIO_BLK_F_MQ: Multiqueue supported,
>          VIRTIO_BLK_F_TOPOLOGY: Topology information available,
>          VIRTIO_BLK_F_BLK_SIZE: Block size of disk available,
>          VIRTIO_BLK_F_GEOMETRY: Legacy geometry available,
>          VIRTIO_BLK_F_SEG_MAX: Max segments in a request is seg_max
>    unknown-features(0x0000010000000000)
>    Backend features:

Great!

>
> Cheers, Matias