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Re: [PATCH 2/2] virtio-blk: add zoned storage emulation for zoned device
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From: |
Sam Li |
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Subject: |
Re: [PATCH 2/2] virtio-blk: add zoned storage emulation for zoned devices |
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Date: |
Thu, 29 Sep 2022 03:55:40 +0800 |
Stefan Hajnoczi <stefanha@redhat.com> 于2022年9月20日周二 05:31写道：
>
> On Sat, Sep 10, 2022 at 02:50:57PM +0800, 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 having zoned device support can use blkzone(8) to test those
> > commands. Furthermore, using zonefs to test zone append write is also
> > supported.
> >
> > Signed-off-by: Sam Li <faithilikerun@gmail.com>
> > ---
> > hw/block/virtio-blk.c | 326 ++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 326 insertions(+)
> >
> > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> > index e9ba752f6b..3ef74c01db 100644
> > --- a/hw/block/virtio-blk.c
> > +++ b/hw/block/virtio-blk.c
> > @@ -46,6 +46,8 @@ 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)},
> > {}
> > };
> >
> > @@ -614,6 +616,273 @@ err:
> > return err_status;
> > }
> >
> > +typedef struct ZoneCmdData {
> > + VirtIOBlockReq *req;
> > + union {
> > + struct {
> > + unsigned int nr_zones;
> > + BlockZoneDescriptor *zones;
> > + } ZoneReportData;
> > + struct {
> > + int64_t append_sector;
> > + } ZoneAppendData;
>
> Field names should be lowercase:
>
> struct {
> unsigned int nr_zones;
> BlockZoneDescriptor *zones;
> } zone_report_data;
> struct {
> int64_t append_sector;
> } zone_append_data;
>
> > + };
> > +} ZoneCmdData;
> > +
> > +/*
> > + * check zone_model: error checking before issuing requests. If all checks
>
> Maybe rename it to check_zoned_request()? It does more than check the
> model.
>
> > + * passed, return true.
> > + * append: true if only zone append request issued.
> > + */
> > +static bool check_zone_model(VirtIOBlock *s, int64_t sector, int64_t
> > nr_sector,
> > + bool append, uint8_t *status) {
> > + BlockDriverState *bs = blk_bs(s->blk);
> > + BlockZoneDescriptor *zone = &bs->bl.zones[sector /
> > bs->bl.zone_sectors];
>
> Inputs from the guest driver are untrusted and must be validated before
> using them. sector could have any value here, including invalid values.
> Please check that sector is less than the device capacity and also that
> it is positive.
>
> > + int64_t max_append_sector = bs->bl.max_append_sectors;
> > +
> > + if (!virtio_has_feature(s->host_features, VIRTIO_BLK_F_ZONED)) {
> > + *status = VIRTIO_BLK_S_UNSUPP;
> > + return false;
> > + }
> > +
> > + if (zone->cond == BLK_ZS_OFFLINE) {
> > + *status = VIRTIO_BLK_S_ZONE_INVALID_CMD;
> > + return false;
> > + }
> > +
> > + if (append) {
> > + if ((zone->type != BLK_ZT_SWR) || (zone->cond == BLK_ZS_RDONLY) ||
> > + (sector + nr_sector > (*(zone + 1)).start)) {
> > + /* the end sector of the request exceeds to next zone */
> > + *status = VIRTIO_BLK_S_ZONE_INVALID_CMD;
> > + return false;
> > + }
> > +
> > + if (nr_sector > max_append_sector) {
> > + if (max_append_sector == 0) {
> > + *status = VIRTIO_BLK_S_UNSUPP;
> > + } else {
> > + *status = VIRTIO_BLK_S_ZONE_INVALID_CMD;
> > + }
> > + return false;
> > + }
> > + }
> > + return true;
> > +}
> > +
> > +static void virtio_blk_zone_report_complete(void *opaque, int ret)
> > +{
> > + ZoneCmdData *data = opaque;
> > + VirtIOBlockReq *req = data->req;
> > + VirtIOBlock *s = req->dev;
> > + VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
> > + struct iovec *in_iov = req->elem.in_sg;
> > + unsigned in_num = req->elem.in_num;
> > + int64_t zrp_size, nz, n, j = 0;
> > + int8_t err_status = VIRTIO_BLK_S_OK;
> > +
> > + nz = data->ZoneReportData.nr_zones;
> > + struct virtio_blk_zone_report zrp_hdr = (struct
> > virtio_blk_zone_report) {
> > + .nr_zones = cpu_to_le64(nz),
> > + };
> > +
> > + zrp_size = sizeof(struct virtio_blk_zone_report)
> > + + sizeof(struct virtio_blk_zone_descriptor) * nz;
> > + n = iov_from_buf(in_iov, in_num, 0, &zrp_hdr, sizeof(zrp_hdr));
> > + if (n != sizeof(zrp_hdr)) {
> > + virtio_error(vdev, "Driver provided intput buffer that is too
> > small!");
> > + err_status = VIRTIO_BLK_S_ZONE_INVALID_CMD;
> > + goto out;
> > + }
> > +
> > + for (size_t i = sizeof(zrp_hdr); i < zrp_size; i += sizeof(struct
> > virtio_blk_zone_descriptor), ++j) {
> > + struct virtio_blk_zone_descriptor desc =
> > + (struct virtio_blk_zone_descriptor) {
> > + .z_start =
> > cpu_to_le64(data->ZoneReportData.zones[j].start),
> > + .z_cap =
> > cpu_to_le64(data->ZoneReportData.zones[j].cap),
> > + .z_wp =
> > cpu_to_le64(data->ZoneReportData.zones[j].wp),
>
> If the QEMU block layer uses byte constants it will be necessary to
> convert the above fields to sectors. I think the code is correct right
> now because the QEMU block layer patches still use sectors, but using
> bytes would be consistent with the QEMU block layer conventions.
>
> > + .z_type = data->ZoneReportData.zones[j].type,
> > + .z_state = data->ZoneReportData.zones[j].cond,
>
> The QEMU type and cond field constants might not match the virtio-blk
> constants. Please convert them explicitly (e.g. with a switch
> statement in a helper function) so there is no assumption about the
> values of the constants.
>
> > + };
> > + n = iov_from_buf(in_iov, in_num, i, &desc, sizeof(desc));
>
> This is O(n^2) time complexity since it's called from the loop, but
> nevermind for now... Maybe add a TODO comment so anyone trying to
> optimize this code will immediately see the expensive part.
>
> > + if (n != sizeof(desc)) {
> > + virtio_error(vdev, "Driver provided input buffer "
> > + "for descriptors that is too small!");
> > + err_status = VIRTIO_BLK_S_ZONE_INVALID_CMD;
> > + goto out;
> > + }
> > + }
> > + goto out;
> > +
> > +out:
> > + aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
> > + virtio_blk_req_complete(req, err_status);
> > + virtio_blk_free_request(req);
> > + aio_context_release(blk_get_aio_context(s->conf.conf.blk));
> > + g_free(data->ZoneReportData.zones);
> > + g_free(data);
> > +}
> > +
> > +static int virtio_blk_handle_zone_report(VirtIOBlockReq *req) {
> > + VirtIOBlock *s = req->dev;
> > + VirtIODevice *vdev = VIRTIO_DEVICE(s);
> > + unsigned int nr_zones;
> > + ZoneCmdData *data;
> > + int64_t zone_size, offset;
> > + uint8_t err_status;
> > +
> > + if (req->in_len <= sizeof(struct virtio_blk_inhdr) +
> > + sizeof(struct virtio_blk_zone_report)) {
> > + virtio_error(vdev, "in buffer too small for zone report");
> > + return -1;
> > + }
> > +
> > + /* start byte offset of the zone report */
> > + offset = virtio_ldq_p(vdev, &req->out.sector) * 512;
> > + if (!check_zone_model(s, offset / 512, 0, false, &err_status)) {
> > + goto out;
> > + }
> > +
> > + nr_zones = (req->in_len - sizeof(struct virtio_blk_inhdr) -
> > + sizeof(struct virtio_blk_zone_report)) /
> > + sizeof(struct virtio_blk_zone_descriptor);
> > +
> > + zone_size = sizeof(BlockZoneDescriptor) * nr_zones;
> > + data = g_malloc(sizeof(ZoneCmdData));
> > + data->req = req;
> > + data->ZoneReportData.nr_zones = nr_zones;
> > + data->ZoneReportData.zones = g_malloc(zone_size),
>
> nr_zones = 0 and zones = NULL is possible when in_len is sizeof(struct
> virtio_blk_inhdr) + sizeof(struct virtio_blk_zone_report) + 1. Maybe the
> code handles it okay without dereferencing a NULL pointer, but it would
> be safer to change the check above like this:
>
> if (req->in_len < sizeof(struct virtio_blk_inhdr) +
> sizeof(struct virtio_blk_zone_report) +
> sizeof(struct virtio_blk_zone_descriptor)) {
> virtio_error(vdev, "in buffer too small for zone report");
> return -1;
> }
>
> > +
> > + blk_aio_zone_report(s->blk, offset, &data->ZoneReportData.nr_zones,
> > + data->ZoneReportData.zones,
> > + virtio_blk_zone_report_complete, data);
> > + return 0;
> > +
> > +out:
> > + aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
> > + virtio_blk_req_complete(req, err_status);
> > + virtio_blk_free_request(req);
> > + aio_context_release(blk_get_aio_context(s->conf.conf.blk));
> > + return err_status;
> > +}
> > +
> > +static void virtio_blk_zone_mgmt_complete(void *opaque, int ret) {
> > + ZoneCmdData *data = opaque;
> > + VirtIOBlockReq *req = data->req;
> > + VirtIOBlock *s = req->dev;
>
> Missing ret < 0 error handling.
>
> > +
> > + aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
> > + virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
> > + virtio_blk_free_request(req);
> > + aio_context_release(blk_get_aio_context(s->conf.conf.blk));
> > + g_free(data);
> > +}
> > +
> > +static int virtio_blk_handle_zone_mgmt(VirtIOBlockReq *req, BlockZoneOp
> > op) {
> > + VirtIOBlock *s = req->dev;
> > + VirtIODevice *vdev = VIRTIO_DEVICE(s);
> > + BlockDriverState *bs = blk_bs(s->blk);
> > + int64_t offset = virtio_ldq_p(vdev, &req->out.sector) * 512;
> > + uint64_t len;
> > + uint32_t type;
> > + uint8_t err_status = VIRTIO_BLK_S_OK;
> > +
> > + if (!check_zone_model(s, offset / 512, 0, false, &err_status)) {
> > + goto out;
> > + }
> > +
> > + ZoneCmdData *data = g_malloc(sizeof(ZoneCmdData));
> > + data->req = req;
> > +
> > + type = virtio_ldl_p(vdev, &req->out.type);
> > + if (type == VIRTIO_BLK_T_ZONE_RESET_ALL) {
> > + /* Entire drive capacity */
> > + offset = 0;
> > + blk_get_geometry(s->blk, &len);
> > + len *= 512;
> > + } else {
> > + len = bs->bl.zone_sectors * 512;
>
> Is this correct when accessing the last zone of the device?
>
> > + }
> > +
> > + blk_aio_zone_mgmt(s->blk, op, offset, len,
> > + virtio_blk_zone_mgmt_complete, data);
> > +
> > + return 0;
> > +out:
> > + aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
> > + virtio_blk_req_complete(req, err_status);
> > + virtio_blk_free_request(req);
> > + aio_context_release(blk_get_aio_context(s->conf.conf.blk));
> > + return err_status;
> > +}
> > +
> > +static void virtio_blk_zone_append_complete(void *opaque, int ret) {
> > + ZoneCmdData *data = opaque;
> > + VirtIOBlockReq *req = data->req;
> > + VirtIOBlock *s = req->dev;
> > + VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
> > + int64_t append_sector, n;
> > + struct iovec *out_iov = req->elem.out_sg;
> > + unsigned out_num = req->elem.out_num;
> > + uint8_t err_status = VIRTIO_BLK_S_OK;
>
> Error handling code for the ret < 0 case is missing.
>
> > +
> > + append_sector = data->ZoneAppendData.append_sector;
> > + int write_granularity = s->conf.conf.logical_block_size;
> > + if ((append_sector * 512 % write_granularity) != 0) {
> > + err_status = VIRTIO_BLK_S_ZONE_UNALIGNED_WP;
> > + goto out;
> > + }
>
> This looks like input validation. Why is it performed after the I/O
> request has completed?
UNALIGNED_WP should be checked in both input and output validation. By
checking if the starting/ending sector of the request data is aligned
with write_granularity(value of physical block size), the device sets
the UNALIGNED_WP bit and completes the request. According to spec
here:
+VIRTIO_BLK_S_ZONE_UNALIGNED_WP is set by the device when the request received
+from the driver attempts to perform a write to an SWR zone and at least one of
+the following conditions is met:
+
+\begin{itemize}
+\item the starting sector of the request is not equal to the current value of
+ the zone write pointer.
+
+\item the ending sector of the request data multiplied by 512 is not a multiple
+ of the value reported by the device in the field \field{write_granularity}
+ in the device configuration space.
+\end{itemize}
>
> I guess the intent is to check the value that the guest driver provided,
> not the value produced by the device after the I/O request completed?
>
> > + n = iov_to_buf(out_iov, out_num, 0, &append_sector,
> > sizeof(append_sector));
>
> Please use virtio_stq_p() on append_sector first to ensure that the
> endianness is correct.
>
> > + if (n != sizeof(append_sector)) {
> > + virtio_error(vdev, "Driver provided input buffer less than size of
> > "
> > + "append_sector");
> > + err_status = VIRTIO_BLK_S_ZONE_INVALID_CMD;
> > + goto out;
> > + }
> > + goto out;
> > +
> > +out:
> > + aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
> > + virtio_blk_req_complete(req, err_status);
> > + virtio_blk_free_request(req);
> > + aio_context_release(blk_get_aio_context(s->conf.conf.blk));
> > + g_free(data);
> > +}
> > +
> > +static int virtio_blk_handle_zone_append(VirtIOBlockReq *req) {
>
> The return value is not used. Please change the return type to void.
The return type should be int actually. Otherwise, QEMU will terminate
when the zone_append request is issued from the guest. It is the one
cause that failed some of the zonefs tests. After coredump, backtrace
indicates address_space_unmap: Assertion `mr ! = NULL` failed rooted
from virtio_blk_zone_append_complete(). I haven't figured out exactly
why but my guess is virtio_blk_zone_op_complete() needs the return
value of virtio_blk_zone_op() ......
>
> > + VirtIOBlock *s = req->dev;
> > + VirtIODevice *vdev = VIRTIO_DEVICE(s);
> > + uint64_t niov = req->elem.out_num;
> > + struct iovec *out_iov = req->elem.out_sg;
> > + uint8_t err_status = VIRTIO_BLK_S_OK;
> > +
> > + int64_t offset = virtio_ldq_p(vdev, &req->out.sector) * 512;
> > + int64_t len = 0;
> > + for (int i = 1; i < niov; ++i) {
> > + len += out_iov[i].iov_len;
> > + }
>
> Why is the first iovec skipped?
Because the first iovec is normally headers, and the rest is buffer
that out_iov needs.
>
> > +
> > + if (!check_zone_model(s, offset / 512, len / 512, true, &err_status)) {
> > + goto out;
> > + }
> > +
> > + ZoneCmdData *data = g_malloc(sizeof(ZoneCmdData));
> > + data->req = req;
> > + data->ZoneAppendData.append_sector = offset;
> > + qemu_iovec_init_external(&req->qiov, &out_iov[1], niov-1);
> > + blk_aio_zone_append(s->blk, &data->ZoneAppendData.append_sector,
> > &req->qiov, 0,
> > + virtio_blk_zone_append_complete, data);
> > +
> > + return 0;
> > +
> > +out:
> > + aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
> > + virtio_blk_req_complete(req, err_status);
> > + virtio_blk_free_request(req);
> > + aio_context_release(blk_get_aio_context(s->conf.conf.blk));
> > + return err_status;
> > +}
> > +
> > static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer
> > *mrb)
> > {
> > uint32_t type;
> > @@ -700,6 +969,24 @@ static int virtio_blk_handle_request(VirtIOBlockReq
> > *req, MultiReqBuffer *mrb)
> > case VIRTIO_BLK_T_FLUSH:
> > virtio_blk_handle_flush(req, mrb);
> > break;
> > + case VIRTIO_BLK_T_ZONE_REPORT:
> > + virtio_blk_handle_zone_report(req);
> > + break;
> > + case VIRTIO_BLK_T_ZONE_OPEN:
> > + virtio_blk_handle_zone_mgmt(req, BLK_ZO_OPEN);
> > + break;
> > + case VIRTIO_BLK_T_ZONE_CLOSE:
> > + virtio_blk_handle_zone_mgmt(req, BLK_ZO_CLOSE);
> > + break;
> > + case VIRTIO_BLK_T_ZONE_FINISH:
> > + virtio_blk_handle_zone_mgmt(req, BLK_ZO_FINISH);
> > + break;
> > + case VIRTIO_BLK_T_ZONE_RESET:
> > + virtio_blk_handle_zone_mgmt(req, BLK_ZO_RESET);
> > + break;
> > + case VIRTIO_BLK_T_ZONE_RESET_ALL:
> > + virtio_blk_handle_zone_mgmt(req, BLK_ZO_RESET_ALL);
> > + break;
> > case VIRTIO_BLK_T_SCSI_CMD:
> > virtio_blk_handle_scsi(req);
> > break;
> > @@ -718,6 +1005,9 @@ static int virtio_blk_handle_request(VirtIOBlockReq
> > *req, MultiReqBuffer *mrb)
> > virtio_blk_free_request(req);
> > break;
> > }
> > + case VIRTIO_BLK_T_ZONE_APPEND & ~VIRTIO_BLK_T_OUT:
> > + virtio_blk_handle_zone_append(req);
> > + break;
> > /*
> > * VIRTIO_BLK_T_DISCARD and VIRTIO_BLK_T_WRITE_ZEROES are defined with
> > * VIRTIO_BLK_T_OUT flag set. We masked this flag in the switch
> > statement,
> > @@ -917,6 +1207,7 @@ static void virtio_blk_update_config(VirtIODevice
> > *vdev, uint8_t *config)
> > {
> > VirtIOBlock *s = VIRTIO_BLK(vdev);
> > BlockConf *conf = &s->conf.conf;
> > + BlockDriverState *state = blk_bs(s->blk);
>
> Usually the variable is called "bs". Please use that name here and
> elsewhere in the patch.
>
> > struct virtio_blk_config blkcfg;
> > uint64_t capacity;
> > int64_t length;
> > @@ -976,6 +1267,31 @@ static void virtio_blk_update_config(VirtIODevice
> > *vdev, uint8_t *config)
> > blkcfg.write_zeroes_may_unmap = 1;
> > virtio_stl_p(vdev, &blkcfg.max_write_zeroes_seg, 1);
> > }
> > +#ifdef CONFIG_BLKZONED
>
> Is this ifdef appropriate? I think bs->bl.zoned should always be
> available, even when <blkzoned.h> is missing (e.g. non-Linux system). In
> the future there may be an emulated zoned BlockDriver. virtio-blk
> should be able to use the emulated zoned BlockDriver even on non-Linux
> systems.
>
Ok, you are right.
> I think CONFIG_BLKZONED should be limited to block/file-posix.c.
I'm not sure. There may be some places where virtio-blk needs this
config. Like in transforming blk_zone_descriptor to
virtio_blk_zone_descriptor, it needs to use Linux's constants to
ensure nothing go wrong here.
>
> > + if (state->bl.zoned != BLK_Z_NONE) {
> > + switch (state->bl.zoned) {
> > + case BLK_Z_HM:
> > + blkcfg.zoned.model = VIRTIO_BLK_Z_HM;
> > + virtio_stl_p(vdev, &blkcfg.zoned.zone_sectors,
> > + state->bl.zone_sectors);
> > + virtio_stl_p(vdev, &blkcfg.zoned.max_active_zones,
> > + state->bl.max_active_zones);
> > + virtio_stl_p(vdev, &blkcfg.zoned.max_open_zones,
> > + state->bl.max_open_zones);
> > + virtio_stl_p(vdev, &blkcfg.zoned.write_granularity, blk_size);
> > + virtio_stl_p(vdev, &blkcfg.zoned.max_append_sectors,
> > + state->bl.max_append_sectors);
> > + break;
> > + case BLK_Z_HA:
> > + blkcfg.zoned.model = VIRTIO_BLK_Z_HA;
>
> The block limits aren't relevant to host-aware zoned devices?
Yes, the HA devices are seen as non-zoned device and the driver just
ignore all other fields in zoned.
+\item if the driver that can not support zoned devices reads
+ VIRTIO_BLK_Z_HA from the \field{model} field of \field{zoned}, the driver
+ MAY handle the device as a non-zoned device. In this case, the
+ driver SHOULD ignore all other fields in \field{zoned}.
+\end{itemize}
>
> > + break;
> > + default:
> > + blkcfg.zoned.model = VIRTIO_BLK_Z_NONE;
> > + virtio_error(vdev, "Invalid zoned model %x \n",
> > (int)state->bl.zoned);
> > + break;
> > + }
> > + }
> > +#endif
> > memcpy(config, &blkcfg, s->config_size);
> > }
> >
> > @@ -995,6 +1311,7 @@ static uint64_t virtio_blk_get_features(VirtIODevice
> > *vdev, uint64_t features,
> > Error **errp)
> > {
> > VirtIOBlock *s = VIRTIO_BLK(vdev);
> > + BlockDriverState *state = blk_bs(s->blk);
> >
> > /* Firstly sync all virtio-blk possible supported features */
> > features |= s->host_features;
> > @@ -1003,6 +1320,12 @@ static uint64_t virtio_blk_get_features(VirtIODevice
> > *vdev, uint64_t features,
> > virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY);
> > virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY);
> > virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
> > + if (state->bl.zoned != BLK_Z_NONE) {
> > + virtio_add_feature(&s->host_features, VIRTIO_BLK_F_ZONED);
> > + if (state->bl.zoned == BLK_Z_HM) {
> > + virtio_clear_feature(&features, VIRTIO_BLK_F_DISCARD);
>
> Why is features modified here but s->host_features is modified in the
> line above?
Because F_DISCARD should not be offered by the driver when the device
offers F_ZONED with the HM model.
>
> > + }
> > + }
>
> This detects VIRTIO_BLK_F_ZONED based on the BlockDriverState...
(This part can be removed.)
>
> > if (virtio_has_feature(features, VIRTIO_F_VERSION_1)) {
> > if (virtio_has_feature(s->host_features, VIRTIO_BLK_F_SCSI)) {
> > error_setg(errp, "Please set scsi=off for virtio-blk devices
> > in order to use virtio 1.0");
> > @@ -1286,6 +1609,9 @@ static Property virtio_blk_properties[] = {
> > #ifdef __linux__
> > DEFINE_PROP_BIT64("scsi", VirtIOBlock, host_features,
> > VIRTIO_BLK_F_SCSI, false),
> > +#endif
> > +#ifdef CONFIG_BLKZONED
> > + DEFINE_PROP_BIT64("zoned", VirtIOBlock, host_features,
> > VIRTIO_BLK_F_ZONED, true),
> > #endif
>
> ...but this allows users to enable/disable the flag from the
> command-line.
>
> I think DEFINE_PROP_BIT64() can be removed, but please check that the
> config space size is still correct. It may be necessary to move the
> bs->bl.zoned check into virtio_blk_device_realize() and set
> the VIRTIO_BLK_F_ZONED s->host_features bit there instead. That will
> allow the s->config_size calculation to work correctly.
Ok, it works. Thanks!
Additionally, the DEFINE_PROP_BIT here is to declare that the supports
zones. Then the virtio-blk driver will not need to look at that
feature. So the former part detecting the F_ZONED feature based on
BlockDriverState can be removed. If removing this macro, then the
virio-blk driver must set the F_ZONED feature by itself.