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author | Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> | 2021-08-24 11:38:26 +0300 |
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committer | Hanna Reitz <hreitz@redhat.com> | 2021-09-01 12:57:31 +0200 |
commit | d1a58c176a11b439007c3a23223757497c02c332 (patch) | |
tree | f788666944d01dd1c5820fd2677d91c54cc804fb /hw | |
parent | deb2bb163f798a4bc044be5e474792852cb0366b (diff) | |
download | qemu-d1a58c176a11b439007c3a23223757497c02c332.zip qemu-d1a58c176a11b439007c3a23223757497c02c332.tar.gz qemu-d1a58c176a11b439007c3a23223757497c02c332.tar.bz2 |
qdev: allow setting drive property for realized device
We need an ability to insert filters above top block node, attached to
block device. It can't be achieved with blockdev-reopen command. So, we
want do it with help of qom-set.
Intended usage:
Assume there is a node A that is attached to some guest device.
1. blockdev-add to create a filter node B that has A as its child.
2. qom-set to change the node attached to the guest device’s
BlockBackend from A to B.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210824083856.17408-5-vsementsov@virtuozzo.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r-- | hw/core/qdev-properties-system.c | 43 |
1 files changed, 31 insertions, 12 deletions
diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c index 2760c21..e71f5d6 100644 --- a/hw/core/qdev-properties-system.c +++ b/hw/core/qdev-properties-system.c @@ -36,11 +36,11 @@ static bool check_prop_still_unset(Object *obj, const char *name, const void *old_val, const char *new_val, - Error **errp) + bool allow_override, Error **errp) { const GlobalProperty *prop = qdev_find_global_prop(obj, name); - if (!old_val) { + if (!old_val || (!prop && allow_override)) { return true; } @@ -93,16 +93,34 @@ static void set_drive_helper(Object *obj, Visitor *v, const char *name, BlockBackend *blk; bool blk_created = false; int ret; + BlockDriverState *bs; + AioContext *ctx; if (!visit_type_str(v, name, &str, errp)) { return; } - /* - * TODO Should this really be an error? If no, the old value - * needs to be released before we store the new one. - */ - if (!check_prop_still_unset(obj, name, *ptr, str, errp)) { + if (!check_prop_still_unset(obj, name, *ptr, str, true, errp)) { + return; + } + + if (*ptr) { + /* BlockBackend alread exists. So, we want to change attached node */ + blk = *ptr; + ctx = blk_get_aio_context(blk); + bs = bdrv_lookup_bs(NULL, str, errp); + if (!bs) { + return; + } + + if (ctx != bdrv_get_aio_context(bs)) { + error_setg(errp, "Different aio context is not supported for new " + "node"); + } + + aio_context_acquire(ctx); + blk_replace_bs(blk, bs, errp); + aio_context_release(ctx); return; } @@ -114,7 +132,7 @@ static void set_drive_helper(Object *obj, Visitor *v, const char *name, blk = blk_by_name(str); if (!blk) { - BlockDriverState *bs = bdrv_lookup_bs(NULL, str, NULL); + bs = bdrv_lookup_bs(NULL, str, NULL); if (bs) { /* * If the device supports iothreads, it will make sure to move the @@ -123,8 +141,7 @@ static void set_drive_helper(Object *obj, Visitor *v, const char *name, * aware of iothreads require their BlockBackends to be in the main * AioContext. */ - AioContext *ctx = iothread ? bdrv_get_aio_context(bs) : - qemu_get_aio_context(); + ctx = iothread ? bdrv_get_aio_context(bs) : qemu_get_aio_context(); blk = blk_new(ctx, 0, BLK_PERM_ALL); blk_created = true; @@ -196,6 +213,7 @@ static void release_drive(Object *obj, const char *name, void *opaque) const PropertyInfo qdev_prop_drive = { .name = "str", .description = "Node name or ID of a block device to use as a backend", + .realized_set_allowed = true, .get = get_drive, .set = set_drive, .release = release_drive, @@ -204,6 +222,7 @@ const PropertyInfo qdev_prop_drive = { const PropertyInfo qdev_prop_drive_iothread = { .name = "str", .description = "Node name or ID of a block device to use as a backend", + .realized_set_allowed = true, .get = get_drive, .set = set_drive_iothread, .release = release_drive, @@ -238,7 +257,7 @@ static void set_chr(Object *obj, Visitor *v, const char *name, void *opaque, * TODO Should this really be an error? If no, the old value * needs to be released before we store the new one. */ - if (!check_prop_still_unset(obj, name, be->chr, str, errp)) { + if (!check_prop_still_unset(obj, name, be->chr, str, false, errp)) { return; } @@ -408,7 +427,7 @@ static void set_netdev(Object *obj, Visitor *v, const char *name, * TODO Should this really be an error? If no, the old value * needs to be released before we store the new one. */ - if (!check_prop_still_unset(obj, name, ncs[i], str, errp)) { + if (!check_prop_still_unset(obj, name, ncs[i], str, false, errp)) { goto out; } |