Copying block maintainers, since while this is in QOM source files, this
method is defacto block layer code.
On Fri, May 23, 2025 at 09:02:11AM +0200, Fiona Ebner wrote:
> Currently, changing the 'drive' property of e.g. a scsi-hd object will
> result in an assertion failure if the aio context of the block node
> it's replaced with doesn't match the current aio context:
>
> > bdrv_replace_child_noperm: Assertion `bdrv_get_aio_context(old_bs) ==
> > bdrv_get_aio_context(new_bs)' failed.
>
> The problematic scenario is already detected, but a 'return' statement
> was missing.
>
> Cc: qemu-sta...@nongnu.org
> Fixes: d1a58c176a ("qdev: allow setting drive property for realized device")
> Signed-off-by: Fiona Ebner <f.eb...@proxmox.com>
> ---
>
> Changes in v2:
> * Add missing condition in commit message, sorry for the noise!
>
> Reproducer:
>
> #!/bin/bash
> rm /tmp/disk0.raw
> rm /tmp/disk1.raw
> ./qemu-img create -f raw /tmp/disk0.raw 1G
> ./qemu-img create -f raw /tmp/disk1.raw 1G
> ./qemu-system-x86_64 --qmp stdio \
> --blockdev file,node-name=node0,filename=/tmp/disk0.raw \
> --blockdev file,node-name=node1,filename=/tmp/disk1.raw \
> --nodefaults \
> --object 'iothread,id=iothread0' \
> --device
> 'virtio-scsi-pci,id=virtioscsi0,bus=pci.0,addr=0x3,iothread=iothread0' \
> --device 'scsi-hd,bus=virtioscsi0.0,scsi-id=1,drive=node0,id=scsi0' \
> <<EOF
> {"execute": "qmp_capabilities"}
> {"execute": "qom-set", "arguments": { "path": "/machine/peripheral/scsi0",
> "property": "drive", "value": "node1" } }
> {"execute": "quit"}
> EOF
>
> hw/core/qdev-properties-system.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/hw/core/qdev-properties-system.c
> b/hw/core/qdev-properties-system.c
> index 8e11e6388b..24e145d870 100644
> --- a/hw/core/qdev-properties-system.c
> +++ b/hw/core/qdev-properties-system.c
> @@ -145,6 +145,7 @@ static void set_drive_helper(Object *obj, Visitor *v,
> const char *name,
> if (ctx != bdrv_get_aio_context(bs)) {
> error_setg(errp, "Different aio context is not supported for new
> "
> "node");
> + return;
> }
>
> blk_replace_bs(blk, bs, errp);
Reviewed-by: Daniel P. Berrangé <berra...@redhat.com>
With regards,
Daniel
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