Re: [Qemu-devel] [PATCH v7 0/4] Introduce a new vhost-user-blk host device to QEMU

[Stefan Hajnoczi]

On Wed, Dec 13, 2017 at 10:28:59AM +0800, Changpeng Liu wrote:
> Although virtio scsi specification was designed as a replacement for 
> virtio_blk,
> there are still many users using virtio_blk. QEMU 2.9 introduced a new device
> vhost user scsi which can process I/O in user space for virtio_scsi, this 
> commit
> introduces a new vhost user block host device, which can support virtio_blk in
> Guest OS, and I/O processing in another I/O target.
> 
> Due to the limitation for virtio_blk specification, virtio_blk device cannot 
> get
> block information such as capacity, block size etc via the specification, 
> several
> new vhost user messages were added to deliver virtio config space
> information between Qemu and I/O target, 
> VHOST_USER_GET_CONFIG/VHOST_USER_SET_CONFIG
> messages used for get/set config space from/to I/O target, 
> VHOST_USER_SET_CONFIG_FD
> was added for event notifier in case the change of virtio config space. Also, 
> those
> messages can be used for vhost device live migration as well.

Michael or Marc-André, please take this through your tree once you've
reviewed it.

Stefan

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