Re: [Qemu-devel] [PATCH 1/2] virtio-blk: support VIRTIO_BLK_F_CONFIG_WCE

[Paolo Bonzini]

Il 03/07/2012 15:46, Kevin Wolf ha scritto:
>> > Introduce a new feature bit and configuration field that provide
>> > support for toggling the cache mode between writethrough and writeback.
>> > 
>> > Also rename VIRTIO_BLK_F_WCACHE to VIRTIO_BLK_F_WCE for consistency with
>> > the spec.
> My spec (and my kernel as well) call it VIRTIO_BLK_F_FLUSH.
> 
> What's the status of the kernel and spec side of the change?

Both posted.  The spec patch that introduces VIRTIO_BLK_F_CONFIG_WCE
also renames it to VIRTIO_BLK_F_WCE, since that's really what it does.
See this old comment in the kernel (not in the latest git anymore):

       /*
        * If the FLUSH feature is supported we do have support for
        * flushing a volatile write cache on the host.  [...]
        * otherwise, we must assume that the host does not
        * perform any kind of volatile write caching.
        */

Paolo