Re: [PATCH] vhost-blk: Add vhost-blk support v2

[Rusty Russell <rusty@rustcorp.com.au>]

"Michael S. Tsirkin" <mst@redhat.com> writes:
> On Thu, Oct 18, 2012 at 02:50:56PM +1030, Rusty Russell wrote:
>> Asias He <asias@redhat.com> writes:
>> >>> +#define BLK_HDR	0
>> >> 
>> >> What's this for, exactly? Please add a comment.
>> >
>> > The block headr is in the first and separate buffer.
>> 
>> Please don't assume this!  We're trying to fix all the assumptions in
>> qemu at the moment.
>> 
>> vhost_net handles this correctly, taking bytes off the descriptor chain
>> as required.
>> 
>> Thanks,
>> Rusty.
>
> BTW are we agreed on the spec update that makes cmd 32 bytes?

vhost-blk doesn't handle scsi requests, does it?

But since we're forced to use a feature bit, we could just put the cmd
size in explicitly.  Though Paulo seems convinced that 32 is always
sufficient.  Whoever implements it gets to decide...

Here's my TODO list:
1) Create qemu helpers to efficiently handle iovecs.
2) Switch all the qemu devices to use them.
3) ... except a special hack for virtio-blk in old-layout mode.
4) Implement pci capability layout RFC for qemu.
   - Detect whether guest uses capabilities.
   - Device config in new mode is le.
   - Add strict checking mode for extra compliance checks?
5) Add explicit size-based accessors to virtio_config in kernel.
6) Update pci capability RFC patches for linux to match.
   - Use explicit accessors to allow for endian conversion.
6) Push virtio torture patch to test variable boundaries.
7) Update spec.

That should keep me amused for a while...

Cheers,
Rusty.