From: Rusty Russell <rusty@rustcorp•com.au>
To: Paolo Bonzini <pbonzini@redhat•com>
Cc: kvm@vger•kernel.org, "Michael S. Tsirkin" <mst@redhat•com>,
netdev@vger•kernel.org, linux-kernel@vger•kernel.org,
virtualization@lists•linux-foundation.org,
Sasha Levin <levinsasha928@gmail•com>,
avi@redhat•com, Thomas Lendacky <tahm@linux•vnet.ibm.com>
Subject: Re: [PATCH 0/3] virtio-net: inline header support
Date: Tue, 09 Oct 2012 15:29:09 +1030 [thread overview]
Message-ID: <878vbg8cma.fsf@rustcorp.com.au> (raw)
In-Reply-To: <507029EB.2050405@redhat.com>
Paolo Bonzini <pbonzini@redhat•com> writes:
> Il 05/10/2012 07:43, Rusty Russell ha scritto:
>> That's good. But virtio_blk's scsi command is insoluble AFAICT. As I
>> said to Anthony, the best rules are "always" and "never", so I'd really
>> rather not have to grandfather that in.
>
> It is, but we can add a rule that if the (transport) flag
> VIRTIO_RING_F_ANY_HEADER_SG is set, the cdb field is always 32 bytes in
> virtio-blk.
Could we do that? It's the cmd length I'm concerned about; is it always
32 in practice for some reason?
Currently qemu does:
struct sg_io_hdr hdr;
memset(&hdr, 0, sizeof(struct sg_io_hdr));
hdr.interface_id = 'S';
hdr.cmd_len = req->elem.out_sg[1].iov_len;
hdr.cmdp = req->elem.out_sg[1].iov_base;
hdr.dxfer_len = 0;
If it's a command which expects more output data, there's no way to
guess where the boundary is between that command and the data.
Cheers,
Rusty.
next prev parent reply other threads:[~2012-10-09 4:59 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-28 9:26 [PATCH 0/3] virtio-net: inline header support Michael S. Tsirkin
2012-09-28 9:26 ` [PATCH 1/3] virtio: add API to query ring capacity Michael S. Tsirkin
2012-09-28 9:26 ` [PATCH 2/3] virtio-net: correct capacity math on ring full Michael S. Tsirkin
2012-10-04 0:24 ` Rusty Russell
2012-09-28 9:26 ` [PATCH 3/3] virtio-net: put virtio net header inline with data Michael S. Tsirkin
2012-10-03 6:44 ` [PATCH 0/3] virtio-net: inline header support Rusty Russell
2012-10-03 7:10 ` Rusty Russell
2012-10-04 1:24 ` Anthony Liguori
2012-10-04 3:34 ` Rusty Russell
2012-10-04 4:29 ` Anthony Liguori
2012-10-04 7:44 ` Rusty Russell
2012-10-05 7:47 ` Paolo Bonzini
2012-10-08 21:31 ` Michael S. Tsirkin
2012-10-04 1:35 ` Anthony Liguori
2012-10-04 5:17 ` Rusty Russell
2012-10-08 20:41 ` Michael S. Tsirkin
[not found] ` <87vces2gxq.fsf__45058.6618776017$1349247807$gmane$org@rustcorp.com.au>
2012-10-03 10:53 ` Paolo Bonzini
2012-10-04 0:11 ` Rusty Russell
2012-10-04 7:09 ` Paolo Bonzini
2012-10-04 12:51 ` Rusty Russell
2012-10-04 13:23 ` Paolo Bonzini
2012-10-05 5:43 ` Rusty Russell
[not found] ` <87391t1nkq.fsf__40391.6521034718$1349505001$gmane$org@rustcorp.com.au>
2012-10-06 12:54 ` Paolo Bonzini
2012-10-09 4:59 ` Rusty Russell [this message]
2012-10-09 7:27 ` Paolo Bonzini
2012-10-11 0:03 ` Rusty Russell
2012-10-11 11:04 ` Michael S. Tsirkin
2012-10-11 22:37 ` Rusty Russell
2012-10-12 7:38 ` Paolo Bonzini
2012-10-12 11:52 ` Cornelia Huck
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