Re: [virtio-comment] Re: Chained VIRTQ_DESC_F_INDIRECT (again!)

[Rusty Russell <rusty@au1.ibm.com>]

"Michael S. Tsirkin" <mst@redhat.com> writes:
> On Fri, Feb 13, 2015 at 01:13:44PM +1030, Rusty Russell wrote:
>> "Michael S. Tsirkin" <mst@redhat.com> writes:
>> > On Thu, Feb 12, 2015 at 12:14:52PM +1030, Rusty Russell wrote:
>> >> Hi all,
>> >> 
>> >>         I was reading through the spec, and realized that it doesn't
>> >> explicitly ban chaining of indirect descriptors.  After virtio-15, it
>> >> says:
>> >> 
>> >>    An indirect descriptor without next field
>> >>    (with flags&VRING_DESC_F_NEXT off) signals the end of the descriptor.
>> >> 
>> >> This *implies* that there can't be a "next" after an indirect, but
>> >> doesn't explicitly say that a driver shouldn't do that.  That was the
>> >> intent, so I suggest adding to 2.4.5.3.1 Driver Requirements: Indirect
>> >> Descriptors:
>> >> 
>> >>         The driver MUST NOT set the VIRTQ_DESC_F_NEXT flag on a
>> >>         descriptor with the VIRTQ_DESC_F_INDIRECT flag set.
>> >
>> > I agree, explicit is good.
>> > Will you open an issue for that?
>> 
>> Yep, I'll post a patch and then open an issue linking to it.
>
> OK, there are issues, great, but pls note they aren't open yet.
> When you feel there was sufficient time for review on
> the mailing list, please set "Fix Versions" and open them,
> so we can start ballots.
>
> Also, was this reported by yourself?
> Please remember to set environment to list name and
> email of the reporter.

Yes, these are all me.  I went through the spec again to annotate
all the requirements in the lguest source code.

Cheers,
Rusty.