Re: [PATCH] kvm tools: virtio-net mergable rx buffers

[Sasha Levin <sasha.levin@oracle.com>]

On 04/23/2013 12:35 PM, Eric Northup wrote:
> Do you care about guests with drivers that don't negotiate
> VIRTIO_NET_F_MRG_RXBUF?

We usually try to keep backward compatibility, but in this case
mergable RX buffers are about 5 years old now, so it's safe to
assume they'll be running in any guest.

Unless there is a specific reason to allow working without them
I'd rather keep the code simple in this case.

> On Mon, Apr 22, 2013 at 5:32 PM, Sasha Levin <sasha.levin@oracle.com> wrote:
>> +                               copied = memcpy_toiovecend(iov, in, buffer, len);
>> +                               len -= copied;
>> +                               hdr->num_buffers++;
>> +                               virt_queue__set_used_elem(vq, head, copied);
>> +                               if (len == 0)
>> +                                       break;
>> +                               head = virt_queue__get_iov(vq, iov, &out, &in, kvm);
> 
> Need to check that virt_queue__available(vq) first?

Yup. I wonder why it didn't blow up running 'ping -f' with a huge packet size.


Thanks,
Sasha