On 6/20/22 12:43, Cornelia Huck wrote: > CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe. > > > > On Thu, Jun 16 2022, "Michael S. Tsirkin" wrote: > >> On Tue, Jun 14, 2022 at 01:57:34PM +0200, Halil Pasic wrote: >>> On Mon, 13 Jun 2022 13:40:38 +0300 >>> Laura Loghin wrote: >>> >>>> @@ -57,6 +62,25 @@ \subsection{Device configuration layout}\label{sec:Device Types / Socket Device >>>> \hline >>>> \end{tabular} >>>> >>>> +The following driver-read-only field, \field{data_max_size} only exists if >>>> +VIRTIO_VSOCK_F_SIZE_MAX is set. This field specifies the maximum packet payload >>>> +size for the driver to use. >>>> + >>>> +\devicenormative{\subsubsection}{Device configuration layout}{Device Types / Socket Device / Device configuration layout} >>>> + >>>> +The device MUST NOT change the value exposed through \field{data_max_size}. >>>> + >>>> +\drivernormative{\subsubsection}{Device configuration layout}{Device Types / Socket Device / Device configuration layout} >>>> + >>>> +A driver SHOULD negotiate VIRTIO_VSOCK_F_SIZE_MAX if the device offers it. >>>> + >>>> +If the driver negotiates VIRTIO_VSOCK_F_SIZE_MAX, the receive buffers it >>>> +supplies for a packet MUST have a total size that doesn't exceed the size >>>> +\field{data_max_size} (plus header length). >>>> + >>>> +If the driver negotiates VIRTIO_VSOCK_F_SIZE_MAX, it MUST NOT transmit packets >>>> +of size exceeding the value of \field{data_max_size} (plus header length). >>>> + >>> Hi and sorry for being late to the party! >>> >>> I believe I do understand why do we want to put a restriction on the >>> size of the transmitted packets, but I would appreciate if you could >>> explain to me why do we want to limit the receive buffer size. >>> >>> Also I find the wording regarding a little bit ambiguous because >>> in a networking context it also makes sense to talk about the size of the >>> receive buffer. I guess hear we are talking about a single virtio buffer >>> (a descriptor chain described potentially non-continuous (or compact in >>> the mathematical sense of the word) which is composed from as many >>> continuous chunks of memory as many descriptors are contained within the >>> descriptor chain). If we are indeed talking about a single virtio buffer, >>> I don't understand the plural. If not, I'm not sure what are we talking >>> about. >> I think I agree here, I don't understand the mix of "buffers" and "a >> packet" either. >> >> I voted "no" on the ballot, though if others feel we should apply as >> is and fix up later, that is not too bad. > I now switched to "no" as well; it's not too bad to fix things later, > but it would be good if we had a common understanding before the change > goes in. > Hi! Sorry, I will address your comments this week. Thanks everyone for the feedback! Laura Amazon Development Center (Romania) S.R.L. registered office: 27A Sf. Lazar Street, UBC5, floor 2, Iasi, Iasi County, 700045, Romania. Registered in Romania. Registration number J22/2621/2005.