On Mon, Feb 1, 2021 at 4:11 PM Ben Widawsky <[email protected]> wrote: > > On 21-02-01 15:58:09, David Rientjes wrote: > > On Mon, 1 Feb 2021, Ben Widawsky wrote: > > > > > > I haven't seen the update to 8.2.8.4.5 to know yet :) > > > > > > > > You make a good point of at least being able to interact with the > > > > driver. > > > > I think you could argue that if the driver binds, then the payload size > > > > is > > > > accepted, in which case it would be strange to get an EINVAL when using > > > > the ioctl with anything >1MB. > > > > > > > > Concern was that if we mask off the reserved bits from the command > > > > register that we could be masking part of the payload size that is being > > > > passed if the accepted max is >1MB. Idea was to avoid any possibility > > > > of > > > > this inconsistency. If this is being checked for ioctl, seems like it's > > > > checking reserved bits. > > > > > > > > But maybe I should just wait for the spec update. > > > > > > Well, I wouldn't hold your breath (it would be an errata in this case > > > anyway). > > > My preference would be to just allow allow mailbox payload size to be > > > 2^31 and > > > not deal with this. > > > > > > My question was how strongly do you feel it's an error that should prevent > > > binding. > > > > > > > I don't have an objection to binding, but doesn't this require that the > > check in cxl_validate_cmd_from_user() guarantees send_cmd->size_in cannot > > be greater than 1MB? > > You're correct. I'd need to add: > cxlm->mbox.payload_size = > min_t(size_t, 1 << CXL_GET_FIELD(cap, CXLDEV_MB_CAP_PAYLOAD_SIZE), 1<<20)
nit, use the existing SZ_1M define.
