[Differential] D20276: [bhyve][virtio-net] Allow guest VM's to set JUMBO MTU in case of using the VALE switch.

[aleksandr.fedorov_itglobal.com (Aleksandr Fedorov)]

aleksandr.fedorov_itglobal.com added a comment.


  Vincenzo, thanks for the review.
  The main motivation to write the custom method is optimization. Function vq_getchain() returns virtio descriptors which chained using VRING_DESCR_F_NEXT flag. But viritio-net guest drivers do not represent the available descriptors in the form of a chain, so  vq_getchain() returns only one descriptor per call. Also this function has side effect - it's increment vq->vq_last_avail index, which should be decremented if there is no enough descriptors to store the RX packet.

CHANGES SINCE LAST ACTION
  https://reviews.freebsd.org/D20276/new/

REVISION DETAIL
  https://reviews.freebsd.org/D20276

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To: aleksandr.fedorov_itglobal.com, #bhyve, jhb, rgrimes, krion, v.maffione_gmail.com
Cc: mizhka_gmail.com, novel, olevole_olevole.ru, freebsd-virtualization-list, evgueni.gavrilov_itglobal.com, bcran