Hi Mattias, If I recall the issue is transmit. The problem is there is only one register on the part for recording Tx timestamps when packets exit the PHY. As such you can receive Rx timestamps, but to perform timesync you normally need to be able to determine when the packet left the wire and that is difficult for a VF to do unless you support recording the Tx timestamp per VF which would require additional resources in hardware as well as a means of identifying which VF any given packet was transmitted from.
- Alex On Tue, Aug 22, 2017 at 10:15 AM, Mattias Barthel <mbart...@accedian.com> wrote: > Hi Alexander, thanks for your reply. > > When using the igb and PF the NIC clock really isnt modified but only > synched virtually against guest time through timecompare. > I cannot understand why it wouldnt work to have the PF clock untouched and > synch virtually to various guests. > > Regards, > Mattias > > On Tue, Aug 22, 2017 at 6:58 PM, Alexander Duyck <alexander.du...@gmail.com> > wrote: >> >> On Tue, Aug 22, 2017 at 5:16 AM, Mattias Barthel <mbart...@accedian.com> >> wrote: >> > Hello, >> > >> > >> > I am trying to add hw timestamping to the igbvf driver in a KVM guest. >> > >> > But some of the registers I need to access are offset further away than >> > the >> > BAR0 size (16k). >> > >> > pci 0000:00:0d.0: reg 10: [mem 0xfebd4000-0xfebd7fff] >> > >> > ls -l /sys/bus/pci/devices/0000\:00\:0d.0/resource0 >> > -rw------- 1 root root 16384 Aug 22 12:00 >> > /sys/bus/pci/devices/0000:00:0d.0/resource0 >> > >> > >> > I need for instance to access register: >> > #define E1000_TSAUXC 0x0B640 /* Timesync Auxiliary Control register >> > */ >> > >> > But this is of course not mapped. >> > >> > I get the feeling this is not meant to be working but I would like some >> > confirmation, please. >> > >> > Any help is highly appreciated. >> > >> > >> > Regards, >> > Mattias >> >> Timestamping for the VF isn't meant to be supported. >> >> The main issue is that you cannot have the clock for the PF getting >> synced to multiple guests since there is only one clock in the part. >> If you need timestamping in the guest you would need to use the igb >> driver on the PF. >> >> - Alex > > > > Avis de confidentialité > > Les informations contenues dans le présent message et dans toute pièce qui > lui est jointe sont confidentielles et peuvent être protégées par le secret > professionnel. Ces informations sont à l’usage exclusif de son ou de ses > destinataires. Si vous recevez ce message par erreur, veuillez s’il vous > plait communiquer immédiatement avec l’expéditeur et en détruire tout > exemplaire. De plus, il vous est strictement interdit de le divulguer, de le > distribuer ou de le reproduire sans l’autorisation de l’expéditeur. Merci. > > Confidentiality notice > > This e-mail message and any attachment hereto contain confidential > information which may be privileged and which is intended for the exclusive > use of its addressee(s). If you receive this message in error, please inform > sender immediately and destroy any copy thereof. Furthermore, any > disclosure, distribution or copying of this message and/or any attachment > hereto without the consent of the sender is strictly prohibited. Thank you. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
