-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On Mon, Aug 30, 2021 at 05:39:40PM -0700, Andrew David Wong wrote: > On 8/30/21 2:12 PM, haaber wrote: > > > > > > Kind of answering my own question, but disabling hyperthreading > > > > happened to > > > > be a workaround for the resume from suspend issue. > > > > > > But shouldn't hyperthreading have already been disabled ever since > > > QSB-043? > > > > > > https://www.qubes-os.org/news/2018/09/02/qsb-43/ > > > > > I admit that I missed that one as well. Shame on me. Is there some way > > to detect active hyperthreading on boot && print out a big red warning ? > > > > That seems a reasonable measure, especially for new-comers how cannot > > reasonably be asked to read all old QSB's first :) > > > > I'm confused. I was under the impression that Qubes OS (after the QSB-043 > patches) automatically disables hyper-threading for you such that you don't > have to know anything, do anything, or read any past QSBs. > > As QSB-043 explains, you would have had to follow special instructions to > re-enable hyper-threading in Qubes 3.2, and no such instructions were > provided for re-enabling it in Qubes 4.0 (since, as the QSB explains, it's > never safe in that release), so I don't even know how'd you do it in that > release. > > But perhaps I'm mistaken or misunderstanding the question.
There are (at least) two ways to disable hyper-threading: 1. In system BIOS (if there is such option) 2. In software - by disabling every second thread of each core. The QSB-043 uses the second method. It has is drawbacks, as the logic to bring up and down CPUs is quite complex. And yes, there are known issues[1] affecting suspend. Disabling hyper-threading in BIOS, prevents Xen from starting those secondary threads at all, and so it doesn't need to bring them down. [1] https://github.com/QubesOS/qubes-issues/issues/6066#issuecomment-901843312 - -- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhrpukzGPukRmQqkK24/THMrX1ywFAmEtfVgACgkQ24/THMrX 1yxJVgf8DMIUPdVfDjhTP6Lc/NEwIV+Fmgr0PZCa8zKQRVmKDosKH1zB2f5+fbl0 fJPygQBjx4YWu8J4p8a2kLb9T9QGRJuSFUZ1xtH0/wb5S9nZHsEEJSsFvD1NjOFN I5ynF1U+qaVbalztFSESJgRkTvTfgJLcCBT2GUvDsm6xqHEdK1BtaS0Mxogx00mQ 8xGHAUpUoC37FgLz2dSitgjmg6PzJJNiWQ14bDlKwydHy3ug9Z+fln0K9C3Pqv1s GzPs9LwM3OsNRZcKYwMNB3QGshJYIxFZMPn9s+dI9cy+DRQ6LWpGSgSdq3HLspYY MwMnD/wFxQCbNjp7c83uI7VD0wW50w== =lfCs -----END PGP SIGNATURE----- -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/YS19WGKe0oTDpKhE%40mail-itl.
