On 08.03.2023 16:23, Elliott Mitchell wrote: > Mostly SSIA. As originally identified by "Neowutran", appears Xen's > x2apic wrapper implementation fails with current generation AMD hardware > (Ryzen 7xxx/Zen 4). This can be worked around by passing "x2apic=false" > on Xen's command-line, though I'm wondering about the performance impact. > > There hasn't been much activity on xen-devel WRT x2apic, so a patch which > fixed this may have flown under the radar. Most testing has also been > somewhat removed from HEAD. > > Thanks to "Neowutran" for falling on this grenade and making it easier > for the followers. Pointer to first report: > https://forum.qubes-os.org/t/ryzen-7000-serie/14538
I'm sorry, but when you point at this long a report, would you please be a little more specific as to where the problem in question is actually mentioned? Searching the page for "x2apic" didn't give any hits at all until I first scrolled to the bottom of the (at present) 95 comments. And then while there are five mentions, there's nothing I could spot that would actually help understanding what is actually wrong. A statement like "... is because the implementation of x2apic is incorrect" isn't helpful on its own. And a later statement by another person puts under question whether "x2apic=false" actually helps in all cases. Please can we get a proper bug report here with suitable technical detail? Or alternatively a patch to discuss? Jan
