On Mon, Nov 30 2020 at 16:16, Marcelo Tosatti wrote: >> Besides, Linux guests don't sync the TSC via IA32_TSC write, >> but rather use IA32_TSC_ADJUST which currently doesn't participate >> in the tsc sync heruistics. > > Linux should not try to sync the TSC with IA32_TSC_ADJUST. It expects > the BIOS to boot with synced TSCs. That's wishful thinking. Reality is that BIOS tinkerers fail to get it right. TSC_ADJUST allows us to undo the wreckage they create. Thanks, tglx