Hello Jeremi,
Hi Ashish, I just noticed that the kernel shouts at me about this bit when I offline->online a CPU in an SNP host:
Yes, i also observe the same warning when i bring a CPU back online.
[2692586.589194] smpboot: CPU 63 is now offline [2692589.366822] [Firmware Warn]: MTRR: CPU 0: SYSCFG[MtrrFixDramModEn] not cleared by BIOS, clearing this bit [2692589.376582] smpboot: Booting Node 0 Processor 63 APIC 0x3f [2692589.378070] [Firmware Warn]: MTRR: CPU 63: SYSCFG[MtrrFixDramModEn] not cleared by BIOS, clearing this bit [2692589.388845] microcode: CPU63: new patch_level=0x0a0011d1 Now I understand if you say "CPU offlining is not supported" but there's nothing currently blocking it.
There is CPU hotplug support for SNP platform to do __snp_enable() when bringing a CPU back online, but not really sure what needs to be done for MtrrFixDramModeEn bit in SYSCFG, discussing with the FW developers.
Thanks, Ashish
