On 12.06.2023 20:25, Andrew Cooper wrote: > On 12/06/2023 4:46 pm, Jan Beulich wrote: >> On 05.06.2023 19:08, Alejandro Vallejo wrote: >>> @@ -878,5 +887,17 @@ int __init early_microcode_init(unsigned long >>> *module_map, >>> if ( ucode_mod.mod_end || ucode_blob.size ) >>> rc = early_microcode_update_cpu(); >>> >>> + early_read_cpuid_7d0(); >>> + >>> + /* >>> + * tsx_init() needs MSR_ARCH_CAPS, but it runs before identify_cpu() >>> + * populates boot_cpu_data, so we read it here to centralize early >>> + * CPUID/MSR reads in the same place. >>> + */ >>> + if ( cpu_has_arch_caps ) >>> + rdmsr(MSR_ARCH_CAPABILITIES, >>> + boot_cpu_data.x86_capability[FEATURESET_m10Al], >>> + boot_cpu_data.x86_capability[FEATURESET_m10Ah]); >> ... "centralize" aspect goes away, and hence the comment needs adjusting. > > I find it weird splitting apart the various reads into x86_capability[], > but in light of the feedback, only the rdmsr() needs to stay.
Hmm, wait: When updating a CPU from a pre-arch-caps ucode level on one that supports arch-caps, don't we need to re-read 7d0 here? (I.e. the call to early_read_cpuid_7d0() needs to stay, but for a reason different from the one presently stated in the description, and possibly even worth a brief comment.) Jan
