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Andrew Cooper
fb5b6f6744
RFDS affects Atom cores, also branded E-cores, between the Goldmont and Gracemont microarchitectures. This includes Alder Lake and Raptor Lake hybrid clien systems which have a mix of Gracemont and other types of cores. Two new bits have been defined; RFDS_CLEAR to indicate VERW has more side effets, and RFDS_NO to incidate that the system is unaffected. Plenty of unaffected CPUs won't be getting RFDS_NO retrofitted in microcode, so we synthesise it. Alder Lake and Raptor Lake Xeon-E's are unaffected due to their platform configuration, and we must use the Hybrid CPUID bit to distinguish them from their non-Xeon counterparts. Like MD_CLEAR and FB_CLEAR, RFDS_CLEAR needs OR-ing across a resource pool, so set it in the max policies and reflect the host setting in default. This is part of XSA-452 / CVE-2023-28746. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>