Other than in the feature sets, where we indeed want to offer the feature even if not enumerated on hardware, we shouldn't dictate the feature being available if tool stack or host admin have decided not to expose it (for whatever [questionable?] reason).
Signed-off-by: Jan Beulich <jbeul...@suse.com> --- This is effectively accompanying the discussion rooted at the 4.8/4.7 patch at https://lists.xenproject.org/archives/html/xen-devel/2018-05/msg01028.html dealing with a feature leveling issue. --- a/xen/arch/x86/cpuid.c +++ b/xen/arch/x86/cpuid.c @@ -642,14 +642,6 @@ void recalculate_cpuid_policy(struct dom recalculate_xstate(p); recalculate_misc(p); - /* - * Override STIBP to match IBRS. Guests can safely use STIBP - * functionality on non-HT hardware, but can't necesserily protect - * themselves from SP2/Spectre/Branch Target Injection if STIBP is hidden - * on HT-capable hardware. - */ - p->feat.stibp = p->feat.ibrsb; - for ( i = 0; i < ARRAY_SIZE(p->cache.raw); ++i ) { if ( p->cache.subleaf[i].type >= 1 && _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
