On 4/7/2025 6:47 PM, Borislav Petkov wrote: > On Wed, Apr 02, 2025 at 04:04:34PM +0530, Neeraj Upadhyay wrote: >> - snp_get_unsupported_features() looks like below. >> It checks that, for the feature bits which are part of SNP_FEATURES_IMPL_REQ, >> if they are enabled in hypervisor (and so reported in sev_status), >> guest need to implement/enable those features. SAVIC also falls in that category >> of SNP features. >> >> So, if CONFIG_AMD_SECURE_AVIC is disabled, guest would run with SAVIC feature >> disabled in guest. This would cause undefined behavior for that guest if SAVIC >> feature is active for that guest in hypervisor. > > Ok, so SNP_FEATURES_IMPL_REQ will contain the SAVIC bit (unconditionally, > without the ifdeffery) and SNP_FEATURES_PRESENT will contain that thing you > had suggested with the ifdeffery to denote whether SAVIC support has been > enabled at build time: > > https://lore.kernel.org/r/e0362a96-4b3a-44b1-8d54-806a6b045799@xxxxxxx > > or not. > > Right? > Yes, that is the intent here. - Neeraj
