On Sun, Feb 18, 2024, Yang Weijiang wrote: > Define a new XFEATURE_MASK_KERNEL_DYNAMIC mask to specify the features I still don't understand why this is being called DYNAMIC. CET_SS isn't dynamic, as KVM is _always_ allowed to save/restore CET_SS, i.e. whether or not KVM can expose CET_SS to a guest is a static, boot-time decision. Whether or not a guest XSS actually enables CET_SS is "dynamic", but that's true of literally every xfeature in XCR0 and XSS. XFEATURE_MASK_XTILE_DATA is labeled as dynamic because userspace has to explicitly request that XTILE_DATA be enabled, and thus whether or not KVM is allowed to expose XTILE_DATA to the guest is a dynamic, runtime decision. So IMO, the umbrella macro should be XFEATURE_MASK_KERNEL_GUEST_ONLY.
