On Tue, Jul 27, 2021 at 05:26:04PM -0500, Tom Lendacky via iommu wrote: > In prep for other protected virtualization technologies, introduce a > generic helper function, prot_guest_has(), that can be used to check > for specific protection attributes, like memory encryption. This is > intended to eliminate having to add multiple technology-specific checks > to the code (e.g. if (sev_active() || tdx_active())). So common checks obviously make sense, but I really hate the stupid multiplexer. Having one well-documented helper per feature is much easier to follow. > +#define PATTR_MEM_ENCRYPT 0 /* Encrypted memory */ > +#define PATTR_HOST_MEM_ENCRYPT 1 /* Host encrypted memory */ > +#define PATTR_GUEST_MEM_ENCRYPT 2 /* Guest encrypted memory */ > +#define PATTR_GUEST_PROT_STATE 3 /* Guest encrypted state */ The kerneldoc comments on these individual helpers will give you plenty of space to properly document what they indicate and what a (potential) caller should do based on them. Something the above comments completely fail to.