On Fri, 2024-05-03 at 14:17 +1200, Huang, Kai wrote: > > > On 3/05/2024 12:21 pm, Edgecombe, Rick P wrote: > > On Sat, 2024-03-02 at 00:20 +1300, Kai Huang wrote: > > > KVM will need to read a bunch of non-TDMR related metadata to create and > > > run TDX guests. Export the metadata read infrastructure for KVM to use. > > > > > > Specifically, export two helpers: > > > > > > 1) The helper which reads multiple metadata fields to a buffer of a > > > structure based on the "field ID -> structure member" mapping table. > > > > > > 2) The low level helper which just reads a given field ID. > > > > > Could 2 be a static inline in a helper, and then only have one export? > > I assume you were thinking about making 2) call the 1), so we don't need > to export 2). > > This is not feasible due to: > > a). 1) must 'struct tdx_metadata_field_mapping' table as input, and for > that we need to ues the TDX_SYSINFO_MAP() macro to define a structure > for just one 'u64' and define a 'struct tdx_metadata_field_mapping' > table which only has one element for that. > > b). TDX_SYSINFO_MAP() macro actually doesn't support taking a metadata > field "variable", but can only support using the name of the metadata field. > > However we can try to make 1) as a wrapper of 2). But this would > require some change to the patch 4. > > I'll reply separately to patch 4 and you can take a look whether that is > better. Having one export would be nice. Yea, since the multiple field processing version just loops anyway, doing it like you propose seems reasonable.
