On 12.03.2018 14:06, Borislav Petkov wrote: > On Mon, Mar 12, 2018 at 01:56:59PM +0100, Maciej S. Szmigiero wrote: (..) >> Since the maximum entry count in current microcode files is 18 the > > Where did you dream up that 18?
"microcode_amd.bin" in linux-firmware. >> Also, looking in the past, there probably won't be more than 256 AMD CPU >> types in one CPU family. > > Wrong. There is no problem raising this value in that (future) case. As I wrote previously, currently the maximum used count is 18. > The only limitation on the equivalence table size we have is the 32-bit > unsigned length field at offset 8 in the equivalence table header. Not really, since even in the existing code CONTAINER_HDR_SZ (12) gets added to this size, then the sum is cast to a (signed) int. If this value is negative then the file get rejected. >> This limit is an absolute upper cap of a patch size. > > More dreamt up crap. > > See verify_patch_size() for the actual patch sizes. > It can be changed to the current maximum across sizes for particular families, but then the limit will need to be raised when adding a new family (if it uses a larger patch). Maciej
