Re: [PATCH v15 11/23] x86/sgx: Add definitions for SGX's CPUID leaf and variable sub-leafs

From: Andy Shevchenko
Date: Sat Nov 03 2018 - 09:11:54 EST


On Sat, Nov 3, 2018 at 1:16 AM Jarkko Sakkinen
<jarkko.sakkinen@xxxxxxxxxxxxxxx> wrote:
>
> SGX defines its own CPUID leaf, 0x12, along with a variable number of
> sub-leafs. Sub-leafs 0 and 1 are always available if SGX is supported
> and enumerate various SGX features, e.g. instruction sets and enclave
> capabilities. Sub-leafs 2+ are variable, both in their existence and
> in what they enumerate. Bits 3:0 of EAX report the sub-leaf type,
> with the remaining bits in EAX, EBX, ECX and EDX being type-specific.
> Currently, the only known sub-leaf type enumerates an EPC section. An
> EPC section is simply a range of EPC memory available to software.
> The "list" of varaible SGX sub-leafs is NULL-terminated, i.e. software
> is expected to query CPUID until an invalid sub-leaf is encountered.

> + SGX_CPUID_SUB_LEAF_TYPE_MASK = 0xF,

GENMASK() if it suits here?

P.S. Btw, BIT() and GENMASK() macros are now in a separate header,
i.e. linux/bits.h, perhaps you might need to revisit code to include
it explicitly

--
With Best Regards,
Andy Shevchenko