lkml.org 
[lkml]   [2018]   [Sep]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v13 04/13] x86/sgx: Architectural structures
On Mon, Sep 03, 2018 at 04:16:42PM +0300, Andy Shevchenko wrote:
> On Mon, Aug 27, 2018 at 9:57 PM Jarkko Sakkinen
> <jarkko.sakkinen@linux.intel.com> wrote:
> >
> > Add arch/x86/include/asm/sgx_arch.h, which contains definitions for the
> > architectural data structures used by the CPU to implement the SGX.
>
> > +/**
> > + * enum sgx_encls_leaves - ENCLS leaf functions
> > + * %ECREATE: Create an enclave.
> > + * %EADD: Add a page to an enclave.
> > + * %EINIT: Launch an enclave.
> > + * %EREMOVE: Remove a page from an enclave.
> > + * %EDBGRD: Read a word from an enclve (peek).
> > + * %EDBGWR: Write a word to an enclave (poke).
> > + * %EEXTEND: Measure 256 bytes of an added enclave page.
> > + * %ELDB: Load a swapped page in blocked state.
> > + * %ELDU: Load a swapped page in unblocked state.
> > + * %EBLOCK: Change page state to blocked i.e. entering hardware threads
> > + * cannot access it and create new TLB entries.
> > + * %EPA: Create a Version Array (VA) page used to store isvsvn number
> > + * for a swapped EPC page.
> > + * %EWB: Swap an enclave page to the regular memory. Checks that all
> > + * threads have exited that were in the previous shoot-down
> > + * sequence.
> > + * %ETRACK: Start a new shoot down sequence. Used to together with EBLOCK
> > + * to make sure that a page is safe to swap.
> > + */
> > +enum sgx_encls_leaves {
> > + ECREATE = 0x0,
> > + EADD = 0x1,
> > + EINIT = 0x2,
> > + EREMOVE = 0x3,
> > + EDGBRD = 0x4,
> > + EDGBWR = 0x5,
> > + EEXTEND = 0x6,
> > + ELDB = 0x7,
> > + ELDU = 0x8,
> > + EBLOCK = 0x9,
> > + EPA = 0xA,
> > + EWB = 0xB,
> > + ETRACK = 0xC,
> > + EAUG = 0xD,
> > + EMODPR = 0xE,
> > + EMODT = 0xF,
> > +};
>
> Hmm... This E prefix confuses me with (system wide) error codes. Has
> it been discussed before? If so, can you point on the conclusion why
> the current format is good?

That is how they are prefixed in the SDM.

> > +enum sgx_miscselect {
> > + SGX_MISC_EXINFO = 0x01,
> > +};
> > +
> > +#define SGX_MISC_RESERVED_MASK 0xFFFFFFFFFFFFFFFEULL
>
> Any idea why we are not using BIT_ULL() / BIT() and GENMASK_ULL() /
> GENMASK() in the code?

No good reason. I'll change it.

> > +enum sgx_attribute {
> > + SGX_ATTR_DEBUG = 0x02,
> > + SGX_ATTR_MODE64BIT = 0x04,
> > + SGX_ATTR_PROVISIONKEY = 0x10,
> > + SGX_ATTR_EINITTOKENKEY = 0x20,
> > +};
> > +
> > +#define SGX_ATTR_RESERVED_MASK 0xFFFFFFFFFFFFFFC9ULL
>
> Some times listing explicitly not-reserved bits might be better and
> figuring out reserved mask is a simple ~ operation.

Yea, agreed.

> > +enum sgx_tcs_flags {
> > + SGX_TCS_DBGOPTIN = 0x01,
> > +};
> > +
> > +#define SGX_TCS_RESERVED_MASK 0xFFFFFFFFFFFFFFFEULL
>
> > +#define SGX_SECINFO_PERMISSION_MASK 0x0000000000000007ULL
> > +#define SGX_SECINFO_PAGE_TYPE_MASK 0x000000000000FF00ULL
> > +#define SGX_SECINFO_RESERVED_MASK 0xFFFFFFFFFFFF00F8ULL
>
> So, something like
>
> MASK1 GENMASK_ULL
> MASK2 GENMASK_ULL
> MASK3 ~(MASK1 | MASK2)
>
> ?

Definitely. I think it is just a matter of legacy why they are like they
are :-) These constants have gone over long time and they are not
usually places where you have to look for regressions. Thanks for
spotting these.

>
> --
> With Best Regards,
> Andy Shevchenko

/Jarkko

\
 
 \ /
  Last update: 2018-09-03 21:19    [W:0.096 / U:2.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site