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Date: Fri, 5 May 2017 19:28:47 +0200
From: Borislav Petkov <bp@suse.de>
To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
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Subject: Re: [v6 PATCH 08/21] x86/insn-eval: Add utility function to get
 segment descriptor base address
Message-ID: <20170505172847.x3i2kca2xdb735ca@pd.tnic>
References: <20170308003254.27833-1-ricardo.neri-calderon@linux.intel.com>
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 <20170420082533.hwc6eon3aom43qzo@pd.tnic>
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On Wed, Apr 26, 2017 at 03:52:41PM -0700, Ricardo Neri wrote:
> Probably insn_get_seg_base() itself can verify if there are segment
> override prefixes in the struct insn. If yes, use them except for
> specific cases such as CS.

... and depending on whether in long mode or not.

> On an unrelated note, I still have the problem of using DS vs ES for
> string instructions. Perhaps instead of a use_default_seg flag, a
> string_instruction flag that indicates how to determine the default
> segment.

... or you can look at the insn opcode directly. AFAICT, you need
to check whether the opcode is 0xa4 or 0xa5 and that the insn is a
single-byte opcode, i.e., not from the secondary map escaped with 0xf or
some of the other multi-byte opcode maps.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--