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Groups > linux.kernel > #1397521
| From | Dave Hansen <dave.hansen@linux.intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v5 12/13] x86/xsaves: Fix fpstate_init() for XSAVES |
| Date | 2016-05-10 01:50 +0200 |
| Message-ID | <rx362-7sX-29@gated-at.bofh.it> (permalink) |
| References | <rx0rx-4yi-11@gated-at.bofh.it> <rx0ry-4yi-45@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 05/09/2016 01:46 PM, Yu-cheng Yu wrote: > When XSAVES is used, xsave.header.xcomp_bv[63] must be set. So, that's not strictly correct. XSAVES can write to a completely empty (0'd) memory buffer. It's only XRSTORS that _needs_ bit 63 set. The instruction reference is pretty clear on this point. Oh, and if you decided to do this for some reason, please have mercy and go make a macro for 1<<63. Also, I don't think the kernel ever checks for this bit. So are we really calling XRSTORS on otherwise uninitialized xsave buffers?
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[PATCH v5 12/13] x86/xsaves: Fix fpstate_init() for XSAVES Yu-cheng Yu <yu-cheng.yu@intel.com> - 2016-05-09 23:00 +0200
Re: [PATCH v5 12/13] x86/xsaves: Fix fpstate_init() for XSAVES Dave Hansen <dave.hansen@linux.intel.com> - 2016-05-10 01:50 +0200
Re: [PATCH v5 12/13] x86/xsaves: Fix fpstate_init() for XSAVES Yu-cheng Yu <yu-cheng.yu@intel.com> - 2016-05-10 02:00 +0200
Re: [PATCH v5 12/13] x86/xsaves: Fix fpstate_init() for XSAVES Dave Hansen <dave.hansen@linux.intel.com> - 2016-05-10 02:10 +0200
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