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Groups > linux.kernel > #1398326
| From | Dave Hansen <dave.hansen@linux.intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v5 02/13] x86/xsaves: Rename xstate_size to kernel_xstate_size to explicitly distinguish xstate size in kernel from user space |
| Date | 2016-05-10 19:10 +0200 |
| Message-ID | <rxjku-6P9-11@gated-at.bofh.it> (permalink) |
| References | <rx0rx-4yi-11@gated-at.bofh.it> <rx0rx-4yi-21@gated-at.bofh.it> <rxjku-6P9-13@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 05/10/2016 10:01 AM, Borislav Petkov wrote:
>> > pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n",
>> > xfeatures_mask,
>> > - xstate_size,
>> > + kernel_xstate_size,
>> > cpu_has_xsaves ? "compacted" : "standard");
> I think we should dump user_xstate_size in the compacted case since it
> is != kernel_xstate_size.
Why? "kernel_xstate_size" is important to the kernel because it impacts
task_struct size.
But the kernel never actually stores "user_xstate_size" anywhere or
really ever even cares about it except when copying in/out of userspace.
"user_xstate_size" is also entirely enumerable in userspace with a
single cpuid instruction.
It's nice to dump out interesting data in dmesg, but I'm curious why you
think it's interesting.
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[PATCH v5 02/13] x86/xsaves: Rename xstate_size to kernel_xstate_size to explicitly distinguish xstate size in kernel from user space Yu-cheng Yu <yu-cheng.yu@intel.com> - 2016-05-09 23:00 +0200
Re: [PATCH v5 02/13] x86/xsaves: Rename xstate_size to kernel_xstate_size to explicitly distinguish xstate size in kernel from user space Dave Hansen <dave.hansen@linux.intel.com> - 2016-05-10 19:10 +0200
Re: [PATCH v5 02/13] x86/xsaves: Rename xstate_size to kernel_xstate_size to explicitly distinguish xstate size in kernel from user space Borislav Petkov <bp@suse.de> - 2016-05-10 19:30 +0200
Re: [PATCH v5 02/13] x86/xsaves: Rename xstate_size to kernel_xstate_size to explicitly distinguish xstate size in kernel from user space Dave Hansen <dave.hansen@linux.intel.com> - 2016-05-10 19:40 +0200
Re: [PATCH v5 02/13] x86/xsaves: Rename xstate_size to kernel_xstate_size to explicitly distinguish xstate size in kernel from user space Borislav Petkov <bp@suse.de> - 2016-05-10 19:10 +0200
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