linux-kernel - Re: [PATCH v6 00/13] x86/xsaves: Fix XSAVES issues

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Message-ID: <20160512064130.GB29495@gmail.com>
Date:	Thu, 12 May 2016 08:41:30 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Yu-cheng Yu <yu-cheng.yu@...el.com>
Cc:	linux-kernel@...r.kernel.org, x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Andy Lutomirski <luto@...nel.org>,
	Borislav Petkov <bp@...e.de>,
	Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>,
	"Ravi V. Shankar" <ravi.v.shankar@...el.com>,
	Fenghua Yu <fenghua.yu@...el.com>
Subject: Re: [PATCH v6 00/13] x86/xsaves: Fix XSAVES issues


* Yu-cheng Yu <yu-cheng.yu@...el.com> wrote:

> XSAVES is a kernel-mode instruction. It offers a compacted format and
> memory-write optimization. These patches fix issues in the first
> implementation.
> 
> Changes since Version 5:
> 
> Patch 1, 2 - Change names to fpu_user_xstate_size and fpu_kernel_xstate_size;
>              fix some comments, etc.
> 
> Patch 11 - In addition to a warning, make __raw_xsave_addr() return NULL
>            when a disabled xstate component address is requested.
> 
> Patch 12 - Add more details in the comments of why this patch is needed;
>            make a new macro for xcomp_bv[63].
> 
> Yu-cheng Yu (13):
>   x86/xsaves: Define and use fpu_user_xstate_size

So if you look at the git log of arch/x86/kernel/fpu/ then you'll see that the 
standard tag for FPU code is 'x86/fpu: ', for purely xstate related patch it's 
'x86/fpu/xstate: '.

>   x86/xsaves: Rename xstate_size to fpu_kernel_xstate_size to distinguish from fpu_user_xstate_size
>   x86/xsaves: Keep init_fpstate.xsave.header.xfeatures as zero for init optimization
>   x86/xsaves: Introduce a new check that allows correct xstates copy from kernel to user directly
>   x86/xsaves: Align xstate components according to CPUID
>   x86/xsaves: Supervisor state component offset

Please start all commit titles with verbs.

Also, this series is clearly too big. I was under the impression that the series 
was ready, but there's a number of small details that were pointed out (none of 
them very serious) - so how about you send a series of the first 4 patches next 
time around, and only send another 4 once those 4 first patches get applied to 
x86/fpu?

This makes it much easier to review, which reduces reviewer frustration; and it 
also allows you to focus more on incorporating feedback, without having to juggle 
13 patches all the time.

Ok?

Thanks,

	Ingo