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From: Dave Hansen <dave.hansen@intel.com>
To: "Yu, Fenghua" <fenghua.yu@intel.com>,
	"H. Peter Anvin" <hpa@linux.intel.com>,
	Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
	"Mallick, Asit K" <asit.k.mallick@intel.com>,
	"Williamson, Glenn P" <glenn.p.williamson@intel.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH Bugfix v2 2/4] x86/xsaves: Define and use user_xstate_size for xstate size in signal context
Date: Thu, 23 Apr 2015 14:32:01 -0700	[thread overview]
Message-ID: <553964D1.300@intel.com> (raw)
In-Reply-To: <3E5A0FA7E9CA944F9D5414FEC6C712205C8D0B81@ORSMSX106.amr.corp.intel.com>

On 04/23/2015 10:09 AM, Yu, Fenghua wrote:
>> > If those untouched fields of the xsave buffer are in the "init state", then
>> > we've got no problem.  But, are those "untouched since (1)" fields in the
>> > kernel xsave buf *GUARANTEED* to be in the init state?
> In fact, those untouched fields in kernel xsave buf "IS GUARANTEED" to be in
> the init state.
> 
> Please check __sanitize_i387_state() called just before copy_to_user_xstate().
> That functions GUARANTEES the untouched fields in kernel xsave buf to be in
> init state.

OK, that makes sense.  Other than the horribly-named
sanitize_i387_state(). :)

  reply	other threads:[~2015-04-23 21:32 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-22  4:51 [PATCH Bugfix v2 0/4] x86/xsave/xsaves: Fix a few xsave/xsaves related bugs Fenghua Yu
2015-04-22  4:51 ` [PATCH Bugfix v2 1/4] x86/xsave.c: Fix xstate offsets and sizes enumeration Fenghua Yu
2015-04-22  4:51 ` [PATCH Bugfix v2 2/4] x86/xsaves: Define and use user_xstate_size for xstate size in signal context Fenghua Yu
2015-04-22 18:45   ` Dave Hansen
2015-04-22 19:05     ` Yu, Fenghua
2015-04-22 19:34       ` Dave Hansen
2015-04-23  0:06         ` Yu, Fenghua
2015-04-23  0:21           ` Dave Hansen
2015-04-23  0:23             ` Yu, Fenghua
2015-04-23  0:34           ` Dave Hansen
2015-04-23 17:09             ` Yu, Fenghua
2015-04-23 21:32               ` Dave Hansen [this message]
2015-04-28 14:28   ` Dave Hansen
2015-04-28 22:09   ` Dave Hansen
2015-04-28 22:11     ` Yu, Fenghua
2015-04-29 13:53   ` Dave Hansen
2015-04-22  4:51 ` [PATCH Bugfix v2 3/4] x86/xsaves: Rename xstate_size to kernel_xstate_size to explicitly distinguish xstate size in kernel from user space Fenghua Yu
2015-04-22  4:51 ` [PATCH Bugfix v2 4/4] x86/xsave: Don't add new states in xsave_struct Fenghua Yu

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