From: Dave Hansen <dave.hansen@intel.com>
To: Fenghua Yu <fenghua.yu@intel.com>,
"H. Peter Anvin" <hpa@linux.intel.com>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Asit K Mallick <asit.k.mallick@intel.com>,
Glenn Williamson <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: Tue, 28 Apr 2015 15:09:17 -0700 [thread overview]
Message-ID: <5540050D.2000008@intel.com> (raw)
In-Reply-To: <1429678319-61356-3-git-send-email-fenghua.yu@intel.com>
On 04/21/2015 09:51 PM, Fenghua Yu wrote:
> + /*
> + * Clear xcomp_bv[63] in user's xsave area header to indicate
> + * buf_fx is in standard format.
> + */
> + xcomp_bv = xsave->xsave_hdr.xcomp_bv;
> + user_xsave = buf_fx;
> + xcomp_bv &= ~((u64)1 << 63);
I ran in to another bug. xrestor_user() is hitting a #GP with these values:
[ 6.258743] xrestore_user() tmp: ffff88003f813000
[ 6.261122] XCR0: 000000000000001f
[ 6.261868] xstate_bv: 0000000000000003
[ 6.262613] xcomp_bv: 000000000000001f
I think it is because bit 63 is clear in xcomp_bv, but there are other
bits set in there.
I think the above needs to just do:
/*
* We are uncompacting the state for the user buffer. We need
* to clear out the xcomp_bv field entirely. The uncompacted
* form of xsave/xrstor treats this field as reserved.
*/
if (__put_user(0, &user_xsave->xsave_hdr.xcomp_bv))
return -1;
next prev parent reply other threads:[~2015-04-28 22:09 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
2015-04-28 14:28 ` Dave Hansen
2015-04-28 22:09 ` Dave Hansen [this message]
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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