From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: fenghua.yu@intel.com, dvlasenk@redhat.com, peterz@infradead.org,
oleg@redhat.com, mingo@kernel.org, linux-kernel@vger.kernel.org,
brgerst@gmail.com, luto@kernel.org, bp@alien8.de,
jpoimboe@redhat.com, haokexin@gmail.com, hpa@zytor.com,
quentin.casasnovas@oracle.com, tglx@linutronix.de,
torvalds@linux-foundation.org, riel@redhat.com,
linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/urgent] x86/fpu: Set the xcomp_bv when we fake up a XSAVES area
Date: Mon, 23 Jan 2017 08:55:30 -0800 [thread overview]
Message-ID: <20170123165529.GA4996@test-lenovo> (raw)
In-Reply-To: <f2fb890d-f8ff-69e2-acc7-b3c810d6cf02@linux.intel.com>
On Mon, Jan 23, 2017 at 07:36:20AM -0800, Dave Hansen wrote:
> The kernel xsave buffer should *ALWAYS* have the
> XCOMP_BV_COMPACTED_FORMAT bit set. It should have been set before the
> copyin and it should be set when it's finished.
>
> The best fix here would be not to paper over the issue in the copy
> function but find where it got clobbered, or where some initialization
> code failed to set it.
Someone else reported different issues from the same bug and a different
patch was just tested OK this morning. I think that adding xfeatures bits
to xcomp_bv should have been done in fpstate_init().
Also, in copy_init_fpstate_to_fpregs(), we do:
copy_kernel_to_xregs(&init_fpstate.xsave, -1).
That (-1) could mean (0) because the parameters are declared as:
copy_kernel_to_xregs(struct xregs_state *, u64)
Yu-cheng
next prev parent reply other threads:[~2017-01-23 16:59 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-22 8:50 [PATCH] x86/fpu: set the xcomp_bv when we fake up a XSAVES area Kevin Hao
2017-01-23 8:28 ` [tip:x86/urgent] x86/fpu: Set " tip-bot for Kevin Hao
2017-01-23 15:36 ` Dave Hansen
2017-01-23 16:55 ` Yu-cheng Yu [this message]
2017-01-23 17:23 ` Dave Hansen
2017-01-23 20:57 ` Yu-cheng Yu
2017-01-23 21:10 ` Dave Hansen
2017-01-23 21:16 ` Yu-cheng Yu
2017-01-23 21:28 ` Dave Hansen
2017-01-24 0:14 ` Kevin Hao
2017-01-24 0:53 ` Dave Hansen
2017-01-24 1:50 ` Kevin Hao
2017-01-24 2:01 ` Dave Hansen
2017-01-24 2:09 ` Kevin Hao
2017-01-24 2:38 ` Dave Hansen
2017-01-24 5:18 ` Kevin Hao
2017-01-24 8:08 ` Ingo Molnar
2017-01-23 9:43 ` tip-bot for Kevin Hao
2017-02-14 16:47 ` Dave Hansen
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