From: Dave Hansen <dave.hansen@intel.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, jannh@google.com,
riel@surriel.com, mingo@redhat.com, bp@suse.de, Jason@zx2c4.com,
luto@kernel.org, tglx@linutronix.de, rkrcmar@redhat.com,
mingo@kernel.org, hpa@zytor.com, kvm@vger.kernel.org,
pbonzini@redhat.com, kurt.kanzenbach@linutronix.de
Subject: Re: [RFC PATCH] x86/fpu: Don't unconditionally add XFEATURE_MASK_FPSSE on sigentry
Date: Fri, 26 Apr 2019 09:33:28 -0700 [thread overview]
Message-ID: <89ed2d26-a73c-99ad-76d8-e4b46755c783@intel.com> (raw)
In-Reply-To: <20190426072659.swew4mvfz7dfjyqq@linutronix.de>
On 4/26/19 12:26 AM, Sebastian Andrzej Siewior wrote:
>> That's just a guess, though.
>>
>> If we care, I think we should just use XSAVE instead of XSAVEOPT and
>> trying to reconstruct the init state in software.
> We can't use XSAVE directly in the slowpath. We need to reconstruct the
> init state. We have the mxcsr quirk. We would need just to extend it and
> set the FP area to init state if the FP state is missing like we do in
> fpstate_sanitize_xstate().
Can you remind me why we can't use XSAVE directly in the slow path?
next prev parent reply other threads:[~2019-04-26 16:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-25 17:35 [RFC PATCH] x86/fpu: Don't unconditionally add XFEATURE_MASK_FPSSE on sigentry Sebastian Andrzej Siewior
2019-04-25 21:13 ` Dave Hansen
2019-04-26 7:26 ` Sebastian Andrzej Siewior
2019-04-26 16:33 ` Dave Hansen [this message]
2019-04-26 16:50 ` Sebastian Andrzej Siewior
2019-04-26 19:04 ` Dave Hansen
2019-04-26 20:05 ` Sebastian Andrzej Siewior
2019-04-26 20:44 ` Dave Hansen
2019-04-29 16:39 ` [PATCH] x86/fpu: Fault-in user stack if copy_fpstate_to_sigframe() fails Sebastian Andrzej Siewior
2019-04-29 18:52 ` [tip:x86/fpu] " tip-bot for Sebastian Andrzej Siewior
2019-04-30 14:20 ` Dave Hansen
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