From: "Liu, Jing2" <jing2.liu@linux.intel.com>
To: "Bae, Chang Seok" <chang.seok.bae@intel.com>
Cc: Len Brown <lenb@kernel.org>, Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@suse.de>, Ingo Molnar <mingo@kernel.org>,
X86 ML <x86@kernel.org>, "Brown, Len" <len.brown@intel.com>,
"Hansen, Dave" <dave.hansen@intel.com>,
"Liu, Jing2" <jing2.liu@intel.com>,
"Shankar, Ravi V" <ravi.v.shankar@intel.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 14/22] x86/fpu/xstate: Expand the xstate buffer on the first use of dynamic user state
Date: Thu, 25 Mar 2021 15:26:08 +0800 [thread overview]
Message-ID: <84047b4a-48e3-6efc-643a-06cfcc0630cc@linux.intel.com> (raw)
In-Reply-To: <A2F31E33-4F15-431B-8407-438750186895@intel.com>
>>> For AMX, we must still reserve the space, but we are not going to write zeros
>>> for clean state. We so this in software by checking XINUSE=0, and clearing
>>> the xstate_bf for the XSAVE. As a result, for XINUSE=0, we can skip
>>> writing the zeros, even though we can't compress the space.
>> So my understanding is that clearing xstate_bv will not help prevent saving
>> zeros, but only not masking EDX:EAX, since the following logic. Not sure if
>> this is just what you mean. :)
> FWIW, PATCH21 [1] uses the instruction mask to skip writing zeros on sigframe.
> Then, XSAVE will clear the xstate_bv for the xtile data state bit.
>
> [1] https://lore.kernel.org/lkml/20210221185637.19281-22-chang.seok.bae@intel.com/
Yes, no mask in EDX:EAX works in such case. Thanks for pointing out the
patch.
BRs,
Jing
>
> Thanks,
> Chang
next prev parent reply other threads:[~2021-03-25 7:27 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-21 18:56 [PATCH v4 00/22] x86: Support Intel Advanced Matrix Extensions Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 01/22] x86/fpu/xstate: Modify the initialization helper to handle both static and dynamic buffers Chang S. Bae
2021-03-10 13:40 ` Borislav Petkov
2021-02-21 18:56 ` [PATCH v4 02/22] x86/fpu/xstate: Modify state copy helpers " Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 03/22] x86/fpu/xstate: Modify address finders " Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 04/22] x86/fpu/xstate: Modify the context restore helper " Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 05/22] x86/fpu/xstate: Add a new variable to indicate dynamic user states Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 06/22] x86/fpu/xstate: Add new variables to indicate dynamic xstate buffer size Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 07/22] x86/fpu/xstate: Calculate and remember dynamic xstate buffer sizes Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 08/22] x86/fpu/xstate: Convert the struct fpu 'state' field to a pointer Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 09/22] x86/fpu/xstate: Introduce helpers to manage the xstate buffer dynamically Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 10/22] x86/fpu/xstate: Define the scope of the initial xstate data Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 11/22] x86/fpu/xstate: Update the xstate save function to support dynamic states Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 12/22] x86/fpu/xstate: Update the xstate buffer address finder " Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 13/22] x86/fpu/xstate: Update the xstate context copy function " Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 14/22] x86/fpu/xstate: Expand the xstate buffer on the first use of dynamic user state Chang S. Bae
2021-03-20 22:13 ` Thomas Gleixner
2021-03-20 22:21 ` Andy Lutomirski
2021-03-23 21:01 ` Len Brown
2021-03-24 3:14 ` Liu, Jing2
2021-03-24 21:09 ` Len Brown
2021-03-24 21:26 ` Andy Lutomirski
2021-03-24 21:30 ` Dave Hansen
2021-03-24 21:42 ` Andy Lutomirski
2021-03-24 21:58 ` Dave Hansen
2021-03-24 22:12 ` Andy Lutomirski
2021-03-25 5:12 ` Liu, Jing2
2021-03-25 6:59 ` Bae, Chang Seok
2021-03-25 7:26 ` Liu, Jing2 [this message]
2021-03-23 21:52 ` Bae, Chang Seok
2021-03-24 14:24 ` Dave Hansen
2021-03-29 13:14 ` Len Brown
2021-03-29 13:33 ` Thomas Gleixner
2021-03-29 15:43 ` Len Brown
2021-03-29 16:06 ` Len Brown
2021-03-29 17:43 ` Andy Lutomirski
2021-03-29 18:57 ` Len Brown
2021-03-29 18:49 ` Thomas Gleixner
2021-03-29 22:16 ` Len Brown
2021-03-30 8:28 ` Thomas Gleixner
2021-03-30 16:38 ` Len Brown
2021-03-26 16:34 ` Jann Horn
2021-03-29 18:14 ` Bae, Chang Seok
2021-02-21 18:56 ` [PATCH v4 15/22] x86/fpu/xstate: Support ptracer-induced xstate buffer expansion Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 16/22] x86/fpu/xstate: Extend the table to map state components with features Chang S. Bae
2021-03-20 21:25 ` Thomas Gleixner
2021-03-23 21:52 ` Bae, Chang Seok
2021-02-21 18:56 ` [PATCH v4 17/22] x86/cpufeatures/amx: Enumerate Advanced Matrix Extension (AMX) feature bits Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 18/22] x86/fpu/amx: Define AMX state components and have it used for boot-time checks Chang S. Bae
2021-03-20 21:31 ` Thomas Gleixner
2021-03-23 21:52 ` Bae, Chang Seok
2021-02-21 18:56 ` [PATCH v4 19/22] x86/fpu/amx: Enable the AMX feature in 64-bit mode Chang S. Bae
2021-03-20 21:26 ` Thomas Gleixner
2021-03-23 21:51 ` Bae, Chang Seok
2021-02-21 18:56 ` [PATCH v4 20/22] selftest/x86/amx: Include test cases for the AMX state management Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 21/22] x86/fpu/xstate: Support dynamic user state in the signal handling path Chang S. Bae
2021-02-21 18:56 ` [PATCH v4 22/22] x86/fpu/xstate: Introduce boot-parameters to control state component support Chang S. Bae
2021-02-21 19:30 ` Randy Dunlap
2021-02-21 20:10 ` Bae, Chang Seok
2021-02-21 20:37 ` Randy Dunlap
2021-03-20 20:56 ` Thomas Gleixner
2021-03-25 22:59 ` Len Brown
2021-03-25 23:10 ` Dave Hansen
2021-03-26 15:27 ` Len Brown
2021-03-26 19:22 ` Thomas Gleixner
2021-03-26 1:41 ` Andy Lutomirski
2021-03-26 15:33 ` Len Brown
2021-03-26 15:48 ` Andy Lutomirski
2021-03-26 17:53 ` Len Brown
2021-03-26 18:12 ` Andy Lutomirski
2021-03-27 4:53 ` Len Brown
2021-03-27 22:20 ` Thomas Gleixner
2021-03-29 13:31 ` Len Brown
2021-03-29 14:10 ` Thomas Gleixner
2021-03-26 18:17 ` Borislav Petkov
2021-03-27 4:41 ` Len Brown
2021-03-26 1:50 ` Thomas Gleixner
2021-03-26 15:36 ` Len Brown
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