linux-kernel - Re: [PATCH 0/2] x86/fpu: Extend kernel_fpu_begin

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Message-ID: <2ea9e144-7d94-4dee-b642-657306a0f9b3@intel.com>
Date: Thu, 2 May 2024 13:52:36 -0700
From: "Chang S. Bae" <chang.seok.bae@...el.com>
To: <linux-kernel@...r.kernel.org>
CC: <x86@...nel.org>, <platform-driver-x86@...r.kernel.org>,
	<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
	<dave.hansen@...ux.intel.com>, <hdegoede@...hat.com>,
	<ilpo.jarvinen@...ux.intel.com>, <tony.luck@...el.com>,
	<ashok.raj@...el.com>, <jithu.joseph@...el.com>
Subject: Re: [PATCH 0/2] x86/fpu: Extend kernel_fpu_begin_mask() for the
 In-Field Scan driver

On 4/30/2024 2:25 PM, Chang S. Bae wrote:
> The recent update [1] in the SDM highlights the requirement of
> initializing the AMX state for executing the scan test:
>      "... maintaining AMX state in a non-initialized state ... will
>       prevent the execution of In-Field Scan tests."
> which is one of CPU state conditions required for the test's execution.

This brief mention may prompt questions about why the hardware must 
refuse to run the test under these conditions. Because this is part of 
its internal, we'd go back to folks who wrote this test and will grab 
their write-up to provide the logic behind this requirement.

Thanks,
Chang