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From: Dave Hansen <dave.hansen@intel.com>
To: Tony W Wang-oc <TonyWWang-oc@zhaoxin.com>,
	herbert@gondor.apana.org.au, davem@davemloft.net,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	x86@kernel.org, hpa@zytor.com, tony.luck@intel.com,
	seanjc@google.com, fenghua.yu@intel.com, thomas.lendacky@amd.com,
	kyung.min.park@intel.com, kim.phillips@amd.com,
	mgross@linux.intel.com, peterz@infradead.org,
	krish.sadhukhan@oracle.com, liam.merwick@oracle.com,
	mlevitsk@redhat.com, reinette.chatre@intel.com,
	babu.moger@amd.com, linux-crypto@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: TimGuo-oc@zhaoxin.com, CooperYan@zhaoxin.com,
	QiyuanWang@zhaoxin.com, HerryYang@zhaoxin.com,
	CobeChen@zhaoxin.com, SilviaZhao@zhaoxin.com
Subject: Re: [PATCH v1 2/3] x86/cpu: Set low performance CRC32C flag on some Zhaoxin CPUs
Date: Thu, 7 Jan 2021 07:52:49 -0800	[thread overview]
Message-ID: <607494aa-674a-fe93-50f6-2c45f385f7e9@intel.com> (raw)
In-Reply-To: <1610000348-17316-3-git-send-email-TonyWWang-oc@zhaoxin.com>

On 1/6/21 10:19 PM, Tony W Wang-oc wrote:
> +	/*
> +	 * These CPUs declare support SSE4.2 instruction sets but
> +	 * having low performance CRC32C instruction implementation.
> +	 */
> +	if (c->x86 == 0x6 || (c->x86 == 0x7 && c->x86_model <= 0x3b))
> +		set_cpu_cap(c, X86_FEATURE_CRC32C);
>  }

On the Intel side, we've tried to move away from open-coded model
numbers.  Say another CPU is released that has a microarchitecture close
to 0x3b, but has a model of 0x3c.  It's a *LOT* easier to grep for
INTEL_FAM6_NEHALEM (or whatever) than 0x3c.  See:

	arch/x86/include/asm/intel-family.h

for examples.

  reply	other threads:[~2021-01-07 15:53 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-07  6:19 [PATCH v1 0/3] crypto: x86/crc32c-intel - Exclude some Zhaoxin CPUs Tony W Wang-oc
2021-01-07  6:19 ` [PATCH v1 1/3] x86/cpufeatures: Add low performance CRC32C instruction CPU feature Tony W Wang-oc
2021-01-07  6:37   ` Borislav Petkov
2021-01-11 10:51     ` Tony W Wang-oc
2021-01-11 11:03       ` Borislav Petkov
2021-01-15  1:43         ` Tony W Wang-oc
2021-01-11 15:20     ` hpa
2021-01-07  6:19 ` [PATCH v1 2/3] x86/cpu: Set low performance CRC32C flag on some Zhaoxin CPUs Tony W Wang-oc
2021-01-07 15:52   ` Dave Hansen [this message]
2021-01-11 10:54     ` Tony W Wang-oc
2021-01-07  6:19 ` [PATCH v1 3/3] crypto: x86/crc32c-intel Exclude low performance CRC32C instruction CPUs Tony W Wang-oc

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