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From: Heiko Carstens <hca@linux.ibm.com>
To: Hendrik Brueckner <brueckner@linux.ibm.com>
Cc: Steffen Eiden <seiden@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, nrb@linux.ibm.com
Subject: Re: [PATCH v2 1/3] s390/cpufeature: rework to allow more than only hwcap bits
Date: Fri, 15 Jul 2022 11:32:06 +0200	[thread overview]
Message-ID: <YtE0FmnL9iDMMA9n@osiris> (raw)
In-Reply-To: <YtEedTrWv3Wc+cZQ@linux.ibm.com>

On Fri, Jul 15, 2022 at 09:59:49AM +0200, Hendrik Brueckner wrote:
> Regarding facility bits for cpu features:  Initially, I used
> MSA hwcap to cover all ciphers among all hw generations. With facility bit
> checks, it makes more sense to fine-tune and load based on respective
> MSA level or CPACF functions that is required for ciphers/hashes.
...
> > -module_cpu_feature_match(MSA, init);
> > +module_cpu_feature_match(S390_CPU_FEATURE_MSA, init);
> >  module_exit(fini);
> 
> which becomes automatically loaded if (any) MSA is available and then
> performs this check:
> 
> 	cpacf_query_func(CPACF_KIMD, CPACF_KIMD_SHA_512
> 
> which in the worst case would fail.
> 
> This might be a very useful follow-up patch to remove those mod init checks
> into the cpu feature.

Yes, that makes a lot of sense. Thanks for suggesting this!


  reply	other threads:[~2022-07-15  9:32 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-13 12:56 [PATCH v2 0/3] s390/cpufeature: rework to allow different types of cpufeatures Steffen Eiden
2022-07-13 12:56 ` [PATCH v2 1/3] s390/cpufeature: rework to allow more than only hwcap bits Steffen Eiden
2022-07-13 13:50   ` Claudio Imbrenda
2022-07-15  7:59   ` Hendrik Brueckner
2022-07-15  9:32     ` Heiko Carstens [this message]
2022-07-13 12:56 ` [PATCH v2 2/3] s390/cpufeature: allow for facility bits Steffen Eiden
2022-07-13 12:56 ` [PATCH v2 3/3] s390/uvdevice: autoload module based on CPU facility Steffen Eiden
2022-07-14 10:53 ` [PATCH v2 0/3] s390/cpufeature: rework to allow different types of cpufeatures Heiko Carstens
2022-07-15  7:49 ` Hendrik Brueckner

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