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From: Prarit Bhargava <prarit@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>, Andi Kleen <ak@linux.intel.com>,
	x86@kernel.org, linux-doc@vger.kernel.org
Subject: Re: [PATCH] x86/fpu: Parse comma separated list passed in clearcpuid
Date: Wed, 27 Feb 2019 18:48:11 -0500	[thread overview]
Message-ID: <388fecd4-9b99-f405-fed4-1f6c3b53bc8b@redhat.com> (raw)
In-Reply-To: <20190221134847.GQ32494@hirez.programming.kicks-ass.net>



On 2/21/19 8:48 AM, Peter Zijlstra wrote:
> On Thu, Feb 21, 2019 at 08:12:25AM -0500, Prarit Bhargava wrote:
>> Users cannot disable multiple CPU features with the kernel parameter
>> clearcpuid=.  For example, "clearcpuid=154 clearcpuid=227" only disables
>> CPUID bit 154.
>>
>> Previous to commit 0c2a3913d6f5 ("x86/fpu: Parse clearcpuid= as early XSAVE
>> argument") it was possible to pass multiple clearcpuid options as kernel
>> parameters using individual entries.  With the new code it isn't easy to
>> replicate exactly that behaviour but a comma separated list can be easily
>> implemented, eg) "clearcpuid=154,227"
>>
>> Make the clearcpuid parse a comma-separated list of values instead of only
>> a single value.
> 
> Can we also please kill the value thing entirely and only accept
> strings. Having to reverse engineer the numbers is madness.
> 
> Also, wth would you want to disable XSAVE and EPB ?
> 

It looks like Fenghua has implemented this here:

https://marc.info/?l=linux-kernel&m=154908490105208&w=2

so please drop this patch.

Thanks,

P.

      reply	other threads:[~2019-02-27 23:48 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-21 13:12 [PATCH] x86/fpu: Parse comma separated list passed in clearcpuid Prarit Bhargava
2019-02-21 13:37 ` Peter Zijlstra
2019-02-21 18:58   ` Andi Kleen
2019-02-21 19:01     ` Prarit Bhargava
2019-02-21 13:48 ` Peter Zijlstra
2019-02-27 23:48   ` Prarit Bhargava [this message]

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