Message-ID: <5591A1D3.6010003@zytor.com>
Date: Mon, 29 Jun 2015 12:51:47 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Prarit Bhargava <prarit@redhat.com>, Andy Lutomirski <luto@amacapital.net>
CC: Ingo Molnar <mingo@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        X86 ML <x86@kernel.org>, Len Brown <len.brown@intel.com>,
        Dasaratharaman Chandramouli 
	<dasaratharaman.chandramouli@intel.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
        Denys Vlasenko <dvlasenk@redhat.com>, Brian Gerst <brgerst@gmail.com>,
        Arnaldo Carvalho de Melo <acme@infradead.org>
Subject: Re: [PATCH] x86, msr: Allow read access to /dev/cpu/X/msr
References: <1435341131-3279-1-git-send-email-prarit@redhat.com> <20150627083354.GA12834@gmail.com> <20150627083921.GA13074@gmail.com> <CALCETrXpiMWwiAfbxcKTDYCewrwq-UTwLV+xXTxdOkd+B3G-OQ@mail.gmail.com> <559005DD.3070003@redhat.com>
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On 06/28/2015 07:34 AM, Prarit Bhargava wrote:
>>
>> Seriously, though, it would be straightforward to make it handle a
>> more general list, complete with non-architectural stuff (such as the
>> upcoming PPERF in Skylake).
> 
> Is it easier to blacklist MSRs we don't want generally exposed, or only expose
> the ones that we think are safe?  That's sort of a devil's advocate sort of
> question ;) and I'm wondering what the shorter list is.
> 

The second is the only option.  Blacklisting MSRs is not safe, as you
have no idea what new MSRs might be introduced.

	-hpa


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