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Date: Mon, 14 Mar 2016 11:15:09 -0700
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Subject: Re: [PATCH v4 2/5] x86/msr: Carry on after a non-"safe" MSR access
 fails without !panic_on_oops
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>, xen-devel <Xen-devel@lists.xen.org>,
        Arjan van de Ven <arjan@linux.intel.com>,
        Borislav Petkov <bp@alien8.de>, X86 ML <x86@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        KVM list <kvm@vger.kernel.org>, Andy Lutomirski <luto@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>
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On Mon, Mar 14, 2016 at 11:10 AM, Andy Lutomirski <luto@amacapital.net> wrote:
>
> A couple of the wrmsr users actually care about performance.  These
> are the ones involved in context switching and, to a lesser extent, in
> switching in and out of guest mode.

.. ok, see the crossed emails.

I'd *much* rather special case the special cases. Not make the generic
case something complex.

And *particularly* not make the generic case be something where people
think it's sane to oops and kill the machine. Christ.

                  Linus