From: Peter Zijlstra <peterz@infradead.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>,
x86@kernel.org, KVM list <kvm@vger.kernel.org>,
Arjan van de Ven <arjan@linux.intel.com>,
xen-devel <Xen-devel@lists.xen.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] x86/paravirt: Fix baremetal paravirt MSR ops
Date: Thu, 17 Sep 2015 14:27:50 +0200 [thread overview]
Message-ID: <20150917122750.GH3604@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <55FAA6AE.9050503@redhat.com>
On Thu, Sep 17, 2015 at 01:40:30PM +0200, Paolo Bonzini wrote:
>
>
> On 17/09/2015 10:58, Peter Zijlstra wrote:
> > But the far greater problem I have with the whole virt thing is that
> > you cannot use rdmsr_safe() to probe if an MSR exists at all because, as
> > you told me, these virt thingies return 0 for all 'unknown' MSRs instead
> > of faulting.
>
> At least for KVM, that behavior is opt-in (the ignore_msrs parameter)
> and no distro that I know enables it by default.
Ah, that would be good news. Andy earlier argued I could not rely on
rdmsr_safe() faulting on unknown MSRs. If practically we can there's
some code I can simplify :-)
next prev parent reply other threads:[~2015-09-17 12:33 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-16 23:33 Andy Lutomirski
2015-09-16 23:33 ` [PATCH 1/3] x86/paravirt: Add _safe to the read_msr and write_msr PV hooks Andy Lutomirski
2015-09-16 23:33 ` [PATCH 2/3] x86/paravirt: Add paravirt_{read,write}_msr Andy Lutomirski
2015-09-16 23:33 ` [PATCH 3/3] x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y Andy Lutomirski
2015-09-17 7:19 ` [PATCH 0/3] x86/paravirt: Fix baremetal paravirt MSR ops Ingo Molnar
2015-09-17 9:31 ` Borislav Petkov
2015-09-17 11:22 ` H. Peter Anvin
2015-09-17 11:39 ` Paolo Bonzini
2015-09-17 15:27 ` Borislav Petkov
2015-09-17 15:32 ` [Xen-devel] " Andrew Cooper
2015-09-17 15:37 ` Borislav Petkov
2015-09-17 15:23 ` Andy Lutomirski
2015-09-17 15:27 ` Arjan van de Ven
2015-09-17 15:29 ` Paolo Bonzini
2015-09-17 15:31 ` Arjan van de Ven
2015-09-17 15:33 ` Paolo Bonzini
2015-09-17 17:30 ` Ingo Molnar
2015-09-17 18:51 ` Andy Lutomirski
2015-09-17 8:58 ` Peter Zijlstra
2015-09-17 11:40 ` Paolo Bonzini
2015-09-17 12:27 ` Peter Zijlstra [this message]
2015-09-17 15:17 ` Andy Lutomirski
2015-09-17 15:17 ` Peter Zijlstra
2015-09-17 15:26 ` Andy Lutomirski
2015-09-17 15:29 ` Paolo Bonzini
2015-09-17 9:10 ` [Xen-devel] " Andrew Cooper
2015-09-17 15:11 ` Boris Ostrovsky
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