From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Borislav Petkov <bp@alien8.de>, Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
KVM list <kvm@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>, <x86@kernel.org>,
<linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
xen-devel <Xen-devel@lists.xen.org>,
Andy Lutomirski <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Arjan van de Ven" <arjan@linux.intel.com>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [Xen-devel] [PATCH 0/3] x86/paravirt: Fix baremetal paravirt MSR ops
Date: Thu, 17 Sep 2015 16:32:53 +0100 [thread overview]
Message-ID: <55FADD25.6040909@citrix.com> (raw)
In-Reply-To: <20150917152709.GB17766@nazgul.tnic>
On 17/09/15 16:27, Borislav Petkov wrote:
> On Thu, Sep 17, 2015 at 01:39:26PM +0200, Paolo Bonzini wrote:
>> That's not a big deal, that's what *_safe is for. The problem is that
>> there are definitely some cases where the *_safe version is not being used.
> I mean to do feature checks which assure you that those MSRs are
> there so you don't need the safe variants. And that is not always
> easy/possible.
>
There are plenty of non-architectural MSRs in use which don't have
feature bits.
Xen used to have problems booting when using the masking MSRs when
booting virtualised. Nowadays it uses a cpu vendor check and _safe()
probe to detect support.
~Andrew
next prev parent reply other threads:[~2015-09-17 15:32 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-16 23:33 [PATCH 0/3] x86/paravirt: Fix baremetal paravirt MSR ops 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 ` 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 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
2015-09-16 23:33 ` Andy Lutomirski
2015-09-17 7:19 ` [PATCH 0/3] x86/paravirt: Fix baremetal paravirt MSR ops Ingo Molnar
2015-09-17 7:19 ` Ingo Molnar
2015-09-17 9:31 ` Borislav Petkov
2015-09-17 9:31 ` Borislav Petkov
2015-09-17 11:22 ` H. Peter Anvin
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 15:27 ` Borislav Petkov
2015-09-17 15:32 ` Andrew Cooper [this message]
2015-09-17 15:37 ` Borislav Petkov
2015-09-17 15:37 ` [Xen-devel] " Borislav Petkov
2015-09-17 15:32 ` Andrew Cooper
2015-09-17 11:39 ` Paolo Bonzini
2015-09-17 15:23 ` Andy Lutomirski
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 15:29 ` Paolo Bonzini
2015-09-17 15:31 ` Arjan van de Ven
2015-09-17 15:33 ` Paolo Bonzini
2015-09-17 15:33 ` Paolo Bonzini
2015-09-17 15:31 ` Arjan van de Ven
2015-09-17 15:27 ` Arjan van de Ven
2015-09-17 17:30 ` Ingo Molnar
2015-09-17 17:30 ` Ingo Molnar
2015-09-17 18:51 ` Andy Lutomirski
2015-09-17 18:51 ` Andy Lutomirski
2015-09-17 8:58 ` Peter Zijlstra
2015-09-17 8:58 ` Peter Zijlstra
2015-09-17 11:40 ` Paolo Bonzini
2015-09-17 12:27 ` Peter Zijlstra
2015-09-17 12:27 ` Peter Zijlstra
2015-09-17 15:17 ` Andy Lutomirski
2015-09-17 15:17 ` Peter Zijlstra
2015-09-17 15:17 ` Peter Zijlstra
2015-09-17 15:26 ` Andy Lutomirski
2015-09-17 15:26 ` Andy Lutomirski
2015-09-17 15:29 ` Paolo Bonzini
2015-09-17 15:29 ` Paolo Bonzini
2015-09-17 15:17 ` Andy Lutomirski
2015-09-17 11:40 ` Paolo Bonzini
2015-09-17 9:10 ` Andrew Cooper
2015-09-17 9:10 ` [Xen-devel] " Andrew Cooper
2015-09-17 15:11 ` Boris Ostrovsky
2015-09-17 15:11 ` Boris Ostrovsky
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