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From: Andy Lutomirski <luto@amacapital.net>
To: David Vrabel <david.vrabel@citrix.com>
Cc: Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>,
	KVM list <kvm@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	xen-devel <Xen-devel@lists.xen.org>,
	Borislav Petkov <bp@alien8.de>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Arjan van de Ven <arjan@linux.intel.com>
Subject: Re: [Xen-devel] [PATCH v5 7/9] x86/paravirt: Add paravirt_{read, write}_msr
Date: Mon, 4 Apr 2016 09:40:51 -0700	[thread overview]
Message-ID: <CALCETrUT8SCD=XLFXEPaNPtPddKzv+YO23GyAkLhgY+3fEJFAA@mail.gmail.com> (raw)
In-Reply-To: <5702974A.1030003@citrix.com>

On Mon, Apr 4, 2016 at 9:33 AM, David Vrabel <david.vrabel@citrix.com> wrote:
> On 02/04/16 15:01, Andy Lutomirski wrote:
>> This adds paravirt hooks for unsafe MSR access.  On native, they
>> call native_{read,write}_msr.  On Xen, they use
>> xen_{read,write}_msr_safe.
>>
>> Nothing uses them yet for ease of bisection.  The next patch will
>> use them in rdmsrl, wrmsrl, etc.
>>
>> I intentionally didn't make them warn on #GP on Xen.  I think that
>> should be done separately by the Xen maintainers.
> ...
>> --- a/arch/x86/xen/enlighten.c
>> +++ b/arch/x86/xen/enlighten.c
>
> Reviewed-by: David Vrabel <david.vrabel@citrix.com>
>
>> @@ -1092,6 +1092,26 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
>>       return ret;
>>  }
>>
>> +static u64 xen_read_msr(unsigned int msr)
>> +{
>> +     /*
>> +      * This will silently swallow a #GP from RDMSR.  It may be worth
>> +      * changing that.
>
> This probably isn't important.
>

It might be nice to do a WARN_ON_ONCE like this series does for the
native case to help shake out latent bugs.

--Andy

  reply	other threads:[~2016-04-04 16:41 UTC|newest]

Thread overview: 101+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-02 14:01 [PATCH v5 0/9] Improve non-"safe" MSR access failure handling Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 1/9] x86/head: Pass a real pt_regs and trapnr to early_fixup_exception Andy Lutomirski
2016-04-02 14:01   ` Andy Lutomirski
2016-04-13 11:43   ` [tip:x86/asm] x86/head: Pass a real pt_regs and trapnr to early_fixup_exception() tip-bot for Andy Lutomirski
2016-04-13 11:43   ` tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 2/9] x86/head: Move the early NMI fixup into C Andy Lutomirski
2016-04-02 14:01 ` Andy Lutomirski
2016-04-13 11:43   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-04-13 11:43   ` tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 3/9] x86/head: Move early exception panic code into early_fixup_exception Andy Lutomirski
2016-04-02 14:01   ` Andy Lutomirski
2016-04-02 18:39   ` Borislav Petkov
2016-04-02 18:39   ` Borislav Petkov
2016-04-02 20:13     ` Andy Lutomirski
2016-04-02 20:47       ` Borislav Petkov
2016-04-02 20:47       ` Borislav Petkov
2016-04-02 20:58         ` Andy Lutomirski
2016-04-02 20:58         ` Andy Lutomirski
2016-04-04 11:52           ` Jan Kara
2016-04-04 11:52           ` Jan Kara
2016-04-04 12:46             ` Peter Zijlstra
2016-04-04 12:46             ` Peter Zijlstra
2016-04-04 15:32             ` Andy Lutomirski
2016-04-04 15:36               ` Arjan van de Ven
2016-04-04 15:36               ` Arjan van de Ven
2016-04-04 16:00               ` Peter Zijlstra
2016-04-04 16:00               ` Peter Zijlstra
2016-04-04 19:38                 ` Borislav Petkov
2016-04-04 19:38                 ` Borislav Petkov
2016-04-04 21:31                   ` Andy Lutomirski
2016-04-04 21:40                     ` Borislav Petkov
2016-04-04 21:40                     ` Borislav Petkov
2016-04-04 21:31                   ` Andy Lutomirski
2016-04-04 15:32             ` Andy Lutomirski
2016-04-02 20:13     ` Andy Lutomirski
2016-04-13 11:44   ` [tip:x86/asm] x86/head: Move early exception panic code into early_fixup_exception() tip-bot for Andy Lutomirski
2016-04-13 11:44   ` tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 4/9] x86/traps: Enable all exception handler callbacks early Andy Lutomirski
2016-04-02 18:52   ` Borislav Petkov
2016-04-02 20:16     ` Andy Lutomirski
2016-04-02 20:52       ` Borislav Petkov
2016-04-02 20:52       ` Borislav Petkov
2016-04-03  8:07         ` Borislav Petkov
2016-04-03  8:07         ` Borislav Petkov
2016-04-03 13:22           ` Andy Lutomirski
2016-04-03 13:22           ` Andy Lutomirski
2016-04-03 13:51           ` Linus Torvalds
2016-04-03 13:51           ` Linus Torvalds
2016-04-03 13:55             ` Andy Lutomirski
2016-04-03 14:10               ` Borislav Petkov
2016-04-03 14:10               ` Borislav Petkov
2016-04-04 15:47                 ` Andy Lutomirski
2016-04-04 15:47                 ` Andy Lutomirski
2016-04-03 14:17               ` Linus Torvalds
2016-04-03 14:17               ` Linus Torvalds
2016-04-03 13:55             ` Andy Lutomirski
2016-04-02 20:16     ` Andy Lutomirski
2016-04-02 18:52   ` Borislav Petkov
2016-04-13 11:44   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-04-13 11:44   ` tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 4/9] " Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 5/9] x86/paravirt: Add _safe to the read_msr and write_msr PV hooks Andy Lutomirski
2016-04-02 14:01   ` Andy Lutomirski
2016-04-03  8:41   ` Borislav Petkov
2016-04-03 13:23     ` Andy Lutomirski
2016-04-03 14:07       ` Borislav Petkov
2016-04-03 14:07       ` Borislav Petkov
2016-04-03 13:23     ` Andy Lutomirski
2016-04-03  8:41   ` Borislav Petkov
2016-04-13 11:44   ` [tip:x86/asm] x86/paravirt: Add _safe to the read_ms()r and write_msr() PV callbacks tip-bot for Andy Lutomirski
2016-04-13 11:44   ` tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 6/9] x86/msr: Carry on after a non-"safe" MSR access fails Andy Lutomirski
2016-04-02 14:01 ` Andy Lutomirski
2016-04-13 11:45   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-04-13 11:45   ` tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 7/9] x86/paravirt: Add paravirt_{read, write}_msr Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 7/9] x86/paravirt: Add paravirt_{read,write}_msr Andy Lutomirski
2016-04-04 16:33   ` [PATCH v5 7/9] x86/paravirt: Add paravirt_{read, write}_msr David Vrabel
2016-04-04 16:33   ` [Xen-devel] " David Vrabel
2016-04-04 16:40     ` Andy Lutomirski [this message]
2016-04-04 16:40     ` Andy Lutomirski
2016-04-13 11:45   ` [tip:x86/asm] x86/paravirt: Add paravirt_{read, write}_msr() tip-bot for Andy Lutomirski
2016-04-13 11:45   ` [tip:x86/asm] x86/paravirt: Add paravirt_{read,write}_msr() tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 8/9] x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y Andy Lutomirski
2016-04-02 14:01   ` Andy Lutomirski
2016-04-13 11:46   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-04-13 11:46   ` tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 9/9] x86/msr: Set the return value to zero when native_rdmsr_safe fails Andy Lutomirski
2016-04-13 11:46   ` [tip:x86/asm] x86/msr: Set the return value to zero when native_rdmsr_safe() fails tip-bot for Andy Lutomirski
2016-04-13 11:46   ` tip-bot for Andy Lutomirski
2016-04-02 14:01 ` [PATCH v5 9/9] x86/msr: Set the return value to zero when native_rdmsr_safe fails Andy Lutomirski
2016-04-02 14:24 ` [PATCH v5 0/9] Improve non-"safe" MSR access failure handling Linus Torvalds
2016-04-02 15:13   ` Andy Lutomirski
2016-04-02 15:21     ` Linus Torvalds
2016-04-02 15:21     ` Linus Torvalds
2016-04-02 15:13   ` Andy Lutomirski
2016-04-02 14:24 ` Linus Torvalds
2016-04-04 16:23 ` Borislav Petkov
2016-04-04 16:23 ` Borislav Petkov
2016-04-05 15:38 ` Boris Ostrovsky
2016-04-05 15:38 ` [Xen-devel] " Boris Ostrovsky

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