From: Andy Lutomirski <luto@amacapital.net>
To: Kyle Huey <me@kylehuey.com>
Cc: "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Huang Rui <ray.huang@amd.com>,
Kristen Carlson Accardi <kristen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Robert O'Callahan <robert@ocallahan.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
"moderated list:XEN HYPERVISOR INTERFACE"
<xen-devel@lists.xenproject.org>, Borislav Petkov <bp@suse.de>,
Len Brown <len.brown@intel.com>,
Andy Lutomirski <luto@kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 2/3] x86 Test and expose CPUID faulting capabilities in /proc/cpuinfo
Date: Wed, 14 Sep 2016 18:17:51 -0700 [thread overview]
Message-ID: <CALCETrWeFQpUhCn7y45EU9h32QVfaxGS5yP7hfW70zfU2UmWMA__6305.52141597054$1473902386$gmane$org@mail.gmail.com> (raw)
In-Reply-To: <CAP045Aqd47UBHgGEPR4BwceCG24P6YxYFCvo-TX2xegf2r5hxA@mail.gmail.com>
On Wed, Sep 14, 2016 at 3:03 PM, Kyle Huey <me@kylehuey.com> wrote:
> On Wed, Sep 14, 2016 at 2:35 PM, Dave Hansen
> <dave.hansen@linux.intel.com> wrote:
>> On 09/14/2016 02:01 PM, Kyle Huey wrote:
>> Is any of this useful to optimize away at compile-time? We have config
>> options for when we're running as a guest, and this seems like a feature
>> that isn't available when running on bare metal.
>
> On the contrary, this is only available when we're on bare metal.
> Neither Xen nor KVM virtualize CPUID faulting (although KVM correctly
> suppresses MSR_PLATFORM_INFO's report of support for it).
KVM could easily support this. If rr starts using it, I think KVM
*should* add support, possibly even for older CPUs that don't support
the feature in hardware.
It's too bad that x86 doesn't give us the instruction bytes on a
fault. Otherwise we could lazily switch this feature.
--Andy
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-09-15 1:18 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1473886902-17902-1-git-send-email-khuey@kylehuey.com>
2016-09-14 21:01 ` [PATCH v2 1/3] syscalls,x86 Expose arch_prctl on x86-32 Kyle Huey
2016-09-14 21:29 ` Dave Hansen
2016-09-14 21:35 ` Kyle Huey
2016-09-14 21:46 ` Dave Hansen
2016-09-14 21:56 ` Kyle Huey
2016-09-14 22:23 ` kbuild test robot
2016-09-15 0:01 ` kbuild test robot
2016-09-15 0:01 ` kbuild test robot
2016-09-15 1:14 ` Andy Lutomirski
2016-09-14 21:01 ` [PATCH v2 2/3] x86 Test and expose CPUID faulting capabilities in /proc/cpuinfo Kyle Huey
2016-09-14 21:35 ` Dave Hansen
2016-09-14 21:35 ` Dave Hansen
2016-09-14 22:03 ` Kyle Huey
2016-09-15 1:17 ` Andy Lutomirski [this message]
2016-09-15 1:17 ` Andy Lutomirski
2016-09-15 2:20 ` Kyle Huey
2016-09-15 2:20 ` Kyle Huey
2016-09-15 20:38 ` H. Peter Anvin
2016-09-15 23:18 ` Andy Lutomirski
2016-09-15 23:18 ` Andy Lutomirski
2016-09-15 20:38 ` H. Peter Anvin
2016-09-14 22:03 ` Kyle Huey
2016-09-15 10:07 ` David Vrabel
2016-09-15 10:07 ` David Vrabel
2016-09-15 10:05 ` [Xen-devel] " David Vrabel
2016-09-15 10:25 ` Jan Beulich
2016-09-15 10:25 ` [Xen-devel] " Jan Beulich
2016-09-15 19:11 ` Kyle Huey
2016-09-15 19:11 ` [Xen-devel] " Kyle Huey
2016-09-15 19:37 ` Andy Lutomirski
2016-09-15 23:36 ` Kyle Huey
2016-09-15 23:36 ` Kyle Huey
2016-09-15 19:37 ` Andy Lutomirski
2016-09-15 19:41 ` [Xen-devel] " Boris Ostrovsky
2016-09-15 19:41 ` Boris Ostrovsky
2016-09-15 10:05 ` David Vrabel
2016-09-14 21:01 ` Kyle Huey
2016-09-14 21:01 ` [PATCH v2 3/3] x86,arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction Kyle Huey
2016-09-15 1:29 ` Andy Lutomirski
2016-09-15 1:47 ` Kyle Huey
2016-09-15 1:54 ` Andy Lutomirski
2016-09-15 2:19 ` Kyle Huey
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