From: Thomas Gleixner <tglx@linutronix.de>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Kyle Huey <me@kylehuey.com>,
Robert O'Callahan <robert@ocallahan.org>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
X86 ML <x86@kernel.org>, Jeff Dike <jdike@addtoit.com>,
Richard Weinberger <richard@nod.at>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@suse.de>,
Dmitry Safonov <dsafonov@virtuozzo.com>,
Peter Zijlstra <peterz@infradead.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Shuah Khan <shuah@kernel.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Len Brown <len.brown@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"user-mode-linux-devel@lists.sourceforge.net"
<user-mode-linux-devel>
Subject: Re: [PATCH v7 6/6] x86/arch_prctl: Add ARCH_[GET|SET]_CPUID
Date: Fri, 28 Oct 2016 00:38:54 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1610280038260.4913@nanos> (raw)
In-Reply-To: <CALCETrUXCA+-gWxvAVJf=zRPFP=_t600pdVPC44SFL5v_YxOMQ@mail.gmail.com>
On Thu, 27 Oct 2016, Andy Lutomirski wrote:
> On Thu, Oct 27, 2016 at 4:15 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> Let's just do this right from day one:
>
> static void set_cpuid_faulting(bool on)
> {
> u64 msrval;
>
> DEBUG_LOCKS_WARN_ON(!irqs_disabled());
>
> msrval = this_cpu_read(msr_misc_features_enables_shadow);
> msrval &= CPUID_FAULT_ENABLE;
> msrval |= (on << CPUID_FAULT_ENABLE_BIT);
> this_cpu_write(msr_misc_features_enables_shadow, msrval);
> wrmsrl(MSR_MISC_FEATURES_ENABLES, msrval);
> }
>
> RDMSR may be considerably faster than WRMSR, but that doesn't mean it's *fast*.
Good point!
next prev parent reply other threads:[~2016-10-27 22:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-19 2:03 [PATCH v7 0/6] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction Kyle Huey
2016-10-19 2:03 ` [PATCH v7 1/6] x86/arch_prctl/64: Use SYSCALL_DEFINE2 to define sys_arch_prctl Kyle Huey
2016-10-19 2:03 ` [PATCH v7 2/6] x86/arch_prctl/64: Rename do_arch_prctl to do_arch_prctl_64 Kyle Huey
2016-10-19 2:03 ` [PATCH v7 3/6] x86/arch_prctl: Add do_arch_prctl_common Kyle Huey
[not found] ` <20161019020333.3766-1-khuey-OhBmq/TcCDJWk0Htik3J/w@public.gmane.org>
2016-10-19 2:03 ` [PATCH v7 4/6] x86/syscalls/32: Wire up arch_prctl on x86-32 Kyle Huey
2016-10-19 2:03 ` [PATCH v7 5/6] x86/cpufeature: Detect CPUID faulting support Kyle Huey
[not found] ` <20161019020333.3766-6-khuey-OhBmq/TcCDJWk0Htik3J/w@public.gmane.org>
2016-10-27 8:21 ` Thomas Gleixner
2016-10-19 2:03 ` [PATCH v7 6/6] x86/arch_prctl: Add ARCH_[GET|SET]_CPUID Kyle Huey
[not found] ` <20161019020333.3766-7-khuey-OhBmq/TcCDJWk0Htik3J/w@public.gmane.org>
2016-10-27 11:15 ` Thomas Gleixner
2016-10-27 22:34 ` Andy Lutomirski
2016-10-27 22:38 ` Thomas Gleixner [this message]
2016-10-25 5:30 ` [PATCH v7 0/6] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction Kyle Huey
[not found] ` <CAP045Apcsb3dVJ1PaDpbJSGmtxK23GRijKWFt5qcBxTnzoyMJQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-10-25 16:47 ` Thomas Gleixner
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