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From: Thomas Gleixner <tglx@linutronix.de>
To: Kyle Huey <me@kylehuey.com>
Cc: "Robert O'Callahan" <robert@ocallahan.org>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Jeff Dike" <jdike@addtoit.com>,
	"Richard Weinberger" <richard@nod.at>,
	"Alexander Viro" <viro@zeniv.linux.org.uk>,
	"Shuah Khan" <shuah@kernel.org>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Borislav Petkov" <bp@suse.de>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
	"Len Brown" <len.brown@intel.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	"Dmitry Safonov" <dsafonov@virtuozzo.com>,
	"David Matlack" <dmatlack@google.com>,
	"Nadav Amit" <nadav.amit@gmail.com>,
	"Andi Kleen" <andi@firstfloor.org>,
	linux-kernel@vger.kernel.org,
	user-mode-linux-devel@lists.sourceforge.net,
	user-mode-linux-user@lists.sourceforge.net,
	linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	kvm@vger.kernel.org
Subject: Re: [PATCH v14 0/9] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction
Date: Fri, 10 Feb 2017 14:07:03 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1702101405570.4036@nanos> (raw)
In-Reply-To: <20170208080917.24320-1-khuey@kylehuey.com>

On Wed, 8 Feb 2017, Kyle Huey wrote:

> rr (http://rr-project.org/), a userspace record-and-replay reverse-
> execution debugger, would like to trap and emulate the CPUID instruction.
> This would allow us to a) mask away certain hardware features that rr does
> not support (e.g. RDRAND) and b) enable trace portability across machines
> by providing constant results.
> 
> Newer Intel CPUs (Ivy Bridge and later) can fault when CPUID is executed at
> CPL > 0. Expose this capability to userspace as a new pair of arch_prctls,
> ARCH_GET_CPUID and ARCH_SET_CPUID.
> 
> Since v13:
> All: rebased on top of tglx's __switch_to_xtra patches
> (https://lkml.org/lkml/2016/12/15/432)

That doesn't help because that patchset is stale and it has unresolved
comments. I don't know when I have cycles to revisit it, but if you want to
have a try feel free to do so.

Thanks,

	tglx

WARNING: multiple messages have this Message-ID (diff)
From: Thomas Gleixner <tglx@linutronix.de>
To: Kyle Huey <me@kylehuey.com>
Cc: "Robert O'Callahan" <robert@ocallahan.org>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Jeff Dike" <jdike@addtoit.com>,
	"Richard Weinberger" <richard@nod.at>,
	"Alexander Viro" <viro@zeniv.linux.org.uk>,
	"Shuah Khan" <shuah@kernel.org>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Borislav Petkov" <bp@suse.de>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
	"Len Brown" <len.brown@intel.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	"Dmitry Safonov" <dsafonov@virtuozzo.com>,
	"David Matlack" <dmatlack@google.com>,
	"Nadav Amit" <nadav.amit@gmail.com>
Subject: Re: [PATCH v14 0/9] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction
Date: Fri, 10 Feb 2017 14:07:03 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1702101405570.4036@nanos> (raw)
In-Reply-To: <20170208080917.24320-1-khuey@kylehuey.com>

On Wed, 8 Feb 2017, Kyle Huey wrote:

> rr (http://rr-project.org/), a userspace record-and-replay reverse-
> execution debugger, would like to trap and emulate the CPUID instruction.
> This would allow us to a) mask away certain hardware features that rr does
> not support (e.g. RDRAND) and b) enable trace portability across machines
> by providing constant results.
> 
> Newer Intel CPUs (Ivy Bridge and later) can fault when CPUID is executed at
> CPL > 0. Expose this capability to userspace as a new pair of arch_prctls,
> ARCH_GET_CPUID and ARCH_SET_CPUID.
> 
> Since v13:
> All: rebased on top of tglx's __switch_to_xtra patches
> (https://lkml.org/lkml/2016/12/15/432)

That doesn't help because that patchset is stale and it has unresolved
comments. I don't know when I have cycles to revisit it, but if you want to
have a try feel free to do so.

Thanks,

	tglx

  parent reply	other threads:[~2017-02-10 14:04 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-08  8:09 [PATCH v14 0/9] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction Kyle Huey
2017-02-08  8:09 ` Kyle Huey
2017-02-08  8:09 ` [PATCH v14 1/9] x86/arch_prctl/64: Use SYSCALL_DEFINE2 to define sys_arch_prctl Kyle Huey
2017-02-08  8:09   ` Kyle Huey
2017-02-08  8:09 ` [PATCH v14 2/9] x86/arch_prctl/64: Rename do_arch_prctl to do_arch_prctl_64 Kyle Huey
2017-02-08  8:09   ` Kyle Huey
2017-02-08  8:09 ` [PATCH v14 3/9] x86/arch_prctl: Add do_arch_prctl_common Kyle Huey
2017-02-08  8:09   ` Kyle Huey
2017-02-08  8:09 ` [PATCH v14 4/9] x86/syscalls/32: Wire up arch_prctl on x86-32 Kyle Huey
2017-02-08  8:09   ` Kyle Huey
2017-02-08  8:09 ` [PATCH v14 5/9] x86/cpufeature: Detect CPUID faulting support Kyle Huey
2017-02-08  8:09   ` Kyle Huey
2017-02-08  8:09 ` [PATCH v14 6/9] x86/arch_prctl: Add ARCH_[GET|SET]_CPUID Kyle Huey
2017-02-08  8:09   ` Kyle Huey
2017-02-08  8:09 ` [PATCH v14 7/9] x86/arch_prctl: Selftest for ARCH_[GET|SET]_CPUID Kyle Huey
2017-02-08  8:09   ` Kyle Huey
2017-02-08  8:09 ` [PATCH v14 8/9] KVM: x86: virtualize cpuid faulting Kyle Huey
2017-02-08  8:09   ` Kyle Huey
2018-07-27 17:15   ` Jim Mattson
2018-07-27 17:15     ` Jim Mattson
2018-07-27 17:15     ` Jim Mattson
2018-07-27 17:15     ` jmattson
2018-07-27 19:41   ` Andy Lutomirski
2018-07-27 19:41     ` Andy Lutomirski
2018-07-27 19:41     ` Andy Lutomirski
2018-07-27 19:41     ` luto
2018-07-27 20:28     ` Jim Mattson
2018-07-27 20:28       ` Jim Mattson
2018-07-27 20:28       ` Jim Mattson
2018-07-27 20:28       ` jmattson
2018-07-27 20:46       ` Andy Lutomirski
2018-07-27 20:46         ` Andy Lutomirski
2018-07-27 20:46         ` Andy Lutomirski
2018-07-27 20:46         ` luto
2018-07-27 21:03         ` Jim Mattson
2018-07-27 21:03           ` Jim Mattson
2018-07-27 21:03           ` Jim Mattson
2018-07-27 21:03           ` jmattson
2018-07-27 21:05           ` Andy Lutomirski
2018-07-27 21:05             ` Andy Lutomirski
2018-07-27 21:05             ` Andy Lutomirski
2018-07-27 21:05             ` luto
2018-07-27 21:30             ` Jim Mattson
2018-07-27 21:30               ` Jim Mattson
2018-07-27 21:30               ` Jim Mattson
2018-07-27 21:30               ` jmattson
2018-07-27 22:58               ` Andy Lutomirski
2018-07-27 22:58                 ` Andy Lutomirski
2018-07-27 22:58                 ` Andy Lutomirski
2018-07-27 22:58                 ` luto
2017-02-08  8:09 ` [PATCH v14 9/9] x86/arch_prctl: Rename 'code' argument to 'option' Kyle Huey
2017-02-08  8:09   ` Kyle Huey
2017-02-10 13:07 ` Thomas Gleixner [this message]
2017-02-10 13:07   ` [PATCH v14 0/9] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction Thomas Gleixner

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