From: Nadav Amit <nadav.amit@gmail.com>
To: Kyle Huey <me@kylehuey.com>
Cc: "Robert O'Callahan" <robert@ocallahan.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Andy Lutomirski" <luto@kernel.org>,
"Ingo Molnar" <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>, "X86 ML" <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>,
LKML <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 <kvm@vger.kernel.org>
Subject: Re: [PATCH v11 7/7] KVM: x86: virtualize cpuid faulting
Date: Fri, 11 Nov 2016 12:54:46 -0800 [thread overview]
Message-ID: <26413C89-E639-4834-A600-C4B6679162F2@gmail.com> (raw)
In-Reply-To: <20161110234055.8654-8-khuey@kylehuey.com>
> On Nov 10, 2016, at 3:40 PM, Kyle Huey <me@kylehuey.com> wrote:
>
> Hardware support for faulting on the cpuid instruction is not required to
> emulate it, because cpuid triggers a VM exit anyways. KVM handles the relevant
> MSRs (MSR_PLATFORM_INFO and MSR_MISC_FEATURES_ENABLE) and upon a
> cpuid-induced VM exit checks the cpuid faulting state and the CPL.
> kvm_require_cpl is even kind enough to inject the GP fault for us.
I think that for consistency you should also revise em_cpuid() of KVM
instruction emulator. Otherwise it may be a potential security
hazard (as far fetched as it currently seems).
Nadav
next prev parent reply other threads:[~2016-11-11 21:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-10 23:40 [PATCH v11 0/7] x86/arch_prctl Add ARCH_[GET|SET]_CPUID for controlling the CPUID instruction Kyle Huey
2016-11-10 23:40 ` [PATCH v11 1/7] x86/arch_prctl/64: Use SYSCALL_DEFINE2 to define sys_arch_prctl Kyle Huey
2016-11-10 23:40 ` [PATCH v11 2/7] x86/arch_prctl/64: Rename do_arch_prctl to do_arch_prctl_64 Kyle Huey
2016-11-10 23:40 ` [PATCH v11 3/7] x86/arch_prctl: Add do_arch_prctl_common Kyle Huey
2016-11-10 23:40 ` [PATCH v11 4/7] x86/syscalls/32: Wire up arch_prctl on x86-32 Kyle Huey
2016-11-10 23:40 ` [PATCH v11 5/7] x86/cpufeature: Detect CPUID faulting support Kyle Huey
2016-11-10 23:40 ` [PATCH v11 6/7] x86/arch_prctl: Add ARCH_[GET|SET]_CPUID Kyle Huey
2016-11-11 1:25 ` kbuild test robot
2016-11-11 1:31 ` Kyle Huey
2016-11-10 23:40 ` [PATCH v11 7/7] KVM: x86: virtualize cpuid faulting Kyle Huey
2016-11-11 20:54 ` Nadav Amit [this message]
2016-11-16 16:40 ` Kyle Huey
2016-11-16 20:42 ` Paolo Bonzini
2016-11-17 1:59 ` Kyle Huey
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