x86/cpufeature: Detect CPUID faulting support
Intel supports faulting on the CPUID instruction beginning with Ivy Bridge. When enabled, the processor will fault on attempts to execute the CPUID instruction with CPL>0. This will allow a ptracer to emulate the CPUID instruction. Bit 31 of MSR_PLATFORM_INFO advertises support for this feature. It is documented in detail in Section 2.3.2 of https://bugzilla.kernel.org/attachment.cgi?id=243991 Detect support for this feature and expose it as X86_FEATURE_CPUID_FAULT. Signed-off-by:Kyle Huey <khuey@kylehuey.com> Reviewed-by:
Borislav Petkov <bp@suse.de> Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: linux-kselftest@vger.kernel.org Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Robert O'Callahan <robert@ocallahan.org> Cc: Richard Weinberger <richard@nod.at> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Len Brown <len.brown@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: user-mode-linux-devel@lists.sourceforge.net Cc: Jeff Dike <jdike@addtoit.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: user-mode-linux-user@lists.sourceforge.net Cc: David Matlack <dmatlack@google.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: linux-fsdevel@vger.kernel.org Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/20170320081628.18952-8-khuey@kylehuey.comSigned-off-by:
Thomas Gleixner <tglx@linutronix.de>
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