KVM/SVM: Allow direct access to MSR_IA32_SPEC_CTRL
authorKarimAllah Ahmed <karahmed@amazon.de>
Sat, 3 Feb 2018 14:56:23 +0000 (15:56 +0100)
committerThomas Gleixner <tglx@linutronix.de>
Sat, 3 Feb 2018 22:06:52 +0000 (23:06 +0100)
commitb2ac58f90540e39324e7a29a7ad471407ae0bf48
treeb9c902f1141226f16d24c30e0fd808f2b95c698d
parentd28b387fb74da95d69d2615732f50cceb38e9a4d
KVM/SVM: Allow direct access to MSR_IA32_SPEC_CTRL

[ Based on a patch from Paolo Bonzini <pbonzini@redhat.com> ]

... basically doing exactly what we do for VMX:

- Passthrough SPEC_CTRL to guests (if enabled in guest CPUID)
- Save and restore SPEC_CTRL around VMExit and VMEntry only if the guest
  actually used it.

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jun Nakajima <jun.nakajima@intel.com>
Cc: kvm@vger.kernel.org
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Asit Mallick <asit.k.mallick@intel.com>
Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ashok Raj <ashok.raj@intel.com>
Link: https://lkml.kernel.org/r/1517669783-20732-1-git-send-email-karahmed@amazon.de
arch/x86/kvm/svm.c