KVM: x86: Add a framework for supporting MSR-based features

KVM: x86: Add a framework for supporting MSR-based features

Provide a new KVM capability that allows bits within MSRs to be recognized
as features.  Two new ioctls are added to the /dev/kvm ioctl routine to
retrieve the list of these MSRs and then retrieve their values. A kvm_x86_ops
callback is used to determine support for the listed MSR-based features.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[Tweaked documentation. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Orabug: 28220674
CVE: CVE-2018-3646

(cherry picked from commit 801e459a6f3a63af9d447e6249088c76ae16efc4)

This was needed in order to backport commit cd28325249a1ca0d771557ce823e0308ad629f98.

Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Conflicts:
	arch/x86/include/asm/kvm_host.h
	arch/x86/kvm/svm.c
	arch/x86/kvm/vmx.c
	arch/x86/kvm/x86.c
	include/uapi/linux/kvm.h
Contextual: different content