KVM: SVM: Enable INVPCID feature on AMD

The following intercept bit has been added to support VMEXIT
for INVPCID instruction:
Code    Name            Cause
A2h     VMEXIT_INVPCID  INVPCID instruction

The following bit has been added to the VMCB layout control area
to control intercept of INVPCID:
Byte Offset     Bit(s)    Function
14h             2         intercept INVPCID

Enable the interceptions when the the guest is running with shadow
page table enabled and handle the tlbflush based on the invpcid
instruction type.

For the guests with nested page table (NPT) support, the INVPCID
feature works as running it natively. KVM does not need to do any
special handling in this case.

AMD documentation for INVPCID feature is available at "AMD64
Architecture Programmer’s Manual Volume 2: System Programming,
Pub. 24593 Rev. 3.34(or later)"

The documentation can be obtained at the links below:
Link: https://www.amd.com/system/files/TechDocs/24593.pdf
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537

Signed-off-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <159985255929.11252.17346684135277453258.stgit@bmoger-ubuntu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>