x86/hvm: always do SMAP check when updating runstate_guest(v)

x86/hvm: always do SMAP check when updating runstate_guest(v)

In the current implementation, we honor the guest's CPL and AC
to determain whether do the SMAP check or not for runstate_guest(v).
However, this doesn't work. The VMCS feild is invalid when we try
to get geust's SS by hvm_get_segment_register(), since the
right VMCS has not beed loaded for the current VCPU.

In this patch, we always do the SMAP check when updating
runstate_guest(v) for the guest when SMAP is enabled by it.

Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>