vvmx: fix the wrong address width in c/s 08fac63

c/s 08fac63 misused v->domain-arch.paging.gfn_bits as the width of
guest physical address and missed adding PAGE_SHIFT to it when
checking vmxon operand.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>

xen/arch/x86/hvm/vmx/vvmx.c

@@ -1388,7 +1388,8 @@ int nvmx_handle_vmxon(struct cpu_user_regs *regs)
         return X86EMUL_OKAY;
     }
 
-    if ( (gpa & ~PAGE_MASK) || (gpa >> v->domain->arch.paging.gfn_bits) )
+    if ( (gpa & ~PAGE_MASK) ||
+         (gpa >> (v->domain->arch.paging.gfn_bits + PAGE_SHIFT)) )
     {
         vmreturn(regs, VMFAIL_INVALID);
         return X86EMUL_OKAY;