x86/cpuid: gate the hypervisor PV-only leaf on is_pv_domain()

Hypervisor leaf 5 is PV-specific, but is gated with !is_hvm_domain(),
which stays a runtime test in a build without PV support. Test for a
PV domain directly so the compiler can discard the leaf when
CONFIG_PV is disabled.

Suggested-by: Roger Pau Monné <roger@xenproject.org>
Signed-off-by: Jiaqing Zhao <Zhao.Jiaqing@amd.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/cpuid.c

@@ -157,7 +157,7 @@ static void cpuid_hypervisor_leaves(const struct vcpu *v, uint32_t leaf,
         break;
 
     case 5: /* PV-specific parameters */
-        if ( is_hvm_domain(d) || subleaf != 0 )
+        if ( !is_pv_domain(d) || subleaf != 0 )
             break;
 
         res->b = flsl(get_upper_mfn_bound()) + PAGE_SHIFT;