xen: assume XENFEAT_mmu_pt_update_preserve_ad being set for pv guests

XENFEAT_mmu_pt_update_preserve_ad is always set in Xen 4.0 and newer.
Remove coding assuming it might be zero.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210730071804.4302-3-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>

Author: jgross1

arch/x86/xen/enlighten_pv.c

@@ -116,9 +116,8 @@ static void __init xen_banner(void)
 	HYPERVISOR_xen_version(XENVER_extraversion, &extra);
 
 	pr_info("Booting paravirtualized kernel on %s\n", pv_info.name);
-	printk(KERN_INFO "Xen version: %d.%d%s%s\n",
-	       version >> 16, version & 0xffff, extra.extraversion,
-	       xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
+	pr_info("Xen version: %d.%d%s (preserve-AD)\n",
+		version >> 16, version & 0xffff, extra.extraversion);
 }
 
 static void __init xen_pv_init_platform(void)
@@ -1302,13 +1301,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
 	xen_init_apic();
 #endif
 
-	if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
-		pv_ops.mmu.ptep_modify_prot_start =
-			xen_ptep_modify_prot_start;
-		pv_ops.mmu.ptep_modify_prot_commit =
-			xen_ptep_modify_prot_commit;
-	}
-
 	machine_ops = xen_machine_ops;
 
 	/*

arch/x86/xen/mmu_pv.c

@@ -2099,8 +2099,8 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
 	.set_pte = xen_set_pte_init,
 	.set_pmd = xen_set_pmd_hyper,
 
-	.ptep_modify_prot_start = __ptep_modify_prot_start,
-	.ptep_modify_prot_commit = __ptep_modify_prot_commit,
+	.ptep_modify_prot_start = xen_ptep_modify_prot_start,
+	.ptep_modify_prot_commit = xen_ptep_modify_prot_commit,
 
 	.pte_val = PV_CALLEE_SAVE(xen_pte_val),
 	.pgd_val = PV_CALLEE_SAVE(xen_pgd_val),