commit 3829640049cf516d229620e5919b0ab66fd6ac86
author Marc-André Lureau <marcandre.lureau@redhat.com> Thu Sep 06 20:14:15 2018 +0400
committer Paolo Bonzini <pbonzini@redhat.com> Tue Oct 02 18:47:55 2018 +0200
tree ef5eb722c0fe8fd4ece5bf28bf0065374f98cdde
parent 7184de64a1cf23a72191484b9a6995c3bfc9fb0b

hostmem-memfd: add checks before adding hostmem-memfd & properties

Run some memfd-related checks before registering hostmem-memfd &
various properties. This will help libvirt to figure out what the host
is supposed to be capable of.

qemu_memfd_check() is changed to a less optimized version, since it is
used with various flags, it no longer caches the result.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180906161415.8543-1-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

backends/hostmem-memfd.c

diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c
index 1e20fe0..3800bd0 100644
--- a/backends/hostmem-memfd.c
+++ b/backends/hostmem-memfd.c
@@ -140,18 +140,22 @@
 
     bc->alloc = memfd_backend_memory_alloc;
 
-    object_class_property_add_bool(oc, "hugetlb",
-                                   memfd_backend_get_hugetlb,
-                                   memfd_backend_set_hugetlb,
-                                   &error_abort);
-    object_class_property_add(oc, "hugetlbsize", "int",
-                              memfd_backend_get_hugetlbsize,
-                              memfd_backend_set_hugetlbsize,
-                              NULL, NULL, &error_abort);
-    object_class_property_add_bool(oc, "seal",
-                                   memfd_backend_get_seal,
-                                   memfd_backend_set_seal,
-                                   &error_abort);
+    if (qemu_memfd_check(MFD_HUGETLB)) {
+        object_class_property_add_bool(oc, "hugetlb",
+                                       memfd_backend_get_hugetlb,
+                                       memfd_backend_set_hugetlb,
+                                       &error_abort);
+        object_class_property_add(oc, "hugetlbsize", "int",
+                                  memfd_backend_get_hugetlbsize,
+                                  memfd_backend_set_hugetlbsize,
+                                  NULL, NULL, &error_abort);
+    }
+    if (qemu_memfd_check(MFD_ALLOW_SEALING)) {
+        object_class_property_add_bool(oc, "seal",
+                                       memfd_backend_get_seal,
+                                       memfd_backend_set_seal,
+                                       &error_abort);
+    }
 }
 
 static const TypeInfo memfd_backend_info = {
@@ -164,7 +168,9 @@
 
 static void register_types(void)
 {
-    type_register_static(&memfd_backend_info);
+    if (qemu_memfd_check(0)) {
+        type_register_static(&memfd_backend_info);
+    }
 }
 
 type_init(register_types);