vircgroup: introduce virCgroupV2DevicesGetKey

Device rules are stored in BPF map that is a hash type, this function
will create a key based on major and minor id of device.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/libvirt_private.syms

@@ -1721,6 +1721,7 @@ virCgroupV2DevicesAttachProg;
 virCgroupV2DevicesAvailable;
 virCgroupV2DevicesCreateProg;
 virCgroupV2DevicesDetectProg;
+virCgroupV2DevicesGetKey;
 virCgroupV2DevicesGetPerms;
 virCgroupV2DevicesPrepareProg;
 virCgroupV2DevicesRemoveProg;

src/util/vircgroupv2devices.c

@@ -647,3 +647,11 @@ virCgroupV2DevicesGetPerms(int perms G_GNUC_UNUSED,
     return 0;
 }
 #endif /* !HAVE_DECL_BPF_CGROUP_DEVICE */
+
+
+uint64_t
+virCgroupV2DevicesGetKey(int major,
+                         int minor)
+{
+    return (uint64_t)major << 32 | ((uint64_t)minor & 0x00000000ffffffff);
+}

src/util/vircgroupv2devices.h

@@ -45,3 +45,7 @@ virCgroupV2DevicesRemoveProg(virCgroupPtr group);
 uint32_t
 virCgroupV2DevicesGetPerms(int perms,
                            char type);
+
+uint64_t
+virCgroupV2DevicesGetKey(int major,
+                         int minor);