[PATCH v2 02/17] xen/arm: implement helpers to get and update NUMA status

[Wei Chen <wei.chen@xxxxxxx>]

NUMA has one global and one implementation specific switches. For
ACPI NUMA implementation, Xen has acpi_numa, so we introduce
device_tree_numa for device tree NUMA implementation. And use
enumerations to indicate init, off and on status.

arch_numa_disabled will get device_tree_numa status, but for
arch_numa_setup we have not provided boot arguments to setup
device_tree_numa. So we just return -EINVAL in this patch.

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
v1 -> v2:
1. Use arch_numa_disabled to replace numa_enable_with_firmware.
2. Introduce enumerations for device tree numa status.
3. Use common numa_disabled, drop Arm version numa_disabled.
4. Introduce arch_numa_setup for Arm.
5. Rename bad_srat to numa_bad.
6. Add numa_enable_with_firmware helper.
7. Add numa_disabled helper.
8. Refine commit message.
---
 xen/arch/arm/include/asm/numa.h | 17 +++++++++++++
 xen/arch/arm/numa.c             | 44 +++++++++++++++++++++++++++++++++
 xen/arch/x86/include/asm/numa.h |  1 -
 xen/include/xen/numa.h          |  1 +
 4 files changed, 62 insertions(+), 1 deletion(-)
 create mode 100644 xen/arch/arm/numa.c

diff --git a/xen/arch/arm/include/asm/numa.h b/xen/arch/arm/include/asm/numa.h
index 7d6ae36a19..52ca414e47 100644
--- a/xen/arch/arm/include/asm/numa.h
+++ b/xen/arch/arm/include/asm/numa.h
@@ -22,6 +22,12 @@ typedef u8 nodeid_t;
  */
 #define NR_NODE_MEMBLKS NR_MEM_BANKS
 
+enum dt_numa_status {
+    DT_NUMA_INIT,
+    DT_NUMA_ON,
+    DT_NUMA_OFF,
+};
+
 #else
 
 /* Fake one node for now. See also node_online_map. */
@@ -39,6 +45,17 @@ extern mfn_t first_valid_mfn;
 #define node_start_pfn(nid) (mfn_x(first_valid_mfn))
 #define __node_distance(a, b) (20)
 
+#define numa_disabled() (true)
+static inline bool arch_numa_unavailable(void)
+{
+    return true;
+}
+
+static inline bool arch_numa_broken(void)
+{
+    return true;
+}
+
 #endif
 
 #define arch_want_default_dmazone() (false)
diff --git a/xen/arch/arm/numa.c b/xen/arch/arm/numa.c
new file mode 100644
index 0000000000..1c02b6a25d
--- /dev/null
+++ b/xen/arch/arm/numa.c
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Arm Architecture support layer for NUMA.
+ *
+ * Copyright (C) 2021 Arm Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#include <xen/init.h>
+#include <xen/numa.h>
+
+static enum dt_numa_status __read_mostly device_tree_numa;
+
+void __init numa_fw_bad(void)
+{
+    printk(KERN_ERR "NUMA: device tree numa info table not used.\n");
+    device_tree_numa = DT_NUMA_OFF;
+}
+
+bool __init arch_numa_unavailable(void)
+{
+    return device_tree_numa != DT_NUMA_ON;
+}
+
+bool arch_numa_disabled(void)
+{
+    return device_tree_numa == DT_NUMA_OFF;
+}
+
+int __init arch_numa_setup(const char *opt)
+{
+    return -EINVAL;
+}
diff --git a/xen/arch/x86/include/asm/numa.h b/xen/arch/x86/include/asm/numa.h
index 7866afa408..61efe60a95 100644
--- a/xen/arch/x86/include/asm/numa.h
+++ b/xen/arch/x86/include/asm/numa.h
@@ -12,7 +12,6 @@ extern unsigned int numa_node_to_arch_nid(nodeid_t n);
 
 #define ZONE_ALIGN (1UL << (MAX_ORDER+PAGE_SHIFT))
 
-extern bool numa_disabled(void);
 extern nodeid_t setup_node(unsigned int pxm);
 extern void srat_detect_node(int cpu);
 
diff --git a/xen/include/xen/numa.h b/xen/include/xen/numa.h
index b86d0851fc..7d7aeb3a3c 100644
--- a/xen/include/xen/numa.h
+++ b/xen/include/xen/numa.h
@@ -55,6 +55,7 @@ extern void numa_init_array(void);
 extern void numa_set_node(unsigned int cpu, nodeid_t node);
 extern void numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn);
 extern void numa_fw_bad(void);
+extern bool numa_disabled(void);
 
 extern int arch_numa_setup(const char *opt);
 extern bool arch_numa_unavailable(void);
-- 
2.25.1