[XEN RFC PATCH 37/40] xen: introduce an arch helper to do NUMA init failed fallback

[Wei Chen <wei.chen@xxxxxxx>]

When Xen initialize NUMA failed, some architectures may need to
do fallback actions. For example, in device tree based NUMA, Arm
need to reset the distance between any two nodes.

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
 xen/arch/arm/numa.c        | 13 +++++++++++++
 xen/common/numa.c          |  3 +++
 xen/include/asm-arm/numa.h |  1 +
 xen/include/asm-x86/numa.h |  6 ++++++
 4 files changed, 23 insertions(+)

diff --git a/xen/arch/arm/numa.c b/xen/arch/arm/numa.c
index 6eebf8e8bc..2a18c97470 100644
--- a/xen/arch/arm/numa.c
+++ b/xen/arch/arm/numa.c
@@ -140,3 +140,16 @@ int __init arch_meminfo_get_ram_bank_range(int bank,
 
        return 0;
 }
+
+void __init arch_numa_init_failed_fallback(void)
+{
+    int i, j;
+
+    /* Reset all node distance to remote_distance */
+    for ( i = 0; i < MAX_NUMNODES; i++ ) {
+        for ( j = 0; j < MAX_NUMNODES; j++ ) {
+            numa_set_distance(i, j,
+                (i == j) ? NUMA_LOCAL_DISTANCE : NUMA_REMOTE_DISTANCE);
+        }
+    }
+}
diff --git a/xen/common/numa.c b/xen/common/numa.c
index d15c2fc311..88f1594127 100644
--- a/xen/common/numa.c
+++ b/xen/common/numa.c
@@ -405,4 +405,7 @@ void __init numa_initmem_init(unsigned long start_pfn, 
unsigned long end_pfn)
     cpumask_copy(&node_to_cpumask[0], cpumask_of(0));
     setup_node_bootmem(0, (u64)start_pfn << PAGE_SHIFT,
                     (u64)end_pfn << PAGE_SHIFT);
+
+    /* architecture specified fallback operations */
+    arch_numa_init_failed_fallback();
 }
diff --git a/xen/include/asm-arm/numa.h b/xen/include/asm-arm/numa.h
index dd31324b0b..a3982a94b6 100644
--- a/xen/include/asm-arm/numa.h
+++ b/xen/include/asm-arm/numa.h
@@ -28,6 +28,7 @@ extern s8 device_tree_numa;
 extern void numa_init(bool acpi_off);
 extern int numa_device_tree_init(const void *fdt);
 extern void numa_set_distance(nodeid_t from, nodeid_t to, uint32_t distance);
+extern void arch_numa_init_failed_fallback(void);
 
 /*
  * Temporary for fake NUMA node, when CPU, memory and distance
diff --git a/xen/include/asm-x86/numa.h b/xen/include/asm-x86/numa.h
index e63869135c..26280b0f3a 100644
--- a/xen/include/asm-x86/numa.h
+++ b/xen/include/asm-x86/numa.h
@@ -22,4 +22,10 @@ extern void init_cpu_to_node(void);
 void srat_parse_regions(u64 addr);
 unsigned int arch_get_dma_bitsize(void);
 
+/* Dummy function for numa init failed in numa_initmem_init */
+static inline void arch_numa_init_failed_fallback(void)
+{
+    return;
+}
+
 #endif
-- 
2.25.1