[PATCH 08/37] xen/x86: add detection of discontinous node memory range

[Wei Chen <wei.chen@xxxxxxx>]

One NUMA node may contain several memory blocks. In current Xen
code, Xen will maintain a node memory range for each node to cover
all its memory blocks. But here comes the problem, in the gap of
one node's two memory blocks, if there are some memory blocks don't
belong to this node (remote memory blocks). This node's memory range
will be expanded to cover these remote memory blocks.

One node's memory range contains othe nodes' memory, this is obviously
not very reasonable. This means current NUMA code only can support
node has continous memory blocks. However, on a physical machine, the
addresses of multiple nodes can be interleaved.

So in this patch, we add code to detect discontinous memory blocks
for one node. NUMA initializtion will be failed and error messages
will be printed when Xen detect such hardware configuration.

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
 xen/arch/x86/srat.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/xen/arch/x86/srat.c b/xen/arch/x86/srat.c
index 7d20d7f222..2f08fa4660 100644
--- a/xen/arch/x86/srat.c
+++ b/xen/arch/x86/srat.c
@@ -271,6 +271,36 @@ acpi_numa_processor_affinity_init(const struct 
acpi_srat_cpu_affinity *pa)
                       pxm, pa->apic_id, node);
 }
 
+/*
+ * Check to see if there are other nodes within this node's range.
+ * We just need to check full contains situation. Because overlaps
+ * have been checked before by conflicting_memblks.
+ */
+static bool __init is_node_memory_continuous(nodeid_t nid,
+    paddr_t start, paddr_t end)
+{
+       nodeid_t i;
+
+       struct node *nd = &nodes[nid];
+       for_each_node_mask(i, memory_nodes_parsed)
+       {
+               /* Skip itself */
+               if (i == nid)
+                       continue;
+
+               nd = &nodes[i];
+               if (start < nd->start && nd->end < end)
+               {
+                       printk(KERN_ERR
+                              "NODE %u: (%"PRIpaddr"-%"PRIpaddr") intertwine 
with NODE %u (%"PRIpaddr"-%"PRIpaddr")\n",
+                              nid, start, end, i, nd->start, nd->end);
+                       return false;
+               }
+       }
+
+       return true;
+}
+
 /* Callback for parsing of the Proximity Domain <-> Memory Area mappings */
 void __init
 acpi_numa_memory_affinity_init(const struct acpi_srat_mem_affinity *ma)
@@ -344,6 +374,12 @@ acpi_numa_memory_affinity_init(const struct 
acpi_srat_mem_affinity *ma)
                                nd->start = start;
                        if (nd->end < end)
                                nd->end = end;
+
+                       /* Check whether this range contains memory for other 
nodes */
+                       if (!is_node_memory_continuous(node, nd->start, 
nd->end)) {
+                               bad_srat();
+                               return;
+                       }
                }
        }
        printk(KERN_INFO "SRAT: Node %u PXM %u %"PRIpaddr"-%"PRIpaddr"%s\n",
-- 
2.25.1