[PATCH v2 5/9] xen/x86: use arch_get_memory_map to get information from E820 map

[Wei Chen <wei.chen@xxxxxxx>]

The sanity check performed by the nodes_cover_memory function is
also necessary for other architectures that do not yet support NUMA.
But now, the code of nodes_cover_memory is tied to the x86 E820.
In this case, we introduce arch_get_memory_map to decouple
architecture specific memory map from this function. This means,
other architectures like Arm can also use it to check its bootmem
info.

Depending on arch_get_memory_map, we make nodes_cover_memory become
architecture independent. We also use neutral words to replace
SRAT and E820 in the print message of this function. This will
make the message more common.

As arch_get_memory_map use unsigned int for index, we also adjust
the index in nodes_cover_memory from int to unsigned int.

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
v1 -> v2:
1. Use arch_get_memory_map to replace arch_get_memory_bank_range
   and arch_get_memory_bank_number.
2. Remove the !start || !end check, because caller guarantee
   these two pointers will not be NULL.
---
 xen/arch/x86/numa.c    | 23 +++++++++++++++++++++++
 xen/arch/x86/srat.c    | 18 +++++++++++-------
 xen/include/xen/numa.h |  3 +++
 3 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/numa.c b/xen/arch/x86/numa.c
index 193314dbd9..fb235c07ec 100644
--- a/xen/arch/x86/numa.c
+++ b/xen/arch/x86/numa.c
@@ -9,6 +9,7 @@
 #include <xen/nodemask.h>
 #include <xen/numa.h>
 #include <asm/acpi.h>
+#include <asm/e820.h>
 
 #ifndef Dprintk
 #define Dprintk(x...)
@@ -82,3 +83,25 @@ unsigned int __init arch_get_dma_bitsize(void)
                  flsl(node_start_pfn(node) + node_spanned_pages(node) / 4 - 1)
                  + PAGE_SHIFT, 32);
 }
+
+/*
+ * This function provides the ability for caller to get one RAM entry
+ * from architectural memory map by index.
+ *
+ * This function will return zero if it can return a proper RAM entry.
+ * otherwise it will return -ENODEV for out of scope index, or return
+ * -EINVAL for non-RAM type memory entry.
+ */
+int __init arch_get_memory_map(unsigned int idx, paddr_t *start, paddr_t *end)
+{
+    if ( idx >= e820.nr_map )
+        return -ENODEV;
+
+    if ( e820.map[idx].type != E820_RAM )
+        return -EINVAL;
+
+    *start = e820.map[idx].addr;
+    *end = e820.map[idx].addr + e820.map[idx].size;
+
+    return 0;
+}
diff --git a/xen/arch/x86/srat.c b/xen/arch/x86/srat.c
index 422e4c73e3..5bc9096a15 100644
--- a/xen/arch/x86/srat.c
+++ b/xen/arch/x86/srat.c
@@ -427,18 +427,22 @@ acpi_numa_memory_affinity_init(const struct 
acpi_srat_mem_affinity *ma)
    Make sure the PXMs cover all memory. */
 static int __init nodes_cover_memory(void)
 {
-       int i;
+       unsigned int i;
 
-       for (i = 0; i < e820.nr_map; i++) {
+       for (i = 0; ; i++) {
                int j, found;
                paddr_t start, end;
 
-               if (e820.map[i].type != E820_RAM) {
+               /* Try to loop memory map from index 0 to end. */
+               found = arch_get_memory_map(i, &start, &end);
+
+               /* Index relate entry is not RAM, skip it. */
+               if (found == -EINVAL)
                        continue;
-               }
 
-               start = e820.map[i].addr;
-               end = e820.map[i].addr + e820.map[i].size;
+               /* Reach the end of arch's memory map */
+               if (found == -ENODEV)
+                       break;
 
                do {
                        found = 0;
@@ -457,7 +461,7 @@ static int __init nodes_cover_memory(void)
                } while (found && start < end);
 
                if (start < end) {
-                       printk(KERN_ERR "SRAT: No PXM for e820 range: "
+                       printk(KERN_ERR "NUMA: No node for memory map range: "
                                "[%"PRIpaddr", %"PRIpaddr"]\n", start, end - 1);
                        return 0;
                }
diff --git a/xen/include/xen/numa.h b/xen/include/xen/numa.h
index 695ad51df0..6d02204991 100644
--- a/xen/include/xen/numa.h
+++ b/xen/include/xen/numa.h
@@ -88,6 +88,9 @@ static inline __attribute__((pure)) nodeid_t 
phys_to_nid(paddr_t addr)
 #define node_end_pfn(nid)       (NODE_DATA(nid)->node_start_pfn + \
                                 NODE_DATA(nid)->node_spanned_pages)
 
+extern int arch_get_memory_map(unsigned int idx,
+                               paddr_t *start, paddr_t *end);
+
 #endif
 
 #endif /* _XEN_NUMA_H */
-- 
2.25.1