[PATCH 21/37] xen/arm: Keep memory nodes in dtb for NUMA when boot from EFI

[Wei Chen <wei.chen@xxxxxxx>]

EFI can get memory map from EFI system table. But EFI system
table doesn't contain memory NUMA information, EFI depends on
ACPI SRAT or device tree memory node to parse memory blocks'
NUMA mapping.

But in current code, when Xen is booting from EFI, it will
delete all memory nodes in device tree. So in UEFI + DTB
boot, we don't have numa-node-id for memory blocks any more.

So in this patch, we will keep memory nodes in device tree for
NUMA code to parse memory numa-node-id later.

As a side effect, if we still parse boot memory information in
early_scan_node, bootmem.info will calculate memory ranges in
memory nodes twice. So we have to prevent early_scan_node to
parse memory nodes in EFI boot.

As EFI APIs only can be used in Arm64, so we introduced a stub
API for non-EFI supported Arm32. This will prevent

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
 xen/arch/arm/bootfdt.c      |  8 +++++++-
 xen/arch/arm/efi/efi-boot.h | 25 -------------------------
 xen/include/xen/efi.h       |  7 +++++++
 3 files changed, 14 insertions(+), 26 deletions(-)

diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
index afaa0e249b..6bc5a465ec 100644
--- a/xen/arch/arm/bootfdt.c
+++ b/xen/arch/arm/bootfdt.c
@@ -11,6 +11,7 @@
 #include <xen/lib.h>
 #include <xen/kernel.h>
 #include <xen/init.h>
+#include <xen/efi.h>
 #include <xen/device_tree.h>
 #include <xen/libfdt/libfdt.h>
 #include <xen/sort.h>
@@ -370,7 +371,12 @@ static int __init early_scan_node(const void *fdt,
 {
     int rc = 0;
 
-    if ( device_tree_node_matches(fdt, node, "memory") )
+    /*
+     * If Xen has been booted via UEFI, the memory banks will already
+     * be populated. So we should skip the parsing.
+     */
+    if ( !efi_enabled(EFI_BOOT) &&
+         device_tree_node_matches(fdt, node, "memory"))
         rc = process_memory_node(fdt, node, name, depth,
                                  address_cells, size_cells, &bootinfo.mem);
     else if ( depth == 1 && !dt_node_cmp(name, "reserved-memory") )
diff --git a/xen/arch/arm/efi/efi-boot.h b/xen/arch/arm/efi/efi-boot.h
index cf9c37153f..d0a9987fa4 100644
--- a/xen/arch/arm/efi/efi-boot.h
+++ b/xen/arch/arm/efi/efi-boot.h
@@ -197,33 +197,8 @@ EFI_STATUS __init fdt_add_uefi_nodes(EFI_SYSTEM_TABLE 
*sys_table,
     int status;
     u32 fdt_val32;
     u64 fdt_val64;
-    int prev;
     int num_rsv;
 
-    /*
-     * Delete any memory nodes present.  The EFI memory map is the only
-     * memory description provided to Xen.
-     */
-    prev = 0;
-    for (;;)
-    {
-        const char *type;
-        int len;
-
-        node = fdt_next_node(fdt, prev, NULL);
-        if ( node < 0 )
-            break;
-
-        type = fdt_getprop(fdt, node, "device_type", &len);
-        if ( type && strncmp(type, "memory", len) == 0 )
-        {
-            fdt_del_node(fdt, node);
-            continue;
-        }
-
-        prev = node;
-    }
-
    /*
     * Delete all memory reserve map entries. When booting via UEFI,
     * kernel will use the UEFI memory map to find reserved regions.
diff --git a/xen/include/xen/efi.h b/xen/include/xen/efi.h
index 661a48286a..b52a4678e9 100644
--- a/xen/include/xen/efi.h
+++ b/xen/include/xen/efi.h
@@ -47,6 +47,13 @@ int efi_runtime_call(struct xenpf_efi_runtime_call *);
 int efi_compat_get_info(uint32_t idx, union compat_pf_efi_info *);
 int efi_compat_runtime_call(struct compat_pf_efi_runtime_call *);
 
+#else
+
+static inline bool efi_enabled(unsigned int feature)
+{
+    return false;
+}
+
 #endif /* CONFIG_EFI*/
 
 #endif /* !__ASSEMBLY__ */
-- 
2.25.1