[xen staging] xen/arm: Keep memory nodes in device tree when Xen boots from EFI

[patchbot@xxxxxxx]

commit 53701ecb8f8b124b62ff50925032468c2df3745e
Author:     Wei Chen <wei.chen@xxxxxxx>
AuthorDate: Fri Jun 10 13:53:10 2022 +0800
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Fri Jun 17 09:36:12 2022 +0100

    xen/arm: Keep memory nodes in device tree when Xen boots from EFI
    
    In current code, when Xen is booting from EFI, it will delete
    all memory nodes in device tree. This would work well in current
    stage, because Xen can get memory map from EFI system table.
    However, EFI system table cannot completely replace memory nodes
    of device tree. EFI system table doesn't contain memory NUMA
    information. Xen depends on ACPI SRAT or device tree memory nodes
    to parse memory blocks' NUMA mapping. So in EFI + DTB boot, Xen
    doesn't have any method to get numa-node-id for memory blocks any
    more. This makes device tree based NUMA support become impossible
    for Xen in EFI + DTB boot.
    
    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.
    
    Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
    Tested-by: Jiamei Xie <jiamei.xie@xxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 xen/arch/arm/bootfdt.c      |  8 +++++++-
 xen/arch/arm/efi/efi-boot.h | 25 -------------------------
 2 files changed, 7 insertions(+), 26 deletions(-)

diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
index 29671c8df0..ec81a45de9 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>
@@ -367,7 +368,12 @@ 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 are
+     * 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 e452b687d8..59d93c24a1 100644
--- a/xen/arch/arm/efi/efi-boot.h
+++ b/xen/arch/arm/efi/efi-boot.h
@@ -231,33 +231,8 @@ 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.
--
generated by git-patchbot for /home/xen/git/xen.git#staging