[xen staging] xen/arm: fix duplicate /reserved-memory node in Dom0

[patchbot@xxxxxxx]

commit 51a2b3f109189ec2f3ea9a14921e6976e6098577
Author:     Penny Zheng <Penny.Zheng@xxxxxxx>
AuthorDate: Thu Apr 18 08:36:51 2024 +0100
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Wed Apr 24 19:13:35 2024 +0100

    xen/arm: fix duplicate /reserved-memory node in Dom0
    
    In case there is a /reserved-memory node already present in the host
    dtb, current Xen codes would create yet another /reserved-memory node
    when the static shared memory feature is enabled and static shared
    memory regions are present.
    This would result in an incorrect device tree generation and hwdom
    would not be able to detect the static shared memory region.
    
    Avoid this issue by checking the presence of the /reserved-memory
    node and appending the nodes instead of generating a duplicate
    /reserved-memory.
    
    Make make_shm_memory_node externally visible and rename it to
    make_shm_resv_memory_node to make clear it produces childs for
    /reserved-memory.
    
    Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
    Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
    Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
---
 xen/arch/arm/domain_build.c             | 23 ++++++++++++++++++++---
 xen/arch/arm/include/asm/static-shmem.h |  9 +++++++++
 xen/arch/arm/static-shmem.c             |  8 ++++----
 3 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 0cc39b0bd7..68532ddc08 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1640,6 +1640,7 @@ static int __init handle_node(struct domain *d, struct 
kernel_info *kinfo,
         DT_MATCH_PATH("/hypervisor"),
         { /* sentinel */ },
     };
+    static __initdata bool res_mem_node_found = false;
     struct dt_device_node *child;
     int res, i, nirq, irq_id;
     const char *name;
@@ -1734,6 +1735,19 @@ static int __init handle_node(struct domain *d, struct 
kernel_info *kinfo,
     if ( res )
         return res;
 
+    if ( dt_node_path_is_equal(node, "/reserved-memory") )
+    {
+        res_mem_node_found = true;
+        /*
+         * Avoid duplicate /reserved-memory nodes in Device Tree, so add the
+         * static shared memory nodes there.
+         */
+        res = make_shm_resv_memory_node(kinfo, dt_n_addr_cells(node),
+                                        dt_n_size_cells(node));
+        if ( res )
+            return res;
+    }
+
     for ( child = node->child; child != NULL; child = child->sibling )
     {
         res = handle_node(d, kinfo, child, p2mt);
@@ -1786,9 +1800,12 @@ static int __init handle_node(struct domain *d, struct 
kernel_info *kinfo,
                 return res;
         }
 
-        res = make_resv_memory_node(kinfo, addrcells, sizecells);
-        if ( res )
-            return res;
+        if ( !res_mem_node_found )
+        {
+            res = make_resv_memory_node(kinfo, addrcells, sizecells);
+            if ( res )
+                return res;
+        }
     }
 
     res = fdt_end_node(kinfo->fdt);
diff --git a/xen/arch/arm/include/asm/static-shmem.h 
b/xen/arch/arm/include/asm/static-shmem.h
index 2e8b138eb9..7495a91e7a 100644
--- a/xen/arch/arm/include/asm/static-shmem.h
+++ b/xen/arch/arm/include/asm/static-shmem.h
@@ -34,6 +34,9 @@ int remove_shm_from_rangeset(const struct kernel_info *kinfo,
 int remove_shm_holes_for_domU(const struct kernel_info *kinfo,
                               struct membanks *ext_regions);
 
+int make_shm_resv_memory_node(const struct kernel_info *kinfo, int addrcells,
+                              int sizecells);
+
 #else /* !CONFIG_STATIC_SHM */
 
 static inline int make_resv_memory_node(const struct kernel_info *kinfo,
@@ -77,6 +80,12 @@ static inline int remove_shm_holes_for_domU(const struct 
kernel_info *kinfo,
     return 0;
 }
 
+static inline int make_shm_resv_memory_node(const struct kernel_info *kinfo,
+                                            int addrcells, int sizecells)
+{
+    return 0;
+}
+
 #endif /* CONFIG_STATIC_SHM */
 
 #endif /* __ASM_STATIC_SHMEM_H_ */
diff --git a/xen/arch/arm/static-shmem.c b/xen/arch/arm/static-shmem.c
index 12e2df9399..c85f60dd1b 100644
--- a/xen/arch/arm/static-shmem.c
+++ b/xen/arch/arm/static-shmem.c
@@ -297,8 +297,8 @@ int __init process_shm(struct domain *d, struct kernel_info 
*kinfo,
     return 0;
 }
 
-static int __init make_shm_memory_node(const struct kernel_info *kinfo,
-                                       int addrcells, int sizecells)
+int __init make_shm_resv_memory_node(const struct kernel_info *kinfo,
+                                     int addrcells, int sizecells)
 {
     const struct membanks *mem = &kinfo->shm_mem.common;
     void *fdt = kinfo->fdt;
@@ -306,7 +306,7 @@ static int __init make_shm_memory_node(const struct 
kernel_info *kinfo,
     int res = 0;
 
     if ( mem->nr_banks == 0 )
-        return -ENOENT;
+        return 0;
 
     /*
      * For each shared memory region, a range is exposed under
@@ -544,7 +544,7 @@ int __init make_resv_memory_node(const struct kernel_info 
*kinfo, int addrcells,
     if ( res )
         return res;
 
-    res = make_shm_memory_node(kinfo, addrcells, sizecells);
+    res = make_shm_resv_memory_node(kinfo, addrcells, sizecells);
     if ( res )
         return res;
 
--
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