[xen master] xen/arm: Account for domU dtb bootmodule size separately

[patchbot@xxxxxxx]

commit d27d274ffab06b42e5680073db11b592d282d53d
Author:     Michal Orzel <michal.orzel@xxxxxxx>
AuthorDate: Tue Jul 11 10:29:31 2023 +0200
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Fri Jul 14 17:34:43 2023 +0100

    xen/arm: Account for domU dtb bootmodule size separately
    
    At the moment, we limit the allocation size when creating a domU dtb to
    4KB, which is not enough when using a passthrough dtb with several nodes.
    Improve the handling by accounting for a dtb bootmodule (if present)
    size separately, while keeping 4KB for the Xen generated nodes (still
    plenty of space for new nodes). Also, cap the allocation size to 2MB,
    which is the max dtb size allowed.
    
    Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
    Acked-by: Julien Grall <jgrall@xxxxxxxxxx>
    Reviewed-by: Luca Fancellu <luca.fancellu@xxxxxxx>
---
 xen/arch/arm/domain_build.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index f2134f24b9..1dc0eca37b 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -3257,14 +3257,15 @@ static int __init domain_handle_dtb_bootmodule(struct 
domain *d,
 }
 
 /*
- * The max size for DT is 2MB. However, the generated DT is small, 4KB
- * are enough for now, but we might have to increase it in the future.
+ * The max size for DT is 2MB. However, the generated DT is small (not 
including
+ * domU passthrough DT nodes whose size we account separately), 4KB are enough
+ * for now, but we might have to increase it in the future.
  */
 #define DOMU_DTB_SIZE 4096
 static int __init prepare_dtb_domU(struct domain *d, struct kernel_info *kinfo)
 {
     int addrcells, sizecells;
-    int ret;
+    int ret, fdt_size = DOMU_DTB_SIZE;
 
     kinfo->phandle_gic = GUEST_PHANDLE_GIC;
     kinfo->gnttab_start = GUEST_GNTTAB_BASE;
@@ -3273,11 +3274,18 @@ static int __init prepare_dtb_domU(struct domain *d, 
struct kernel_info *kinfo)
     addrcells = GUEST_ROOT_ADDRESS_CELLS;
     sizecells = GUEST_ROOT_SIZE_CELLS;
 
-    kinfo->fdt = xmalloc_bytes(DOMU_DTB_SIZE);
+    /* Account for domU passthrough DT size */
+    if ( kinfo->dtb_bootmodule )
+        fdt_size += kinfo->dtb_bootmodule->size;
+
+    /* Cap to max DT size if needed */
+    fdt_size = min(fdt_size, SZ_2M);
+
+    kinfo->fdt = xmalloc_bytes(fdt_size);
     if ( kinfo->fdt == NULL )
         return -ENOMEM;
 
-    ret = fdt_create(kinfo->fdt, DOMU_DTB_SIZE);
+    ret = fdt_create(kinfo->fdt, fdt_size);
     if ( ret < 0 )
         goto err;
 
--
generated by git-patchbot for /home/xen/git/xen.git#master