[v4,2/3] xen/arm: Extend the memory overlap check to include bootmodules

Commit Message

Henry Wang Feb. 1, 2023, 2:15 a.m. UTC

Similarly as the static regions defined in bootinfo.reserved_mem,
the bootmodule regions defined in bootinfo.modules should also not
be overlapping with memory regions in either bootinfo.reserved_mem
or bootinfo.modules.

Therefore, this commit introduces a helper `bootmodules_overlap_check()`
and uses this helper to extend the check in function
`check_reserved_regions_overlap()` so that memory regions in
bootinfo.modules are included. Use `check_reserved_regions_overlap()`
in `add_boot_module()` to return early if any error occurs.

Signed-off-by: Henry Wang <[e-mail]>
Reviewed-by: Stefano Stabellini <[e-mail]>
---
v3 -> v4:
1. Correct printk error message, end should be exclusive.
2. Add comment explaining the unhandled case where '*_end' could be 0
   if the module/region is at the end of the physical address space.
3. Add Stefano's reviewed-by tag.
v2 -> v3:
1. Use "[start, end]" format in printk error message.
2. Change the return type of helper functions to bool.
3. Use 'start' and 'size' in helper functions to describe a region.
v1 -> v2:
1. Split original `overlap_check()` to `bootmodules_overlap_check()`.
2. Rework commit message.
---
 xen/arch/arm/setup.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

Patch

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 28c79a413f..1ea42a0386 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -291,6 +291,36 @@  static bool __init meminfo_overlap_check(struct meminfo *meminfo,
     return false;
 }
 
+/*
+ * TODO: '*_end' could be 0 if the module/region is at the end of the physical
+ * address space. This is for now not handled as it requires more rework.
+ */
+static bool __init bootmodules_overlap_check(struct bootmodules *bootmodules,
+                                             paddr_t region_start,
+                                             paddr_t region_size)
+{
+    paddr_t mod_start = INVALID_PADDR, mod_end = 0;
+    paddr_t region_end = region_start + region_size;
+    unsigned int i, mod_num = bootmodules->nr_mods;
+
+    for ( i = 0; i < mod_num; i++ )
+    {
+        mod_start = bootmodules->module[i].start;
+        mod_end = mod_start + bootmodules->module[i].size;
+
+        if ( region_end <= mod_start || region_start >= mod_end )
+            continue;
+        else
+        {
+            printk("Region: [%#"PRIpaddr", %#"PRIpaddr") overlapping with mod[%u]: [%#"PRIpaddr", %#"PRIpaddr")\n",
+                   region_start, region_end, i, mod_start, mod_end);
+            return true;
+        }
+    }
+
+    return false;
+}
+
 void __init fw_unreserved_regions(paddr_t s, paddr_t e,
                                   void (*cb)(paddr_t, paddr_t),
                                   unsigned int first)
@@ -315,6 +345,11 @@  bool __init check_reserved_regions_overlap(paddr_t region_start,
                                region_start, region_size) )
         return true;
 
+    /* Check if input region is overlapping with bootmodules */
+    if ( bootmodules_overlap_check(&bootinfo.modules,
+                                   region_start, region_size) )
+        return true;
+
     return false;
 }
 
@@ -332,6 +367,10 @@  struct bootmodule __init *add_boot_module(bootmodule_kind kind,
                boot_module_kind_as_string(kind), start, start + size);
         return NULL;
     }
+
+    if ( check_reserved_regions_overlap(start, size) )
+        return NULL;
+
     for ( i = 0 ; i < mods->nr_mods ; i++ )
     {
         mod = &mods->module[i];