[PATCH 5/6] xen/arm: map reserved-memory regions as normal memory in dom0

[Stefano Stabellini <sstabellini@kernel.org>]

reserved-memory regions should be mapped as normal memory. At the
moment, they get remapped as device memory in dom0 because Xen doesn't
know any better. Add an explicit check for it.

However, reserved-memory regions are allowed to overlap partially or
completely with memory nodes. In these cases, the overlapping memory is
reserved-memory and should be handled accordingly.

Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
---
 xen/arch/arm/domain_build.c |  7 ++++
 xen/arch/arm/setup.c        | 84 +++++++++++++++++++++++++++++++++++++--------
 2 files changed, 77 insertions(+), 14 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index f552154..c7df4cf 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1307,6 +1307,13 @@ static int __init handle_node(struct domain *d, struct kernel_info *kinfo,
                "WARNING: Path %s is reserved, skip the node as we may re-use the path.\n",
                path);
 
+    /*
+     * reserved-memory ranges should be mapped as normal memory in the
+     * p2m.
+     */
+    if ( !strcmp(dt_node_name(node), "reserved-memory") )
+        p2mt = p2m_ram_rw;
+
     res = handle_device(d, node, p2mt);
     if ( res)
         return res;
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 80f0028..74c4707 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -470,10 +470,52 @@ static void __init init_pdx(void)
     }
 }
 
+static void __init check_reserved_memory(paddr_t *bank_start, paddr_t *bank_size)
+{
+    paddr_t bank_end = *bank_start + *bank_size;
+    struct meminfo mem = bootinfo.mem;
+    int i;
+
+    for ( i = 0; i < bootinfo.reserved_mem.nr_banks; i++ )
+    {
+        struct membank rbank = bootinfo.reserved_mem.bank[i];
+
+        if ( *bank_start < rbank.start && bank_end <= rbank.start )
+            continue;
+
+        if ( *bank_start >= (rbank.start + rbank.size) )
+            continue;
+
+        /* memory bank overlaps with reserved memory region */
+        if ( rbank.start > *bank_start )
+        {
+            bank_end = rbank.start;
+            if ( *bank_start + *bank_size > rbank.start + rbank.size )
+            {
+                mem.bank[mem.nr_banks].start = rbank.start + rbank.size;
+                mem.bank[mem.nr_banks].size = *bank_start + *bank_size -
+                    mem.bank[mem.nr_banks].start;
+                mem.nr_banks++;
+            }
+        }
+        else if ( rbank.start + rbank.size > *bank_start)
+        {
+           if (rbank.start + rbank.size < bank_end )
+               *bank_start = rbank.start + rbank.size;
+           else
+               *bank_start = bank_end;
+        }
+
+        *bank_size = bank_end - *bank_start;
+    }
+}
+
 #ifdef CONFIG_ARM_32
 static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
 {
-    paddr_t ram_start, ram_end, ram_size;
+    paddr_t ram_start = ~0;
+    paddr_t ram_end = 0;
+    paddr_t ram_size = 0;
     paddr_t s, e;
     unsigned long ram_pages;
     unsigned long heap_pages, xenheap_pages, domheap_pages;
@@ -487,18 +529,19 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
 
     init_pdx();
 
-    ram_start = bootinfo.mem.bank[0].start;
-    ram_size  = bootinfo.mem.bank[0].size;
-    ram_end   = ram_start + ram_size;
-
-    for ( i = 1; i < bootinfo.mem.nr_banks; i++ )
+    for ( i = 0; i < bootinfo.mem.nr_banks; i++ )
     {
-        paddr_t bank_start = bootinfo.mem.bank[i].start;
-        paddr_t bank_size = bootinfo.mem.bank[i].size;
-        paddr_t bank_end = bank_start + bank_size;
+        paddr_t bank_end;
 
-        ram_size  = ram_size + bank_size;
-        ram_start = min(ram_start,bank_start);
+        check_reserved_memory(&bootinfo.mem.bank[i].start,
+                              &bootinfo.mem.bank[i].size);
+
+        if ( !bootinfo.mem.bank[i].size )
+            continue;
+
+        bank_end = bootinfo.mem.bank[i].start + bootinfo.mem.bank[i].size;
+        ram_size  = ram_size + bootinfo.mem.bank[i].size;
+        ram_start = min(ram_start, bootinfo.mem.bank[i].start);
         ram_end   = max(ram_end,bank_end);
     }
 
@@ -570,6 +613,9 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
         paddr_t bank_start = bootinfo.mem.bank[i].start;
         paddr_t bank_end = bank_start + bootinfo.mem.bank[i].size;
 
+        if ( !bootinfo.mem.bank[i].size )
+            continue;
+
         s = bank_start;
         while ( s < bank_end )
         {
@@ -627,11 +673,21 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
     total_pages = 0;
     for ( bank = 0 ; bank < bootinfo.mem.nr_banks; bank++ )
     {
-        paddr_t bank_start = bootinfo.mem.bank[bank].start;
-        paddr_t bank_size = bootinfo.mem.bank[bank].size;
-        paddr_t bank_end = bank_start + bank_size;
+        paddr_t bank_start;
+        paddr_t bank_size;
+        paddr_t bank_end;
         paddr_t s, e;
 
+        check_reserved_memory(&bootinfo.mem.bank[bank].start,
+                              &bootinfo.mem.bank[bank].size);
+
+        bank_start = bootinfo.mem.bank[bank].start;
+        bank_size = bootinfo.mem.bank[bank].size;
+        bank_end = bank_start + bank_size;
+
+        if ( !bank_size )
+            continue;
+
         ram_size = ram_size + bank_size;
         ram_start = min(ram_start,bank_start);
         ram_end = max(ram_end,bank_end);
-- 
1.9.1


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