1 files changed, 67 insertions, 1 deletions

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index a8a66a50d446..fa0269a99377 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -52,6 +52,8 @@ phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
 
 static __init void xen_add_extra_mem(unsigned long pages)
 {
+        unsigned long pfn;
+
         u64 size = (u64)pages * PAGE_SIZE;
         u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
 
@@ -66,6 +68,9 @@ static __init void xen_add_extra_mem(unsigned long pages)
         xen_extra_mem_size += size;
 
         xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
+
+        for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++)
+                __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
 }
 
 static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
@@ -104,7 +109,7 @@ static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
                 WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n",
                      start, end, ret);
                 if (ret == 1) {
-                        set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+                        __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
                         len++;
                 }
         }
@@ -138,12 +143,55 @@ static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
         return released;
 }
 
+static unsigned long __init xen_set_identity(const struct e820entry *list,
+                                             ssize_t map_size)
+{
+        phys_addr_t last = xen_initial_domain() ? 0 : ISA_END_ADDRESS;
+        phys_addr_t start_pci = last;
+        const struct e820entry *entry;
+        unsigned long identity = 0;
+        int i;
+
+        for (i = 0, entry = list; i < map_size; i++, entry++) {
+                phys_addr_t start = entry->addr;
+                phys_addr_t end = start + entry->size;
+
+                if (start < last)
+                        start = last;
+
+                if (end <= start)
+                        continue;
+
+                /* Skip over the 1MB region. */
+                if (last > end)
+                        continue;
+
+                if (entry->type == E820_RAM) {
+                        if (start > start_pci)
+                                identity += set_phys_range_identity(
+                                                PFN_UP(start_pci), PFN_DOWN(start));
+
+                        /* Without saving 'last' we would gooble RAM too
+                         * at the end of the loop. */
+                        last = end;
+                        start_pci = end;
+                        continue;
+                }
+                start_pci = min(start, start_pci);
+                last = end;
+        }
+        if (last > start_pci)
+                identity += set_phys_range_identity(
+                                        PFN_UP(start_pci), PFN_DOWN(last));
+        return identity;
+}
 /**
  * machine_specific_memory_setup - Hook for machine specific memory setup.
  **/
 char * __init xen_memory_setup(void)
 {
         static struct e820entry map[E820MAX] __initdata;
+        static struct e820entry map_raw[E820MAX] __initdata;
 
         unsigned long max_pfn = xen_start_info->nr_pages;
         unsigned long long mem_end;
@@ -151,6 +199,7 @@ char * __init xen_memory_setup(void)
         struct xen_memory_map memmap;
         unsigned long extra_pages = 0;
         unsigned long extra_limit;
+        unsigned long identity_pages = 0;
         int i;
         int op;
 
@@ -176,6 +225,7 @@ char * __init xen_memory_setup(void)
         }
         BUG_ON(rc);
 
+        memcpy(map_raw, map, sizeof(map));
         e820.nr_map = 0;
         xen_extra_mem_start = mem_end;
         for (i = 0; i < memmap.nr_entries; i++) {
@@ -194,6 +244,15 @@ char * __init xen_memory_setup(void)
                         end -= delta;
 
                         extra_pages += PFN_DOWN(delta);
+                        /*
+                         * Set RAM below 4GB that is not for us to be unusable.
+                         * This prevents "System RAM" address space from being
+                         * used as potential resource for I/O address (happens
+                         * when 'allocate_resource' is called).
+                         */
+                        if (delta &&
+                                (xen_initial_domain() && end < 0x100000000ULL))
+                                e820_add_region(end, delta, E820_UNUSABLE);
                 }
 
                 if (map[i].size > 0 && end > xen_extra_mem_start)
@@ -251,6 +310,13 @@ char * __init xen_memory_setup(void)
 
         xen_add_extra_mem(extra_pages);
 
+        /*
+         * Set P2M for all non-RAM pages and E820 gaps to be identity
+         * type PFNs. We supply it with the non-sanitized version
+         * of the E820.
+         */
+        identity_pages = xen_set_identity(map_raw, memmap.nr_entries);
+        printk(KERN_INFO "Set %ld page(s) to 1-1 mapping.\n", identity_pages);
         return "Xen";
 }