1 files changed, 26 insertions, 16 deletions

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 500290b150bb..43f9f02c7db0 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -50,6 +50,7 @@
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>
 #include <asm/tlb.h>
+#include <asm/e820.h>
 
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
@@ -119,7 +120,7 @@ static void scrub_page(struct page *page)
 }
 
 /* balloon_append: add the given page to the balloon. */
-static void balloon_append(struct page *page)
+static void __balloon_append(struct page *page)
 {
         /* Lowmem is re-populated first, so highmem pages go at list tail. */
         if (PageHighMem(page)) {
@@ -130,7 +131,11 @@ static void balloon_append(struct page *page)
                 list_add(&page->lru, &ballooned_pages);
                 balloon_stats.balloon_low++;
         }
+}
 
+static void balloon_append(struct page *page)
+{
+        __balloon_append(page);
         totalram_pages--;
 }
 
@@ -191,7 +196,7 @@ static unsigned long current_target(void)
 
 static int increase_reservation(unsigned long nr_pages)
 {
-        unsigned long  pfn, i, flags;
+        unsigned long  pfn, i;
         struct page   *page;
         long           rc;
         struct xen_memory_reservation reservation = {
@@ -203,8 +208,6 @@ static int increase_reservation(unsigned long nr_pages)
         if (nr_pages > ARRAY_SIZE(frame_list))
                 nr_pages = ARRAY_SIZE(frame_list);
 
-        spin_lock_irqsave(&xen_reservation_lock, flags);
-
         page = balloon_first_page();
         for (i = 0; i < nr_pages; i++) {
                 BUG_ON(page == NULL);
@@ -247,14 +250,12 @@ static int increase_reservation(unsigned long nr_pages)
         balloon_stats.current_pages += rc;
 
  out:
-        spin_unlock_irqrestore(&xen_reservation_lock, flags);
-
         return rc < 0 ? rc : rc != nr_pages;
 }
 
 static int decrease_reservation(unsigned long nr_pages)
 {
-        unsigned long  pfn, i, flags;
+        unsigned long  pfn, i;
         struct page   *page;
         int            need_sleep = 0;
         int ret;
@@ -292,8 +293,6 @@ static int decrease_reservation(unsigned long nr_pages)
         kmap_flush_unused();
         flush_tlb_all();
 
-        spin_lock_irqsave(&xen_reservation_lock, flags);
-
         /* No more mappings: invalidate P2M and add to balloon. */
         for (i = 0; i < nr_pages; i++) {
                 pfn = mfn_to_pfn(frame_list[i]);
@@ -308,8 +307,6 @@ static int decrease_reservation(unsigned long nr_pages)
 
         balloon_stats.current_pages -= nr_pages;
 
-        spin_unlock_irqrestore(&xen_reservation_lock, flags);
-
         return need_sleep;
 }
 
@@ -395,7 +392,7 @@ static struct notifier_block xenstore_notifier;
 
 static int __init balloon_init(void)
 {
-        unsigned long pfn;
+        unsigned long pfn, extra_pfn_end;
         struct page *page;
 
         if (!xen_pv_domain())
@@ -415,11 +412,24 @@ static int __init balloon_init(void)
 
         register_balloon(&balloon_sysdev);
 
-        /* Initialise the balloon with excess memory space. */
-        for (pfn = xen_start_info->nr_pages; pfn < max_pfn; pfn++) {
+        /*
+         * Initialise the balloon with excess memory space.  We need
+         * to make sure we don't add memory which doesn't exist or
+         * logically exist.  The E820 map can be trimmed to be smaller
+         * than the amount of physical memory due to the mem= command
+         * line parameter.  And if this is a 32-bit non-HIGHMEM kernel
+         * on a system with memory which requires highmem to access,
+         * don't try to use it.
+         */
+        extra_pfn_end = min(min(max_pfn, e820_end_of_ram_pfn()),
+                            (unsigned long)PFN_DOWN(xen_extra_mem_start + xen_extra_mem_size));
+        for (pfn = PFN_UP(xen_extra_mem_start);
+             pfn < extra_pfn_end;
+             pfn++) {
                 page = pfn_to_page(pfn);
-                if (!PageReserved(page))
-                        balloon_append(page);
+                /* totalram_pages doesn't include the boot-time
+                   balloon extension, so don't subtract from it. */
+                __balloon_append(page);
         }
 
         target_watch.callback = watch_target;