mini-os: respect memory map when ballooning up

Today Mini-OS won't look at the memory map when ballooning up. This can
result in problems for PVH domains with more than 4 GB of RAM, as
ballooning will happily run into the ACPI area.

Fix that by adding only pages being marked as RAM in the memory map and
by distinguishing between the current number of RAM pages and the first
unallocated page.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

diff --git a/arch/arm/mm.c b/arch/arm/mm.c
index 90681661a380b7ca058f2ac761bd11d318353029..11962f8baf7986bf95f48d76f661b92498e6fd2e 100644 (file)
--- a/arch/arm/mm.c
+++ b/arch/arm/mm.c
@@ -3,6 +3,7 @@
 #include <arch_mm.h>
 #include <mini-os/errno.h>
 #include <mini-os/hypervisor.h>
+#include <mini-os/balloon.h>
 #include <libfdt.h>
 #include <lib.h>
 
@@ -70,6 +71,8 @@ void arch_init_mm(unsigned long *start_pfn_p, unsigned long *max_pfn_p)
     }
     device_tree = new_device_tree;
     *max_pfn_p = to_phys(new_device_tree) >> PAGE_SHIFT;
+
+    balloon_set_nr_pages(*max_pfn_p, *max_pfn_p);
 }
 
 void arch_init_demand_mapping_area(void)

diff --git a/arch/x86/balloon.c b/arch/x86/balloon.c
index 10b440ce5eead6bcc30516622c266ceda4396865..fe7964472d6a52e385bdf357f81bd69a2b396e2d 100644 (file)
--- a/arch/x86/balloon.c
+++ b/arch/x86/balloon.c
@@ -61,10 +61,10 @@ void arch_remap_p2m(unsigned long max_pfn)
     p2m_invalidate(l2_list, L2_P2M_IDX(max_pfn - 1) + 1);
     p2m_invalidate(l1_list, L1_P2M_IDX(max_pfn - 1) + 1);
 
-    if ( p2m_pages(nr_max_pages) <= p2m_pages(max_pfn) )
+    if ( p2m_pages(nr_max_pfn) <= p2m_pages(max_pfn) )
         return;
 
-    new_p2m = alloc_virt_kernel(p2m_pages(nr_max_pages));
+    new_p2m = alloc_virt_kernel(p2m_pages(nr_max_pfn));
     for ( pfn = 0; pfn < max_pfn; pfn += P2M_ENTRIES )
     {
         map_frame_rw(new_p2m + PAGE_SIZE * (pfn / P2M_ENTRIES),

diff --git a/arch/x86/mm.c b/arch/x86/mm.c
index 3bf6170a4543d712f2d03732232ab5cb351c448c..c30d8bc8f4fc13b61dffed65770a2ebfdf07e574 100644 (file)
--- a/arch/x86/mm.c
+++ b/arch/x86/mm.c
@@ -72,6 +72,7 @@ void arch_mm_preinit(void *p)
     pt_base = (pgentry_t *)si->pt_base;
     first_free_pfn = PFN_UP(to_phys(pt_base)) + si->nr_pt_frames;
     last_free_pfn = si->nr_pages;
+    balloon_set_nr_pages(last_free_pfn, last_free_pfn);
 }
 #else
 #include <mini-os/desc.h>
@@ -118,6 +119,7 @@ void arch_mm_preinit(void *p)
     }
 
     last_free_pfn = e820_get_maxpfn(ret);
+    balloon_set_nr_pages(ret, last_free_pfn);
 }
 #endif
 

diff --git a/balloon.c b/balloon.c
index 5676d3b47a1fdc3032a28d288048838e30069a79..9dc77c545cbe5a05e1587f0877f5345b57a94f5c 100644 (file)
--- a/balloon.c
+++ b/balloon.c
@@ -23,14 +23,24 @@
 
 #include <mini-os/os.h>
 #include <mini-os/balloon.h>
+#include <mini-os/e820.h>
 #include <mini-os/errno.h>
 #include <mini-os/lib.h>
 #include <mini-os/paravirt.h>
 #include <xen/xen.h>
 #include <xen/memory.h>
 
-unsigned long nr_max_pages;
-unsigned long nr_mem_pages;
+unsigned long nr_max_pfn;
+
+static unsigned long nr_max_pages;
+static unsigned long nr_mem_pfn;
+static unsigned long nr_mem_pages;
+
+void balloon_set_nr_pages(unsigned long pages, unsigned long pfn)
+{
+    nr_mem_pages = pages;
+    nr_mem_pfn = pfn;
+}
 
 void get_max_pages(void)
 {
@@ -46,16 +56,18 @@ void get_max_pages(void)
 
     nr_max_pages = ret;
     printk("Maximum memory size: %ld pages\n", nr_max_pages);
+
+    nr_max_pfn = e820_get_maxpfn(nr_max_pages);
 }
 
 void mm_alloc_bitmap_remap(void)
 {
     unsigned long i, new_bitmap;
 
-    if ( mm_alloc_bitmap_size >= ((nr_max_pages + 1) >> 3) )
+    if ( mm_alloc_bitmap_size >= ((nr_max_pfn + 1) >> 3) )
         return;
 
-    new_bitmap = alloc_virt_kernel(PFN_UP((nr_max_pages + 1) >> 3));
+    new_bitmap = alloc_virt_kernel(PFN_UP((nr_max_pfn + 1) >> 3));
     for ( i = 0; i < mm_alloc_bitmap_size; i += PAGE_SIZE )
     {
         map_frame_rw(new_bitmap + i,
@@ -70,7 +82,7 @@ static unsigned long balloon_frames[N_BALLOON_FRAMES];
 
 int balloon_up(unsigned long n_pages)
 {
-    unsigned long page, pfn;
+    unsigned long page, pfn, start_pfn;
     int rc;
     struct xen_memory_reservation reservation = {
         .domid        = DOMID_SELF
@@ -81,8 +93,11 @@ int balloon_up(unsigned long n_pages)
     if ( n_pages > N_BALLOON_FRAMES )
         n_pages = N_BALLOON_FRAMES;
 
+    start_pfn = e820_get_maxpfn(nr_mem_pages + 1) - 1;
+    n_pages = e820_get_max_contig_pages(start_pfn, n_pages);
+
     /* Resize alloc_bitmap if necessary. */
-    while ( mm_alloc_bitmap_size * 8 < nr_mem_pages + n_pages )
+    while ( mm_alloc_bitmap_size * 8 < start_pfn + n_pages )
     {
         page = alloc_page();
         if ( !page )
@@ -99,14 +114,14 @@ int balloon_up(unsigned long n_pages)
         mm_alloc_bitmap_size += PAGE_SIZE;
     }
 
-    rc = arch_expand_p2m(nr_mem_pages + n_pages);
+    rc = arch_expand_p2m(start_pfn + n_pages);
     if ( rc )
         return rc;
 
     /* Get new memory from hypervisor. */
     for ( pfn = 0; pfn < n_pages; pfn++ )
     {
-        balloon_frames[pfn] = nr_mem_pages + pfn;
+        balloon_frames[pfn] = start_pfn + pfn;
     }
     set_xen_guest_handle(reservation.extent_start, balloon_frames);
     reservation.nr_extents = n_pages;
@@ -116,7 +131,7 @@ int balloon_up(unsigned long n_pages)
 
     for ( pfn = 0; pfn < rc; pfn++ )
     {
-        arch_pfn_add(nr_mem_pages + pfn, balloon_frames[pfn]);
+        arch_pfn_add(start_pfn + pfn, balloon_frames[pfn]);
         free_page(pfn_to_virt(nr_mem_pages + pfn));
     }
 

diff --git a/e820.c b/e820.c
index 4c726d1f3879b2975a1de42eaf9705032ff62015..d60eb83eed2366c75ea28cddeb06cdc83b6c27b2 100644 (file)
--- a/e820.c
+++ b/e820.c
@@ -290,7 +290,8 @@ unsigned long e820_get_maxpfn(unsigned long pages)
     int i;
     unsigned long pfns = 0, start = 0;
 
-    e820_get_memmap();
+    if ( !e820_entries )
+        e820_get_memmap();
 
     for ( i = 0; i < e820_entries; i++ )
     {
@@ -305,3 +306,21 @@ unsigned long e820_get_maxpfn(unsigned long pages)
 
     return start + pfns;
 }
+
+unsigned long e820_get_max_contig_pages(unsigned long pfn, unsigned long pages)
+{
+    int i;
+    unsigned long end;
+
+    for ( i = 0; i < e820_entries && e820_map[i].addr <= (pfn << PAGE_SHIFT);
+          i++ )
+    {
+        end = (e820_map[i].addr + e820_map[i].size) >> PAGE_SHIFT;
+        if ( e820_map[i].type != E820_RAM || end <= pfn )
+            continue;
+
+        return ((end - pfn) > pages) ? pages : end - pfn;
+    }
+
+    return 0;
+}

diff --git a/include/balloon.h b/include/balloon.h
index 6cfec4ffb60701fd7ede85f9352f22d4d24bce1e..8f7c8bd8fa158602b5e8143704a5452f429206d7 100644 (file)
--- a/include/balloon.h
+++ b/include/balloon.h
@@ -32,11 +32,11 @@
  */
 #define BALLOON_EMERGENCY_PAGES   64
 
-extern unsigned long nr_max_pages;
-extern unsigned long nr_mem_pages;
+extern unsigned long nr_max_pfn;
 
 void get_max_pages(void);
 int balloon_up(unsigned long n_pages);
+void balloon_set_nr_pages(unsigned long pages, unsigned long pfn);
 
 void mm_alloc_bitmap_remap(void);
 void arch_pfn_add(unsigned long pfn, unsigned long mfn);
@@ -50,6 +50,7 @@ static inline int chk_free_pages(unsigned long needed)
 {
     return needed <= nr_free_pages;
 }
+static inline balloon_set_nr_pages(unsigned long pages, unsigned long pfn) { }
 
 #endif /* CONFIG_BALLOON */
 #endif /* _BALLOON_H_ */

diff --git a/include/e820.h b/include/e820.h
index 6a57f05ec28f6a098fd7ce52c601ea2ff6a0a71f..8d4d371f5a5404c41e3aba3fd99ba40843754227 100644 (file)
--- a/include/e820.h
+++ b/include/e820.h
@@ -50,5 +50,6 @@ extern struct e820entry e820_map[];
 extern unsigned e820_entries;
 
 unsigned long e820_get_maxpfn(unsigned long pages);
+unsigned long e820_get_max_contig_pages(unsigned long pfn, unsigned long pages);
 
 #endif /*__E820_HEADER*/

diff --git a/mm.c b/mm.c
index 932ceebc2867a3a2cdf982751d6ce70f4e195741..6493bdd4ea5ed2ab9cdc6a61d01cfe07f4d3c83c 100644 (file)
--- a/mm.c
+++ b/mm.c
@@ -396,8 +396,9 @@ void init_mm(void)
 
     printk("MM: Init\n");
 
-    get_max_pages();
     arch_init_mm(&start_pfn, &max_pfn);
+    get_max_pages();
+
     /*
      * now we can initialise the page allocator
      */
@@ -407,10 +408,6 @@ void init_mm(void)
     arch_init_p2m(max_pfn);
     
     arch_init_demand_mapping_area();
-
-#ifdef CONFIG_BALLOON
-    nr_mem_pages = max_pfn;
-#endif
 }
 
 void fini_mm(void)