xen: allow balloon driver to use more than one memory region

Allow the xen balloon driver to populate its list of extra pages from
more than one region of memory.  This will allow platforms to provide
(for example) a region of low memory and a region of high memory.

The maximum possible number of extra regions is 128 (== E820MAX) which
is quite large so xen_extra_mem is placed in __initdata.  This is safe
as both xen_memory_setup() and balloon_init() are in __init.

The balloon regions themselves are not altered (i.e., there is still
only the one region).

[upstream git commit 8b5d44a]
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Conflicts:

	drivers/xen/balloon.c
[The "Add support for pv hugepages and support for huge balloon pages." has
a lot of these fixes in]

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 09688eb4a899b8bd64e28b4dd4142e851dbc70bb..43efed38fbd328ae71a8c7565a97b58b42eee270 100644 (file)
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -36,7 +36,7 @@ extern void xen_syscall_target(void);
 extern void xen_syscall32_target(void);
 
 /* Amount of extra memory space we add to the e820 ranges */
-phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
+struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
 
 /* 
  * The maximum amount of extra memory compared to the base size.  The
@@ -55,7 +55,7 @@ static void __init 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;
+       u64 extra_start = xen_extra_mem[0].start + xen_extra_mem[0].size;
 
        if (!pages)
                return;
@@ -65,7 +65,7 @@ static void __init xen_add_extra_mem(unsigned long pages)
 
        memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA");
 
-       xen_extra_mem_size += size;
+       xen_extra_mem[0].size += size;
 
        xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
 
@@ -238,7 +238,7 @@ char * __init xen_memory_setup(void)
 
        memcpy(map_raw, map, sizeof(map));
        e820.nr_map = 0;
-       xen_extra_mem_start = mem_end;
+       xen_extra_mem[0].start = mem_end;
        for (i = 0; i < memmap.nr_entries; i++) {
                unsigned long long end;
 
@@ -266,8 +266,8 @@ char * __init xen_memory_setup(void)
                                e820_add_region(end, delta, E820_UNUSABLE);
                }
 
-               if (map[i].size > 0 && end > xen_extra_mem_start)
-                       xen_extra_mem_start = end;
+               if (map[i].size > 0 && end > xen_extra_mem[0].start)
+                       xen_extra_mem[0].start = end;
 
                /* Add region if any remains */
                if (map[i].size > 0)
@@ -275,10 +275,10 @@ char * __init xen_memory_setup(void)
        }
        /* Align the balloon area so that max_low_pfn does not get set
         * to be at the _end_ of the PCI gap at the far end (fee01000).
-        * Note that xen_extra_mem_start gets set in the loop above to be
-        * past the last E820 region. */
-       if (xen_initial_domain() && (xen_extra_mem_start < (1ULL<<32)))
-               xen_extra_mem_start = (1ULL<<32);
+        * Note that the start of balloon area gets set in the loop above
+        * to be past the last E820 region. */
+       if (xen_initial_domain() && (xen_extra_mem[0].start < (1ULL<<32)))
+               xen_extra_mem[0].start = (1ULL<<32);
 
        /*
         * In domU, the ISA region is normal, usable memory, but we

diff --git a/include/xen/page.h b/include/xen/page.h
index 0be36b976f4b02905034532919e7fc576eba19d7..2ba101cc72244afd338299d25e6985c25294a7eb 100644 (file)
--- a/include/xen/page.h
+++ b/include/xen/page.h
@@ -3,6 +3,14 @@
 
 #include <asm/xen/page.h>
 
-extern phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
+struct xen_memory_region {
+       phys_addr_t start;
+       phys_addr_t size;
+};
+
+#define XEN_EXTRA_MEM_MAX_REGIONS 128 /* == E820MAX */
+
+extern __initdata
+struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS];
 
 #endif /* _XEN_PAGE_H */