X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=arch%2Fx86%2Fxen%2Fsetup.c;fp=arch%2Fx86%2Fxen%2Fsetup.c;h=105db2501050483901a3ba9be6b37310b4152481;hp=9729c903404b1633a0eaed2b06bd0cfadabf9aa7;hb=520045db940a381d2bee1c1b2179f7921b40fb10;hpb=426e1f5cec4821945642230218876b0e89aafab1

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 9729c903404b..105db2501050 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -18,8 +18,10 @@
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
 
+#include <xen/xen.h>
 #include <xen/page.h>
 #include <xen/interface/callback.h>
+#include <xen/interface/memory.h>
 #include <xen/interface/physdev.h>
 #include <xen/interface/memory.h>
 #include <xen/features.h>
@@ -34,6 +36,39 @@ extern void xen_sysenter_target(void);
 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;
+
+/* 
+ * The maximum amount of extra memory compared to the base size.  The
+ * main scaling factor is the size of struct page.  At extreme ratios
+ * of base:extra, all the base memory can be filled with page
+ * structures for the extra memory, leaving no space for anything
+ * else.
+ * 
+ * 10x seems like a reasonable balance between scaling flexibility and
+ * leaving a practically usable system.
+ */
+#define EXTRA_MEM_RATIO		(10)
+
+static __init void xen_add_extra_mem(unsigned long pages)
+{
+	u64 size = (u64)pages * PAGE_SIZE;
+	u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
+
+	if (!pages)
+		return;
+
+	e820_add_region(extra_start, size, E820_RAM);
+	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+
+	memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA");
+
+	xen_extra_mem_size += size;
+
+	xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
+}
+
 static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
 					      phys_addr_t end_addr)
 {
@@ -105,16 +140,65 @@ static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
 /**
  * machine_specific_memory_setup - Hook for machine specific memory setup.
  **/
-
 char * __init xen_memory_setup(void)
 {
+	static struct e820entry map[E820MAX] __initdata;
+
 	unsigned long max_pfn = xen_start_info->nr_pages;
+	unsigned long long mem_end;
+	int rc;
+	struct xen_memory_map memmap;
+	unsigned long extra_pages = 0;
+	unsigned long extra_limit;
+	int i;
+	int op;
 
 	max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
+	mem_end = PFN_PHYS(max_pfn);
+
+	memmap.nr_entries = E820MAX;
+	set_xen_guest_handle(memmap.buffer, map);
+
+	op = xen_initial_domain() ?
+		XENMEM_machine_memory_map :
+		XENMEM_memory_map;
+	rc = HYPERVISOR_memory_op(op, &memmap);
+	if (rc == -ENOSYS) {
+		memmap.nr_entries = 1;
+		map[0].addr = 0ULL;
+		map[0].size = mem_end;
+		/* 8MB slack (to balance backend allocations). */
+		map[0].size += 8ULL << 20;
+		map[0].type = E820_RAM;
+		rc = 0;
+	}
+	BUG_ON(rc);
 
 	e820.nr_map = 0;
+	xen_extra_mem_start = mem_end;
+	for (i = 0; i < memmap.nr_entries; i++) {
+		unsigned long long end = map[i].addr + map[i].size;
+
+		if (map[i].type == E820_RAM) {
+			if (map[i].addr < mem_end && end > mem_end) {
+				/* Truncate region to max_mem. */
+				u64 delta = end - mem_end;
+
+				map[i].size -= delta;
+				extra_pages += PFN_DOWN(delta);
+
+				end = mem_end;
+			}
+		}
 
-	e820_add_region(0, PFN_PHYS((u64)max_pfn), E820_RAM);
+		if (end > xen_extra_mem_start)
+			xen_extra_mem_start = end;
+
+		/* If region is non-RAM or below mem_end, add what remains */
+		if ((map[i].type != E820_RAM || map[i].addr < mem_end) &&
+		    map[i].size > 0)
+			e820_add_region(map[i].addr, map[i].size, map[i].type);
+	}
 
 	/*
 	 * Even though this is normal, usable memory under Xen, reserve
@@ -136,7 +220,29 @@ char * __init xen_memory_setup(void)
 
 	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
 
-	xen_return_unused_memory(xen_start_info->nr_pages, &e820);
+	extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820);
+
+	/*
+	 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
+	 * factor the base size.  On non-highmem systems, the base
+	 * size is the full initial memory allocation; on highmem it
+	 * is limited to the max size of lowmem, so that it doesn't
+	 * get completely filled.
+	 *
+	 * In principle there could be a problem in lowmem systems if
+	 * the initial memory is also very large with respect to
+	 * lowmem, but we won't try to deal with that here.
+	 */
+	extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
+			  max_pfn + extra_pages);
+
+	if (extra_limit >= max_pfn)
+		extra_pages = extra_limit - max_pfn;
+	else
+		extra_pages = 0;
+
+	if (!xen_initial_domain())
+		xen_add_extra_mem(extra_pages);
 
 	return "Xen";
 }