1 files changed, 72 insertions, 0 deletions

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index ad0047f47cd4..328b00305426 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -20,6 +20,7 @@
 #include <xen/page.h>
 #include <xen/interface/callback.h>
 #include <xen/interface/physdev.h>
+#include <xen/interface/memory.h>
 #include <xen/features.h>
 
 #include "xen-ops.h"
@@ -32,6 +33,73 @@ extern void xen_sysenter_target(void);
 extern void xen_syscall_target(void);
 extern void xen_syscall32_target(void);
 
+static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
+                                              phys_addr_t end_addr)
+{
+        struct xen_memory_reservation reservation = {
+                .address_bits = 0,
+                .extent_order = 0,
+                .domid        = DOMID_SELF
+        };
+        unsigned long start, end;
+        unsigned long len = 0;
+        unsigned long pfn;
+        int ret;
+
+        start = PFN_UP(start_addr);
+        end = PFN_DOWN(end_addr);
+
+        if (end <= start)
+                return 0;
+
+        printk(KERN_INFO "xen_release_chunk: looking at area pfn %lx-%lx: ",
+               start, end);
+        for(pfn = start; pfn < end; pfn++) {
+                unsigned long mfn = pfn_to_mfn(pfn);
+
+                /* Make sure pfn exists to start with */
+                if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
+                        continue;
+
+                set_xen_guest_handle(reservation.extent_start, &mfn);
+                reservation.nr_extents = 1;
+
+                ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
+                                           &reservation);
+                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);
+                        len++;
+                }
+        }
+        printk(KERN_CONT "%ld pages freed\n", len);
+
+        return len;
+}
+
+static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
+                                                     const struct e820map *e820)
+{
+        phys_addr_t max_addr = PFN_PHYS(max_pfn);
+        phys_addr_t last_end = 0;
+        unsigned long released = 0;
+        int i;
+
+        for (i = 0; i < e820->nr_map && last_end < max_addr; i++) {
+                phys_addr_t end = e820->map[i].addr;
+                end = min(max_addr, end);
+
+                released += xen_release_chunk(last_end, end);
+                last_end = e820->map[i].addr + e820->map[i].size;
+        }
+
+        if (last_end < max_addr)
+                released += xen_release_chunk(last_end, max_addr);
+
+        printk(KERN_INFO "released %ld pages of unused memory\n", released);
+        return released;
+}
 
 /**
  * machine_specific_memory_setup - Hook for machine specific memory setup.
@@ -67,6 +135,8 @@ 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);
+
         return "Xen";
 }
 
@@ -156,6 +226,8 @@ void __init xen_arch_setup(void)
         struct physdev_set_iopl set_iopl;
         int rc;
 
+        xen_panic_handler_init();
+
         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);