Update the memory_op() hypercall. Add two new subcommands, to

query a domain's current and maximum memory reservation. Also,
XENMEM_maximum_ram_page now returns the max_page directly,
rather than writing through a passed-in pointer.

Also, disable PAE in the default config (accidentally checked
in two changesets ago).

Signed-off-by: Keir Fraser <keir@xensource.com>

Config.mk

@@ -3,7 +3,7 @@
 # Currently supported architectures: x86_32, x86_64
 XEN_COMPILE_ARCH    ?= $(shell uname -m | sed -e s/i.86/x86_32/)
 XEN_TARGET_ARCH     ?= $(XEN_COMPILE_ARCH)
-XEN_TARGET_X86_PAE  ?= y
+XEN_TARGET_X86_PAE  ?= n
 
 # Tools to run on system hosting the build
 HOSTCC     = gcc

linux-2.6-xen-sparse/arch/xen/i386/kernel/swiotlb.c

@@ -178,6 +178,8 @@ swiotlb_init_with_default_size (size_t default_size)
 void
 swiotlb_init(void)
 {
+	long ram_end;
+
 	/* The user can forcibly enable swiotlb. */
 	if (swiotlb_force)
 		swiotlb = 1;
@@ -187,9 +189,7 @@ swiotlb_init(void)
          * which we take to mean more than 2GB.
          */
 	if (xen_start_info->flags & SIF_INITDOMAIN) {
-		unsigned long ram_end;
-		if (HYPERVISOR_memory_op(XENMEM_maximum_ram_page, &ram_end))
-			BUG();
+		ram_end = HYPERVISOR_memory_op(XENMEM_maximum_ram_page, NULL);
 		if (ram_end > 0x7ffff)
 			swiotlb = 1;
 	}

linux-2.6-xen-sparse/arch/xen/x86_64/kernel/e820.c

@@ -586,7 +586,7 @@ void __init e820_reserve_resources(void)
 	free_bootmem(__pa(map), PAGE_SIZE);
 
 	if (!found) {
-		HYPERVISOR_memory_op(XENMEM_maximum_ram_page, &gapstart);
+		gapstart = HYPERVISOR_memory_op(XENMEM_maximum_ram_page, NULL);
 		gapstart = (gapstart << PAGE_SHIFT) + 1024*1024;
 		printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit address range\n"
 		       KERN_ERR "PCI: Unassigned devices with 32bit resource registers may break!\n");

tools/libxc/xc_private.c

@@ -214,13 +214,6 @@ int xc_memory_op(int xc_handle,
             goto out1;
         }
         break;
-    case XENMEM_maximum_ram_page:
-        if ( mlock(arg, sizeof(unsigned long)) != 0 )
-        {
-            PERROR("Could not mlock");
-            goto out1;
-        }
-        break;
     }
 
     ret = do_xen_hypercall(xc_handle, &hypercall);
@@ -234,9 +227,6 @@ int xc_memory_op(int xc_handle,
             safe_munlock(reservation->extent_start,
                          reservation->nr_extents * sizeof(unsigned long));
         break;
-    case XENMEM_maximum_ram_page:
-        safe_munlock(arg, sizeof(unsigned long));
-        break;
     }
 
  out1:

tools/libxc/xg_save_restore.h

@@ -64,7 +64,6 @@ static int get_platform_info(int xc_handle, uint32_t dom,
 { 
     xen_capabilities_info_t xen_caps = "";
     xen_platform_parameters_t xen_params;
-    
 
     if (xc_version(xc_handle, XENVER_platform_parameters, &xen_params) != 0)
         return 0;
@@ -72,8 +71,7 @@ static int get_platform_info(int xc_handle, uint32_t dom,
     if (xc_version(xc_handle, XENVER_capabilities, &xen_caps) != 0)
         return 0;
 
-    if (xc_memory_op(xc_handle, XENMEM_maximum_ram_page, max_mfn) != 0)
-        return 0; 
+    *max_mfn = xc_memory_op(xc_handle, XENMEM_maximum_ram_page, NULL);
     
     *hvirt_start = xen_params.virt_start;
 

xen/common/memory.c

@@ -136,6 +136,7 @@ long do_memory_op(int cmd, void *arg)
     struct domain *d;
     int rc, start_extent, op, flags = 0, preempted = 0;
     struct xen_memory_reservation reservation;
+    domid_t domid;
 
     op = cmd & ((1 << START_EXTENT_SHIFT) - 1);
 
@@ -191,9 +192,26 @@ long do_memory_op(int cmd, void *arg)
         break;
 
     case XENMEM_maximum_ram_page:
-        if ( put_user(max_page, (unsigned long *)arg) )
+        rc = max_page;
+        break;
+
+    case XENMEM_current_reservation:
+    case XENMEM_maximum_reservation:
+        if ( get_user(domid, (domid_t *)arg) )
             return -EFAULT;
-        rc = 0;
+
+        if ( likely((domid = (unsigned long)arg) == DOMID_SELF) )
+            d = current->domain;
+        else if ( !IS_PRIV(current->domain) )
+            return -EPERM;
+        else if ( (d = find_domain_by_id(domid)) == NULL )
+            return -ESRCH;
+
+        rc = (op == XENMEM_current_reservation) ? d->tot_pages : d->max_pages;
+
+        if ( unlikely(domid != DOMID_SELF) )
+            put_domain(d);
+
         break;
 
     default:

xen/include/public/memory.h

@@ -9,15 +9,13 @@
 #ifndef __XEN_PUBLIC_MEMORY_H__
 #define __XEN_PUBLIC_MEMORY_H__
 
-/* arg == addr of struct xen_memory_reservation. */
+/*
+ * Increase or decrease the specified domain's memory reservation. Returns a
+ * -ve errcode on failure, or the # extents successfully allocated or freed.
+ * arg == addr of struct xen_memory_reservation.
+ */
 #define XENMEM_increase_reservation 0
-
-/* arg == addr of struct xen_memory_reservation. */
 #define XENMEM_decrease_reservation 1
-
-/* arg == addr of unsigned long. */
-#define XENMEM_maximum_ram_page     2
-
 typedef struct xen_memory_reservation {
 
     /*
@@ -47,6 +45,21 @@ typedef struct xen_memory_reservation {
 
 } xen_memory_reservation_t;
 
+/*
+ * Returns the maximum machine frame number of mapped RAM in this system.
+ * This command always succeeds (it never returns an error code).
+ * arg == NULL.
+ */
+#define XENMEM_maximum_ram_page     2
+
+/*
+ * Returns the current or maximum memory reservation, in pages, of the
+ * specified domain (may be DOMID_SELF). Returns -ve errcode on failure.
+ * arg == addr of domid_t.
+ */
+#define XENMEM_current_reservation  3
+#define XENMEM_maximum_reservation  4
+
 #endif /* __XEN_PUBLIC_MEMORY_H__ */
 
 /*