diff -r a24dbfcbdf69 tools/python/xen/xend/XendCheckpoint.py
--- a/tools/python/xen/xend/XendCheckpoint.py	Tue Jun 22 07:19:38 2010 +0100
+++ b/tools/python/xen/xend/XendCheckpoint.py	Tue Jun 22 12:52:56 2010 +0200
@@ -64,6 +64,78 @@ def insert_after(list, pred, value):
               list.insert (i+1, value)
     return
 
+def get_avail_memory():
+    """Get available memory for new guest creation (in KiB, for restore)"""
+    from xen.xend import XendOptions
+
+    # First get total memory in KiB
+    xc = xen.lowlevel.xc.xc()
+    info = xc.domain_getinfo()
+    total_mem  = xc.physinfo()['total_memory']
+    del xc
+
+    # Count memory of all running guests in KiB
+    mem_used = 0L
+    for x in info:
+        if x['domid'] != 0:
+            # If blocked & paused & !paused & no online_vcpus we most
+            # probably migrate so we get maxmem instead (since mem_kb
+            # is having currently transferred amount of memory so we
+            # cannot use it for good calculations)
+            if (x['blocked'] == 1 and x['paused'] == 1 and
+                x['running'] == 0 and x['online_vcpus'] == 0):
+                log.debug("Domain %d seems to be restoring" % x['domid'])
+                mem_used += x['maxmem_kb']
+            else:
+                mem_used += x['mem_kb']
+
+    # Get minimal memory for dom0 and convert to KiB
+    min_mem = XendOptions.instance().get_dom0_min_mem() * 1024
+
+    return total_mem - mem_used - min_mem
+
+def check_for_restore_bail(msg):
+    raise VmError("Cannot restore: %s" % msg)
+
+def check_for_enough_mem(val):
+    mem_avail = get_avail_memory() / 1024
+    log.debug("Available memory: %s MiB, guest requires: %s MiB" % (mem_avail, val))
+    return int(mem_avail) > int(val)
+
+def check_for_restore_is_hvm(cfg):
+    for item in cfg:
+        if (type(item) == list):
+           if item[0] == 'image':
+               return type(item[1]) == list and item[1][0] == 'hvm'
+
+def check_for_restore_hvm_have_readonly_ide(cfg):
+    """Check the configuration for read-only IDE devices
+       Fail if such a device is found."""
+    disallow = None
+    if type(cfg) == list and cfg[0] in ('tap', 'vbd'):
+        for p in cfg:
+            if (type(p) != str):
+                if p[0] == 'dev':
+                    disallow = ((p[1].find('hd') >= 0) and
+                                (p[1].find('cdrom') == -1))
+                if p[0] == 'mode' and disallow:
+                    if p[1] == 'r':
+                        return True
+    return False
+
+def check_for_restore(cfg):
+    is_hvm = check_for_restore_is_hvm(cfg)
+    name = None
+    for item in cfg:
+        if (type(item) == list):
+            # Check for enough memory to create the guest
+            if item[0] == 'memory':
+                if not check_for_enough_mem(item[1]):
+                    check_for_restore_bail('Host machine doesn\'t have enough memory to create the guest')
+            # We disable read-only IDE drives only for HVM guests
+            if item[0] == 'device' and is_hvm:
+                if check_for_restore_hvm_have_readonly_ide(item[1]):
+                    check_for_restore_bail('HVM domains cannot be using read-only IDE drives')
 
 def save(fd, dominfo, network, live, dst, checkpoint=False, node=-1):
     from xen.xend import XendDomain
@@ -220,6 +292,7 @@ def restore(xd, fd, dominfo = None, paus
             othervm = xd.domain_lookup_nr(domconfig["uuid"])
         if othervm is not None and othervm.domid is not None: 
             raise VmError("Domain '%s' already exists with ID '%d'" % (domconfig["name_label"], othervm.domid))
+        check_for_restore(vmconfig)
 
     if dominfo:
         dominfo.resume()
diff -r a24dbfcbdf69 tools/python/xen/xend/XendDomainInfo.py
--- a/tools/python/xen/xend/XendDomainInfo.py	Tue Jun 22 07:19:38 2010 +0100
+++ b/tools/python/xen/xend/XendDomainInfo.py	Tue Jun 22 12:52:56 2010 +0200
@@ -82,6 +82,32 @@ log = logging.getLogger("xend.XendDomain
 log = logging.getLogger("xend.XendDomainInfo")
 #log.setLevel(logging.TRACE)
 
+def cfg_is_hvm(cfg):
+    for item in cfg:
+        if (type(item) == list):
+           if item[0] == 'image':
+               return type(item[1]) == list and item[1][0] == 'hvm'
+
+def cfg_hvm_have_readonly_ide_disks(cfg):
+    """Check whether the configuration for read-only IDE disks since
+       they are not supported according to IDE specifications."""
+    if not cfg_is_hvm(cfg):
+        return False
+
+    disallow = None
+    for item in cfg:
+        if (type(item) == list):
+            if item[0] == 'device':
+                if type(item[1]) == list and item[1][0] in ('tap', 'vbd'):
+                    for p in item[1]:
+                        if (type(p) != str):
+                            if p[0] == 'dev':
+                              disallow = ((p[1].find('hd') >= 0) and
+                                          (p[1].find('cdrom') == -1))
+                        if p[0] == 'mode' and disallow:
+                            if p[1] == 'r':
+                                return True
+    return False
 
 def create(config):
     """Creates and start a VM using the supplied configuration. 
@@ -100,6 +126,10 @@ def create(config):
         othervm = XendDomain.instance().domain_lookup_nr(domconfig["uuid"])
     if othervm is not None and othervm.domid is not None:
         raise VmError("Domain '%s' already exists with ID '%d'" % (domconfig["name_label"], othervm.domid))
+
+    if cfg_hvm_have_readonly_ide_disks(config):
+        raise VmError("HVM domains cannot be using read-only IDE drives")
+
     log.debug("XendDomainInfo.create(%s)", scrub_password(config))
     vm = XendDomainInfo(domconfig)
     try: