diff -r 85f92475b943 tools/libxc/xc_linux_build.c
--- a/tools/libxc/xc_linux_build.c	Mon Oct  3 18:14:02 2005
+++ b/tools/libxc/xc_linux_build.c	Tue Oct  4 16:37:44 2005
@@ -847,7 +847,7 @@
 
     launch_op.u.setdomaininfo.domain = (domid_t)domid;
     launch_op.u.setdomaininfo.vcpu   = 0;
-    launch_op.u.setdomaininfo.ctxt   = ctxt;
+    launch_op.u.setdomaininfo.ctxt.ptr = ctxt;
 
     launch_op.cmd = DOM0_SETDOMAININFO;
     rc = xc_dom0_op(xc_handle, &launch_op);
diff -r 85f92475b943 tools/libxc/xc_linux_restore.c
--- a/tools/libxc/xc_linux_restore.c	Mon Oct  3 18:14:02 2005
+++ b/tools/libxc/xc_linux_restore.c	Tue Oct  4 16:37:44 2005
@@ -631,7 +631,7 @@
     op.cmd = DOM0_SETDOMAININFO;
     op.u.setdomaininfo.domain = (domid_t)dom;
     op.u.setdomaininfo.vcpu   = 0;
-    op.u.setdomaininfo.ctxt   = &ctxt;
+    op.u.setdomaininfo.ctxt.ptr = &ctxt;
     rc = xc_dom0_op(xc_handle, &op);
 
     if ( rc != 0 )
diff -r 85f92475b943 tools/libxc/xc_ptrace.c
--- a/tools/libxc/xc_ptrace.c	Mon Oct  3 18:14:02 2005
+++ b/tools/libxc/xc_ptrace.c	Tue Oct  4 16:37:44 2005
@@ -385,7 +385,7 @@
         op.u.setdomaininfo.domain = domid;
         /* XXX need to understand multiple vcpus */
         op.u.setdomaininfo.vcpu = cpu;
-        op.u.setdomaininfo.ctxt = &ctxt[cpu];
+        op.u.setdomaininfo.ctxt.ptr = &ctxt[cpu];
         retval = do_dom0_op(xc_handle, &op);
         if (retval)
             goto error_out;
@@ -416,7 +416,7 @@
         op.cmd = DOM0_SETDOMAININFO;
         op.u.setdomaininfo.domain = domid;
         op.u.setdomaininfo.vcpu = 0;
-        op.u.setdomaininfo.ctxt = &ctxt[cpu];
+        op.u.setdomaininfo.ctxt.ptr = &ctxt[cpu];
         retval = do_dom0_op(xc_handle, &op); 
         if ( retval )
         {
@@ -437,7 +437,7 @@
                 op.cmd = DOM0_SETDOMAININFO;
                 op.u.setdomaininfo.domain = domid;
                 op.u.setdomaininfo.vcpu = cpu;
-                op.u.setdomaininfo.ctxt = &ctxt[cpu];
+                op.u.setdomaininfo.ctxt.ptr = &ctxt[cpu];
                 retval = do_dom0_op(xc_handle, &op); 
                 if ( retval )
                 {
diff -r 85f92475b943 tools/libxc/xc_vmx_build.c
--- a/tools/libxc/xc_vmx_build.c	Mon Oct  3 18:14:02 2005
+++ b/tools/libxc/xc_vmx_build.c	Tue Oct  4 16:37:44 2005
@@ -700,7 +700,7 @@
 
     launch_op.u.setdomaininfo.domain = (domid_t)domid;
     launch_op.u.setdomaininfo.vcpu   = 0;
-    launch_op.u.setdomaininfo.ctxt   = ctxt;
+    launch_op.u.setdomaininfo.ctxt.ptr = ctxt;
 
     launch_op.cmd = DOM0_SETDOMAININFO;
     rc = xc_dom0_op(xc_handle, &launch_op);
diff -r 85f92475b943 xen/common/domain.c
--- a/xen/common/domain.c	Mon Oct  3 18:14:02 2005
+++ b/xen/common/domain.c	Tue Oct  4 16:37:44 2005
@@ -351,7 +351,7 @@
     if ( (c = xmalloc(struct vcpu_guest_context)) == NULL )
         return -ENOMEM;
 
-    if ( copy_from_user(c, setdomaininfo->ctxt, sizeof(*c)) )
+    if ( copy_from_user(c, setdomaininfo->ctxt.ptr, sizeof(*c)) )
     {
         rc = -EFAULT;
         goto out;
diff -r 85f92475b943 xen/include/public/dom0_ops.h
--- a/xen/include/public/dom0_ops.h	Mon Oct  3 18:14:02 2005
+++ b/xen/include/public/dom0_ops.h	Tue Oct  4 16:37:44 2005
@@ -99,7 +99,10 @@
     domid_t                   domain;
     u16                       vcpu;
     /* IN/OUT parameters */
-    vcpu_guest_context_t *ctxt;
+    union {
+        vcpu_guest_context_t *ptr;
+        u64 _;
+    } ctxt;
 } dom0_setdomaininfo_t;
 
 #define DOM0_MSR              15