x86: allow control domain to limit machine addresses given to a particular guest

This allows domains which make buggy assumptions about the maximum
possible MFN to be worked around.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

2 files changed, 35 insertions, 0 deletions

diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 3b08922067..551d8d1ada 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -993,6 +993,35 @@ int xc_domain_subscribe_for_suspend(
     return do_domctl(xc_handle, &domctl);
 }
 
+int xc_domain_set_machine_address_size(int xc,
+                                       uint32_t domid,
+                                       unsigned int width)
+{
+    DECLARE_DOMCTL;
+
+    memset(&domctl, 0, sizeof(domctl));
+    domctl.domain = domid;
+    domctl.cmd    = XEN_DOMCTL_set_machine_address_size;
+    domctl.u.address_size.size = width;
+
+    return do_domctl(xc, &domctl);
+}
+
+
+int xc_domain_get_machine_address_size(int xc, uint32_t domid)
+{
+    DECLARE_DOMCTL;
+    int rc;
+
+    memset(&domctl, 0, sizeof(domctl));
+    domctl.domain = domid;
+    domctl.cmd    = XEN_DOMCTL_get_machine_address_size;
+
+    rc = do_domctl(xc, &domctl);
+
+    return rc == 0 ? domctl.u.address_size.size : rc;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index b70c3b8193..69d58950d5 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -1076,6 +1076,12 @@ int xc_domain_bind_pt_isa_irq(int xc_handle,
                               uint32_t domid,
                               uint8_t machine_irq);
 
+int xc_domain_set_machine_address_size(int handle,
+				       uint32_t domid,
+				       unsigned int width);
+int xc_domain_get_machine_address_size(int handle,
+				       uint32_t domid);
+
 /* Set the target domain */
 int xc_domain_set_target(int xc_handle,
                          uint32_t domid,