xen: use libxendevice model to restrict operations

This patch adds a command-line option (-xen-domid-restrict) which will
use the new libxendevicemodel API to restrict devicemodel [1] operations
to the specified domid. (Such operations are not applicable to the xenpv
machine type).

This patch also adds a tracepoint to allow successful enabling of the
restriction to be monitored.

[1] I.e. operations issued by libxendevicemodel. Operation issued by other
    xen libraries (e.g. libxenforeignmemory) are currently still unrestricted
    but this will be rectified by subsequent patches.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/xen-hvm.c b/xen-hvm.c
index 4b928cfb30..335e263834 100644
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -1226,6 +1226,14 @@ void xen_hvm_init(PCMachineState *pcms, MemoryRegion **ram_memory)
         goto err;
     }
 
+    if (xen_domid_restrict) {
+        rc = xen_restrict(xen_domid);
+        if (rc < 0) {
+            error_report("failed to restrict: error %d", errno);
+            goto err;
+        }
+    }
+
     xen_create_ioreq_server(xen_domid, &state->ioservid);
 
     state->exit.notify = xen_exit_notifier;