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/vl.c b/vl.c
index 0b4ed52..f46e070 100644
--- a/vl.c
+++ b/vl.c
@@ -205,6 +205,7 @@ static NotifierList machine_init_done_notifiers =
 bool xen_allowed;
 uint32_t xen_domid;
 enum xen_mode xen_mode = XEN_EMULATE;
+bool xen_domid_restrict;
 
 static int has_defaults = 1;
 static int default_serial = 1;
@@ -3933,6 +3934,13 @@ int main(int argc, char **argv, char **envp)
                 }
                 xen_mode = XEN_ATTACH;
                 break;
+            case QEMU_OPTION_xen_domid_restrict:
+                if (!(xen_available())) {
+                    error_report("Option not supported for this target");
+                    exit(1);
+                }
+                xen_domid_restrict = true;
+                break;
             case QEMU_OPTION_trace:
                 g_free(trace_file);
                 trace_file = trace_opt_parse(optarg);