[Qemu-devel] [PATCH 4/6] xen: Set HVM_PARAM_DM_DOMAIN for stubdom on older Xen

[Jason Andryuk <jandryuk@gmail.com>]

When running in a stubdom, we have to inform the hypervisor that the
stubdom and not dom0 is handling the device model.  Explicitly created
ioreq servers are fine, but a call to HVM_PARAM_DM_DOMAIN is needed for
the default ioreq server.

Xen 4.12 removes the default ioreq server.  With that, Xen started
returning an error when setting HVM_PARAM_DM_DOMAIN.  Put the
HVM_PARAM_DM_DOMAIN call in the version compatibility header.  When we
fallback to the default ioreq server, issue the call and don't bother to
check the return value.

Original patch by Anthony PERARD <anthony.perard@citrix.com>

Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
---
 include/hw/xen/xen_common.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
index 9a8155e172..f59f841a43 100644
--- a/include/hw/xen/xen_common.h
+++ b/include/hw/xen/xen_common.h
@@ -616,6 +616,11 @@ static inline void xen_create_ioreq_server(domid_t dom,
 
     *ioservid = 0;
     use_default_ioreq_server = true;
+
+    if (xen_stubdom_enabled()) {
+        xc_hvm_param_set(xen_xc, xen_domid, HVM_PARAM_DM_DOMAIN, DOMID_SELF);
+    }
+
     trace_xen_default_ioreq_server();
 }
 
-- 
2.20.1