[PATCH] xen: Fix BUFIOREQ evtchn init for a stubdom.

[Anthony PERARD <anthony.perard@citrix.com>]

This is a missing part from the previous patch that add the BUFIOREQ_EVTCHN
parameter. This patch changes the ownership of the buifioreq event channel to
the stubdom (when HVM_PARAM_DM_DOMAIN is set within the stubdom).

This fix the initialization of QEMU inside the stubdomain.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>

---
 xen/arch/x86/hvm/hvm.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index e0d495d..9ff1ded 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3788,6 +3788,22 @@ long do_hvm_op(unsigned long op, XEN_GUEST_HANDLE(void) arg)
                     /* xchg() ensures that only we free_xen_event_channel() */
                     old_port = xchg(&v->arch.hvm_vcpu.xen_port, new_port);
                     free_xen_event_channel(v, old_port);
+
+                    if ( v->vcpu_id == 0 )
+                    {
+                        new_port = alloc_unbound_xen_event_channel(
+                            v, a.value, NULL);
+                        if ( new_port < 0 )
+                        {
+                            rc = new_port;
+                            break;
+                        }
+                        old_port = xchg(
+                            &v->domain->arch.hvm_domain.params[HVM_PARAM_BUFIOREQ_EVTCHN],
+                            new_port);
+                        free_xen_event_channel(v, old_port);
+                    }
+
                     spin_lock(&iorp->lock);
                     if ( iorp->va != NULL )
                         get_ioreq(v)->vp_eport = v->arch.hvm_vcpu.xen_port;
-- 
Anthony PERARD