hw/xen: Pass grant ref to gnttab unmap operation

The previous commit introduced redirectable gnttab operations fairly
much like-for-like, with the exception of the extra arguments to the
->open() call which were always NULL/0 anyway.

This *changes* the arguments to the ->unmap() operation to include the
original ref# that was mapped. Under real Xen it isn't necessary; all we
need to do from QEMU is munmap(), then the kernel will release the grant,
and Xen does the tracking/refcounting for the guest.

When we have emulated grant tables though, we need to do all that for
ourselves. So let's have the back ends keep track of what they mapped
and pass it in to the ->unmap() method for us.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c
index b247e86f28..aee6a8c9b0 100644
--- a/hw/xen/xen-bus.c
+++ b/hw/xen/xen-bus.c
@@ -967,10 +967,10 @@ void *xen_device_map_grant_refs(XenDevice *xendev, uint32_t *refs,
     return map;
 }
 
-void xen_device_unmap_grant_refs(XenDevice *xendev, void *map,
+void xen_device_unmap_grant_refs(XenDevice *xendev, void *map, uint32_t *refs,
                                  unsigned int nr_refs, Error **errp)
 {
-    if (qemu_xen_gnttab_unmap(xendev->xgth, map, nr_refs)) {
+    if (qemu_xen_gnttab_unmap(xendev->xgth, map, refs, nr_refs)) {
         error_setg_errno(errp, errno, "xengnttab_unmap failed");
     }
 }