libxc: add xc_gnttab_map_grant_ref_notify

Normally, when a userspace process mapping a grant crashes, the domain
providing the reference receives no indication that its peer has
crashed, possibly leading to unexpected freezes or timeouts. This
function provides a notification of the unmap by signalling an event
channel and/or clearing a specific byte in the page.

This also unifies the 3 very similar grant-mapping osdep interfaces into
a single function instead of introducing yet another minor variation.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 6 insertions, 14 deletions

diff --git a/tools/libxc/xenctrlosdep.h b/tools/libxc/xenctrlosdep.h
index bfe46e02fc..1c6317e52e 100644
--- a/tools/libxc/xenctrlosdep.h
+++ b/tools/libxc/xenctrlosdep.h
@@ -105,20 +105,12 @@ struct xc_osdep_ops
             int (*unmask)(xc_evtchn *xce, xc_osdep_handle h, evtchn_port_t port);
         } evtchn;
         struct {
-            void *(*map_grant_ref)(xc_gnttab *xcg, xc_osdep_handle h,
-                                   uint32_t domid,
-                                   uint32_t ref,
-                                   int prot);
-            void *(*map_grant_refs)(xc_gnttab *xcg, xc_osdep_handle h,
-                                    uint32_t count,
-                                    uint32_t *domids,
-                                    uint32_t *refs,
-                                    int prot);
-            void *(*map_domain_grant_refs)(xc_gnttab *xcg, xc_osdep_handle h,
-                                           uint32_t count,
-                                           uint32_t domid,
-                                           uint32_t *refs,
-                                           int prot);
+#define XC_GRANT_MAP_SINGLE_DOMAIN 0x1
+            void *(*grant_map)(xc_gnttab *xcg, xc_osdep_handle h,
+                               uint32_t count, int flags, int prot,
+                               uint32_t *domids, uint32_t *refs,
+                               uint32_t notify_offset,
+                               evtchn_port_t notify_port);
             int (*munmap)(xc_gnttab *xcg, xc_osdep_handle h,
                           void *start_address,
                           uint32_t count);