mem_event: use different ringbuffers for share, paging and access

Up to now a single ring buffer was used for mem_share, xenpaging and
xen-access.  Each helper would have to cooperate and pull only its own
requests from the ring.  Unfortunately this was not implemented. And
even if it was, it would make the whole concept fragile because a crash
or early exit of one helper would stall the others.

What happend up to now is that active xenpaging + memory_sharing would
push memsharing requests in the buffer. xenpaging is not prepared for
such requests.

This patch creates an independet ring buffer for mem_share, xenpaging
and xen-access and adds also new functions to enable xenpaging and
xen-access. The xc_mem_event_enable/xc_mem_event_disable functions will
be removed. The various XEN_DOMCTL_MEM_EVENT_* macros were cleaned up.
Due to the removal the API changed, so the SONAME will be changed too.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Tim Deegan <tim@xen.org>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Tim Deegan <tim@xen.org>

1 files changed, 25 insertions, 8 deletions

diff --git a/tools/libxc/xc_mem_paging.c b/tools/libxc/xc_mem_paging.c
index db5be452f5..f917403b39 100644
--- a/tools/libxc/xc_mem_paging.c
+++ b/tools/libxc/xc_mem_paging.c
@@ -24,36 +24,53 @@
 #include "xc_private.h"
 
 
+int xc_mem_paging_enable(xc_interface *xch, domid_t domain_id,
+                        void *shared_page, void *ring_page)
+{
+    return xc_mem_event_control(xch, domain_id,
+                                XEN_DOMCTL_MEM_EVENT_OP_PAGING_ENABLE,
+                                XEN_DOMCTL_MEM_EVENT_OP_PAGING,
+                                shared_page, ring_page, INVALID_MFN);
+}
+
+int xc_mem_paging_disable(xc_interface *xch, domid_t domain_id)
+{
+    return xc_mem_event_control(xch, domain_id,
+                                XEN_DOMCTL_MEM_EVENT_OP_PAGING_DISABLE,
+                                XEN_DOMCTL_MEM_EVENT_OP_PAGING,
+                                NULL, NULL, INVALID_MFN);
+}
+
 int xc_mem_paging_nominate(xc_interface *xch, domid_t domain_id, unsigned long gfn)
 {
     return xc_mem_event_control(xch, domain_id,
                                 XEN_DOMCTL_MEM_EVENT_OP_PAGING_NOMINATE,
-                                XEN_DOMCTL_MEM_EVENT_OP_PAGING, NULL, NULL,
-                                gfn);
+                                XEN_DOMCTL_MEM_EVENT_OP_PAGING,
+                                NULL, NULL, gfn);
 }
 
 int xc_mem_paging_evict(xc_interface *xch, domid_t domain_id, unsigned long gfn)
 {
     return xc_mem_event_control(xch, domain_id,
                                 XEN_DOMCTL_MEM_EVENT_OP_PAGING_EVICT,
-                                XEN_DOMCTL_MEM_EVENT_OP_PAGING, NULL, NULL,
-                                gfn);
+                                XEN_DOMCTL_MEM_EVENT_OP_PAGING,
+                                NULL, NULL, gfn);
 }
 
 int xc_mem_paging_prep(xc_interface *xch, domid_t domain_id, unsigned long gfn)
 {
     return xc_mem_event_control(xch, domain_id,
                                 XEN_DOMCTL_MEM_EVENT_OP_PAGING_PREP,
-                                XEN_DOMCTL_MEM_EVENT_OP_PAGING, NULL, NULL,
-                                gfn);
+                                XEN_DOMCTL_MEM_EVENT_OP_PAGING,
+                                NULL, NULL, gfn);
 }
 
 int xc_mem_paging_resume(xc_interface *xch, domid_t domain_id, unsigned long gfn)
 {
     return xc_mem_event_control(xch, domain_id,
                                 XEN_DOMCTL_MEM_EVENT_OP_PAGING_RESUME,
-                                XEN_DOMCTL_MEM_EVENT_OP_PAGING, NULL, NULL,
-                                gfn);
+                                XEN_DOMCTL_MEM_EVENT_OP_PAGING,
+                                NULL, NULL, gfn);
 }