mem_event: remove type member

When mem_event was added the type flag should indicate who the consumer
is. But the concept of a single ring buffer for multiple event types can
not work for two reasons. One is that no multiplexer exists which
provides individual event types to the final consumer, and second is
that even if such multiplexer can not work reliable because a request
needs to be answered with a response. The response should be sent
roughly in the order of received events. But with multiple consumers one
of them can so stall all the others.

For that reason the single mem_event buffer for all types of events was
split into individual ring buffers with commit 23842:483c5f8319ad. This
commit made the type member already obsolete because the meaning of each
buffer is now obvious.

This change removes the type member and increases the flags field.

Even though this is an ABI incompatible change, it will have no practical
impact on existing binaries because the changeset referenced above already
bumped the SONAME. So these binaries have to be recompiled anyway for the
upcoming major release.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Tim Deegan <tim@xen.org>

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 6bbb4252e424f306ba9a290041763cd3ed40a677..d00eaf5fed7909931e00ff46e32deb8471a8fb72 100644 (file)
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4322,7 +4322,6 @@ static int hvm_memory_event_traps(long p, uint32_t reason,
         return rc;
 
     memset(&req, 0, sizeof(req));
-    req.type = MEM_EVENT_TYPE_ACCESS;
     req.reason = reason;
 
     if ( (p & HVMPME_MODE_MASK) == HVMPME_mode_sync ) 

diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
index b73d48827f7fa3b81188bcdd0c451f1034faca4a..50d3d6ed6d667b487342fe3de1b55fc389a4635c 100644 (file)
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -347,7 +347,7 @@ int mem_sharing_audit(void)
 static void mem_sharing_notify_helper(struct domain *d, unsigned long gfn)
 {
     struct vcpu *v = current;
-    mem_event_request_t req = { .type = MEM_EVENT_TYPE_SHARED };
+    mem_event_request_t req = { .gfn = gfn };
 
     if ( v->domain != d )
     {
@@ -369,7 +369,6 @@ static void mem_sharing_notify_helper(struct domain *d, unsigned long gfn)
     req.flags = MEM_EVENT_FLAG_VCPU_PAUSED;
     vcpu_pause_nosync(v);
 
-    req.gfn = gfn;
     req.p2mt = p2m_ram_shared;
     req.vcpu_id = v->vcpu_id;
     mem_event_put_request(d, &d->mem_event->share, &req);

diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 19b831715e5770d2177bd38bd768ad7d8c73f554..9eb0ba5f351e394e5f690173b0e7e774f304e469 100644 (file)
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -925,7 +925,6 @@ void p2m_mem_paging_drop_page(struct domain *d, unsigned long gfn,
 
     /* Send release notification to pager */
     memset(&req, 0, sizeof(req));
-    req.type = MEM_EVENT_TYPE_PAGING;
     req.gfn = gfn;
     req.flags = MEM_EVENT_FLAG_DROP_PAGE;
 
@@ -982,7 +981,6 @@ void p2m_mem_paging_populate(struct domain *d, unsigned long gfn)
         return;
 
     memset(&req, 0, sizeof(req));
-    req.type = MEM_EVENT_TYPE_PAGING;
 
     /* Fix p2m mapping */
     gfn_lock(p2m, gfn, 0);
@@ -1221,7 +1219,6 @@ bool_t p2m_mem_access_check(unsigned long gpa, bool_t gla_valid, unsigned long g
     {
         *req_ptr = req;
         memset(req, 0, sizeof(req));
-        req->type = MEM_EVENT_TYPE_ACCESS;
         req->reason = MEM_EVENT_REASON_VIOLATION;
 
         /* Pause the current VCPU */

diff --git a/xen/include/public/mem_event.h b/xen/include/public/mem_event.h
index 770cc7cb9a8f9e72d1d76669c5edbc997a154293..29e125a5a7a3eab8c0fbb693500f1ae30dcc807b 100644 (file)
--- a/xen/include/public/mem_event.h
+++ b/xen/include/public/mem_event.h
@@ -30,11 +30,6 @@
 #include "xen.h"
 #include "io/ring.h"
 
-/* Memory event type */
-#define MEM_EVENT_TYPE_SHARED   0
-#define MEM_EVENT_TYPE_PAGING   1
-#define MEM_EVENT_TYPE_ACCESS   2
-
 /* Memory event flags */
 #define MEM_EVENT_FLAG_VCPU_PAUSED  (1 << 0)
 #define MEM_EVENT_FLAG_DROP_PAGE    (1 << 1)
@@ -56,8 +51,7 @@ typedef struct mem_event_shared_page {
 } mem_event_shared_page_t;
 
 typedef struct mem_event_st {
-    uint16_t type;
-    uint16_t flags;
+    uint32_t flags;
     uint32_t vcpu_id;
 
     uint64_t gfn;