memory: prepare for multiple bits in the dirty log mask

When the dirty log mask will also cover other bits than DIRTY_MEMORY_VGA,
some listeners may be interested in the overall zero/non-zero value of
the dirty log mask; others may be interested in the value of single bits.

For this reason, always call log_start/log_stop if bits have respectively
appeared or disappeared, and pass the old and new values of the dirty log
mask so that listeners can distinguish the kinds of change.

For example, KVM checks if dirty logging used to be completely disabled
(in log_start) or is now completely disabled (in log_stop).  On the
other hand, Xen has to check manually if DIRTY_MEMORY_VGA changed,
since that is the only bit it cares about.

Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 53d23d281d24cf0eaf05c1c5ee87cb7760648405..a7fe3c5104c970cab59676f700a85f3b95ebaf4b 100644 (file)
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -676,13 +676,15 @@ static void vhost_log_global_stop(MemoryListener *listener)
 }
 
 static void vhost_log_start(MemoryListener *listener,
-                            MemoryRegionSection *section)
+                            MemoryRegionSection *section,
+                            int old, int new)
 {
     /* FIXME: implement */
 }
 
 static void vhost_log_stop(MemoryListener *listener,
-                           MemoryRegionSection *section)
+                           MemoryRegionSection *section,
+                           int old, int new)
 {
     /* FIXME: implement */
 }

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 156d506063ba8424cc2642b7a0e80f302b381b95..55dc11d55ca8434ab2b779e781569d8c8dc12e05 100644 (file)
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -206,8 +206,10 @@ struct MemoryListener {
     void (*region_add)(MemoryListener *listener, MemoryRegionSection *section);
     void (*region_del)(MemoryListener *listener, MemoryRegionSection *section);
     void (*region_nop)(MemoryListener *listener, MemoryRegionSection *section);
-    void (*log_start)(MemoryListener *listener, MemoryRegionSection *section);
-    void (*log_stop)(MemoryListener *listener, MemoryRegionSection *section);
+    void (*log_start)(MemoryListener *listener, MemoryRegionSection *section,
+                      int old, int new);
+    void (*log_stop)(MemoryListener *listener, MemoryRegionSection *section,
+                     int old, int new);
     void (*log_sync)(MemoryListener *listener, MemoryRegionSection *section);
     void (*log_global_start)(MemoryListener *listener);
     void (*log_global_stop)(MemoryListener *listener);

diff --git a/kvm-all.c b/kvm-all.c
index d5416bbd7451c388365e7ebbd214e466bf5fa1dd..c713b22f8c346d7e051e51372f5c70a456e73389 100644 (file)
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -344,10 +344,15 @@ static int kvm_dirty_pages_log_change(hwaddr phys_addr,
 }
 
 static void kvm_log_start(MemoryListener *listener,
-                          MemoryRegionSection *section)
+                          MemoryRegionSection *section,
+                          int old, int new)
 {
     int r;
 
+    if (old != 0) {
+        return;
+    }
+
     r = kvm_dirty_pages_log_change(section->offset_within_address_space,
                                    int128_get64(section->size), true);
     if (r < 0) {
@@ -356,10 +361,15 @@ static void kvm_log_start(MemoryListener *listener,
 }
 
 static void kvm_log_stop(MemoryListener *listener,
-                          MemoryRegionSection *section)
+                          MemoryRegionSection *section,
+                          int old, int new)
 {
     int r;
 
+    if (new != 0) {
+        return;
+    }
+
     r = kvm_dirty_pages_log_change(section->offset_within_address_space,
                                    int128_get64(section->size), false);
     if (r < 0) {

diff --git a/memory.c b/memory.c
index 72e33e853b06fe24e7ef368ed3e2732e481bcaec..3e3d5b8ad6fa03b8851da9c07b5d837923cbe371 100644 (file)
--- a/memory.c
+++ b/memory.c
@@ -152,7 +152,7 @@ static bool memory_listener_match(MemoryListener *listener,
     } while (0)
 
 /* No need to ref/unref .mr, the FlatRange keeps it alive.  */
-#define MEMORY_LISTENER_UPDATE_REGION(fr, as, dir, callback)            \
+#define MEMORY_LISTENER_UPDATE_REGION(fr, as, dir, callback, _args...)  \
     MEMORY_LISTENER_CALL(callback, dir, (&(MemoryRegionSection) {       \
         .mr = (fr)->mr,                                                 \
         .address_space = (as),                                          \
@@ -160,7 +160,7 @@ static bool memory_listener_match(MemoryListener *listener,
         .size = (fr)->addr.size,                                        \
         .offset_within_address_space = int128_get64((fr)->addr.start),  \
         .readonly = (fr)->readonly,                                     \
-              }))
+              }), ##_args)
 
 struct CoalescedMemoryRange {
     AddrRange addr;
@@ -774,10 +774,15 @@ static void address_space_update_topology_pass(AddressSpace *as,
 
             if (adding) {
                 MEMORY_LISTENER_UPDATE_REGION(frnew, as, Forward, region_nop);
-                if (frold->dirty_log_mask && !frnew->dirty_log_mask) {
-                    MEMORY_LISTENER_UPDATE_REGION(frnew, as, Reverse, log_stop);
-                } else if (frnew->dirty_log_mask && !frold->dirty_log_mask) {
-                    MEMORY_LISTENER_UPDATE_REGION(frnew, as, Forward, log_start);
+                if (frnew->dirty_log_mask & ~frold->dirty_log_mask) {
+                    MEMORY_LISTENER_UPDATE_REGION(frnew, as, Forward, log_start,
+                                                  frold->dirty_log_mask,
+                                                  frnew->dirty_log_mask);
+                }
+                if (frold->dirty_log_mask & ~frnew->dirty_log_mask) {
+                    MEMORY_LISTENER_UPDATE_REGION(frnew, as, Reverse, log_stop,
+                                                  frold->dirty_log_mask,
+                                                  frnew->dirty_log_mask);
                 }
             }
 

diff --git a/xen-hvm.c b/xen-hvm.c
index 338ab291f88edeccdb1a693d5f673db6dde9eade..42356b836a48cfc67a767c81be8020f63ab4ce11 100644 (file)
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -646,21 +646,27 @@ static void xen_sync_dirty_bitmap(XenIOState *state,
 }
 
 static void xen_log_start(MemoryListener *listener,
-                          MemoryRegionSection *section)
+                          MemoryRegionSection *section,
+                          int old, int new)
 {
     XenIOState *state = container_of(listener, XenIOState, memory_listener);
 
-    xen_sync_dirty_bitmap(state, section->offset_within_address_space,
-                          int128_get64(section->size));
+    if (new & ~old & (1 << DIRTY_MEMORY_VGA)) {
+        xen_sync_dirty_bitmap(state, section->offset_within_address_space,
+                              int128_get64(section->size));
+    }
 }
 
-static void xen_log_stop(MemoryListener *listener, MemoryRegionSection *section)
+static void xen_log_stop(MemoryListener *listener, MemoryRegionSection *section,
+                         int old, int new)
 {
     XenIOState *state = container_of(listener, XenIOState, memory_listener);
 
-    state->log_for_dirtybit = NULL;
-    /* Disable dirty bit tracking */
-    xc_hvm_track_dirty_vram(xen_xc, xen_domid, 0, 0, NULL);
+    if (old & ~new & (1 << DIRTY_MEMORY_VGA)) {
+        state->log_for_dirtybit = NULL;
+        /* Disable dirty bit tracking */
+        xc_hvm_track_dirty_vram(xen_xc, xen_domid, 0, 0, NULL);
+    }
 }
 
 static void xen_log_sync(MemoryListener *listener, MemoryRegionSection *section)