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 53d23d2..a7fe3c5 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -676,13 +676,15 @@
}
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 156d506..55dc11d 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -206,8 +206,10 @@
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 d5416bb..c713b22 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -344,10 +344,15 @@
}
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_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 72e33e8..3e3d5b8 100644
--- a/memory.c
+++ b/memory.c
@@ -152,7 +152,7 @@
} 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 @@
.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 @@
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 338ab29..42356b8 100644
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -646,21 +646,27 @@
}
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)
