memory: differentiate memory_region_is_logging and memory_region_get_dirty_log_mask

For now memory regions only track DIRTY_MEMORY_VGA individually, but
this will change soon.  To support this, split memory_region_is_logging
in two functions: one that returns a given bit from dirty_log_mask,
and one that returns the entire mask.  memory_region_is_logging gets an
extra parameter so that the compiler flags misuse.

While VGA-specific users (including the Xen listener!) will want to keep
checking that bit, KVM and vhost check for "any bit except migration"
(because migration is handled via the global start/stop listener
callbacks).

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

hw/display/vmware_vga.c

@@ -1124,7 +1124,7 @@ static void vmsvga_update_display(void *opaque)
      * Is it more efficient to look at vram VGA-dirty bits or wait
      * for the driver to issue SVGA_CMD_UPDATE?
      */
-    if (memory_region_is_logging(&s->vga.vram)) {
+    if (memory_region_is_logging(&s->vga.vram, DIRTY_MEMORY_VGA)) {
         vga_sync_dirty_bitmap(&s->vga);
         dirty = memory_region_get_dirty(&s->vga.vram, 0,
             surface_stride(surface) * surface_height(surface),

hw/virtio/dataplane/vring.c

@@ -42,7 +42,7 @@ static void *vring_map(MemoryRegion **mr, hwaddr phys, hwaddr len,
     }
 
     /* Ignore regions with dirty logging, we cannot mark them dirty */
-    if (memory_region_is_logging(section.mr)) {
+    if (memory_region_get_dirty_log_mask(section.mr)) {
         goto out;
     }
 

hw/virtio/vhost.c

@@ -416,7 +416,8 @@ static void vhost_set_memory(MemoryListener *listener,
                                          memory_listener);
     hwaddr start_addr = section->offset_within_address_space;
     ram_addr_t size = int128_get64(section->size);
-    bool log_dirty = memory_region_is_logging(section->mr);
+    bool log_dirty =
+        memory_region_get_dirty_log_mask(section->mr) & ~(1 << DIRTY_MEMORY_MIGRATION);
     int s = offsetof(struct vhost_memory, regions) +
         (dev->mem->nregions + 1) * sizeof dev->mem->regions[0];
     void *ram;

include/exec/memory.h

@@ -591,11 +591,23 @@ const char *memory_region_name(const MemoryRegion *mr);
 /**
  * memory_region_is_logging: return whether a memory region is logging writes
  *
- * Returns %true if the memory region is logging writes
+ * Returns %true if the memory region is logging writes for the given client
+ *
+ * @mr: the memory region being queried
+ * @client: the client being queried
+ */
+bool memory_region_is_logging(MemoryRegion *mr, uint8_t client);
+
+/**
+ * memory_region_get_dirty_log_mask: return the clients for which a
+ * memory region is logging writes.
+ *
+ * Returns a bitmap of clients, which right now will be either 0 or
+ * (1 << DIRTY_MEMORY_VGA).
  *
  * @mr: the memory region being queried
  */
-bool memory_region_is_logging(MemoryRegion *mr);
+uint8_t memory_region_get_dirty_log_mask(MemoryRegion *mr);
 
 /**
  * memory_region_is_rom: check whether a memory region is ROM

kvm-all.c

@@ -663,7 +663,8 @@ static void kvm_set_phys_mem(MemoryRegionSection *section, bool add)
     KVMSlot *mem, old;
     int err;
     MemoryRegion *mr = section->mr;
-    bool log_dirty = memory_region_is_logging(mr);
+    bool log_dirty =
+        memory_region_get_dirty_log_mask(mr) & ~(1 << DIRTY_MEMORY_MIGRATION);
     bool writeable = !mr->readonly && !mr->rom_device;
     bool readonly_flag = mr->readonly || memory_region_is_romd(mr);
     hwaddr start_addr = section->offset_within_address_space;

memory.c

@@ -1389,11 +1389,16 @@ bool memory_region_is_skip_dump(MemoryRegion *mr)
     return mr->skip_dump;
 }
 
-bool memory_region_is_logging(MemoryRegion *mr)
+uint8_t memory_region_get_dirty_log_mask(MemoryRegion *mr)
 {
     return mr->dirty_log_mask;
 }
 
+bool memory_region_is_logging(MemoryRegion *mr, uint8_t client)
+{
+    return memory_region_get_dirty_log_mask(mr) & (1 << client);
+}
+
 bool memory_region_is_rom(MemoryRegion *mr)
 {
     return mr->ram && mr->readonly;

xen-hvm.c

@@ -488,7 +488,7 @@ static void xen_set_memory(struct MemoryListener *listener,
     XenIOState *state = container_of(listener, XenIOState, memory_listener);
     hwaddr start_addr = section->offset_within_address_space;
     ram_addr_t size = int128_get64(section->size);
-    bool log_dirty = memory_region_is_logging(section->mr);
+    bool log_dirty = memory_region_is_logging(section->mr, DIRTY_MEMORY_VGA);
     hvmmem_type_t mem_type;
 
     if (section->mr == &ram_memory) {