memory: allow creating MemoryRegions before accelerators

Compute the DIRTY_MEMORY_CODE bit in memory_region_get_dirty_log_mask
instead of memory_region_init_*.  This makes it possible to allocate
memory backend objects at any time.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

softmmu/memory.c

@@ -1548,7 +1548,6 @@ void memory_region_init_ram_shared_nomigrate(MemoryRegion *mr,
     mr->terminates = true;
     mr->destructor = memory_region_destructor_ram;
     mr->ram_block = qemu_ram_alloc(size, share, mr, &err);
-    mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
     if (err) {
         mr->size = int128_zero();
         object_unparent(OBJECT(mr));
@@ -1573,7 +1572,6 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr,
     mr->destructor = memory_region_destructor_ram;
     mr->ram_block = qemu_ram_alloc_resizeable(size, max_size, resized,
                                               mr, &err);
-    mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
     if (err) {
         mr->size = int128_zero();
         object_unparent(OBJECT(mr));
@@ -1598,7 +1596,6 @@ void memory_region_init_ram_from_file(MemoryRegion *mr,
     mr->destructor = memory_region_destructor_ram;
     mr->align = align;
     mr->ram_block = qemu_ram_alloc_from_file(size, mr, ram_flags, path, &err);
-    mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
     if (err) {
         mr->size = int128_zero();
         object_unparent(OBJECT(mr));
@@ -1622,7 +1619,6 @@ void memory_region_init_ram_from_fd(MemoryRegion *mr,
     mr->ram_block = qemu_ram_alloc_from_fd(size, mr,
                                            share ? RAM_SHARED : 0,
                                            fd, &err);
-    mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
     if (err) {
         mr->size = int128_zero();
         object_unparent(OBJECT(mr));
@@ -1641,7 +1637,6 @@ void memory_region_init_ram_ptr(MemoryRegion *mr,
     mr->ram = true;
     mr->terminates = true;
     mr->destructor = memory_region_destructor_ram;
-    mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
 
     /* qemu_ram_alloc_from_ptr cannot fail with ptr != NULL.  */
     assert(ptr != NULL);
@@ -1661,7 +1656,7 @@ void memory_region_init_ram_device_ptr(MemoryRegion *mr,
     mr->ops = &ram_device_mem_ops;
     mr->opaque = mr;
     mr->destructor = memory_region_destructor_ram;
-    mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
+
     /* qemu_ram_alloc_from_ptr cannot fail with ptr != NULL.  */
     assert(ptr != NULL);
     mr->ram_block = qemu_ram_alloc_from_ptr(size, ptr, mr, &error_fatal);
@@ -1819,6 +1814,11 @@ uint8_t memory_region_get_dirty_log_mask(MemoryRegion *mr)
                              memory_region_is_iommu(mr))) {
         mask |= (1 << DIRTY_MEMORY_MIGRATION);
     }
+
+    if (tcg_enabled() && rb) {
+        /* TCG only cares about dirty memory logging for RAM, not IOMMU.  */
+        mask |= (1 << DIRTY_MEMORY_CODE);
+    }
     return mask;
 }
 

softmmu/vl.c

@@ -1714,11 +1714,7 @@ static bool object_create_early(const char *type, QemuOpts *opts)
         return false;
     }
 
-    /* Memory allocation by backends needs to be done
-     * after configure_accelerator() (due to the tcg_enabled()
-     * checks at memory_region_init_*()).
-     *
-     * Also, allocation of large amounts of memory may delay
+    /* Allocation of large amounts of memory may delay
      * chardev initialization for too long, and trigger timeouts
      * on software that waits for a monitor socket to be created
      * (e.g. libvirt).