[PATCH v2 07/16] memory: Add memory_region_max_size() and memory_region_is_resizable()

[David Hildenbrand <david@redhat.com>]

We want to pass resizable memory regions to devices that can deal
with them (and autoamtically resize them). Allow them to easily
identify if a region can be resized and what the maximum size is.

Add both functions, adding qemu_ram_is_resizable() as a helper.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 include/exec/memory.h | 17 +++++++++++++++++
 memory.c              | 18 ++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 9f02bb7830..dfedd88f13 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -395,6 +395,7 @@ struct MemoryRegion {
     void *opaque;
     MemoryRegion *container;
     Int128 size;
+    Int128 max_size;
     hwaddr addr;
     void (*destructor)(MemoryRegion *mr);
     uint64_t align;
@@ -1180,6 +1181,13 @@ struct Object *memory_region_owner(MemoryRegion *mr);
  */
 uint64_t memory_region_size(MemoryRegion *mr);
 
+/**
+ * memory_region_max_size: get a memory region's maximum size.
+ *
+ * @mr: the memory region being queried.
+ */
+uint64_t memory_region_max_size(MemoryRegion *mr);
+
 /**
  * memory_region_is_ram: check whether a memory region is random access
  *
@@ -1471,6 +1479,15 @@ MemoryRegion *memory_region_from_host(void *ptr, ram_addr_t *offset);
  */
 void *memory_region_get_ram_ptr(MemoryRegion *mr);
 
+/**
+ * memory_region_is_resizable: check whether a memory region resizable
+ *
+ * Returns %true if a memory region is resizable.
+ *
+ * @mr: the memory region being queried
+ */
+bool memory_region_is_resizable(MemoryRegion *mr);
+
 /* memory_region_ram_resize: Resize a RAM region.
  *
  * Only legal before guest might have detected the memory size: e.g. on
diff --git a/memory.c b/memory.c
index cb09a8ee59..5c62702618 100644
--- a/memory.c
+++ b/memory.c
@@ -1130,6 +1130,7 @@ static void memory_region_do_init(MemoryRegion *mr,
     if (size == UINT64_MAX) {
         mr->size = int128_2_64();
     }
+    mr->max_size = mr->size;
     mr->name = g_strdup(name);
     mr->owner = owner;
     mr->ram_block = NULL;
@@ -1540,6 +1541,10 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr,
 {
     Error *err = NULL;
     memory_region_init(mr, owner, name, size);
+    mr->max_size = int128_make64(max_size);
+    if (max_size == UINT64_MAX) {
+        mr->max_size = int128_2_64();
+    }
     mr->ram = true;
     mr->terminates = true;
     mr->destructor = memory_region_destructor_ram;
@@ -1779,6 +1784,14 @@ uint64_t memory_region_size(MemoryRegion *mr)
     return int128_get64(mr->size);
 }
 
+uint64_t memory_region_max_size(MemoryRegion *mr)
+{
+    if (int128_eq(mr->max_size, int128_2_64())) {
+        return UINT64_MAX;
+    }
+    return int128_get64(mr->max_size);
+}
+
 const char *memory_region_name(const MemoryRegion *mr)
 {
     if (!mr->name) {
@@ -2198,6 +2211,11 @@ ram_addr_t memory_region_get_ram_addr(MemoryRegion *mr)
     return mr->ram_block ? mr->ram_block->offset : RAM_ADDR_INVALID;
 }
 
+bool memory_region_is_resizable(MemoryRegion *mr)
+{
+    return mr->ram_block && qemu_ram_is_resizable(mr->ram_block);
+}
+
 void memory_region_ram_resize(MemoryRegion *mr, ram_addr_t newsize, Error **errp)
 {
     assert(mr->ram_block);
-- 
2.24.1