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-rw-r--r--exec.c82
-rw-r--r--include/exec/cpu-all.h9
-rw-r--r--include/exec/ram_addr.h7
3 files changed, 91 insertions, 7 deletions
diff --git a/exec.c b/exec.c
index b69216ab0e..58ac6d6630 100644
--- a/exec.c
+++ b/exec.c
@@ -75,6 +75,11 @@ static MemoryRegion io_mem_unassigned;
/* RAM is mmap-ed with MAP_SHARED */
#define RAM_SHARED (1 << 1)
+/* Only a portion of RAM (used_length) is actually used, and migrated.
+ * This used_length size can change across reboots.
+ */
+#define RAM_RESIZEABLE (1 << 2)
+
#endif
struct CPUTailQ cpus = QTAILQ_HEAD_INITIALIZER(cpus);
@@ -1186,7 +1191,7 @@ static ram_addr_t find_ram_offset(ram_addr_t size)
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
ram_addr_t end, next = RAM_ADDR_MAX;
- end = block->offset + block->length;
+ end = block->offset + block->max_length;
QTAILQ_FOREACH(next_block, &ram_list.blocks, next) {
if (next_block->offset >= end) {
@@ -1214,7 +1219,7 @@ ram_addr_t last_ram_offset(void)
ram_addr_t last = 0;
QTAILQ_FOREACH(block, &ram_list.blocks, next)
- last = MAX(last, block->offset + block->length);
+ last = MAX(last, block->offset + block->max_length);
return last;
}
@@ -1296,6 +1301,49 @@ static int memory_try_enable_merging(void *addr, size_t len)
return qemu_madvise(addr, len, QEMU_MADV_MERGEABLE);
}
+/* Only legal before guest might have detected the memory size: e.g. on
+ * incoming migration, or right after reset.
+ *
+ * As memory core doesn't know how is memory accessed, it is up to
+ * resize callback to update device state and/or add assertions to detect
+ * misuse, if necessary.
+ */
+int qemu_ram_resize(ram_addr_t base, ram_addr_t newsize, Error **errp)
+{
+ RAMBlock *block = find_ram_block(base);
+
+ assert(block);
+
+ if (block->used_length == newsize) {
+ return 0;
+ }
+
+ if (!(block->flags & RAM_RESIZEABLE)) {
+ error_setg_errno(errp, EINVAL,
+ "Length mismatch: %s: 0x" RAM_ADDR_FMT
+ " in != 0x" RAM_ADDR_FMT, block->idstr,
+ newsize, block->used_length);
+ return -EINVAL;
+ }
+
+ if (block->max_length < newsize) {
+ error_setg_errno(errp, EINVAL,
+ "Length too large: %s: 0x" RAM_ADDR_FMT
+ " > 0x" RAM_ADDR_FMT, block->idstr,
+ newsize, block->max_length);
+ return -EINVAL;
+ }
+
+ cpu_physical_memory_clear_dirty_range(block->offset, block->used_length);
+ block->used_length = newsize;
+ cpu_physical_memory_set_dirty_range(block->offset, block->used_length);
+ memory_region_set_size(block->mr, newsize);
+ if (block->resized) {
+ block->resized(block->idstr, newsize, block->host);
+ }
+ return 0;
+}
+
static ram_addr_t ram_block_add(RAMBlock *new_block, Error **errp)
{
RAMBlock *block;
@@ -1413,7 +1461,12 @@ ram_addr_t qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
}
#endif
-ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
+static
+ram_addr_t qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size,
+ void (*resized)(const char*,
+ uint64_t length,
+ void *host),
+ void *host, bool resizeable,
MemoryRegion *mr, Error **errp)
{
RAMBlock *new_block;
@@ -1421,15 +1474,21 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
Error *local_err = NULL;
size = TARGET_PAGE_ALIGN(size);
+ max_size = TARGET_PAGE_ALIGN(max_size);
new_block = g_malloc0(sizeof(*new_block));
new_block->mr = mr;
+ new_block->resized = resized;
new_block->used_length = size;
new_block->max_length = max_size;
+ assert(max_size >= size);
new_block->fd = -1;
new_block->host = host;
if (host) {
new_block->flags |= RAM_PREALLOC;
}
+ if (resizeable) {
+ new_block->flags |= RAM_RESIZEABLE;
+ }
addr = ram_block_add(new_block, &local_err);
if (local_err) {
g_free(new_block);
@@ -1439,9 +1498,24 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
return addr;
}
+ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
+ MemoryRegion *mr, Error **errp)
+{
+ return qemu_ram_alloc_internal(size, size, NULL, host, false, mr, errp);
+}
+
ram_addr_t qemu_ram_alloc(ram_addr_t size, MemoryRegion *mr, Error **errp)
{
- return qemu_ram_alloc_from_ptr(size, NULL, mr, errp);
+ return qemu_ram_alloc_internal(size, size, NULL, NULL, false, mr, errp);
+}
+
+ram_addr_t qemu_ram_alloc_resizeable(ram_addr_t size, ram_addr_t maxsz,
+ void (*resized)(const char*,
+ uint64_t length,
+ void *host),
+ MemoryRegion *mr, Error **errp)
+{
+ return qemu_ram_alloc_internal(size, maxsz, resized, NULL, true, mr, errp);
}
void qemu_ram_free_from_ptr(ram_addr_t addr)
diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index 6f2130eab2..7ced147fd7 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -299,12 +299,15 @@ CPUArchState *cpu_copy(CPUArchState *env);
/* memory API */
-typedef struct RAMBlock {
+typedef struct RAMBlock RAMBlock;
+
+struct RAMBlock {
struct MemoryRegion *mr;
uint8_t *host;
ram_addr_t offset;
ram_addr_t used_length;
ram_addr_t max_length;
+ void (*resized)(const char*, uint64_t length, void *host);
uint32_t flags;
char idstr[256];
/* Reads can take either the iothread or the ramlist lock.
@@ -312,11 +315,11 @@ typedef struct RAMBlock {
*/
QTAILQ_ENTRY(RAMBlock) next;
int fd;
-} RAMBlock;
+};
static inline void *ramblock_ptr(RAMBlock *block, ram_addr_t offset)
{
- assert(offset < block->length);
+ assert(offset < block->used_length);
assert(block->host);
return (char *)block->host + offset;
}
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index 254931cad4..ff558a4734 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -28,12 +28,19 @@ ram_addr_t qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
MemoryRegion *mr, Error **errp);
ram_addr_t qemu_ram_alloc(ram_addr_t size, MemoryRegion *mr, Error **errp);
+ram_addr_t qemu_ram_alloc_resizeable(ram_addr_t size, ram_addr_t max_size,
+ void (*resized)(const char*,
+ uint64_t length,
+ void *host),
+ MemoryRegion *mr, Error **errp);
int qemu_get_ram_fd(ram_addr_t addr);
void *qemu_get_ram_block_host_ptr(ram_addr_t addr);
void *qemu_get_ram_ptr(ram_addr_t addr);
void qemu_ram_free(ram_addr_t addr);
void qemu_ram_free_from_ptr(ram_addr_t addr);
+int qemu_ram_resize(ram_addr_t base, ram_addr_t newsize, Error **errp);
+
static inline bool cpu_physical_memory_get_dirty(ram_addr_t start,
ram_addr_t length,
unsigned client)
generated by cgit v1.2.3 (git 2.26.2) at 2025-01-10 01:22:32 +0000