Extend qemu_ram_alloc_from_fd to support resizable ram, and define
qemu_ram_resize_cb to clean up the API.
Add a grow parameter to extend the file if necessary. However, if
grow is false, a zero-sized file is always extended.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
include/exec/ram_addr.h | 13 +++++++++----
system/memory.c | 4 ++--
system/physmem.c | 35 ++++++++++++++++++++---------------
3 files changed, 31 insertions(+), 21 deletions(-)
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index ff157c1..94bb3cc 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -111,23 +111,30 @@ long qemu_maxrampagesize(void);
*
* Parameters:
* @size: the size in bytes of the ram block
+ * @max_size: the maximum size of the block after resizing
* @mr: the memory region where the ram block is
+ * @resized: callback after calls to qemu_ram_resize
* @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM,
* RAM_NORESERVE, RAM_PROTECTED, RAM_NAMED_FILE, RAM_READONLY,
* RAM_READONLY_FD, RAM_GUEST_MEMFD
* @mem_path or @fd: specify the backing file or device
* @offset: Offset into target file
+ * @grow: extend file if necessary (but an empty file is always extended).
* @errp: pointer to Error*, to store an error if it happens
*
* Return:
* On success, return a pointer to the ram block.
* On failure, return NULL.
*/
+typedef void (*qemu_ram_resize_cb)(const char *, uint64_t length, void *host);
+
RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
uint32_t ram_flags, const char *mem_path,
off_t offset, Error **errp);
-RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
+RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, ram_addr_t max_size,
+ qemu_ram_resize_cb resized, MemoryRegion *mr,
uint32_t ram_flags, int fd, off_t offset,
+ bool grow,
Error **errp);
RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
@@ -135,9 +142,7 @@ RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void
*host,
RAMBlock *qemu_ram_alloc(ram_addr_t size, uint32_t ram_flags, MemoryRegion
*mr,
Error **errp);
RAMBlock *qemu_ram_alloc_resizeable(ram_addr_t size, ram_addr_t max_size,
- void (*resized)(const char*,
- uint64_t length,
- void *host),
+ qemu_ram_resize_cb resized,
MemoryRegion *mr, Error **errp);
void qemu_ram_free(RAMBlock *block);
diff --git a/system/memory.c b/system/memory.c
index 78e17e0..290c522 100644
--- a/system/memory.c
+++ b/system/memory.c
@@ -1680,8 +1680,8 @@ bool memory_region_init_ram_from_fd(MemoryRegion *mr,
mr->readonly = !!(ram_flags & RAM_READONLY);
mr->terminates = true;
mr->destructor = memory_region_destructor_ram;
- mr->ram_block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, offset,
- &err);
+ mr->ram_block = qemu_ram_alloc_from_fd(size, size, NULL, mr, ram_flags, fd,
+ offset, false, &err);
if (err) {
mr->size = int128_zero();
object_unparent(OBJECT(mr));
diff --git a/system/physmem.c b/system/physmem.c
index c76503a..48c544f 100644
--- a/system/physmem.c
+++ b/system/physmem.c
@@ -1942,8 +1942,10 @@ out_free:
}
#ifdef CONFIG_POSIX
-RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
+RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, ram_addr_t max_size,
+ qemu_ram_resize_cb resized, MemoryRegion *mr,
uint32_t ram_flags, int fd, off_t offset,
+ bool grow,
Error **errp)
{
RAMBlock *new_block;
@@ -1953,7 +1955,9 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size,
MemoryRegion *mr,
/* Just support these ram flags by now. */
assert((ram_flags & ~(RAM_SHARED | RAM_PMEM | RAM_NORESERVE |
RAM_PROTECTED | RAM_NAMED_FILE | RAM_READONLY |
- RAM_READONLY_FD | RAM_GUEST_MEMFD)) == 0);
+ RAM_READONLY_FD | RAM_GUEST_MEMFD |
+ RAM_RESIZEABLE)) == 0);
+ assert(max_size >= size);
if (xen_enabled()) {
error_setg(errp, "-mem-path not supported with Xen");
@@ -1968,12 +1972,14 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size,
MemoryRegion *mr,
size = TARGET_PAGE_ALIGN(size);
size = REAL_HOST_PAGE_ALIGN(size);
+ max_size = TARGET_PAGE_ALIGN(max_size);
+ max_size = REAL_HOST_PAGE_ALIGN(max_size);
file_size = get_file_size(fd);
- if (file_size > offset && file_size < (offset + size)) {
+ if (file_size && file_size < offset + max_size && !grow) {