| Message ID | 1735057028-308595-3-git-send-email-steven.sistare@oracle.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Live update: cpr-transfer | expand |
On Tue, Dec 24, 2024 at 08:16:47AM -0800, Steve Sistare wrote: > 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) { Is this a bugfix for the case offset < fsize? If so, better make it a small patch and copy stable.. $ touch ramfile $ truncate -s 64M ramfile $ ./qemu-system-x86_64 -object memory-backend-file,mem-path=./ramfile,offset=128M,size=128M,id=mem1,prealloc=on qemu-system-x86_64: qemu_prealloc_mem: preallocating memory failed: Bad address So yes, it's a bug.. > error_setg(errp, "backing store size 0x%" PRIx64 > " does not match 'size' option 0x" RAM_ADDR_FMT, > - file_size, size); > + file_size, max_size); > return NULL; > } > > @@ -1988,11 +1994,13 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, > new_block = g_malloc0(sizeof(*new_block)); > new_block->mr = mr; > new_block->used_length = size; > - new_block->max_length = size; > + new_block->max_length = max_size; > + new_block->resized = resized; > new_block->flags = ram_flags; > new_block->guest_memfd = -1; > - new_block->host = file_ram_alloc(new_block, size, fd, !file_size, offset, > - errp); > + new_block->host = file_ram_alloc(new_block, max_size, fd, > + file_size < offset + max_size, Same here, looks like relevant to above. In general, we want to either fail properly detecting wrong-sized files, or making sure qemu can boot correctly with the fd. I confess pretty corner cases.. but still. So the whole patch looks correct, but maybe need a split. > + offset, errp); > if (!new_block->host) { > g_free(new_block); > return NULL; > @@ -2044,7 +2052,8 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, > return NULL; > } > > - block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, offset, errp); > + block = qemu_ram_alloc_from_fd(size, size, NULL, mr, ram_flags, fd, offset, > + false, errp); > if (!block) { > if (created) { > unlink(mem_path); > @@ -2059,9 +2068,7 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, > > static > RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size, > - void (*resized)(const char*, > - uint64_t length, > - void *host), > + qemu_ram_resize_cb resized, > void *host, uint32_t ram_flags, > MemoryRegion *mr, Error **errp) > { > @@ -2113,10 +2120,8 @@ RAMBlock *qemu_ram_alloc(ram_addr_t size, uint32_t ram_flags, > } > > RAMBlock *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) > + qemu_ram_resize_cb resized, > + MemoryRegion *mr, Error **errp) > { > return qemu_ram_alloc_internal(size, maxsz, resized, NULL, > RAM_RESIZEABLE, mr, errp); > -- > 1.8.3.1 >
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) { error_setg(errp, "backing store size 0x%" PRIx64 " does not match 'size' option 0x" RAM_ADDR_FMT, - file_size, size); + file_size, max_size); return NULL; } @@ -1988,11 +1994,13 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, new_block = g_malloc0(sizeof(*new_block)); new_block->mr = mr; new_block->used_length = size; - new_block->max_length = size; + new_block->max_length = max_size; + new_block->resized = resized; new_block->flags = ram_flags; new_block->guest_memfd = -1; - new_block->host = file_ram_alloc(new_block, size, fd, !file_size, offset, - errp); + new_block->host = file_ram_alloc(new_block, max_size, fd, + file_size < offset + max_size, + offset, errp); if (!new_block->host) { g_free(new_block); return NULL; @@ -2044,7 +2052,8 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, return NULL; } - block = qemu_ram_alloc_from_fd(size, mr, ram_flags, fd, offset, errp); + block = qemu_ram_alloc_from_fd(size, size, NULL, mr, ram_flags, fd, offset, + false, errp); if (!block) { if (created) { unlink(mem_path); @@ -2059,9 +2068,7 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, static RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size, - void (*resized)(const char*, - uint64_t length, - void *host), + qemu_ram_resize_cb resized, void *host, uint32_t ram_flags, MemoryRegion *mr, Error **errp) { @@ -2113,10 +2120,8 @@ RAMBlock *qemu_ram_alloc(ram_addr_t size, uint32_t ram_flags, } RAMBlock *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) + qemu_ram_resize_cb resized, + MemoryRegion *mr, Error **errp) { return qemu_ram_alloc_internal(size, maxsz, resized, NULL, RAM_RESIZEABLE, mr, errp);
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(-)