diff options
Diffstat (limited to 'system/physmem.c')
| -rw-r--r-- | system/physmem.c | 150 |
1 files changed, 129 insertions, 21 deletions
diff --git a/system/physmem.c b/system/physmem.c index c76503aea8..67c9db9daa 100644 --- a/system/physmem.c +++ b/system/physmem.c @@ -48,6 +48,7 @@ #include "qemu/qemu-print.h" #include "qemu/log.h" #include "qemu/memalign.h" +#include "qemu/memfd.h" #include "exec/memory.h" #include "exec/ioport.h" #include "system/dma.h" @@ -69,6 +70,7 @@ #include "qemu/pmem.h" +#include "migration/cpr.h" #include "migration/vmstate.h" #include "qemu/range.h" @@ -1660,6 +1662,18 @@ void qemu_ram_unset_idstr(RAMBlock *block) } } +static char *cpr_name(MemoryRegion *mr) +{ + const char *mr_name = memory_region_name(mr); + g_autofree char *id = mr->dev ? qdev_get_dev_path(mr->dev) : NULL; + + if (id) { + return g_strdup_printf("%s/%s", id, mr_name); + } else { + return g_strdup(mr_name); + } +} + size_t qemu_ram_pagesize(RAMBlock *rb) { return rb->page_size; @@ -1942,18 +1956,27 @@ 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) { + ERRP_GUARD(); RAMBlock *new_block; Error *local_err = NULL; - int64_t file_size, file_align; + int64_t file_size, file_align, share_flags; + + share_flags = ram_flags & (RAM_PRIVATE | RAM_SHARED); + assert(share_flags != (RAM_SHARED | RAM_PRIVATE)); + ram_flags &= ~RAM_PRIVATE; /* 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 +1991,16 @@ 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)) { - error_setg(errp, "backing store size 0x%" PRIx64 - " does not match 'size' option 0x" RAM_ADDR_FMT, - file_size, size); + if (file_size && file_size < offset + max_size && !grow) { + error_setg(errp, "%s backing store size 0x%" PRIx64 + " is too small for 'size' option 0x" RAM_ADDR_FMT + " plus 'offset' option 0x%" PRIx64, + memory_region_name(mr), file_size, max_size, + (uint64_t)offset); return NULL; } @@ -1988,11 +2015,13 @@ 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 +2073,8 @@ 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); @@ -2057,21 +2087,97 @@ RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr, } #endif +#ifdef CONFIG_POSIX +/* + * Create MAP_SHARED RAMBlocks by mmap'ing a file descriptor, so it can be + * shared with another process if CPR is being used. Use memfd if available + * because it has no size limits, else use POSIX shm. + */ +static int qemu_ram_get_shared_fd(const char *name, bool *reused, Error **errp) +{ + int fd = cpr_find_fd(name, 0); + + if (fd >= 0) { + *reused = true; + return fd; + } + + if (qemu_memfd_check(0)) { + fd = qemu_memfd_create(name, 0, 0, 0, 0, errp); + } else { + fd = qemu_shm_alloc(0, errp); + } + + if (fd >= 0) { + cpr_save_fd(name, 0, fd); + } + *reused = false; + return fd; +} +#endif + 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) { RAMBlock *new_block; Error *local_err = NULL; - int align; + int align, share_flags; + + share_flags = ram_flags & (RAM_PRIVATE | RAM_SHARED); + assert(share_flags != (RAM_SHARED | RAM_PRIVATE)); + ram_flags &= ~RAM_PRIVATE; assert((ram_flags & ~(RAM_SHARED | RAM_RESIZEABLE | RAM_PREALLOC | RAM_NORESERVE | RAM_GUEST_MEMFD)) == 0); assert(!host ^ (ram_flags & RAM_PREALLOC)); + assert(max_size >= size); + +#ifdef CONFIG_POSIX /* ignore RAM_SHARED for Windows */ + if (!host) { + if (!share_flags && current_machine->aux_ram_share) { + ram_flags |= RAM_SHARED; + } + if (ram_flags & RAM_SHARED) { + bool reused; + g_autofree char *name = cpr_name(mr); + int fd = qemu_ram_get_shared_fd(name, &reused, errp); + + if (fd < 0) { + return NULL; + } + + /* Use same alignment as qemu_anon_ram_alloc */ + mr->align = QEMU_VMALLOC_ALIGN; + + /* + * This can fail if the shm mount size is too small, or alloc from + * fd is not supported, but previous QEMU versions that called + * qemu_anon_ram_alloc for anonymous shared memory could have + * succeeded. Quietly fail and fall back. + * + * After cpr-transfer, new QEMU could create a memory region + * with a larger max size than old, so pass reused to grow the + * region if necessary. The extra space will be usable after a + * guest reset. + */ + new_block = qemu_ram_alloc_from_fd(size, max_size, resized, mr, + ram_flags, fd, 0, reused, NULL); + if (new_block) { + trace_qemu_ram_alloc_shared(name, new_block->used_length, + new_block->max_length, fd, + new_block->host); + return new_block; + } + + cpr_delete_fd(name, 0); + close(fd); + /* fall back to anon allocation */ + } + } +#endif align = qemu_real_host_page_size(); align = MAX(align, TARGET_PAGE_SIZE); @@ -2083,7 +2189,6 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size, 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->guest_memfd = -1; new_block->page_size = qemu_real_host_page_size(); @@ -2108,15 +2213,14 @@ 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) { - assert((ram_flags & ~(RAM_SHARED | RAM_NORESERVE | RAM_GUEST_MEMFD)) == 0); + assert((ram_flags & ~(RAM_SHARED | RAM_NORESERVE | RAM_GUEST_MEMFD | + RAM_PRIVATE)) == 0); return qemu_ram_alloc_internal(size, size, NULL, NULL, ram_flags, mr, errp); } 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); @@ -2147,6 +2251,8 @@ static void reclaim_ramblock(RAMBlock *block) void qemu_ram_free(RAMBlock *block) { + g_autofree char *name = NULL; + if (!block) { return; } @@ -2157,6 +2263,8 @@ void qemu_ram_free(RAMBlock *block) } qemu_mutex_lock_ramlist(); + name = cpr_name(block->mr); + cpr_delete_fd(name, 0); QLIST_REMOVE_RCU(block, next); ram_list.mru_block = NULL; /* Write list before version */ |