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-rw-r--r--exec.c211
1 files changed, 104 insertions, 107 deletions
diff --git a/exec.c b/exec.c
index c3fbbb3fb8..1ca7baca0b 100644
--- a/exec.c
+++ b/exec.c
@@ -70,6 +70,12 @@ AddressSpace address_space_memory;
MemoryRegion io_mem_rom, io_mem_notdirty;
static MemoryRegion io_mem_unassigned;
+/* RAM is pre-allocated and passed into qemu_ram_alloc_from_ptr */
+#define RAM_PREALLOC (1 << 0)
+
+/* RAM is mmap-ed with MAP_SHARED */
+#define RAM_SHARED (1 << 1)
+
#endif
struct CPUTailQ cpus = QTAILQ_HEAD_INITIALIZER(cpus);
@@ -1011,16 +1017,10 @@ static long gethugepagesize(const char *path)
return fs.f_bsize;
}
-static sigjmp_buf sigjump;
-
-static void sigbus_handler(int signal)
-{
- siglongjmp(sigjump, 1);
-}
-
static void *file_ram_alloc(RAMBlock *block,
ram_addr_t memory,
- const char *path)
+ const char *path,
+ Error **errp)
{
char *filename;
char *sanitized_name;
@@ -1039,7 +1039,8 @@ static void *file_ram_alloc(RAMBlock *block,
}
if (kvm_enabled() && !kvm_has_sync_mmu()) {
- fprintf(stderr, "host lacks kvm mmu notifiers, -mem-path unsupported\n");
+ error_setg(errp,
+ "host lacks kvm mmu notifiers, -mem-path unsupported");
goto error;
}
@@ -1056,7 +1057,8 @@ static void *file_ram_alloc(RAMBlock *block,
fd = mkstemp(filename);
if (fd < 0) {
- perror("unable to create backing store for hugepages");
+ error_setg_errno(errp, errno,
+ "unable to create backing store for hugepages");
g_free(filename);
goto error;
}
@@ -1071,53 +1073,22 @@ static void *file_ram_alloc(RAMBlock *block,
* If anything goes wrong with it under other filesystems,
* mmap will fail.
*/
- if (ftruncate(fd, memory))
+ if (ftruncate(fd, memory)) {
perror("ftruncate");
+ }
- area = mmap(0, memory, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+ area = mmap(0, memory, PROT_READ | PROT_WRITE,
+ (block->flags & RAM_SHARED ? MAP_SHARED : MAP_PRIVATE),
+ fd, 0);
if (area == MAP_FAILED) {
- perror("file_ram_alloc: can't mmap RAM pages");
+ error_setg_errno(errp, errno,
+ "unable to map backing store for hugepages");
close(fd);
goto error;
}
if (mem_prealloc) {
- int ret, i;
- struct sigaction act, oldact;
- sigset_t set, oldset;
-
- memset(&act, 0, sizeof(act));
- act.sa_handler = &sigbus_handler;
- act.sa_flags = 0;
-
- ret = sigaction(SIGBUS, &act, &oldact);
- if (ret) {
- perror("file_ram_alloc: failed to install signal handler");
- exit(1);
- }
-
- /* unblock SIGBUS */
- sigemptyset(&set);
- sigaddset(&set, SIGBUS);
- pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
-
- if (sigsetjmp(sigjump, 1)) {
- fprintf(stderr, "file_ram_alloc: failed to preallocate pages\n");
- exit(1);
- }
-
- /* MAP_POPULATE silently ignores failures */
- for (i = 0; i < (memory/hpagesize); i++) {
- memset(area + (hpagesize*i), 0, 1);
- }
-
- ret = sigaction(SIGBUS, &oldact, NULL);
- if (ret) {
- perror("file_ram_alloc: failed to reinstall signal handler");
- exit(1);
- }
-
- pthread_sigmask(SIG_SETMASK, &oldset, NULL);
+ os_mem_prealloc(fd, area, memory);
}
block->fd = fd;
@@ -1129,14 +1100,6 @@ error:
}
return NULL;
}
-#else
-static void *file_ram_alloc(RAMBlock *block,
- ram_addr_t memory,
- const char *path)
-{
- fprintf(stderr, "-mem-path not supported on this host\n");
- exit(1);
-}
#endif
static ram_addr_t find_ram_offset(ram_addr_t size)
@@ -1262,56 +1225,30 @@ static int memory_try_enable_merging(void *addr, size_t len)
return qemu_madvise(addr, len, QEMU_MADV_MERGEABLE);
}
-ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
- MemoryRegion *mr)
+static ram_addr_t ram_block_add(RAMBlock *new_block)
{
- RAMBlock *block, *new_block;
+ RAMBlock *block;
ram_addr_t old_ram_size, new_ram_size;
old_ram_size = last_ram_offset() >> TARGET_PAGE_BITS;
- size = TARGET_PAGE_ALIGN(size);
- new_block = g_malloc0(sizeof(*new_block));
- new_block->fd = -1;
-
/* This assumes the iothread lock is taken here too. */
qemu_mutex_lock_ramlist();
- new_block->mr = mr;
- new_block->offset = find_ram_offset(size);
- if (host) {
- new_block->host = host;
- new_block->flags |= RAM_PREALLOC_MASK;
- } else if (xen_enabled()) {
- if (mem_path) {
- fprintf(stderr, "-mem-path not supported with Xen\n");
- exit(1);
- }
- xen_ram_alloc(new_block->offset, size, mr);
- } else {
- if (mem_path) {
- if (phys_mem_alloc != qemu_anon_ram_alloc) {
- /*
- * file_ram_alloc() needs to allocate just like
- * phys_mem_alloc, but we haven't bothered to provide
- * a hook there.
- */
- fprintf(stderr,
- "-mem-path not supported with this accelerator\n");
- exit(1);
- }
- new_block->host = file_ram_alloc(new_block, size, mem_path);
- }
- if (!new_block->host) {
- new_block->host = phys_mem_alloc(size);
+ new_block->offset = find_ram_offset(new_block->length);
+
+ if (!new_block->host) {
+ if (xen_enabled()) {
+ xen_ram_alloc(new_block->offset, new_block->length, new_block->mr);
+ } else {
+ new_block->host = phys_mem_alloc(new_block->length);
if (!new_block->host) {
fprintf(stderr, "Cannot set up guest memory '%s': %s\n",
new_block->mr->name, strerror(errno));
exit(1);
}
- memory_try_enable_merging(new_block->host, size);
+ memory_try_enable_merging(new_block->host, new_block->length);
}
}
- new_block->length = size;
/* Keep the list sorted from biggest to smallest block. */
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
@@ -1339,18 +1276,75 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
old_ram_size, new_ram_size);
}
}
- cpu_physical_memory_set_dirty_range(new_block->offset, size);
+ cpu_physical_memory_set_dirty_range(new_block->offset, new_block->length);
- qemu_ram_setup_dump(new_block->host, size);
- qemu_madvise(new_block->host, size, QEMU_MADV_HUGEPAGE);
- qemu_madvise(new_block->host, size, QEMU_MADV_DONTFORK);
+ qemu_ram_setup_dump(new_block->host, new_block->length);
+ qemu_madvise(new_block->host, new_block->length, QEMU_MADV_HUGEPAGE);
+ qemu_madvise(new_block->host, new_block->length, QEMU_MADV_DONTFORK);
- if (kvm_enabled())
- kvm_setup_guest_memory(new_block->host, size);
+ if (kvm_enabled()) {
+ kvm_setup_guest_memory(new_block->host, new_block->length);
+ }
return new_block->offset;
}
+#ifdef __linux__
+ram_addr_t qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
+ bool share, const char *mem_path,
+ Error **errp)
+{
+ RAMBlock *new_block;
+
+ if (xen_enabled()) {
+ error_setg(errp, "-mem-path not supported with Xen");
+ return -1;
+ }
+
+ if (phys_mem_alloc != qemu_anon_ram_alloc) {
+ /*
+ * file_ram_alloc() needs to allocate just like
+ * phys_mem_alloc, but we haven't bothered to provide
+ * a hook there.
+ */
+ error_setg(errp,
+ "-mem-path not supported with this accelerator");
+ return -1;
+ }
+
+ size = TARGET_PAGE_ALIGN(size);
+ new_block = g_malloc0(sizeof(*new_block));
+ new_block->mr = mr;
+ new_block->length = size;
+ new_block->flags = share ? RAM_SHARED : 0;
+ new_block->host = file_ram_alloc(new_block, size,
+ mem_path, errp);
+ if (!new_block->host) {
+ g_free(new_block);
+ return -1;
+ }
+
+ return ram_block_add(new_block);
+}
+#endif
+
+ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
+ MemoryRegion *mr)
+{
+ RAMBlock *new_block;
+
+ size = TARGET_PAGE_ALIGN(size);
+ new_block = g_malloc0(sizeof(*new_block));
+ new_block->mr = mr;
+ new_block->length = size;
+ new_block->fd = -1;
+ new_block->host = host;
+ if (host) {
+ new_block->flags |= RAM_PREALLOC;
+ }
+ return ram_block_add(new_block);
+}
+
ram_addr_t qemu_ram_alloc(ram_addr_t size, MemoryRegion *mr)
{
return qemu_ram_alloc_from_ptr(size, NULL, mr);
@@ -1385,7 +1379,7 @@ void qemu_ram_free(ram_addr_t addr)
QTAILQ_REMOVE(&ram_list.blocks, block, next);
ram_list.mru_block = NULL;
ram_list.version++;
- if (block->flags & RAM_PREALLOC_MASK) {
+ if (block->flags & RAM_PREALLOC) {
;
} else if (xen_enabled()) {
xen_invalidate_map_cache_entry(block->host);
@@ -1417,7 +1411,7 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length)
offset = addr - block->offset;
if (offset < block->length) {
vaddr = block->host + offset;
- if (block->flags & RAM_PREALLOC_MASK) {
+ if (block->flags & RAM_PREALLOC) {
;
} else if (xen_enabled()) {
abort();
@@ -1425,12 +1419,8 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length)
flags = MAP_FIXED;
munmap(vaddr, length);
if (block->fd >= 0) {
-#ifdef MAP_POPULATE
- flags |= mem_prealloc ? MAP_POPULATE | MAP_SHARED :
- MAP_PRIVATE;
-#else
- flags |= MAP_PRIVATE;
-#endif
+ flags |= (block->flags & RAM_SHARED ?
+ MAP_SHARED : MAP_PRIVATE);
area = mmap(vaddr, length, PROT_READ | PROT_WRITE,
flags, block->fd, offset);
} else {
@@ -1460,6 +1450,13 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length)
}
#endif /* !_WIN32 */
+int qemu_get_ram_fd(ram_addr_t addr)
+{
+ RAMBlock *block = qemu_get_ram_block(addr);
+
+ return block->fd;
+}
+
/* Return a host pointer to ram allocated with qemu_ram_alloc.
With the exception of the softmmu code in this file, this should
only be used for local memory (e.g. video ram) that the device owns,
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2026-04-30 14:49:45 +0200