qmp-event: Avoid qobject_from_jsonf("%"PRId64)

[mirror_qemu.git] / exec.c

diff --git a/exec.c b/exec.c
index a19ed21bffc51b7fa9f23fe3412fb9a719dfb2d2..3d867f166cc6930b7073bd2d1f17b15faf41ad69 100644 (file)
--- a/exec.c
+++ b/exec.c
@@ -911,11 +911,13 @@ void cpu_abort(CPUState *cpu, const char *fmt, ...)
     fprintf(stderr, "\n");
     cpu_dump_state(cpu, stderr, fprintf, CPU_DUMP_FPU | CPU_DUMP_CCOP);
     if (qemu_log_separate()) {
+        qemu_log_lock();
         qemu_log("qemu: fatal: ");
         qemu_log_vprintf(fmt, ap2);
         qemu_log("\n");
         log_cpu_state(cpu, CPU_DUMP_FPU | CPU_DUMP_CCOP);
         qemu_log_flush();
+        qemu_log_unlock();
         qemu_log_close();
     }
     va_end(ap2);
@@ -1229,6 +1231,15 @@ void qemu_mutex_unlock_ramlist(void)
 }
 
 #ifdef __linux__
+static int64_t get_file_size(int fd)
+{
+    int64_t size = lseek(fd, 0, SEEK_END);
+    if (size < 0) {
+        return -errno;
+    }
+    return size;
+}
+
 static void *file_ram_alloc(RAMBlock *block,
                             ram_addr_t memory,
                             const char *path,
@@ -1240,6 +1251,7 @@ static void *file_ram_alloc(RAMBlock *block,
     char *c;
     void *area = MAP_FAILED;
     int fd = -1;
+    int64_t file_size;
 
     if (kvm_enabled() && !kvm_has_sync_mmu()) {
         error_setg(errp,
@@ -1302,6 +1314,8 @@ static void *file_ram_alloc(RAMBlock *block,
     }
 #endif
 
+    file_size = get_file_size(fd);
+
     if (memory < block->page_size) {
         error_setg(errp, "memory size 0x" RAM_ADDR_FMT " must be equal to "
                    "or larger than page size 0x%zx",
@@ -1309,6 +1323,13 @@ static void *file_ram_alloc(RAMBlock *block,
         goto error;
     }
 
+    if (file_size > 0 && file_size < memory) {
+        error_setg(errp, "backing store %s size 0x%" PRIx64
+                   " does not match 'size' option 0x" RAM_ADDR_FMT,
+                   path, file_size, memory);
+        goto error;
+    }
+
     memory = ROUND_UP(memory, block->page_size);
 
     /*
@@ -1316,8 +1337,16 @@ static void *file_ram_alloc(RAMBlock *block,
      * hosts, so don't bother bailing out on errors.
      * If anything goes wrong with it under other filesystems,
      * mmap will fail.
+     *
+     * Do not truncate the non-empty backend file to avoid corrupting
+     * the existing data in the file. Disabling shrinking is not
+     * enough. For example, the current vNVDIMM implementation stores
+     * the guest NVDIMM labels at the end of the backend file. If the
+     * backend file is later extended, QEMU will not be able to find
+     * those labels. Therefore, extending the non-empty backend file
+     * is disabled as well.
      */
-    if (ftruncate(fd, memory)) {
+    if (!file_size && ftruncate(fd, memory)) {
         perror("ftruncate");
     }