From 72d41eb4b8f923de91e8f06dc20aa86b0a9155fb Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Fri, 30 Aug 2019 10:30:56 +0100 Subject: memory: fetch pmem size in get_file_size() Neither stat(2) nor lseek(2) report the size of Linux devdax pmem character device nodes. Commit 314aec4a6e06844937f1677f6cba21981005f389 ("hostmem-file: reject invalid pmem file sizes") added code to hostmem-file.c to fetch the size from sysfs and compare against the user-provided size=NUM parameter: if (backend->size > size) { error_setg(errp, "size property %" PRIu64 " is larger than " "pmem file \"%s\" size %" PRIu64, backend->size, fb->mem_path, size); return; } It turns out that exec.c:qemu_ram_alloc_from_fd() already has an equivalent size check but it skips devdax pmem character devices because lseek(2) returns 0: if (file_size > 0 && file_size < size) { error_setg(errp, "backing store %s size 0x%" PRIx64 " does not match 'size' option 0x" RAM_ADDR_FMT, mem_path, file_size, size); return NULL; } This patch moves the devdax pmem file size code into get_file_size() so that we check the memory size in a single place: qemu_ram_alloc_from_fd(). This simplifies the code and makes it more general. This also fixes the problem that hostmem-file only checks the devdax pmem file size when the pmem=on parameter is given. An unchecked size=NUM parameter can lead to SIGBUS in QEMU so we must always fetch the file size for Linux devdax pmem character device nodes. Signed-off-by: Stefan Hajnoczi Message-Id: <20190830093056.12572-1-stefanha@redhat.com> Reviewed-by: Eduardo Habkost Signed-off-by: Paolo Bonzini --- include/qemu/osdep.h | 13 ------------- 1 file changed, 13 deletions(-) (limited to 'include') diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index af2b91f0b8..c7d242f476 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -570,19 +570,6 @@ void qemu_set_tty_echo(int fd, bool echo); void os_mem_prealloc(int fd, char *area, size_t sz, int smp_cpus, Error **errp); -/** - * qemu_get_pmem_size: - * @filename: path to a pmem file - * @errp: pointer to a NULL-initialized error object - * - * Determine the size of a persistent memory file. Besides supporting files on - * DAX file systems, this function also supports Linux devdax character - * devices. - * - * Returns: the size or 0 on failure - */ -uint64_t qemu_get_pmem_size(const char *filename, Error **errp); - /** * qemu_get_pid_name: * @pid: pid of a process -- cgit v1.2.3-55-g7522