From patchwork Fri Oct 30 05:56:03 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiao Guangrong X-Patchwork-Id: 538133 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 00485140082 for ; Fri, 30 Oct 2015 17:06:12 +1100 (AEDT) Received: from localhost ([::1]:48613 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zs2pG-0003SI-1R for incoming@patchwork.ozlabs.org; Fri, 30 Oct 2015 02:06:10 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56854) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zs2lY-0004jL-OO for qemu-devel@nongnu.org; Fri, 30 Oct 2015 02:02:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zs2lV-0007gT-LD for qemu-devel@nongnu.org; Fri, 30 Oct 2015 02:02:20 -0400 Received: from mga11.intel.com ([192.55.52.93]:19647) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zs2lV-0007g3-G6 for qemu-devel@nongnu.org; Fri, 30 Oct 2015 02:02:17 -0400 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP; 29 Oct 2015 23:02:16 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,217,1444719600"; d="scan'208";a="590813966" Received: from xiaoreal1.sh.intel.com (HELO xiaoreal1.sh.intel.com.sh.intel.com) ([10.239.48.79]) by FMSMGA003.fm.intel.com with ESMTP; 29 Oct 2015 23:02:11 -0700 From: Xiao Guangrong To: pbonzini@redhat.com, imammedo@redhat.com Date: Fri, 30 Oct 2015 13:56:03 +0800 Message-Id: <1446184587-142784-10-git-send-email-guangrong.xiao@linux.intel.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1446184587-142784-1-git-send-email-guangrong.xiao@linux.intel.com> References: <1446184587-142784-1-git-send-email-guangrong.xiao@linux.intel.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 192.55.52.93 Cc: Xiao Guangrong , ehabkost@redhat.com, kvm@vger.kernel.org, mst@redhat.com, gleb@kernel.org, mtosatti@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, dan.j.williams@intel.com, rth@twiddle.net Subject: [Qemu-devel] [PATCH v6 09/33] exec: allow file_ram_alloc to work on file X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Currently, file_ram_alloc() only works on directory - it creates a file under @path and do mmap on it This patch tries to allow it to work on file directly, if @path is a directory it works as before, otherwise it treats @path as the target file then directly allocate memory from it Signed-off-by: Xiao Guangrong --- exec.c | 80 ++++++++++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 51 insertions(+), 29 deletions(-) diff --git a/exec.c b/exec.c index 3ca7e50..f219010 100644 --- a/exec.c +++ b/exec.c @@ -1174,14 +1174,60 @@ void qemu_mutex_unlock_ramlist(void) } #ifdef __linux__ +static bool path_is_dir(const char *path) +{ + struct stat fs; + + return stat(path, &fs) == 0 && S_ISDIR(fs.st_mode); +} + +static int open_file_path(RAMBlock *block, const char *path, size_t size) +{ + char *filename; + char *sanitized_name; + char *c; + int fd; + + if (!path_is_dir(path)) { + int flags = (block->flags & RAM_SHARED) ? O_RDWR : O_RDONLY; + + flags |= O_EXCL; + return open(path, flags); + } + + /* Make name safe to use with mkstemp by replacing '/' with '_'. */ + sanitized_name = g_strdup(memory_region_name(block->mr)); + for (c = sanitized_name; *c != '\0'; c++) { + if (*c == '/') { + *c = '_'; + } + } + filename = g_strdup_printf("%s/qemu_back_mem.%s.XXXXXX", path, + sanitized_name); + g_free(sanitized_name); + fd = mkstemp(filename); + if (fd >= 0) { + unlink(filename); + /* + * ftruncate is not supported by hugetlbfs in older + * hosts, so don't bother bailing out on errors. + * If anything goes wrong with it under other filesystems, + * mmap will fail. + */ + if (ftruncate(fd, size)) { + perror("ftruncate"); + } + } + g_free(filename); + + return fd; +} + static void *file_ram_alloc(RAMBlock *block, ram_addr_t memory, const char *path, Error **errp) { - char *filename; - char *sanitized_name; - char *c; void *area; int fd; uint64_t pagesize; @@ -1211,38 +1257,14 @@ static void *file_ram_alloc(RAMBlock *block, goto error; } - /* Make name safe to use with mkstemp by replacing '/' with '_'. */ - sanitized_name = g_strdup(memory_region_name(block->mr)); - for (c = sanitized_name; *c != '\0'; c++) { - if (*c == '/') - *c = '_'; - } - - filename = g_strdup_printf("%s/qemu_back_mem.%s.XXXXXX", path, - sanitized_name); - g_free(sanitized_name); + memory = ROUND_UP(memory, pagesize); - fd = mkstemp(filename); + fd = open_file_path(block, path, memory); if (fd < 0) { error_setg_errno(errp, errno, "unable to create backing store for path %s", path); - g_free(filename); goto error; } - unlink(filename); - g_free(filename); - - memory = ROUND_UP(memory, pagesize); - - /* - * ftruncate is not supported by hugetlbfs in older - * hosts, so don't bother bailing out on errors. - * If anything goes wrong with it under other filesystems, - * mmap will fail. - */ - if (ftruncate(fd, memory)) { - perror("ftruncate"); - } area = qemu_ram_mmap(fd, memory, pagesize, block->flags & RAM_SHARED); if (area == MAP_FAILED) {