From patchwork Sun Oct 11 03:52:41 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiao Guangrong X-Patchwork-Id: 528658 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 6B7601402B7 for ; Sun, 11 Oct 2015 07:03:23 +1100 (AEDT) Received: from localhost ([::1]:46083 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zl0MT-00089w-Ey for incoming@patchwork.ozlabs.org; Sat, 10 Oct 2015 16:03:21 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50287) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zl0Hx-00008n-B5 for qemu-devel@nongnu.org; Sat, 10 Oct 2015 15:58:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zl0Ht-0003iO-AL for qemu-devel@nongnu.org; Sat, 10 Oct 2015 15:58:41 -0400 Received: from mga03.intel.com ([134.134.136.65]:60642) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zl0Ht-0003bu-0L for qemu-devel@nongnu.org; Sat, 10 Oct 2015 15:58:37 -0400 Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga103.jf.intel.com with ESMTP; 10 Oct 2015 12:58:37 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,664,1437462000"; d="scan'208";a="661782985" Received: from xiaoreal1.sh.intel.com (HELO xiaoreal1.sh.intel.com.sh.intel.com) ([10.239.48.79]) by orsmga003.jf.intel.com with ESMTP; 10 Oct 2015 12:58:34 -0700 From: Xiao Guangrong To: pbonzini@redhat.com, imammedo@redhat.com Date: Sun, 11 Oct 2015 11:52:41 +0800 Message-Id: <1444535584-18220-10-git-send-email-guangrong.xiao@linux.intel.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1444535584-18220-1-git-send-email-guangrong.xiao@linux.intel.com> References: <1444535584-18220-1-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: 134.134.136.65 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 v3 09/32] 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 | 82 ++++++++++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 52 insertions(+), 30 deletions(-) diff --git a/exec.c b/exec.c index 70cb0ef..c8c7e12 100644 --- a/exec.c +++ b/exec.c @@ -1154,14 +1154,60 @@ 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 *ptr; void *area = NULL; int fd; @@ -1189,39 +1235,15 @@ 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); + total = 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); - total = 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"); - } ptr = mmap(0, total, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);