From patchwork Wed Apr 15 03:35:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Liu, Jingqi" X-Patchwork-Id: 11489689 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 40A0E14B4 for ; Wed, 15 Apr 2020 03:42:10 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 20C492083B for ; Wed, 15 Apr 2020 03:42:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 20C492083B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:42368 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jOYwD-0005GW-A1 for patchwork-qemu-devel@patchwork.kernel.org; Tue, 14 Apr 2020 23:42:09 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48657) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jOYuW-00029H-2P for qemu-devel@nongnu.org; Tue, 14 Apr 2020 23:40:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jOYuU-0000ko-GF for qemu-devel@nongnu.org; Tue, 14 Apr 2020 23:40:23 -0400 Received: from mga01.intel.com ([192.55.52.88]:4321) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jOYuT-0000il-Uv for qemu-devel@nongnu.org; Tue, 14 Apr 2020 23:40:22 -0400 IronPort-SDR: hsv30nG8nXvtUPIKpFnMYV2L9NgJgQM+iS4+kOcIB4lbb6oLR5orFFr0tDjHslRnxEQ5XCCIfQ s4wUB9A1RIow== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2020 20:40:15 -0700 IronPort-SDR: aSpHhgfP5+7mUNptpgEg8lFvXL60uKwnRf6uPJy7OKAjYKNnS7/fLhRD9kPp0v9TGqGvx04iTT lrziVRl0/cPQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,385,1580803200"; d="scan'208";a="256729954" Received: from dazhang1-mobile.sh.intel.com ([10.239.48.70]) by orsmga006.jf.intel.com with ESMTP; 14 Apr 2020 20:40:13 -0700 From: Jingqi Liu To: Paolo Bonzini , Richard Henderson , Xiao Guangrong , Dan Williams Subject: [PATCH v2 1/3] exec: fetch the alignment of Linux devdax pmem character device nodes Date: Wed, 15 Apr 2020 11:35:36 +0800 Message-Id: <20200415033538.43329-2-jingqi.liu@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200415033538.43329-1-jingqi.liu@intel.com> References: <20200415033538.43329-1-jingqi.liu@intel.com> X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x [fuzzy] X-Received-From: 192.55.52.88 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jingqi Liu , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" If the backend file is devdax pmem character device, the alignment specified by the option 'align=NUM' in the '-object memory-backend-file' needs to match the alignment requirement of the devdax pmem character device. This patch uses the interfaces of libdaxctl to fetch the devdax pmem file 'align', so that we can compare it with the NUM of 'align=NUM'. The NUM needs to be larger than or equal to the devdax pmem file 'align'. It also fixes the problem that mmap() returns failure in qemu_ram_mmap() when the NUM of 'align=NUM' is less than the devdax pmem file 'align'. Suggested-by: Dan Williams Signed-off-by: Jingqi Liu --- exec.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 53 insertions(+), 1 deletion(-) diff --git a/exec.c b/exec.c index de9d949902..2c3444e47e 100644 --- a/exec.c +++ b/exec.c @@ -77,6 +77,10 @@ #include "monitor/monitor.h" +#ifdef CONFIG_LIBDAXCTL +#include +#endif + //#define DEBUG_SUBPAGE #if !defined(CONFIG_USER_ONLY) @@ -1736,6 +1740,46 @@ static int64_t get_file_size(int fd) return size; } +static int64_t get_file_align(int fd) +{ + int64_t align = -1; +#if defined(__linux__) && defined(CONFIG_LIBDAXCTL) + struct stat st; + + if (fstat(fd, &st) < 0) { + return -errno; + } + + /* Special handling for devdax character devices */ + if (S_ISCHR(st.st_mode)) { + g_autofree char *path = NULL; + g_autofree char *rpath = NULL; + struct daxctl_ctx *ctx; + struct daxctl_region *region; + int rc = 0; + + path = g_strdup_printf("/sys/dev/char/%d:%d", + major(st.st_rdev), minor(st.st_rdev)); + rpath = realpath(path, NULL); + + rc = daxctl_new(&ctx); + if (rc) { + return -1; + } + + daxctl_region_foreach(ctx, region) { + if (strstr(rpath, daxctl_region_get_path(region))) { + align = daxctl_region_get_align(region); + break; + } + } + daxctl_unref(ctx); + } +#endif /* defined(__linux__) && defined(CONFIG_LIBDAXCTL) */ + + return align; +} + static int file_ram_open(const char *path, const char *region_name, bool *created, @@ -2275,7 +2319,7 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, { RAMBlock *new_block; Error *local_err = NULL; - int64_t file_size; + int64_t file_size, file_align; /* Just support these ram flags by now. */ assert((ram_flags & ~(RAM_SHARED | RAM_PMEM)) == 0); @@ -2311,6 +2355,14 @@ RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr, return NULL; } + file_align = get_file_align(fd); + if (file_align > 0 && mr && file_align > mr->align) { + error_setg(errp, "backing store align 0x%" PRIx64 + " is larger than 'align' option 0x" RAM_ADDR_FMT, + file_align, mr->align); + return NULL; + } + new_block = g_malloc0(sizeof(*new_block)); new_block->mr = mr; new_block->used_length = size;