From patchwork Wed Apr 29 08:50:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Liu, Jingqi" X-Patchwork-Id: 11516427 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 63BD915AB for ; Wed, 29 Apr 2020 08:58:15 +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 445DE20775 for ; Wed, 29 Apr 2020 08:58:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 445DE20775 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]:52120 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jTiXm-00054u-EE for patchwork-qemu-devel@patchwork.kernel.org; Wed, 29 Apr 2020 04:58:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57804) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jTiVc-0000rk-53 for qemu-devel@nongnu.org; Wed, 29 Apr 2020 04:56:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.90_1) (envelope-from ) id 1jTiV8-0001BE-HL for qemu-devel@nongnu.org; Wed, 29 Apr 2020 04:55:59 -0400 Received: from mga05.intel.com ([192.55.52.43]:25913) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jTiV7-0000wb-II for qemu-devel@nongnu.org; Wed, 29 Apr 2020 04:55:30 -0400 IronPort-SDR: 0N+vlx/ELAfT5oIF/ePZwBRbQFV+MakLSGnSBew8Ia7rpK5HlUfbfGfnClNejhKgeD92p1uR7z W6/BRXBXyaqQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Apr 2020 01:55:26 -0700 IronPort-SDR: f+c7rNMlyGB4ZDKLhVjyNARVSQZ5ut6OSNUKkx1QxvDtcF0XOuLKuYpkfDpFvobpv/g3A/0yRS 8QKcGSxvorZA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,331,1583222400"; d="scan'208";a="459114622" Received: from dazhang1-mobile.sh.intel.com ([10.239.48.70]) by fmsmga005.fm.intel.com with ESMTP; 29 Apr 2020 01:55:24 -0700 From: Jingqi Liu To: Paolo Bonzini , Richard Henderson , Joao Martins , Xiao Guangrong , Dan Williams Subject: [PATCH v3 1/3] exec: fetch the alignment of Linux devdax pmem character device nodes Date: Wed, 29 Apr 2020 16:50:09 +0800 Message-Id: <20200429085011.63752-2-jingqi.liu@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200429085011.63752-1-jingqi.liu@intel.com> References: <20200429085011.63752-1-jingqi.liu@intel.com> Received-SPF: pass client-ip=192.55.52.43; envelope-from=jingqi.liu@intel.com; helo=mga05.intel.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/04/29 04:55:24 X-ACL-Warn: Detected OS = FreeBSD 9.x or newer [fuzzy] X-Received-From: 192.55.52.43 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 Reviewed-by: Joao Martins 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;