From patchwork Fri Jun 26 13:56:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 279335 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E997C433DF for ; Fri, 26 Jun 2020 13:58:14 +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 1B0302080C for ; Fri, 26 Jun 2020 13:58:14 +0000 (UTC) Authentication-Results: mail.kernel.org; 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Fri, 26 Jun 2020 13:56:10 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5B08410016E8; Fri, 26 Jun 2020 13:56:09 +0000 (UTC) From: Paolo Bonzini To: qemu-devel@nongnu.org Subject: [PULL v2 09/31] exec: fetch the alignment of Linux devdax pmem character device nodes Date: Fri, 26 Jun 2020 09:56:07 -0400 Message-Id: <20200626135608.6920-2-pbonzini@redhat.com> In-Reply-To: <20200626135608.6920-1-pbonzini@redhat.com> References: <20200626135608.6920-1-pbonzini@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=205.139.110.120; envelope-from=pbonzini@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/26 01:55:55 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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 , Dan Williams , Joao Martins Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Jingqi Liu 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 Message-Id: <20200429085011.63752-2-jingqi.liu@intel.com> Signed-off-by: Paolo Bonzini --- exec.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 53 insertions(+), 1 deletion(-) diff --git a/exec.c b/exec.c index d6712fba7e..21926dc9c7 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) @@ -1745,6 +1749,46 @@ 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, @@ -2296,7 +2340,7 @@ 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); @@ -2332,6 +2376,14 @@ 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%" PRIx64, + file_align, mr->align); + return NULL; + } + new_block = g_malloc0(sizeof(*new_block)); new_block->mr = mr; new_block->used_length = size;