From patchwork Thu Mar 5 14:29:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 11421923 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 79F20174A for ; Thu, 5 Mar 2020 14:33:56 +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 50BD720732 for ; Thu, 5 Mar 2020 14:33:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BOa0dJ54" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 50BD720732 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.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]:50318 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j9rZT-0003Lq-FF for patchwork-qemu-devel@patchwork.kernel.org; Thu, 05 Mar 2020 09:33:55 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35728) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j9rXp-0000GE-Li for qemu-devel@nongnu.org; Thu, 05 Mar 2020 09:32:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j9rXo-0003GV-Cw for qemu-devel@nongnu.org; Thu, 05 Mar 2020 09:32:13 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:33026 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j9rXo-0003GK-9H for qemu-devel@nongnu.org; Thu, 05 Mar 2020 09:32:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583418732; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5lGKktvpp3+XdkvJGg3g7hD+l344AtPs6h6RHl03TEQ=; b=BOa0dJ54G38m9d4UN7JtF8hn/cNNe+5U8wbNI8qrou3R+why31LowI58ccdxS2nGkaefEQ DEMIXIUCowvRJNbWkLHtn/7KiF/N5tazEffMHJWjAavO0viGBjv3LNs24xtjItJ33NPNWW x4d0tRepsj/ryOM3SXmWHFoJyRN2B6o= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-269-sLI3RBJYOAqwvftCriaCiQ-1; Thu, 05 Mar 2020 09:32:10 -0500 X-MC-Unique: sLI3RBJYOAqwvftCriaCiQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 54DD38017DF; Thu, 5 Mar 2020 14:32:09 +0000 (UTC) Received: from t480s.redhat.com (ovpn-120-166.rdu2.redhat.com [10.10.120.166]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6E14090538; Thu, 5 Mar 2020 14:32:01 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v4 09/15] util/mmap-alloc: Factor out activating of memory to mmap_activate() Date: Thu, 5 Mar 2020 15:29:39 +0100 Message-Id: <20200305142945.216465-10-david@redhat.com> In-Reply-To: <20200305142945.216465-1-david@redhat.com> References: <20200305142945.216465-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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: Eduardo Habkost , "Michael S . Tsirkin" , Richard Henderson , Igor Kotrasinski , David Hildenbrand , "Dr . David Alan Gilbert" , Peter Xu , Greg Kurz , Murilo Opsfelder Araujo , Igor Mammedov , Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" We want to activate memory within a reserved memory region, to make it accessible. Let's factor that out. Reviewed-by: Richard Henderson Acked-by: Murilo Opsfelder Araujo Reviewed-by: Peter Xu Cc: Igor Kotrasinski Cc: "Michael S. Tsirkin" Cc: Greg Kurz Cc: Murilo Opsfelder Araujo Cc: Eduardo Habkost Cc: "Dr. David Alan Gilbert" Cc: Igor Mammedov Signed-off-by: David Hildenbrand --- util/mmap-alloc.c | 90 +++++++++++++++++++++++++---------------------- 1 file changed, 48 insertions(+), 42 deletions(-) diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 9e9534a07e..8f40ef4fed 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -114,6 +114,51 @@ static void *mmap_reserve(size_t size, int fd) return mmap(0, size, PROT_NONE, flags, fd, 0); } +/* + * Activate memory in a reserved region from the given fd (if any), to make + * it accessible. + */ +static void *mmap_activate(void *ptr, size_t size, int fd, bool shared, + bool is_pmem) +{ + int map_sync_flags = 0; + int flags = MAP_FIXED; + void *activated_ptr; + + flags |= fd == -1 ? MAP_ANONYMOUS : 0; + flags |= shared ? MAP_SHARED : MAP_PRIVATE; + if (shared && is_pmem) { + map_sync_flags = MAP_SYNC | MAP_SHARED_VALIDATE; + } + + activated_ptr = mmap(ptr, size, PROT_READ | PROT_WRITE, + flags | map_sync_flags, fd, 0); + if (activated_ptr == MAP_FAILED && map_sync_flags) { + if (errno == ENOTSUP) { + char *proc_link = g_strdup_printf("/proc/self/fd/%d", fd); + char *file_name = g_malloc0(PATH_MAX); + int len = readlink(proc_link, file_name, PATH_MAX - 1); + + if (len < 0) { + len = 0; + } + file_name[len] = '\0'; + fprintf(stderr, "Warning: requesting persistence across crashes " + "for backend file %s failed. Proceeding without " + "persistence, data might become corrupted in case of host " + "crash.\n", file_name); + g_free(proc_link); + g_free(file_name); + } + /* + * If mmap failed with MAP_SHARED_VALIDATE | MAP_SYNC, we will try + * again without these flags to handle backwards compatibility. + */ + activated_ptr = mmap(ptr, size, PROT_READ | PROT_WRITE, flags, fd, 0); + } + return activated_ptr; +} + static inline size_t mmap_guard_pagesize(int fd) { #if defined(__powerpc64__) && defined(__linux__) @@ -131,12 +176,8 @@ void *qemu_ram_mmap(int fd, bool is_pmem) { const size_t guard_pagesize = mmap_guard_pagesize(fd); - int flags; - int map_sync_flags = 0; - size_t offset; - size_t total; - void *guardptr; - void *ptr; + size_t offset, total; + void *ptr, *guardptr; /* * Note: this always allocates at least one extra page of virtual address @@ -153,44 +194,9 @@ void *qemu_ram_mmap(int fd, /* Always align to host page size */ assert(align >= guard_pagesize); - flags = MAP_FIXED; - flags |= fd == -1 ? MAP_ANONYMOUS : 0; - flags |= shared ? MAP_SHARED : MAP_PRIVATE; - if (shared && is_pmem) { - map_sync_flags = MAP_SYNC | MAP_SHARED_VALIDATE; - } - offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr; - ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, - flags | map_sync_flags, fd, 0); - - if (ptr == MAP_FAILED && map_sync_flags) { - if (errno == ENOTSUP) { - char *proc_link, *file_name; - int len; - proc_link = g_strdup_printf("/proc/self/fd/%d", fd); - file_name = g_malloc0(PATH_MAX); - len = readlink(proc_link, file_name, PATH_MAX - 1); - if (len < 0) { - len = 0; - } - file_name[len] = '\0'; - fprintf(stderr, "Warning: requesting persistence across crashes " - "for backend file %s failed. Proceeding without " - "persistence, data might become corrupted in case of host " - "crash.\n", file_name); - g_free(proc_link); - g_free(file_name); - } - /* - * if map failed with MAP_SHARED_VALIDATE | MAP_SYNC, - * we will remove these flags to handle compatibility. - */ - ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, - flags, fd, 0); - } - + ptr = mmap_activate(guardptr + offset, size, fd, shared, is_pmem); if (ptr == MAP_FAILED) { munmap(guardptr, total); return MAP_FAILED;