From patchwork Thu Feb 27 10:11:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 1245706 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=jQfpf1pE; dkim-atps=neutral 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 ozlabs.org (Postfix) with ESMTPS id 48SpYz5KVGz9sRY for ; Thu, 27 Feb 2020 21:19:35 +1100 (AEDT) Received: from localhost ([::1]:56632 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j7GGT-0008H5-Js for incoming@patchwork.ozlabs.org; Thu, 27 Feb 2020 05:19:33 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:40045) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j7GBI-0003YR-89 for qemu-devel@nongnu.org; Thu, 27 Feb 2020 05:14:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j7GBG-00088R-Tt for qemu-devel@nongnu.org; Thu, 27 Feb 2020 05:14:12 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:51420 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j7GBG-00086O-PS for qemu-devel@nongnu.org; Thu, 27 Feb 2020 05:14:10 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582798450; 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=m/8TwOF2Sia+Gjod6JfWjCPGtrFF4CPZ36Jyrg9pzx0=; b=jQfpf1pEW1R/UVhPm2z5kf52Mi3fxvVnOYnLQ4ZICaolmzjDCDn0YsdcymkfpQYFXiSxMb hd3bSN4HyMG4Ae5mYjqyFJCZa2GaUJfCPl7/DKfyKF8E3Y2IF6gtvd8vWcaPogUXtbNQBI 1t9aupUu6nJrXvLGrCSD6erZZgwf10w= 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-143--T1rH1jlM2GgK7K_NigEhQ-1; Thu, 27 Feb 2020 05:14:08 -0500 X-MC-Unique: -T1rH1jlM2GgK7K_NigEhQ-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 61AA718A5507; Thu, 27 Feb 2020 10:14:07 +0000 (UTC) Received: from t480s.redhat.com (ovpn-116-36.ams2.redhat.com [10.36.116.36]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9239E6E3EE; Thu, 27 Feb 2020 10:14:01 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v3 09/15] util/mmap-alloc: Factor out populating of memory to mmap_populate() Date: Thu, 27 Feb 2020 11:11:59 +0100 Message-Id: <20200227101205.5616-10-david@redhat.com> In-Reply-To: <20200227101205.5616-1-david@redhat.com> References: <20200227101205.5616-1-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: 207.211.31.81 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+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" We want to populate memory within a reserved memory region. 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 | 89 +++++++++++++++++++++++++---------------------- 1 file changed, 47 insertions(+), 42 deletions(-) diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 9e9534a07e..73179f36d6 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -114,6 +114,50 @@ static void *mmap_reserve(size_t size, int fd) return mmap(0, size, PROT_NONE, flags, fd, 0); } +/* + * Populate memory in a reserved region from the given fd (if any). + */ +static void *mmap_populate(void *ptr, size_t size, int fd, bool shared, + bool is_pmem) +{ + int map_sync_flags = 0; + int flags = MAP_FIXED; + void *populated_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; + } + + populated_ptr = mmap(ptr, size, PROT_READ | PROT_WRITE, + flags | map_sync_flags, fd, 0); + if (populated_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. + */ + populated_ptr = mmap(ptr, size, PROT_READ | PROT_WRITE, flags, fd, 0); + } + return populated_ptr; +} + static inline size_t mmap_guard_pagesize(int fd) { #if defined(__powerpc64__) && defined(__linux__) @@ -131,12 +175,8 @@ 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 +193,9 @@ 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_populate(guardptr + offset, size, fd, shared, is_pmem); if (ptr == MAP_FAILED) { munmap(guardptr, total); return MAP_FAILED;