From patchwork Wed Feb 22 16:01:16 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Halil Pasic X-Patchwork-Id: 9587093 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5E804600CA for ; Wed, 22 Feb 2017 16:06:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4BA2626CFC for ; Wed, 22 Feb 2017 16:06:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 408C62867C; Wed, 22 Feb 2017 16:06:37 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id B63B726CFC for ; Wed, 22 Feb 2017 16:06:36 +0000 (UTC) Received: from localhost ([::1]:53325 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cgZR5-0001GK-P0 for patchwork-qemu-devel@patchwork.kernel.org; Wed, 22 Feb 2017 11:06:35 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34871) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cgZMG-0005La-GC for qemu-devel@nongnu.org; Wed, 22 Feb 2017 11:01:37 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cgZMC-0002tQ-Jo for qemu-devel@nongnu.org; Wed, 22 Feb 2017 11:01:36 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:42867) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cgZMC-0002sh-AN for qemu-devel@nongnu.org; Wed, 22 Feb 2017 11:01:32 -0500 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v1MFwirD059148 for ; Wed, 22 Feb 2017 11:01:30 -0500 Received: from e06smtp08.uk.ibm.com (e06smtp08.uk.ibm.com [195.75.94.104]) by mx0a-001b2d01.pphosted.com with ESMTP id 28rq70rthm-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 22 Feb 2017 11:01:29 -0500 Received: from localhost by e06smtp08.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Wed, 22 Feb 2017 16:01:24 -0000 Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id 563B11B08067; Wed, 22 Feb 2017 16:04:23 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v1MG1NSU1966564; Wed, 22 Feb 2017 16:01:23 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7511CAE06A; Wed, 22 Feb 2017 14:59:14 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 418ECAE070; Wed, 22 Feb 2017 14:59:14 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Wed, 22 Feb 2017 14:59:14 +0000 (GMT) From: Halil Pasic To: qemu-devel@nongnu.org, "Dr. David Alan Gilbert" Date: Wed, 22 Feb 2017 17:01:16 +0100 X-Mailer: git-send-email 2.8.4 In-Reply-To: <20170222160119.52771-1-pasic@linux.vnet.ibm.com> References: <20170222160119.52771-1-pasic@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17022216-0032-0000-0000-00000722E774 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17022216-0033-0000-0000-000023870A7A Message-Id: <20170222160119.52771-3-pasic@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-02-22_10:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1702220150 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.156.1 Subject: [Qemu-devel] [PATCH v2 2/5] migration/vmstate: split up vmstate_base_addr X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Amit Shah , Halil Pasic , Juan Quintela Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Currently vmstate_base_addr does several things: it pinpoints the field within the struct, possibly allocates memory and possibly does the first pointer dereference. Obviously allocation is needed only for load. Let us split up the functionality in vmstate_base_addr and move the address manipulations (that is everything but the allocation logic) to load and save so it becomes more obvious what is actually going on. Like this all the address calculations (and the handling of the flags controlling these) is in one place and the sequence is more obvious. The newly introduced function vmstate_handle_alloc also fixes the allocation for the unused VMS_VBUFFER|VMS_MULTIPLY|VMS_ALLOC scenario and is substantially simpler than the original vmstate_base_addr. In load and save some asserts are added so it's easier to debug situations where we would end up with a null pointer dereference. Signed-off-by: Halil Pasic Reviewed-by: Dr. David Alan Gilbert --- migration/vmstate.c | 39 +++++++++++++++++---------------------- 1 file changed, 17 insertions(+), 22 deletions(-) diff --git a/migration/vmstate.c b/migration/vmstate.c index 36efa80..836a7a4 100644 --- a/migration/vmstate.c +++ b/migration/vmstate.c @@ -52,29 +52,15 @@ static int vmstate_size(void *opaque, VMStateField *field) return size; } -static void *vmstate_base_addr(void *opaque, VMStateField *field, bool alloc) +static void vmstate_handle_alloc(void *ptr, VMStateField *field, void *opaque) { - void *base_addr = opaque + field->offset; - - if (field->flags & VMS_POINTER) { - if (alloc && (field->flags & VMS_ALLOC)) { - gsize size = 0; - if (field->flags & VMS_VBUFFER) { - size = vmstate_size(opaque, field); - } else { - int n_elems = vmstate_n_elems(opaque, field); - if (n_elems) { - size = n_elems * field->size; - } - } - if (size) { - *(void **)base_addr = g_malloc(size); - } + if (field->flags & VMS_POINTER && field->flags & VMS_ALLOC) { + gsize size = vmstate_size(opaque, field); + size *= vmstate_n_elems(opaque, field); + if (size) { + *(void **)ptr = g_malloc(size); } - base_addr = *(void **)base_addr; } - - return base_addr; } int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd, @@ -116,10 +102,15 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd, field->field_exists(opaque, version_id)) || (!field->field_exists && field->version_id <= version_id)) { - void *first_elem = vmstate_base_addr(opaque, field, true); + void *first_elem = opaque + field->offset; int i, n_elems = vmstate_n_elems(opaque, field); int size = vmstate_size(opaque, field); + vmstate_handle_alloc(first_elem, field, opaque); + if (field->flags & VMS_POINTER) { + first_elem = *(void **)first_elem; + assert(first_elem || !n_elems); + } for (i = 0; i < n_elems; i++) { void *curr_elem = first_elem + size * i; @@ -321,13 +312,17 @@ void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd, while (field->name) { if (!field->field_exists || field->field_exists(opaque, vmsd->version_id)) { - void *first_elem = vmstate_base_addr(opaque, field, false); + void *first_elem = opaque + field->offset; int i, n_elems = vmstate_n_elems(opaque, field); int size = vmstate_size(opaque, field); int64_t old_offset, written_bytes; QJSON *vmdesc_loop = vmdesc; trace_vmstate_save_state_loop(vmsd->name, field->name, n_elems); + if (field->flags & VMS_POINTER) { + first_elem = *(void **)first_elem; + assert(first_elem || !n_elems); + } for (i = 0; i < n_elems; i++) { void *curr_elem = first_elem + size * i;