From patchwork Sat May 15 11:32:40 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kiszka X-Patchwork-Id: 52707 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 40CE6B7DFF for ; Sat, 15 May 2010 21:34:21 +1000 (EST) Received: from localhost ([127.0.0.1]:47101 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1ODFdK-0002yE-8Y for incoming@patchwork.ozlabs.org; Sat, 15 May 2010 07:34:18 -0400 Received: from [140.186.70.92] (port=56629 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1ODFbz-0002vI-9A for qemu-devel@nongnu.org; Sat, 15 May 2010 07:32:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1ODFbv-0003ol-7L for qemu-devel@nongnu.org; Sat, 15 May 2010 07:32:55 -0400 Received: from fmmailgate02.web.de ([217.72.192.227]:58604) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1ODFbu-0003o2-KR for qemu-devel@nongnu.org; Sat, 15 May 2010 07:32:51 -0400 Received: from smtp06.web.de ( [172.20.5.172]) by fmmailgate02.web.de (Postfix) with ESMTP id 994DF160BCB6F; Sat, 15 May 2010 13:32:49 +0200 (CEST) Received: from [88.64.22.236] (helo=localhost.localdomain) by smtp06.web.de with asmtp (TLSv1:AES256-SHA:256) (WEB.DE 4.110 #4) id 1ODFbt-0005YN-01; Sat, 15 May 2010 13:32:49 +0200 From: Jan Kiszka To: qemu-devel@nongnu.org Date: Sat, 15 May 2010 13:32:40 +0200 Message-Id: X-Mailer: git-send-email 1.6.0.2 In-Reply-To: References: In-Reply-To: References: X-Sender: jan.kiszka@web.de X-Provags-ID: V01U2FsdGVkX18J6VWfy3bjZj0wVGKY7Ll53CkHJIigqqYQyNvz m0VvYBTcLaPz16fMrekInZx+JfzW1KSRoLOhsiTEL9jaXovz64 CvtUXEhdg= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4-2.6 Cc: Blue Swirl , Jan Kiszka , Juan Quintela Subject: [Qemu-devel] [PATCH v2 3/6] vmstate: Add support for alias ID X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Jan Kiszka Some legacy users (mostly PC devices) of vmstate_register manage instance IDs on their own, and that unfortunately in a way that is incompatible with automatically generated ones. This so far prevents switching those users to vmstates that are registered by qdev. To establish a migration path, this patch introduces the concept of alias IDs. They can be passed to an extended vmstate registration service, and qdev provides a set service to be used during device init. find_se will consider the alias in addition to the default ID. We can then start generating the default ID automatically and writing it on vmsave, thus converting that format without breaking support for upward migration. The user is required specify the highest vmstate version for which the alias is required. Once this version falls behind the minimum required for a specific vmstate, an assertion triggers to motivate cleaning up the obsolete alias. Signed-off-by: Jan Kiszka --- hw/hw.h | 4 ++++ hw/qdev.c | 16 ++++++++++++++-- hw/qdev.h | 4 ++++ savevm.c | 20 +++++++++++++++++--- 4 files changed, 39 insertions(+), 5 deletions(-) diff --git a/hw/hw.h b/hw/hw.h index 2d39724..fc2d184 100644 --- a/hw/hw.h +++ b/hw/hw.h @@ -758,5 +758,9 @@ extern void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd, void *opaque); extern int vmstate_register(int instance_id, const VMStateDescription *vmsd, void *base); +extern int vmstate_register_with_alias_id(int instance_id, + const VMStateDescription *vmsd, + void *base, int alias_id, + int required_for_version); void vmstate_unregister(const VMStateDescription *vmsd, void *opaque); #endif diff --git a/hw/qdev.c b/hw/qdev.c index d3bf0fa..af17486 100644 --- a/hw/qdev.c +++ b/hw/qdev.c @@ -93,6 +93,7 @@ static DeviceState *qdev_create_from_info(BusState *bus, DeviceInfo *info) assert(bus->allow_hotplug); dev->hotplugged = 1; } + dev->instance_id_alias = -1; dev->state = DEV_STATE_CREATED; return dev; } @@ -278,12 +279,23 @@ int qdev_init(DeviceState *dev) return rc; } qemu_register_reset(qdev_reset, dev); - if (dev->info->vmsd) - vmstate_register(-1, dev->info->vmsd, dev); + if (dev->info->vmsd) { + vmstate_register_with_alias_id(-1, dev->info->vmsd, dev, + dev->instance_id_alias, + dev->alias_required_for_version); + } dev->state = DEV_STATE_INITIALIZED; return 0; } +void qdev_set_legacy_instance_id(DeviceState *dev, int alias_id, + int required_for_version) +{ + assert(dev->state == DEV_STATE_CREATED); + dev->instance_id_alias = alias_id; + dev->alias_required_for_version = required_for_version; +} + int qdev_unplug(DeviceState *dev) { if (!dev->parent_bus->allow_hotplug) { diff --git a/hw/qdev.h b/hw/qdev.h index d8fbc73..a44060e 100644 --- a/hw/qdev.h +++ b/hw/qdev.h @@ -44,6 +44,8 @@ struct DeviceState { QLIST_HEAD(, BusState) child_bus; int num_child_bus; QLIST_ENTRY(DeviceState) sibling; + int instance_id_alias; + int alias_required_for_version; }; typedef void (*bus_dev_printfn)(Monitor *mon, DeviceState *dev, int indent); @@ -112,6 +114,8 @@ int qdev_device_help(QemuOpts *opts); DeviceState *qdev_device_add(QemuOpts *opts); int qdev_init(DeviceState *dev) QEMU_WARN_UNUSED_RESULT; void qdev_init_nofail(DeviceState *dev); +void qdev_set_legacy_instance_id(DeviceState *dev, int alias_id, + int required_for_version); int qdev_unplug(DeviceState *dev); void qdev_free(DeviceState *dev); int qdev_simple_unplug_cb(DeviceState *dev); diff --git a/savevm.c b/savevm.c index 74e553c..dc20390 100644 --- a/savevm.c +++ b/savevm.c @@ -991,6 +991,7 @@ typedef struct SaveStateEntry { QTAILQ_ENTRY(SaveStateEntry) entry; char idstr[256]; int instance_id; + int alias_id; int version_id; int section_id; SaveSetParamsHandler *set_params; @@ -1079,11 +1080,16 @@ void unregister_savevm(const char *idstr, void *opaque) } } -int vmstate_register(int instance_id, const VMStateDescription *vmsd, - void *opaque) +int vmstate_register_with_alias_id(int instance_id, + const VMStateDescription *vmsd, + void *opaque, int alias_id, + int required_for_version) { SaveStateEntry *se; + /* If this triggers, alias support can be dropped for the vmsd. */ + assert(alias_id == -1 || required_for_version >= vmsd->minimum_version_id); + se = qemu_mallocz(sizeof(SaveStateEntry)); pstrcpy(se->idstr, sizeof(se->idstr), vmsd->name); se->version_id = vmsd->version_id; @@ -1093,6 +1099,7 @@ int vmstate_register(int instance_id, const VMStateDescription *vmsd, se->load_state = NULL; se->opaque = opaque; se->vmsd = vmsd; + se->alias_id = alias_id; if (instance_id == -1) { se->instance_id = calculate_new_instance_id(vmsd->name); @@ -1104,6 +1111,12 @@ int vmstate_register(int instance_id, const VMStateDescription *vmsd, return 0; } +int vmstate_register(int instance_id, const VMStateDescription *vmsd, + void *opaque) +{ + return vmstate_register_with_alias_id(instance_id, vmsd, opaque, -1, 0); +} + void vmstate_unregister(const VMStateDescription *vmsd, void *opaque) { SaveStateEntry *se, *new_se; @@ -1433,7 +1446,8 @@ static SaveStateEntry *find_se(const char *idstr, int instance_id) QTAILQ_FOREACH(se, &savevm_handlers, entry) { if (!strcmp(se->idstr, idstr) && - instance_id == se->instance_id) + (instance_id == se->instance_id || + instance_id == se->alias_id)) return se; } return NULL;