From patchwork Wed Aug 8 18:29:12 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Baron X-Patchwork-Id: 175948 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 598172C0098 for ; Thu, 9 Aug 2012 04:29:24 +1000 (EST) Received: from localhost ([::1]:47083 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SzB0U-0002Td-Rp for incoming@patchwork.ozlabs.org; Wed, 08 Aug 2012 14:29:22 -0400 Received: from eggs.gnu.org ([208.118.235.92]:40970) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SzB0N-0002TP-Vf for qemu-devel@nongnu.org; Wed, 08 Aug 2012 14:29:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SzB0N-0000wf-0N for qemu-devel@nongnu.org; Wed, 08 Aug 2012 14:29:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9126) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SzB0M-0000wT-Og for qemu-devel@nongnu.org; Wed, 08 Aug 2012 14:29:14 -0400 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q78ITDXd027995 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 8 Aug 2012 14:29:13 -0400 Received: from redhat.com (dhcp-185-114.bos.redhat.com [10.16.185.114]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q78ITCPS030661; Wed, 8 Aug 2012 14:29:12 -0400 Date: Wed, 8 Aug 2012 14:29:12 -0400 From: Jason Baron Message-Id: <201208081829.q78ITCPS030661@int-mx12.intmail.prod.int.phx2.redhat.com> To: mst@redhat.com, quintela@redhat.com X-Scanned-By: MIMEDefang 2.68 on 10.5.11.25 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 209.132.183.28 Cc: yamahata@valinux.co.jp, alex.williamson@redhat.com, aliguori@us.ibm.com, qemu-devel@nongnu.org Subject: [Qemu-devel] [PATCH] pcie: drop version_id field for live migration X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org While testing q35 live migration, I found that the migration would abort with the following error: "Unknown savevm section type 76". The error is due to this check failing in 'vmstate_load_state()': while(field->name) { if ((field->field_exists && field->field_exists(opaque, version_id)) || (!field->field_exists && field->version_id <= version_id)) { The VMSTATE_PCIE_DEVICE() currently has a 'version_id' set to 2. However, 'version_id' in the above check is 1. And thus we fail to load the pcie device field. Further the code returns to 'qemu_loadvm_state()' which produces the error that I saw. I'm proposing to fix this by simply dropping the 'version_id' field from VMSTATE_PCIE_DEVICE(). VMSTATE_PCI_DEVICE() defines no such field and further the vmstate_pcie_device that VMSTATE_PCI_DEVICE() refers to is already versioned. Thus, any versioning issues could be detected at the vmsd level. Taking a step back, I think that the 'field->version_id' should be compared against a saved version number for the field not the 'version_id'. Futhermore, once vmstate_load_state() is called recursively on another vmsd, the check of: if (version_id > vmsd->version_id) { return -EINVAL; } Will never fail since version_id is always equal to vmsd->version_id. So I'm wondering why we aren't storing the vmsd version id of the source in the migration stream? This patch also renames the 'name' field of vmstate_pcie_device from: PCIDevice -> PCIEDevice to differentiate it from vmstate_pci_device. Signed-off-by: Jason Baron --- hw/pci.c | 2 +- hw/pcie.h | 1 - 2 files changed, 1 insertions(+), 2 deletions(-) diff --git a/hw/pci.c b/hw/pci.c index e4e6ad9..8745a55 100644 --- a/hw/pci.c +++ b/hw/pci.c @@ -439,7 +439,7 @@ const VMStateDescription vmstate_pci_device = { }; const VMStateDescription vmstate_pcie_device = { - .name = "PCIDevice", + .name = "PCIEDevice", .version_id = 2, .minimum_version_id = 1, .minimum_version_id_old = 1, diff --git a/hw/pcie.h b/hw/pcie.h index b8ab0c7..4889194 100644 --- a/hw/pcie.h +++ b/hw/pcie.h @@ -133,7 +133,6 @@ extern const VMStateDescription vmstate_pcie_device; #define VMSTATE_PCIE_DEVICE(_field, _state) { \ .name = (stringify(_field)), \ - .version_id = 2, \ .size = sizeof(PCIDevice), \ .vmsd = &vmstate_pcie_device, \ .flags = VMS_STRUCT, \