From patchwork Wed Jul 10 14:14:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 11038653 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9236114DB for ; Wed, 10 Jul 2019 14:16:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 85A1528774 for ; Wed, 10 Jul 2019 14:16:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 79F62287D3; Wed, 10 Jul 2019 14:16:51 +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=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id C75B0289CE for ; Wed, 10 Jul 2019 14:16:50 +0000 (UTC) Received: from localhost ([::1]:33870 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hlDOq-0003f5-SL for patchwork-qemu-devel@patchwork.kernel.org; Wed, 10 Jul 2019 10:16:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41356) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hlDMz-0002a6-Te for qemu-devel@nongnu.org; Wed, 10 Jul 2019 10:14:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hlDMy-0003P8-AU for qemu-devel@nongnu.org; Wed, 10 Jul 2019 10:14:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37865) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hlDMy-0003NE-2R for qemu-devel@nongnu.org; Wed, 10 Jul 2019 10:14:52 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 31C77307D911; Wed, 10 Jul 2019 14:14:50 +0000 (UTC) Received: from localhost (ovpn-112-49.ams2.redhat.com [10.36.112.49]) by smtp.corp.redhat.com (Postfix) with ESMTP id 13D631A92A; Wed, 10 Jul 2019 14:14:42 +0000 (UTC) From: Stefan Hajnoczi To: Date: Wed, 10 Jul 2019 16:14:40 +0200 Message-Id: <20190710141440.27635-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Wed, 10 Jul 2019 14:14:50 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] virtio-balloon: fix QEMU 4.0 config size migration incompatibility 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: Wolfgang Bumiller , Eduardo Habkost , "Michael S. Tsirkin" , "Dr. David Alan Gilbert" , Stefan Hajnoczi Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP The virtio-balloon config size changed in QEMU 4.0 even for existing machine types. Migration from QEMU 3.1 to 4.0 can fail in some circumstances with the following error: qemu-system-x86_64: get_pci_config_device: Bad config data: i=0x10 read: a1 device: 1 cmask: ff wmask: c0 w1cmask:0 This happens because the virtio-balloon config size affects the VIRTIO Legacy I/O Memory PCI BAR size. Introduce a qdev property called "qemu-4-0-config-size" and enable it only for the QEMU 4.0 machine types. This way <4.0 machine types use the old size, 4.0 uses the larger size, and >4.0 machine types use the appropriate size depending on enabled virtio-balloon features. Live migration to and from old QEMUs to QEMU 4.1 works again as long as a versioned machine type is specified (do not use just "pc"!). Originally-by: Wolfgang Bumiller Signed-off-by: Stefan Hajnoczi Reviewed-by: Dr. David Alan Gilbert Tested-by: Dr. David Alan Gilbert Tested-by: Wolfgang Bumiller --- include/hw/virtio/virtio-balloon.h | 2 ++ hw/core/machine.c | 2 ++ hw/virtio/virtio-balloon.c | 28 +++++++++++++++++++++++++--- 3 files changed, 29 insertions(+), 3 deletions(-) diff --git a/include/hw/virtio/virtio-balloon.h b/include/hw/virtio/virtio-balloon.h index 1afafb12f6..5a99293a45 100644 --- a/include/hw/virtio/virtio-balloon.h +++ b/include/hw/virtio/virtio-balloon.h @@ -71,6 +71,8 @@ typedef struct VirtIOBalloon { int64_t stats_poll_interval; uint32_t host_features; PartiallyBalloonedPage *pbp; + + bool qemu_4_0_config_size; } VirtIOBalloon; #endif diff --git a/hw/core/machine.c b/hw/core/machine.c index 2be19ec0cd..c4ead16010 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -34,6 +34,7 @@ GlobalProperty hw_compat_4_0[] = { { "virtio-vga", "edid", "false" }, { "virtio-gpu-pci", "edid", "false" }, { "virtio-device", "use-started", "false" }, + { "virtio-balloon-device", "qemu-4-0-config-size", "true" }, }; const size_t hw_compat_4_0_len = G_N_ELEMENTS(hw_compat_4_0); @@ -49,6 +50,7 @@ GlobalProperty hw_compat_3_1[] = { { "usb-tablet", "serial", "42" }, { "virtio-blk-device", "discard", "false" }, { "virtio-blk-device", "write-zeroes", "false" }, + { "virtio-balloon-device", "qemu-4-0-config-size", "false" }, }; const size_t hw_compat_3_1_len = G_N_ELEMENTS(hw_compat_3_1); diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index 11fad86d64..e85d1c0d5c 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -615,6 +615,22 @@ virtio_balloon_free_page_report_notify(NotifierWithReturn *n, void *data) return 0; } +static size_t virtio_balloon_config_size(VirtIOBalloon *s) +{ + uint64_t features = s->host_features; + + if (s->qemu_4_0_config_size) { + return sizeof(struct virtio_balloon_config); + } + if (virtio_has_feature(features, VIRTIO_BALLOON_F_PAGE_POISON)) { + return sizeof(struct virtio_balloon_config); + } + if (virtio_has_feature(features, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { + return offsetof(struct virtio_balloon_config, poison_val); + } + return offsetof(struct virtio_balloon_config, free_page_report_cmd_id); +} + static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) { VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); @@ -635,7 +651,7 @@ static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) } trace_virtio_balloon_get_config(config.num_pages, config.actual); - memcpy(config_data, &config, sizeof(struct virtio_balloon_config)); + memcpy(config_data, &config, virtio_balloon_config_size(dev)); } static int build_dimm_list(Object *obj, void *opaque) @@ -679,7 +695,7 @@ static void virtio_balloon_set_config(VirtIODevice *vdev, uint32_t oldactual = dev->actual; ram_addr_t vm_ram_size = get_current_ram_size(); - memcpy(&config, config_data, sizeof(struct virtio_balloon_config)); + memcpy(&config, config_data, virtio_balloon_config_size(dev)); dev->actual = le32_to_cpu(config.actual); if (dev->actual != oldactual) { qapi_event_send_balloon_change(vm_ram_size - @@ -766,7 +782,7 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) int ret; virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, - sizeof(struct virtio_balloon_config)); + virtio_balloon_config_size(s)); ret = qemu_add_balloon_handler(virtio_balloon_to_target, virtio_balloon_stat, s); @@ -897,6 +913,12 @@ static Property virtio_balloon_properties[] = { VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false), DEFINE_PROP_BIT("free-page-hint", VirtIOBalloon, host_features, VIRTIO_BALLOON_F_FREE_PAGE_HINT, false), + /* QEMU 4.0 accidentally changed the config size even when free-page-hint + * is disabled, resulting in QEMU 3.1 migration incompatibility. This + * property retains this quirk for QEMU 4.1 machine types. + */ + DEFINE_PROP_BOOL("qemu-4-0-config-size", VirtIOBalloon, + qemu_4_0_config_size, false), DEFINE_PROP_LINK("iothread", VirtIOBalloon, iothread, TYPE_IOTHREAD, IOThread *), DEFINE_PROP_END_OF_LIST(),