From patchwork Thu Dec 22 11:02:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13079581 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 6A0DDC4332F for ; Thu, 22 Dec 2022 11:05:16 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p8JLO-0007qe-SI; Thu, 22 Dec 2022 06:02:34 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p8JLM-0007oN-Mg for qemu-devel@nongnu.org; Thu, 22 Dec 2022 06:02:32 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p8JLK-0000eA-IX for qemu-devel@nongnu.org; Thu, 22 Dec 2022 06:02:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1671706950; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=V1Y9nichDIuJNQpnjB4iEl7ytlahVz9PoK+yJM+RgZ8=; b=AQ3UfPFhRjHk4l7Zbm8fpQVsd+4NGwvdj7i1AwZpAaVR5dycUdZBf2/hWUJOiumBrVeMi4 1M/piU6NJ2TN6vL0ea9D7NrZ8YCBbcFOkR/qcIp5MQ1n3r5vlrLqUC2o4qKWmZ+KsDCDNV mYaBPuDghd9xwlOCc0EiLXzmobbJMfc= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-539-jnlqCxEnN96msoDVpXUTBw-1; Thu, 22 Dec 2022 06:02:28 -0500 X-MC-Unique: jnlqCxEnN96msoDVpXUTBw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1CABF2A59555 for ; Thu, 22 Dec 2022 11:02:28 +0000 (UTC) Received: from t480s.fritz.box (unknown [10.39.193.53]) by smtp.corp.redhat.com (Postfix) with ESMTP id A4E8714152F4; Thu, 22 Dec 2022 11:02:26 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , "Dr . David Alan Gilbert" , Juan Quintela , Peter Xu , "Michael S . Tsirkin" , Michal Privoznik Subject: [PATCH v3 5/6] virtio-mem: Migrate bitmap, size and sanity checks early Date: Thu, 22 Dec 2022 12:02:14 +0100 Message-Id: <20221222110215.130392-6-david@redhat.com> In-Reply-To: <20221222110215.130392-1-david@redhat.com> References: <20221222110215.130392-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org The bitmap and the size are immutable while migration is active: see virtio_mem_is_busy(). We can migrate this information early, before migrating any actual RAM content. Having this information in place early will, for example, allow for properly preallocating memory before touching these memory locations during RAM migration: this way, we can make sure that all memory was actually preallocated and that any user errors (e.g., insufficient hugetlb pages) can be handled gracefully. In contrast, usable_region_size and requested_size can theoretically still be modified on the source while the VM is running. Keep migrating these properties the usual, late, way. Use a new device property to keep behavior of compat machines unmodified. Signed-off-by: David Hildenbrand --- hw/core/machine.c | 4 ++- hw/virtio/virtio-mem.c | 51 ++++++++++++++++++++++++++++++++-- include/hw/virtio/virtio-mem.h | 8 ++++++ 3 files changed, 60 insertions(+), 3 deletions(-) diff --git a/hw/core/machine.c b/hw/core/machine.c index f589b92909..6532190412 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -40,7 +40,9 @@ #include "hw/virtio/virtio-pci.h" #include "qom/object_interfaces.h" -GlobalProperty hw_compat_7_2[] = {}; +GlobalProperty hw_compat_7_2[] = { + { "virtio-mem", "x-early-migration", "false" }, +}; const size_t hw_compat_7_2_len = G_N_ELEMENTS(hw_compat_7_2); GlobalProperty hw_compat_7_1[] = { diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index e0e908d392..043b96f509 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -31,6 +31,8 @@ #include CONFIG_DEVICES #include "trace.h" +static const VMStateDescription vmstate_virtio_mem_device_early; + /* * We only had legacy x86 guests that did not support * VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE. Other targets don't have legacy guests. @@ -878,6 +880,10 @@ static void virtio_mem_device_realize(DeviceState *dev, Error **errp) host_memory_backend_set_mapped(vmem->memdev, true); vmstate_register_ram(&vmem->memdev->mr, DEVICE(vmem)); + if (vmem->early_migration) { + vmstate_register(VMSTATE_IF(vmem), VMSTATE_INSTANCE_ID_ANY, + &vmstate_virtio_mem_device_early, vmem); + } qemu_register_reset(virtio_mem_system_reset, vmem); /* @@ -899,6 +905,10 @@ static void virtio_mem_device_unrealize(DeviceState *dev) */ memory_region_set_ram_discard_manager(&vmem->memdev->mr, NULL); qemu_unregister_reset(virtio_mem_system_reset, vmem); + if (vmem->early_migration) { + vmstate_unregister(VMSTATE_IF(vmem), &vmstate_virtio_mem_device_early, + vmem); + } vmstate_unregister_ram(&vmem->memdev->mr, DEVICE(vmem)); host_memory_backend_set_mapped(vmem->memdev, false); virtio_del_queue(vdev, 0); @@ -1015,18 +1025,53 @@ static const VMStateDescription vmstate_virtio_mem_sanity_checks = { }, }; +static bool virtio_mem_vmstate_field_exists(void *opaque, int version_id) +{ + const VirtIOMEM *vmem = VIRTIO_MEM(opaque); + + /* With early migration, these fields were already migrated. */ + return !vmem->early_migration; +} + static const VMStateDescription vmstate_virtio_mem_device = { .name = "virtio-mem-device", .minimum_version_id = 1, .version_id = 1, .priority = MIG_PRI_VIRTIO_MEM, .post_load = virtio_mem_post_load, + .fields = (VMStateField[]) { + VMSTATE_WITH_TMP_TEST(VirtIOMEM, virtio_mem_vmstate_field_exists, + VirtIOMEMMigSanityChecks, + vmstate_virtio_mem_sanity_checks), + VMSTATE_UINT64(usable_region_size, VirtIOMEM), + VMSTATE_UINT64_TEST(size, VirtIOMEM, virtio_mem_vmstate_field_exists), + VMSTATE_UINT64(requested_size, VirtIOMEM), + VMSTATE_BITMAP_TEST(bitmap, VirtIOMEM, virtio_mem_vmstate_field_exists, + 0, bitmap_size), + VMSTATE_END_OF_LIST() + }, +}; + +/* + * Transfer properties that are immutable while migration is active early, + * such that we have have this information around before migrating any RAM + * content. + * + * Note that virtio_mem_is_busy() makes sure these properties can no longer + * change on the migration source until migration completed. + * + * With QEMU compat machines, we transmit these properties later, via + * vmstate_virtio_mem_device instead -- see virtio_mem_vmstate_field_exists(). + */ +static const VMStateDescription vmstate_virtio_mem_device_early = { + .name = "virtio-mem-device-early", + .minimum_version_id = 1, + .version_id = 1, + .priority = MIG_PRI_POST_SETUP, .fields = (VMStateField[]) { VMSTATE_WITH_TMP(VirtIOMEM, VirtIOMEMMigSanityChecks, vmstate_virtio_mem_sanity_checks), - VMSTATE_UINT64(usable_region_size, VirtIOMEM), VMSTATE_UINT64(size, VirtIOMEM), - VMSTATE_UINT64(requested_size, VirtIOMEM), VMSTATE_BITMAP(bitmap, VirtIOMEM, 0, bitmap_size), VMSTATE_END_OF_LIST() }, @@ -1211,6 +1256,8 @@ static Property virtio_mem_properties[] = { DEFINE_PROP_ON_OFF_AUTO(VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP, VirtIOMEM, unplugged_inaccessible, ON_OFF_AUTO_AUTO), #endif + DEFINE_PROP_BOOL(VIRTIO_MEM_EARLY_MIGRATION_PROP, VirtIOMEM, + early_migration, true), DEFINE_PROP_END_OF_LIST(), }; diff --git a/include/hw/virtio/virtio-mem.h b/include/hw/virtio/virtio-mem.h index 7745cfc1a3..f15e561785 100644 --- a/include/hw/virtio/virtio-mem.h +++ b/include/hw/virtio/virtio-mem.h @@ -31,6 +31,7 @@ OBJECT_DECLARE_TYPE(VirtIOMEM, VirtIOMEMClass, #define VIRTIO_MEM_BLOCK_SIZE_PROP "block-size" #define VIRTIO_MEM_ADDR_PROP "memaddr" #define VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP "unplugged-inaccessible" +#define VIRTIO_MEM_EARLY_MIGRATION_PROP "x-early-migration" #define VIRTIO_MEM_PREALLOC_PROP "prealloc" struct VirtIOMEM { @@ -74,6 +75,13 @@ struct VirtIOMEM { /* whether to prealloc memory when plugging new blocks */ bool prealloc; + /* + * Whether we migrate properties that are immutable while migration is + * active early, before state of other devices and especially, before + * migrating any RAM content. + */ + bool early_migration; + /* notifiers to notify when "size" changes */ NotifierList size_change_notifiers;