From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC478C433DB for ; Thu, 21 Jan 2021 11:07:37 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 2CAB323602 for ; Thu, 21 Jan 2021 11:07:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2CAB323602 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59242 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l2XoN-00072e-Jc for qemu-devel@archiver.kernel.org; Thu, 21 Jan 2021 06:07:35 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:46858) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l2Xmz-00062t-OC for qemu-devel@nongnu.org; Thu, 21 Jan 2021 06:06:09 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:23109) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l2Xmv-0006Ns-Hz for qemu-devel@nongnu.org; Thu, 21 Jan 2021 06:06:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611227163; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=bVI5gOJdZPmnopvlYiZL8OgCI4yzyrOjBNQOMVL0HUk=; b=Ssc7U7yc2C6PN6+Lr4DSPWyV129b4wP2WZADLLuR6p3i+c3FbhCrUyCWs8MEd31YA/lAtD 3yokoZ9ejxY0rwBU41dcnXXf6bclFNiQ6zi9Fxqd/KR4TZFRFijdws1TO0SmNQQlpQQV6p MIYWxWT9cRPGIjrf9Vs5Cx3ey9k9w/0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-343-tjEG0qdZNHC3wB8DHvz3ng-1; Thu, 21 Jan 2021 06:06:01 -0500 X-MC-Unique: tjEG0qdZNHC3wB8DHvz3ng-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 90159107ACE4; Thu, 21 Jan 2021 11:05:59 +0000 (UTC) Received: from t480s.redhat.com (ovpn-115-70.ams2.redhat.com [10.36.115.70]) by smtp.corp.redhat.com (Postfix) with ESMTP id EB5DA10013BD; Thu, 21 Jan 2021 11:05:41 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v5 00/11] virtio-mem: vfio support Date: Thu, 21 Jan 2021 12:05:29 +0100 Message-Id: <20210121110540.33704-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=216.205.24.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.167, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Pankaj Gupta , Wei Yang , David Hildenbrand , "Michael S. Tsirkin" , "Dr. David Alan Gilbert" , Peter Xu , Pankaj Gupta , Auger Eric , Alex Williamson , Paolo Bonzini , teawater , Jonathan Cameron , Igor Mammedov , Marek Kedzierski Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" A virtio-mem device manages a memory region in guest physical address space, represented as a single (currently large) memory region in QEMU, mapped into system memory address space. Before the guest is allowed to use memory blocks, it must coordinate with the hypervisor (plug blocks). After a reboot, all memory is usually unplugged - when the guest comes up, it detects the virtio-mem device and selects memory blocks to plug (based on resize requests from the hypervisor). Memory hot(un)plug consists of (un)plugging memory blocks via a virtio-mem device (triggered by the guest). When unplugging blocks, we discard the memory - similar to memory balloon inflation. In contrast to memory ballooning, we always know which memory blocks a guest may actually use - especially during a reboot, after a crash, or after kexec (and during hibernation as well). Guests agreed to not access unplugged memory again, especially not via DMA. The issue with vfio is, that it cannot deal with random discards - for this reason, virtio-mem and vfio can currently only run mutually exclusive. Especially, vfio would currently map the whole memory region (with possible only little/no plugged blocks), resulting in all pages getting pinned and therefore resulting in a higher memory consumption than expected (turning virtio-mem basically useless in these environments). To make vfio work nicely with virtio-mem, we have to map only the plugged blocks, and map/unmap properly when plugging/unplugging blocks (including discarding of RAM when unplugging). We achieve that by using a new notifier mechanism that communicates changes. It's important to map memory in the granularity in which we could see unmaps again (-> virtio-mem block size) - so when e.g., plugging consecutive 100 MB with a block size of 2 MB, we need 50 mappings. When unmapping, we can use a single vfio_unmap call for the applicable range. We expect that the block size of virtio-mem devices will be fairly large in the future (to not run out of mappings and to improve hot(un)plug performance), configured by the user, when used with vfio (e.g., 128MB, 1G, ...), but it will depend on the setup. More info regarding virtio-mem can be found at: https://virtio-mem.gitlab.io/ v5 is located at: git@github.com:davidhildenbrand/qemu.git virtio-mem-vfio-v5 v4 -> v5: - "vfio: Support for RamDiscardMgr in the !vIOMMU case" -- Added more assertions for granularity vs. iommu supported pagesize - "vfio: Sanity check maximum number of DMA mappings with RamDiscardMgr" -- Fix accounting of mappings - "vfio: Disable only uncoordinated discards for VFIO_TYPE1 iommus" -- Fence off SPAPR and add some comments regarding future support. -- Tweak patch description - Rebase and retest v3 -> v4: - "vfio: Query and store the maximum number of DMA mappings -- Limit the patch to querying and storing only -- Renamed to "vfio: Query and store the maximum number of possible DMA mappings" - "vfio: Support for RamDiscardMgr in the !vIOMMU case" -- Remove sanity checks / warning the user - "vfio: Sanity check maximum number of DMA mappings with RamDiscardMgr" -- Perform sanity checks by looking at the number of memslots and all registered RamDiscardMgr sections - Rebase and retest - Reshuffled the patches slightly v2 -> v3: - Rebased + retested - Fixed some typos - Added RB's v1 -> v2: - "memory: Introduce RamDiscardMgr for RAM memory regions" -- Fix some errors in the documentation -- Make register_listener() notify about populated parts and unregister_listener() notify about discarding populated parts, to simplify future locking inside virtio-mem, when handling requests via a separate thread. - "vfio: Query and store the maximum number of DMA mappings" -- Query number of mappings and track mappings (except for vIOMMU) - "vfio: Support for RamDiscardMgr in the !vIOMMU case" -- Adapt to RamDiscardMgr changes and warn via generic DMA reservation - "vfio: Support for RamDiscardMgr in the vIOMMU case" -- Use vmstate priority to handle migration dependencies RFC - v1: - VFIO migration code. Due to missing kernel support, I cannot really test if that part works. - Understand/test/document vIOMMU implications, also regarding migration - Nicer ram_block_discard_disable/require handling. - s/SparseRAMHandler/RamDiscardMgr/, refactorings, cleanups, documentation, testing, ... David Hildenbrand (11): memory: Introduce RamDiscardMgr for RAM memory regions virtio-mem: Factor out traversing unplugged ranges virtio-mem: Implement RamDiscardMgr interface vfio: Support for RamDiscardMgr in the !vIOMMU case vfio: Query and store the maximum number of possible DMA mappings vfio: Sanity check maximum number of DMA mappings with RamDiscardMgr vfio: Support for RamDiscardMgr in the vIOMMU case softmmu/physmem: Don't use atomic operations in ram_block_discard_(disable|require) softmmu/physmem: Extend ram_block_discard_(require|disable) by two discard types virtio-mem: Require only coordinated discards vfio: Disable only uncoordinated discards for VFIO_TYPE1 iommus hw/vfio/common.c | 348 +++++++++++++++++++++++++++++++-- hw/virtio/virtio-mem.c | 347 ++++++++++++++++++++++++++++---- include/exec/memory.h | 249 ++++++++++++++++++++++- include/hw/vfio/vfio-common.h | 13 ++ include/hw/virtio/virtio-mem.h | 3 + include/migration/vmstate.h | 1 + softmmu/memory.c | 22 +++ softmmu/physmem.c | 108 +++++++--- 8 files changed, 1007 insertions(+), 84 deletions(-) -- 2.29.2