From patchwork Fri Nov 29 21:32:27 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 11267621 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 95610109A for ; Fri, 29 Nov 2019 21:33:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 67395206B5 for ; Fri, 29 Nov 2019 21:33:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="jSNTEX5O" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727187AbfK2Vcu (ORCPT ); Fri, 29 Nov 2019 16:32:50 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:49966 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727116AbfK2Vcu (ORCPT ); Fri, 29 Nov 2019 16:32:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1575063169; 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=peI3w5GhWEX1JieJHH29KyaSX4w2AsTjOin5SLB/5Gw=; b=jSNTEX5OfiErFkF8aJvja4ywZY9ZK6PYxAMszHX4xtvrXwQZQKE/B0kFm/6sIQE5OH1qwJ naWT5q9y9lVYVCo34HLhnJSkGu3o4bkddnLetn3jKtYbztuCw60H3mUG0T6KCN23RuXJz8 lUXm3wq3yMZt4AQkHa+sEOJq7CfiFas= Received: from mail-qv1-f71.google.com (mail-qv1-f71.google.com [209.85.219.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-358-5OIN4PcGNI2DbeqWSDHIXg-1; Fri, 29 Nov 2019 16:32:45 -0500 Received: by mail-qv1-f71.google.com with SMTP id q2so19609884qvo.23 for ; Fri, 29 Nov 2019 13:32:45 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=cn7j7/8SJgeM/ER61fZ1AdZGSd2mYCJ7pUgcBKPF2KQ=; b=M9Z1kNk/KCnC3ihrbHEO0DJbfi8mBlisq4QevcLOr+/2D5LqPifgw7xRLRb1RreM1H +N5r9jTxU8w1DNWHZnGdcD/0+cA6ZJEhxjeSUXsx5LHoZ9ox9ly9h39lSpu8uI4c920B Uj68bQQHKAkO0hj18aH+Ugweu+MCADUdXw+u6NhMqeQrasd39WLvg/SDh8iISLG3ffpp 5Iu+AMU9ljOewOdn/3Ke+LIxF6i6QjUvdXWaGMJkNzVOF7anG3rmZxpUkSeFWW/q92qU n74FqpZZMl09Nz3UilYTWMEJjfF4kaUL/wdUVMVOxG9RtJPS5tUOqos5mDti+/w5+6K8 TYXg== X-Gm-Message-State: APjAAAWNZaFjE+Ur5aa/n/0ArLqneEvG2ggmGZ8yKEGX5KiR3qRV4ooY PY/zOznrw/FlnlnhPIziWm9+GUZedrNP76+jgVEZKzHGb+8M4WS6Uwx7B/fHYQIS1AETTlCwpIv +uq5/6R+ZFopc X-Received: by 2002:ad4:588d:: with SMTP id dz13mr19982295qvb.86.1575063164827; Fri, 29 Nov 2019 13:32:44 -0800 (PST) X-Google-Smtp-Source: APXvYqy5eIATWxerwmd03ez0vmrXtvk2z5PAQi557Z+8gFzf+IEvRetJH80wrZlItjYLRMnxc+PPpA== X-Received: by 2002:ad4:588d:: with SMTP id dz13mr19982258qvb.86.1575063164469; Fri, 29 Nov 2019 13:32:44 -0800 (PST) Received: from xz-x1.yyz.redhat.com ([104.156.64.74]) by smtp.gmail.com with ESMTPSA id n5sm10634817qkf.48.2019.11.29.13.32.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Nov 2019 13:32:43 -0800 (PST) From: Peter Xu To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Cao Lei , peterx@redhat.com, "Dr . David Alan Gilbert" , Sean Christopherson , Vitaly Kuznetsov Subject: [PATCH RFC 00/15] KVM: Dirty ring interface Date: Fri, 29 Nov 2019 16:32:27 -0500 Message-Id: <20191129213242.17144-1-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 X-MC-Unique: 5OIN4PcGNI2DbeqWSDHIXg-1 X-Mimecast-Spam-Score: 0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Branch is here: https://github.com/xzpeter/linux/tree/kvm-dirty-ring Overview ============ This is a continued work from Lei Cao and Paolo on the KVM dirty ring interface. To make it simple, I'll still start with version 1 as RFC. The new dirty ring interface is another way to collect dirty pages for the virtual machine, but it is different from the existing dirty logging interface in a few ways, majorly: - Data format: The dirty data was in a ring format rather than a bitmap format, so the size of data to sync for dirty logging does not depend on the size of guest memory any more, but speed of dirtying. Also, the dirty ring is per-vcpu (currently plus another per-vm ring, so total ring number is N+1), while the dirty bitmap is per-vm. - Data copy: The sync of dirty pages does not need data copy any more, but instead the ring is shared between the userspace and kernel by page sharings (mmap() on either the vm fd or vcpu fd) - Interface: Instead of using the old KVM_GET_DIRTY_LOG, KVM_CLEAR_DIRTY_LOG interfaces, the new ring uses a new interface called KVM_RESET_DIRTY_RINGS when we want to reset the collected dirty pages to protected mode again (works like KVM_CLEAR_DIRTY_LOG, but ring based) And more. I would appreciate if the reviewers can start with patch "KVM: Implement ring-based dirty memory tracking", especially the document update part for the big picture. Then I'll avoid copying into most of them into cover letter again. I marked this series as RFC because I'm at least uncertain on this change of vcpu_enter_guest(): if (kvm_check_request(KVM_REQ_DIRTY_RING_FULL, vcpu)) { vcpu->run->exit_reason = KVM_EXIT_DIRTY_RING_FULL; /* * If this is requested, it means that we've * marked the dirty bit in the dirty ring BUT * we've not written the date. Do it now. */ r = kvm_emulate_instruction(vcpu, 0); r = r >= 0 ? 0 : r; goto out; } I did a kvm_emulate_instruction() when dirty ring reaches softlimit and want to exit to userspace, however I'm not really sure whether there could have any side effect. I'd appreciate any comment of above, or anything else. Tests =========== I wanted to continue work on the QEMU part, but after I noticed that the interface might still prone to change, I posted this series first. However to make sure it's at least working, I've provided unit tests together with the series. The unit tests should be able to test the series in at least three major paths: (1) ./dirty_log_test -M dirty-ring This tests async ring operations: this should be the major work mode for the dirty ring interface, say, when the kernel is queuing more data, the userspace is collecting too. Ring can hardly reaches full when working like this, because in most cases the collection could be fast. (2) ./dirty_log_test -M dirty-ring -c 1024 This set the ring size to be very small so that ring soft-full always triggers (soft-full is a soft limit of the ring state, when the dirty ring reaches the soft limit it'll do a userspace exit and let the userspace to collect the data). (3) ./dirty_log_test -M dirty-ring-wait-queue This sololy test the extreme case where ring is full. When the ring is completely full, the thread (no matter vcpu or not) will be put onto a per-vm waitqueue, and KVM_RESET_DIRTY_RINGS will wake the threads up (assuming until which the ring will not be full any more). Thanks, Cao, Lei (2): KVM: Add kvm/vcpu argument to mark_dirty_page_in_slot KVM: X86: Implement ring-based dirty memory tracking Paolo Bonzini (1): KVM: Move running VCPU from ARM to common code Peter Xu (12): KVM: Add build-time error check on kvm_run size KVM: Implement ring-based dirty memory tracking KVM: Make dirty ring exclusive to dirty bitmap log KVM: Introduce dirty ring wait queue KVM: selftests: Always clear dirty bitmap after iteration KVM: selftests: Sync uapi/linux/kvm.h to tools/ KVM: selftests: Use a single binary for dirty/clear log test KVM: selftests: Introduce after_vcpu_run hook for dirty log test KVM: selftests: Add dirty ring buffer test KVM: selftests: Let dirty_log_test async for dirty ring test KVM: selftests: Add "-c" parameter to dirty log test KVM: selftests: Test dirty ring waitqueue Documentation/virt/kvm/api.txt | 116 +++++ arch/arm/include/asm/kvm_host.h | 2 - arch/arm64/include/asm/kvm_host.h | 2 - arch/x86/include/asm/kvm_host.h | 5 + arch/x86/include/uapi/asm/kvm.h | 1 + arch/x86/kvm/Makefile | 3 +- arch/x86/kvm/mmu/mmu.c | 6 + arch/x86/kvm/vmx/vmx.c | 7 + arch/x86/kvm/x86.c | 12 + include/linux/kvm_dirty_ring.h | 67 +++ include/linux/kvm_host.h | 37 ++ include/linux/kvm_types.h | 1 + include/uapi/linux/kvm.h | 36 ++ tools/include/uapi/linux/kvm.h | 47 ++ tools/testing/selftests/kvm/Makefile | 2 - .../selftests/kvm/clear_dirty_log_test.c | 2 - tools/testing/selftests/kvm/dirty_log_test.c | 452 ++++++++++++++++-- .../testing/selftests/kvm/include/kvm_util.h | 6 + tools/testing/selftests/kvm/lib/kvm_util.c | 103 ++++ .../selftests/kvm/lib/kvm_util_internal.h | 5 + virt/kvm/arm/arm.c | 29 -- virt/kvm/arm/perf.c | 6 +- virt/kvm/arm/vgic/vgic-mmio.c | 15 +- virt/kvm/dirty_ring.c | 156 ++++++ virt/kvm/kvm_main.c | 315 +++++++++++- 25 files changed, 1329 insertions(+), 104 deletions(-) create mode 100644 include/linux/kvm_dirty_ring.h delete mode 100644 tools/testing/selftests/kvm/clear_dirty_log_test.c create mode 100644 virt/kvm/dirty_ring.c