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=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 1F768C56202 for ; Fri, 20 Nov 2020 12:56:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A847D22255 for ; Fri, 20 Nov 2020 12:56:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="kemxds01" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727933AbgKTM44 (ORCPT ); Fri, 20 Nov 2020 07:56:56 -0500 Received: from smtp-fw-4101.amazon.com ([72.21.198.25]:50174 "EHLO smtp-fw-4101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726560AbgKTM44 (ORCPT ); Fri, 20 Nov 2020 07:56:56 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1605877016; x=1637413016; h=from:to:cc:subject:date:message-id:mime-version; bh=Tu3ky8QtpoG4/ntezhBA0uUewx/dtdgS9ou84KSbXl8=; b=kemxds01Hy9ZOiA/cyOlZsjA2fDKKF7z08zVtylrUMQJ8NWoZkPkWnlt I8La4by+AA5nfQb+nQKwlvhSYY+LIttlBvFBSESfGmzpg6whV0R1LA7jU bf5ioDaWQ2bEdSMiViuRG+kKSK1JFA/B1lJ2Lo32zPLyiTzmD9yba1itl k=; X-IronPort-AV: E=Sophos;i="5.78,356,1599523200"; d="scan'208";a="65112994" Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-1a-7d76a15f.us-east-1.amazon.com) ([10.43.8.2]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 20 Nov 2020 12:56:48 +0000 Received: from EX13D01EUA002.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan3.iad.amazon.com [10.40.163.38]) by email-inbound-relay-1a-7d76a15f.us-east-1.amazon.com (Postfix) with ESMTPS id 930ACA18CE; Fri, 20 Nov 2020 12:56:43 +0000 (UTC) Received: from EX13D52EUA002.ant.amazon.com (10.43.165.139) by EX13D01EUA002.ant.amazon.com (10.43.165.199) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 20 Nov 2020 12:56:42 +0000 Received: from uc995cb558fb65a.ant.amazon.com (10.43.162.50) by EX13D52EUA002.ant.amazon.com (10.43.165.139) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 20 Nov 2020 12:56:37 +0000 From: To: CC: , , , , , , , , , , , , Darkhan Mukashov Subject: [PATCH 0/3] Introduce new vcpu ioctls KVM_(GET|SET)_MANY_REGS Date: Fri, 20 Nov 2020 13:56:13 +0100 Message-ID: <20201120125616.14436-1-darkhan@amazon.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.43.162.50] X-ClientProxiedBy: EX13D32UWB001.ant.amazon.com (10.43.161.248) To EX13D52EUA002.ant.amazon.com (10.43.165.139) Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Darkhan Mukashov The ultimate goal is to introduce new vcpu ioctls KVM_(GET|SET)_MANY_REGS. To introduce these ioctls, implementations of KVM_(GET|SET)_ONE_REG have to be refactored. Specifically, KVM_(GET|SET)_ONE_REG should be handled in a generic kvm_vcpu_ioctl function. New KVM APIs KVM_(GET|SET)_MANY_REGS make it possible to bulk read/write vCPU registers at one ioctl call. These ioctls can be very useful when vCPU state serialization/deserialization is required (e.g. live update of kvm, live migration of guests), hence all registers have to be saved/restored. KVM_(GET|SET)_MANY_REGS will help avoid performance overhead associated with syscall (ioctl in our case) handling. Tests conducted on AWS Graviton2 Processors (64-bit ARM Neoverse cores) show that average save/restore time of all vCPU registers can be optimized ~3.5 times per vCPU with new ioctls. Test results can be found in Table 1. +---------+-------------+---------------+ | | kvm_one_reg | kvm_many_regs | +---------+-------------+---------------+ | get all | 123 usec | 33 usec | +---------+-------------+---------------+ | set all | 120 usec | 36 usec | +---------+-------------+---------------+ Table 1. Test results The patches are based out of kvm/queue. Darkhan Mukashov (3): Documentation: KVM: change description of vcpu ioctls KVM_(GET|SET)_ONE_REG KVM: handle vcpu ioctls KVM_(GET|SET)_ONE_REG in a generic function KVM: introduce new vcpu ioctls KVM_GET_MANY_REGS and KVM_SET_MANY_REGS Documentation/virt/kvm/api.rst | 80 ++++++++++++++++++++++++++++-- arch/arm64/include/asm/kvm_host.h | 5 +- arch/arm64/kvm/arm.c | 25 +++------- arch/arm64/kvm/guest.c | 6 ++- arch/mips/include/asm/kvm_host.h | 6 +++ arch/mips/kvm/mips.c | 32 ++++++------ arch/powerpc/include/asm/kvm_ppc.h | 2 - arch/powerpc/kvm/powerpc.c | 20 ++------ arch/s390/include/asm/kvm_host.h | 6 +++ arch/s390/kvm/kvm-s390.c | 38 +++++++------- arch/x86/kvm/x86.c | 12 +++++ include/linux/kvm_host.h | 18 +++++++ include/uapi/linux/kvm.h | 11 ++++ virt/kvm/kvm_main.c | 62 +++++++++++++++++++++++ 14 files changed, 244 insertions(+), 79 deletions(-) -- 2.17.1