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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 D8F9AC3A5A3 for ; Thu, 22 Aug 2019 14:30:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A78612082F for ; Thu, 22 Aug 2019 14:30:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="MAdP3FsX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388891AbfHVOaq (ORCPT ); Thu, 22 Aug 2019 10:30:46 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:40782 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732001AbfHVOap (ORCPT ); Thu, 22 Aug 2019 10:30:45 -0400 Received: by mail-pl1-f195.google.com with SMTP id h3so3582647pls.7; Thu, 22 Aug 2019 07:30:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=a4p8TCPaKfvEooizyzxHRIZAkY4d+DzJCKHmH6UyvCo=; b=MAdP3FsXFIrJVFxUSj2otOJoFvfqmDO4tlehtTrismgS9VWaoUbSDZ7iiGkOIl8ABq +R0lxcqwgaMHRWBPVZjRr11rLMFNfF9E1/n3bm0ur2uDpHcYwNiunvkQDy00EpPZQLkC 2I6b5nyVgR77g3KgCw6cX6JFOmeJIcZy2HBlpQuxK8fKLb5D4lNGkRc8USRR2wIw4kke 0/7jcrc5jpjqbMcIzrUy057QTDW2ZJY242WvPtstx9GFS+F46HAAhQmxnAEIZIuQtt0S kalZ8NM/e2CABcSb4MhGanmdmmSxlCP9tgkTgG5qDF2AWnUPSumsDhIQFa8l4hJ0VtJs IiOA== 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:in-reply-to :references; bh=a4p8TCPaKfvEooizyzxHRIZAkY4d+DzJCKHmH6UyvCo=; b=oJVoikOozfxx12V+M8QYVvx8Kix7pcOHAMvAFw6CDKglRxQolIa6habbdeK+GDK7+O 7jjOtKepIMjLKQOMriwnhF41wSnM1lWFs4+SQ1ESj/5bHbc+uDZg4Cgua60QCWUiU8HF twBkgk0JcLnX2sN8cVxKtjPXkfNIN9EjEEwE1tL9WoJF0wp6cxW9opI4ciDJu/PQY+1z JK4yGOwK0bsGn2ZySChiCmsJrZb3kQ8ftRs1OBsv1LrIbEBwSxthw91F8sdD50otYaai 0DI0u0LzAbgOPwd/i7HJUiqRmmzEHTeNUOfMscGRgWioqLhx/Mdl3yGlBeDFD2vIjxvh Fwkw== X-Gm-Message-State: APjAAAXwSkT4zQvHw2fPeDxuEbYo5xFBCaXCNC7cHv1tXrIEgvwvX3N+ aM0zFrzA0r8D5fquwX+R+NM= X-Google-Smtp-Source: APXvYqwALLBfgiwxGFa9tOYNMRQrYeu3WlICxCBO1gzKOzDYuX9mmAPLFJ71qGPupq8dDLKzgc0xVw== X-Received: by 2002:a17:902:b084:: with SMTP id p4mr39521574plr.309.1566484245065; Thu, 22 Aug 2019 07:30:45 -0700 (PDT) Received: from localhost.corp.microsoft.com ([167.220.255.114]) by smtp.googlemail.com with ESMTPSA id r23sm32263161pfg.10.2019.08.22.07.30.39 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 22 Aug 2019 07:30:44 -0700 (PDT) From: lantianyu1986@gmail.com X-Google-Original-From: Tianyu.Lan@microsoft.com To: pbonzini@redhat.com, rkrcmar@redhat.com, corbet@lwn.net, kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, sashal@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, michael.h.kelley@microsoft.com Cc: Tianyu Lan , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, vkuznets@redhat.com Subject: [PATCH V4 2/3] KVM/Hyper-V: Add new KVM capability KVM_CAP_HYPERV_DIRECT_TLBFLUSH Date: Thu, 22 Aug 2019 22:30:20 +0800 Message-Id: <20190822143021.7518-3-Tianyu.Lan@microsoft.com> X-Mailer: git-send-email 2.14.5 In-Reply-To: <20190822143021.7518-1-Tianyu.Lan@microsoft.com> References: <20190822143021.7518-1-Tianyu.Lan@microsoft.com> Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org From: Tianyu Lan Hyper-V direct tlb flush function should be enabled for guest that only uses Hyper-V hypercall. User space hypervisor(e.g, Qemu) can disable KVM identification in CPUID and just exposes Hyper-V identification to make sure the precondition. Add new KVM capability KVM_CAP_ HYPERV_DIRECT_TLBFLUSH for user space to enable Hyper-V direct tlb function and this function is default to be disabled in KVM. Signed-off-by: Tianyu Lan --- Change since v3: - Update Changelog. Change since v1: - Update description of KVM_CAP_HYPERV_DIRECT_TLBFLUSH in the KVM API doc. --- Documentation/virtual/kvm/api.txt | 13 +++++++++++++ arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/x86.c | 8 ++++++++ include/uapi/linux/kvm.h | 1 + 4 files changed, 24 insertions(+) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 2cd6250b2896..0c6e1b25d0c8 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -5289,3 +5289,16 @@ Architectures: x86 This capability indicates that KVM supports paravirtualized Hyper-V IPI send hypercalls: HvCallSendSyntheticClusterIpi, HvCallSendSyntheticClusterIpiEx. +8.21 KVM_CAP_HYPERV_DIRECT_TLBFLUSH + +Architecture: x86 + +This capability indicates that KVM running on top of Hyper-V hypervisor +enables Direct TLB flush for its guests meaning that TLB flush +hypercalls are handled by Level 0 hypervisor (Hyper-V) bypassing KVM. +Due to the different ABI for hypercall parameters between Hyper-V and +KVM, enabling this capability effectively disables all hypercall +handling by KVM (as some KVM hypercall may be mistakenly treated as TLB +flush hypercalls by Hyper-V) so userspace should disable KVM identification +in CPUID and only exposes Hyper-V identification. In this case, guest +thinks it's running on Hyper-V and only use Hyper-V hypercalls. diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 0cc5b611a113..667d154e89d4 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1205,6 +1205,8 @@ struct kvm_x86_ops { uint16_t (*nested_get_evmcs_version)(struct kvm_vcpu *vcpu); bool (*need_emulation_on_page_fault)(struct kvm_vcpu *vcpu); + + int (*enable_direct_tlbflush)(struct kvm_vcpu *vcpu); }; struct kvm_arch_async_pf { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9d7b9e6a0939..a9d8ee7f7bf0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3183,6 +3183,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = kvm_x86_ops->get_nested_state ? kvm_x86_ops->get_nested_state(NULL, NULL, 0) : 0; break; + case KVM_CAP_HYPERV_DIRECT_TLBFLUSH: + r = kvm_x86_ops->enable_direct_tlbflush ? 1 : 0; + break; default: break; } @@ -3953,6 +3956,11 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu, r = -EFAULT; } return r; + case KVM_CAP_HYPERV_DIRECT_TLBFLUSH: + if (!kvm_x86_ops->enable_direct_tlbflush) + return -ENOTTY; + + return kvm_x86_ops->enable_direct_tlbflush(vcpu); default: return -EINVAL; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index a7c19540ce21..cb959bc925b1 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -996,6 +996,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171 #define KVM_CAP_ARM_PTRAUTH_GENERIC 172 #define KVM_CAP_PMU_EVENT_FILTER 173 +#define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 174 #ifdef KVM_CAP_IRQ_ROUTING -- 2.14.5