From patchwork Mon Aug 19 13:17:36 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tianyu Lan X-Patchwork-Id: 11100973 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 671C314F7 for ; Mon, 19 Aug 2019 13:18:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5582427D16 for ; Mon, 19 Aug 2019 13:18:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 489CF27FA9; Mon, 19 Aug 2019 13:18:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CAE6E27D16 for ; Mon, 19 Aug 2019 13:18:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727782AbfHSNSO (ORCPT ); Mon, 19 Aug 2019 09:18:14 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:40876 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727695AbfHSNSO (ORCPT ); Mon, 19 Aug 2019 09:18:14 -0400 Received: by mail-pf1-f194.google.com with SMTP id w16so1165167pfn.7; Mon, 19 Aug 2019 06:18:13 -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=jhCOccuCzPzG2s+OQkIdwKuf0Hs2BSmGnlAfPo3gJDY=; b=SSbDy30NapSw8nHHwn1JLMwbNA0vfTRGU1iDjq3SKBqN1KGP/m+LeAv3PRlyAzQmQg bkkueQgMJu7eFwNVM6y84oTQ5gHMh6D6iksUAvH45v83RXY5v/dK5qeLWS4Wl2uDFBPz f9ovypltlxBT4ybYgThtMHe8Pul/7LnCbP6RdXytBQmktC7+1MIflQkRl6JoRaOx6K4M u+iZ07xWrHxaRXPTySmoFjWO303tExfRTaBdWvjLLRiIf/J34q1ECFEPxu3YgtmkbCLi rxQUrXLoHtEb613F9ONPS1TC9U64qt995cYo+9xWlwvdBFNMLwvGM6r19ywCR2uk+XNH GqaA== 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=jhCOccuCzPzG2s+OQkIdwKuf0Hs2BSmGnlAfPo3gJDY=; b=XnxOPALrTgal66JBooDbi3IK/swP9lgqyTltWvhMLqxIsQnG7phCa51O8R7tNiBrPf ix87VLa6yZBgltFADQQ6pvif3dgFysrUABiqCFh0FplIY+Vc1Llm2XK/+f3NUWx94lsc LlJe0ucV7MG+TZdZNsb49VcwiEbMSmtKi+NXiPQFibKLvY1ndNKDGLKG3Swt09n3zlq4 TvcOjLuF6Fe7S5zkTMn10r+kzkSCYb5zdT4vmooVZ9T8xt4mu3m0cmaVsDgAoumFnslB bXhLoi+2+dkSveDqjs1u9DtQckBJmRjAeQ1X/l9XFwGTiYAi2cQ/7QmBQJQSE0VT5exa 2ESw== X-Gm-Message-State: APjAAAW1Ta4ffhas5y3+kMEZzXq4/ct6APbxMMPpGKVZ64vlfVWC7xyA boNzLs93raUa9tTwHsvgY5VVvzgiv1o= X-Google-Smtp-Source: APXvYqzO69+SFNQD25sX+v/CwJUb3PhBiHPL7gAr9CGC0HPcUtSl++xVF3BgpvmVUKjdi/rviIxLMw== X-Received: by 2002:a63:ee04:: with SMTP id e4mr19888533pgi.53.1566220691994; Mon, 19 Aug 2019 06:18:11 -0700 (PDT) Received: from localhost.corp.microsoft.com ([167.220.255.114]) by smtp.googlemail.com with ESMTPSA id h20sm16184329pfq.156.2019.08.19.06.18.06 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 19 Aug 2019 06:18:11 -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 V3 2/3] KVM/Hyper-V: Add new KVM cap KVM_CAP_HYPERV_DIRECT_TLBFLUSH Date: Mon, 19 Aug 2019 21:17:36 +0800 Message-Id: <20190819131737.26942-3-Tianyu.Lan@microsoft.com> X-Mailer: git-send-email 2.14.5 In-Reply-To: <20190819131737.26942-1-Tianyu.Lan@microsoft.com> References: <20190819131737.26942-1-Tianyu.Lan@microsoft.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Tianyu Lan This patch adds new KVM cap KVM_CAP_HYPERV_DIRECT_TLBFLUSH and let user space to enable direct tlb flush function when only Hyper-V hypervsior capability is exposed to VM. This patch also adds enable_direct_tlbflush callback in the struct kvm_x86_ops and platforms may use it to implement direct tlb flush support. Signed-off-by: Tianyu Lan --- 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