From patchwork Mon Aug 10 20:11:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aaron Lewis X-Patchwork-Id: 11708107 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 50600739 for ; Mon, 10 Aug 2020 20:11:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3046A20678 for ; Mon, 10 Aug 2020 20:11:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="i59gTdRa" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726396AbgHJULr (ORCPT ); Mon, 10 Aug 2020 16:11:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51418 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726143AbgHJULr (ORCPT ); Mon, 10 Aug 2020 16:11:47 -0400 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 46197C061756 for ; Mon, 10 Aug 2020 13:11:47 -0700 (PDT) Received: by mail-pj1-x1049.google.com with SMTP id s4so535058pjq.8 for ; Mon, 10 Aug 2020 13:11:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=5oAjokWOZe4cAdJFgfr8j682KuQkIW1okam8n6z5dy8=; b=i59gTdRapHyeCjEIgC6k7Z6BefmKEkcLk0+1v8FF7cm2ERlx1uHnIQGWOkDdO2e4j9 TA6kjushKsVVelS0Gfx/Q7ybyzqloGYVNDLuH4Fc08tQpejJrrbJA59wtIW4OiSLPWH3 ur+T82okRpFkuz+lPAkddiP8njjUZl3edbZ92bXK2P13p60m1F15aGYNkk6VEk8oBBb3 Rv680oVKT81RW4hDrYoras8S3pY3YsB/F5AckzuuKDSyCJDyuEdM3XlyvrvsGgNOeKdm 32pZ3yCJwiJR6UCZqBD5suGRD2DGW85wDrUC9uLipWq0VgV88vEhwKL2chEK0lXmEiWy tpPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=5oAjokWOZe4cAdJFgfr8j682KuQkIW1okam8n6z5dy8=; b=PGE32LilIaOowaxX7fqpwXH4S17v3KEIHq3/az7TGog+p99LGhaFzaUExnZCZnynSs TIKOzDBTwFa7veheO9ZoX2NLm1cfrsRMxVhS3EgBKfxHquav1eTxrK8Y5gWIbf8LBVhK PMTyh+PikhS2sOyrxCSnwzXUbfEmFUDs537MZ0URPRM9Mv40NpCw4qVTh5KEtkk3JZwE Q4tyXTSt4g4Twpfjsm3mrngaP9paevo5UEw36Eg6PdqzFPcDTvBdFCLC8mkHNqzgz8+N chH8RmgwBBvgqgTIhxWiTIwbdpkn1cBvNYm8Hreho+lBA2aXKDq9D9YrZByZkJQflwAa JrGw== X-Gm-Message-State: AOAM5321fB2McDDHDUyTqfHr1ZK8KzBcPc3TKTuyWq4WEAqY09Olsshf xAtg8Nqu3mW35fxvGpjqKFuW00yikRvgFhNE X-Google-Smtp-Source: ABdhPJwdJ6t5/vb3IuTDPqMyfW341aPpIqq/ytFj+8mB54vEu+1b3PjuQ0LgzRAdIR/5dEZ1HWnMNmT+YELWCvnU X-Received: by 2002:a17:90a:2110:: with SMTP id a16mr1027012pje.104.1597090306166; Mon, 10 Aug 2020 13:11:46 -0700 (PDT) Date: Mon, 10 Aug 2020 13:11:27 -0700 In-Reply-To: <20200810201134.2031613-1-aaronlewis@google.com> Message-Id: <20200810201134.2031613-2-aaronlewis@google.com> Mime-Version: 1.0 References: <20200810201134.2031613-1-aaronlewis@google.com> X-Mailer: git-send-email 2.28.0.236.gb10cc79966-goog Subject: [PATCH v2 1/8] KVM: x86: Add ioctl for accepting a userspace provided MSR list From: Aaron Lewis To: jmattson@google.com, graf@amazon.com Cc: pshier@google.com, oupton@google.com, kvm@vger.kernel.org, Aaron Lewis Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Add KVM_SET_EXIT_MSRS ioctl to allow userspace to pass in a list of MSRs that force an exit to userspace when rdmsr or wrmsr are used by the guest. KVM_SET_EXIT_MSRS will need to be called before any vCPUs are created to protect the 'user_exit_msrs' list from being mutated while vCPUs are running. Add KVM_CAP_SET_MSR_EXITS to identify the feature exists. Signed-off-by: Aaron Lewis Reviewed-by: Oliver Upton --- Documentation/virt/kvm/api.rst | 24 +++++++++++++++++++ arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/x86.c | 41 +++++++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 2 ++ 4 files changed, 69 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 320788f81a05..7d8167c165aa 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -1006,6 +1006,30 @@ such as migration. :Parameters: struct kvm_vcpu_event (out) :Returns: 0 on success, -1 on error +4.32 KVM_SET_EXIT_MSRS +------------------ + +:Capability: KVM_CAP_SET_MSR_EXITS +:Architectures: x86 +:Type: vm ioctl +:Parameters: struct kvm_msr_list (in) +:Returns: 0 on success, -1 on error + +Sets the userspace MSR list which is used to track which MSRs KVM should send +to userspace to be serviced when the guest executes rdmsr or wrmsr. + +This ioctl needs to be called before vCPUs are setup otherwise the list of MSRs +will not be accepted and an EINVAL error will be returned. Also, if a list of +MSRs has already been supplied, and this ioctl is called again an EEXIST error +will be returned. + +:: + + struct kvm_msr_list { + __u32 nmsrs; + __u32 indices[0]; +}; + X86: ^^^^ diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index be5363b21540..510055471dd0 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1004,6 +1004,8 @@ struct kvm_arch { struct kvm_pmu_event_filter *pmu_event_filter; struct task_struct *nx_lpage_recovery_thread; + + struct kvm_msr_list *user_exit_msrs; }; struct kvm_vm_stat { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 88c593f83b28..46a0fb9e0869 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3419,6 +3419,42 @@ static inline bool kvm_can_mwait_in_guest(void) boot_cpu_has(X86_FEATURE_ARAT); } +static int kvm_vm_ioctl_set_exit_msrs(struct kvm *kvm, + struct kvm_msr_list __user *user_msr_list) +{ + struct kvm_msr_list *msr_list, hdr; + size_t indices_size; + + if (kvm->arch.user_exit_msrs != NULL) + return -EEXIST; + + if (kvm->created_vcpus) + return -EINVAL; + + if (copy_from_user(&hdr, user_msr_list, sizeof(hdr))) + return -EFAULT; + + if (hdr.nmsrs >= MAX_IO_MSRS) + return -E2BIG; + + indices_size = sizeof(hdr.indices[0]) * hdr.nmsrs; + msr_list = kvzalloc(sizeof(struct kvm_msr_list) + indices_size, + GFP_KERNEL_ACCOUNT); + if (!msr_list) + return -ENOMEM; + msr_list->nmsrs = hdr.nmsrs; + + if (copy_from_user(msr_list->indices, user_msr_list->indices, + indices_size)) { + kvfree(msr_list); + return -EFAULT; + } + + kvm->arch.user_exit_msrs = msr_list; + + return 0; +} + int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) { int r = 0; @@ -3476,6 +3512,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_MSR_PLATFORM_INFO: case KVM_CAP_EXCEPTION_PAYLOAD: case KVM_CAP_SET_GUEST_DEBUG: + case KVM_CAP_SET_MSR_EXITS: r = 1; break; case KVM_CAP_SYNC_REGS: @@ -5261,6 +5298,10 @@ long kvm_arch_vm_ioctl(struct file *filp, r = 0; break; } + case KVM_SET_EXIT_MSRS: { + r = kvm_vm_ioctl_set_exit_msrs(kvm, argp); + break; + } case KVM_MEMORY_ENCRYPT_OP: { r = -ENOTTY; if (kvm_x86_ops.mem_enc_op) diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 4fdf30316582..de4638c1bd15 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1031,6 +1031,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_PPC_SECURE_GUEST 181 #define KVM_CAP_HALT_POLL 182 #define KVM_CAP_ASYNC_PF_INT 183 +#define KVM_CAP_SET_MSR_EXITS 185 #ifdef KVM_CAP_IRQ_ROUTING @@ -1371,6 +1372,7 @@ struct kvm_s390_ucas_mapping { /* Available with KVM_CAP_PMU_EVENT_FILTER */ #define KVM_SET_PMU_EVENT_FILTER _IOW(KVMIO, 0xb2, struct kvm_pmu_event_filter) #define KVM_PPC_SVM_OFF _IO(KVMIO, 0xb3) +#define KVM_SET_EXIT_MSRS _IOW(KVMIO, 0xb4, struct kvm_msr_list) /* ioctl for vm fd */ #define KVM_CREATE_DEVICE _IOWR(KVMIO, 0xe0, struct kvm_create_device)