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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 05DC8C433E0 for ; Mon, 22 Jun 2020 22:05:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D5BFD2073E for ; Mon, 22 Jun 2020 22:05:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HaaSEpFV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730942AbgFVWEz (ORCPT ); Mon, 22 Jun 2020 18:04:55 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:31111 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730794AbgFVWEz (ORCPT ); Mon, 22 Jun 2020 18:04:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592863493; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=92xlo56NnQbKrNJm5mldzyMce3skYCA3gpK4Ws+GIX4=; b=HaaSEpFVYPjsqICjv2RQhacI1wO6GXV7A4y5TBzvlO8359EE52v+keaVMsYd+Ux6sIxhtR HLpwcK8QATcCF1XTftfR79weBBqqEGk8OlNoqpwkPF3/9TooVA9WSQg6RiR/7pBPnNSsE0 FFo+C0sf2+EjjE7+UBEvG1+/OTNRcnM= Received: from mail-qk1-f198.google.com (mail-qk1-f198.google.com [209.85.222.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-468-s0HoMUk5Om-LOQzYoBfBvA-1; Mon, 22 Jun 2020 18:04:51 -0400 X-MC-Unique: s0HoMUk5Om-LOQzYoBfBvA-1 Received: by mail-qk1-f198.google.com with SMTP id i6so2684106qkn.22 for ; Mon, 22 Jun 2020 15:04:51 -0700 (PDT) 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:mime-version:content-transfer-encoding; bh=92xlo56NnQbKrNJm5mldzyMce3skYCA3gpK4Ws+GIX4=; b=lhF6ujVstpi9KrInMoySDK+5PK3bkKO7uH+9CcVbDDXgzYdmn+w13MOZWb/V6BbT0l HiWLB+MNBy1bf2vGoJYn41BfmQ4Csclq6YUnahNFzdtWmeacXg3vVLEUV97jwSFhM92x okaZKMjPtqcziBnuuTAtOYaT3gE5yKPKJvHUVGI27LRzrcx+zYpdv6f9m/hrAPUuGWIg 6xVR3uiO8oXqTVc0sO+tvDiGVRe7ZynOSFqahskkf3nXLkzr6dvV20LvN2f0ilohB4YM Yx26dR1G/9tRButLKdK7eHwKMWp0GxTYAJfyQJ4tVqnS9EudZOy9+UWReiQgXuT6RY8c H0tA== X-Gm-Message-State: AOAM530m3XhmzPodlVIst+35RS3G0hF8Q4Dm4aQ16JUAakdo2xx44KkD 9PceZopvQrFyk+dRM6MbceNkM2KmzFvlVhOTJtVxlLvTvQdYsMRPDiJrKRrM7ERG5lbW7FcfjRp IRH4FI6NgKXQ7 X-Received: by 2002:a37:44d5:: with SMTP id r204mr7294737qka.113.1592863490935; Mon, 22 Jun 2020 15:04:50 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzwpw9hXXzrRoZ7uBlSGesnncpPEpLsS//WL8KZ5yVPHkbD2TpWTGus3gca62CrS2n80xyqrg== X-Received: by 2002:a37:44d5:: with SMTP id r204mr7294705qka.113.1592863490646; Mon, 22 Jun 2020 15:04:50 -0700 (PDT) Received: from xz-x1.redhat.com ([2607:9880:19c0:32::2]) by smtp.gmail.com with ESMTPSA id h6sm3506810qtu.2.2020.06.22.15.04.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jun 2020 15:04:50 -0700 (PDT) From: Peter Xu To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Sean Christopherson , Paolo Bonzini , peterx@redhat.com, Vitaly Kuznetsov Subject: [PATCH 1/2] KVM: X86: Move ignore_msrs handling upper the stack Date: Mon, 22 Jun 2020 18:04:41 -0400 Message-Id: <20200622220442.21998-2-peterx@redhat.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200622220442.21998-1-peterx@redhat.com> References: <20200622220442.21998-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org MSR accesses can be one of: (1) KVM internal access, (2) userspace access (e.g., via KVM_SET_MSRS ioctl), (3) guest access. The ignore_msrs was previously handled by kvm_get_msr_common() and kvm_set_msr_common(), which is the bottom of the msr access stack. It's working in most cases, however it could dump unwanted warning messages to dmesg even if kvm get/set the msrs internally when calling __kvm_set_msr() or __kvm_get_msr() (e.g. kvm_cpuid()). Ideally we only want to trap cases (2) or (3), but not (1) above. To achieve this, move the ignore_msrs handling upper until the callers of __kvm_get_msr() and __kvm_set_msr(). To identify the "msr missing" event, a new return value (KVM_MSR_RET_INVALID==2) is used for that. Signed-off-by: Peter Xu --- arch/x86/kvm/x86.c | 80 +++++++++++++++++++++++++++++++--------------- arch/x86/kvm/x86.h | 2 ++ 2 files changed, 56 insertions(+), 26 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c17e6eb9ad43..b49eaf8a2ce5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -245,6 +245,29 @@ EXPORT_SYMBOL_GPL(x86_fpu_cache); static struct kmem_cache *x86_emulator_cache; +/* + * When called, it means the previous get/set msr reached an invalid msr. + * Return 0 if we want to ignore/silent this failed msr access, or 1 if we want + * to fail the caller. + */ +static int kvm_msr_ignored_check(struct kvm_vcpu *vcpu, u32 msr, + u64 data, bool write) +{ + const char *op = write ? "wrmsr" : "rdmsr"; + + if (ignore_msrs) { + if (report_ignored_msrs) + vcpu_unimpl(vcpu, "ignored %s: 0x%x data 0x%llx\n", + op, msr, data); + /* Mask the error */ + return 0; + } else { + vcpu_debug_ratelimited(vcpu, "unhandled %s: 0x%x data 0x%llx\n", + op, msr, data); + return 1; + } +} + static struct kmem_cache *kvm_alloc_emulator_cache(void) { unsigned int useroffset = offsetof(struct x86_emulate_ctxt, src); @@ -1496,6 +1519,17 @@ static int __kvm_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data, return kvm_x86_ops.set_msr(vcpu, &msr); } +static int kvm_set_msr_ignored_check(struct kvm_vcpu *vcpu, + u32 index, u64 data, bool host_initiated) +{ + int ret = __kvm_set_msr(vcpu, index, data, host_initiated); + + if (ret == KVM_MSR_RET_INVALID) + ret = kvm_msr_ignored_check(vcpu, index, data, true); + + return ret; +} + /* * Read the MSR specified by @index into @data. Select MSR specific fault * checks are bypassed if @host_initiated is %true. @@ -1517,15 +1551,29 @@ int __kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data, return ret; } +static int kvm_get_msr_ignored_check(struct kvm_vcpu *vcpu, + u32 index, u64 *data, bool host_initiated) +{ + int ret = __kvm_get_msr(vcpu, index, data, host_initiated); + + if (ret == KVM_MSR_RET_INVALID) { + /* Unconditionally clear *data for simplicity */ + *data = 0; + ret = kvm_msr_ignored_check(vcpu, index, 0, false); + } + + return ret; +} + int kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data) { - return __kvm_get_msr(vcpu, index, data, false); + return kvm_get_msr_ignored_check(vcpu, index, data, false); } EXPORT_SYMBOL_GPL(kvm_get_msr); int kvm_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data) { - return __kvm_set_msr(vcpu, index, data, false); + return kvm_set_msr_ignored_check(vcpu, index, data, false); } EXPORT_SYMBOL_GPL(kvm_set_msr); @@ -1621,12 +1669,12 @@ EXPORT_SYMBOL_GPL(handle_fastpath_set_msr_irqoff); */ static int do_get_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data) { - return __kvm_get_msr(vcpu, index, data, true); + return kvm_get_msr_ignored_check(vcpu, index, data, true); } static int do_set_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data) { - return __kvm_set_msr(vcpu, index, *data, true); + return kvm_set_msr_ignored_check(vcpu, index, *data, true); } #ifdef CONFIG_X86_64 @@ -2977,17 +3025,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return xen_hvm_config(vcpu, data); if (kvm_pmu_is_valid_msr(vcpu, msr)) return kvm_pmu_set_msr(vcpu, msr_info); - if (!ignore_msrs) { - vcpu_debug_ratelimited(vcpu, "unhandled wrmsr: 0x%x data 0x%llx\n", - msr, data); - return 1; - } else { - if (report_ignored_msrs) - vcpu_unimpl(vcpu, - "ignored wrmsr: 0x%x data 0x%llx\n", - msr, data); - break; - } + return KVM_MSR_RET_INVALID; } return 0; } @@ -3234,17 +3272,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) default: if (kvm_pmu_is_valid_msr(vcpu, msr_info->index)) return kvm_pmu_get_msr(vcpu, msr_info->index, &msr_info->data); - if (!ignore_msrs) { - vcpu_debug_ratelimited(vcpu, "unhandled rdmsr: 0x%x\n", - msr_info->index); - return 1; - } else { - if (report_ignored_msrs) - vcpu_unimpl(vcpu, "ignored rdmsr: 0x%x\n", - msr_info->index); - msr_info->data = 0; - } - break; + return KVM_MSR_RET_INVALID; } return 0; } diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index b968acc0516f..62e3e896d059 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -359,4 +359,6 @@ void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu); void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu); u64 kvm_spec_ctrl_valid_bits(struct kvm_vcpu *vcpu); +#define KVM_MSR_RET_INVALID 2 + #endif -- 2.26.2