From patchwork Tue Apr 5 07:30:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 557339 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE278C47080 for ; Tue, 5 Apr 2022 10:17:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353899AbiDEKJp (ORCPT ); Tue, 5 Apr 2022 06:09:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42470 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345972AbiDEJXN (ORCPT ); Tue, 5 Apr 2022 05:23:13 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D6415A7741; Tue, 5 Apr 2022 02:12:40 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1F36161527; Tue, 5 Apr 2022 09:12:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AFF3C385A3; Tue, 5 Apr 2022 09:12:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649149959; bh=uwEM9yJd8yQV8YVnMIu1YlcaI8etPYsnFYaOdz+jFvI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gR8awXETXVzoAu9p/kaKR7LEyXcRkTpYAxZ03i3VmBQBkS4Gr4xgAocCzE50+AT60 ZBC4ZJvrOzEiNPMOSpn+IxvTdW/xaFXclN5BkbwwvpKKHqBm2DQlSoHu5tbV1SCtHJ jcIFle8jV7QahPAd+/FtyrIM44iHTPL6Ac0zHKl8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vitaly Kuznetsov , Paolo Bonzini Subject: [PATCH 5.16 0903/1017] KVM: x86: Forbid VMM to set SYNIC/STIMER MSRs when SynIC wasnt activated Date: Tue, 5 Apr 2022 09:30:16 +0200 Message-Id: <20220405070421.029396714@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070354.155796697@linuxfoundation.org> References: <20220405070354.155796697@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vitaly Kuznetsov commit b1e34d325397a33d97d845e312d7cf2a8b646b44 upstream. Setting non-zero values to SYNIC/STIMER MSRs activates certain features, this should not happen when KVM_CAP_HYPERV_SYNIC{,2} was not activated. Note, it would've been better to forbid writing anything to SYNIC/STIMER MSRs, including zeroes, however, at least QEMU tries clearing HV_X64_MSR_STIMER0_CONFIG without SynIC. HV_X64_MSR_EOM MSR is somewhat 'special' as writing zero there triggers an action, this also should not happen when SynIC wasn't activated. Signed-off-by: Vitaly Kuznetsov Message-Id: <20220325132140.25650-4-vkuznets@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/hyperv.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -236,7 +236,7 @@ static int synic_set_msr(struct kvm_vcpu struct kvm_vcpu *vcpu = hv_synic_to_vcpu(synic); int ret; - if (!synic->active && !host) + if (!synic->active && (!host || data)) return 1; trace_kvm_hv_synic_set_msr(vcpu->vcpu_id, msr, data, host); @@ -282,6 +282,9 @@ static int synic_set_msr(struct kvm_vcpu case HV_X64_MSR_EOM: { int i; + if (!synic->active) + break; + for (i = 0; i < ARRAY_SIZE(synic->sint); i++) kvm_hv_notify_acked_sint(vcpu, i); break; @@ -661,7 +664,7 @@ static int stimer_set_config(struct kvm_ struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); struct kvm_vcpu_hv_synic *synic = to_hv_synic(vcpu); - if (!synic->active && !host) + if (!synic->active && (!host || config)) return 1; if (unlikely(!host && hv_vcpu->enforce_cpuid && new_config.direct_mode && @@ -690,7 +693,7 @@ static int stimer_set_count(struct kvm_v struct kvm_vcpu *vcpu = hv_stimer_to_vcpu(stimer); struct kvm_vcpu_hv_synic *synic = to_hv_synic(vcpu); - if (!synic->active && !host) + if (!synic->active && (!host || count)) return 1; trace_kvm_hv_stimer_set_count(hv_stimer_to_vcpu(stimer)->vcpu_id,