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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 9244CC433E9 for ; Wed, 3 Feb 2021 11:25:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 51C7964F68 for ; Wed, 3 Feb 2021 11:25:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234329AbhBCLZ1 (ORCPT ); Wed, 3 Feb 2021 06:25:27 -0500 Received: from mga01.intel.com ([192.55.52.88]:28346 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234045AbhBCLXp (ORCPT ); Wed, 3 Feb 2021 06:23:45 -0500 IronPort-SDR: d+rpyEnlcHbpvMtdcU9EGpp2X0LpIq6r4SjQjhPuhGFc9XiNHmqqiHopXMmACgTM75A8D4+qAI pBDKyzgXv3IQ== X-IronPort-AV: E=McAfee;i="6000,8403,9883"; a="199981291" X-IronPort-AV: E=Sophos;i="5.79,398,1602572400"; d="scan'208";a="199981291" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2021 03:22:21 -0800 IronPort-SDR: XeYaaLTK1Yej0eTHCLR59Ecd/X0t6d9fPKc/8cK4k13a2zGj8sOKIkOAvhuvVZkH+24sq2Y1sa QOyX/yjOAgsg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.79,398,1602572400"; d="scan'208";a="480311168" Received: from unknown (HELO local-michael-cet-test.sh.intel.com) ([10.239.159.166]) by fmsmga001.fm.intel.com with ESMTP; 03 Feb 2021 03:22:19 -0800 From: Yang Weijiang To: pbonzini@redhat.com, seanjc@google.com, jmattson@google.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: yu.c.zhang@linux.intel.com, Yang Weijiang Subject: [PATCH v15 08/14] KVM: VMX: Add a synthetic MSR to allow userspace VMM to access GUEST_SSP Date: Wed, 3 Feb 2021 19:34:15 +0800 Message-Id: <20210203113421.5759-9-weijiang.yang@intel.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20210203113421.5759-1-weijiang.yang@intel.com> References: <20210203113421.5759-1-weijiang.yang@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Introduce a host-only synthetic MSR, MSR_KVM_GUEST_SSP so that the VMM can read/write the guest's SSP, e.g. to migrate CET state. Use a synthetic MSR, e.g. as opposed to a VCPU_REG_, as GUEST_SSP is subject to the same consistency checks as the PL*_SSP MSRs, i.e. can share code. Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Signed-off-by: Yang Weijiang --- arch/x86/include/uapi/asm/kvm_para.h | 1 + arch/x86/kvm/vmx/vmx.c | 14 ++++++++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h index 950afebfba88..8dd562a94724 100644 --- a/arch/x86/include/uapi/asm/kvm_para.h +++ b/arch/x86/include/uapi/asm/kvm_para.h @@ -54,6 +54,7 @@ #define MSR_KVM_POLL_CONTROL 0x4b564d05 #define MSR_KVM_ASYNC_PF_INT 0x4b564d06 #define MSR_KVM_ASYNC_PF_ACK 0x4b564d07 +#define MSR_KVM_GUEST_SSP 0x4b564d08 struct kvm_steal_time { __u64 steal; diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 694879c2b0b7..4cd6a9710a51 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1816,7 +1816,8 @@ static bool cet_is_ssp_msr_accessible(struct kvm_vcpu *vcpu, if (msr->host_initiated) return true; - if (!guest_cpuid_has(vcpu, X86_FEATURE_SHSTK)) + if (!guest_cpuid_has(vcpu, X86_FEATURE_SHSTK) || + msr->index == MSR_KVM_GUEST_SSP) return false; if (msr->index == MSR_IA32_INT_SSP_TAB) @@ -1994,6 +1995,11 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 1; msr_info->data = vmcs_readl(GUEST_INTR_SSP_TABLE); break; + case MSR_KVM_GUEST_SSP: + if (!cet_is_ssp_msr_accessible(vcpu, msr_info)) + return 1; + msr_info->data = vmcs_readl(GUEST_SSP); + break; case MSR_IA32_PL0_SSP ... MSR_IA32_PL3_SSP: if (!cet_is_ssp_msr_accessible(vcpu, msr_info)) return 1; @@ -2286,12 +2292,16 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 1; vmcs_writel(GUEST_INTR_SSP_TABLE, data); break; + case MSR_KVM_GUEST_SSP: case MSR_IA32_PL0_SSP ... MSR_IA32_PL3_SSP: if (!cet_is_ssp_msr_accessible(vcpu, msr_info)) return 1; if ((data & GENMASK(2, 0)) || is_noncanonical_address(data, vcpu)) return 1; - vmx_set_xsave_msr(msr_info); + if (msr_index == MSR_KVM_GUEST_SSP) + vmcs_writel(GUEST_SSP, data); + else + vmx_set_xsave_msr(msr_info); break; case MSR_TSC_AUX: if (!msr_info->host_initiated && -- 2.26.2