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[2620:137:e000::1:20]) by mx.google.com with ESMTP id w2-20020a17090a4f4200b00262e650abadsi2530036pjl.117.2023.08.03.01.15.39; Thu, 03 Aug 2023 01:15:52 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@intel.com header.s=Intel header.b=FL3yqIDh; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231599AbjHCHhM (ORCPT + 99 others); Thu, 3 Aug 2023 03:37:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231743AbjHCHgG (ORCPT ); Thu, 3 Aug 2023 03:36:06 -0400 Received: from mgamail.intel.com (unknown [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3484249D4; Thu, 3 Aug 2023 00:32:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1691047937; x=1722583937; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=IVhHfi1eWY88vEuzBQ7T04hxto/MpvhMpx9t9R3UaJI=; b=FL3yqIDhm7iZRznFs/SmjEeSmfRy9ViQ0GgjsnYa/sWfRlut/gxTrJwL 80eEys8Fl0f/Lup0c/laHY3jYFTJi0a4CvGPrtaa73AoJ8xn/V72II2mJ Rk47Gngs1r3gUMXbeSo/fcqjV060b7x8KIWXZfo7CXoV2RX6jtsf27feG 6lB5WSjDOjhTKWWl1YZt+oVEKEegoyq+Npfr+xoQ2+JwrLpJyDRwpcWUz gTJE3hbQTid8NXOIwkWPFQxPQ9/dPkaqHX5KgiHWztSniZLNHiSgelo1t mjSnbqkXjc+hmGipSC4RjdM2dhb/Nee20JbGt4CsAg44749ryDEyFMMbb Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10790"; a="354708099" X-IronPort-AV: E=Sophos;i="6.01,251,1684825200"; d="scan'208";a="354708099" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Aug 2023 00:32:15 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10790"; a="794888475" X-IronPort-AV: E=Sophos;i="6.01,251,1684825200"; d="scan'208";a="794888475" Received: from embargo.jf.intel.com ([10.165.9.183]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Aug 2023 00:32:15 -0700 From: Yang Weijiang To: seanjc@google.com, pbonzini@redhat.com, peterz@infradead.org, john.allen@amd.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: rick.p.edgecombe@intel.com, chao.gao@intel.com, binbin.wu@linux.intel.com, weijiang.yang@intel.com, Zhang Yi Z Subject: [PATCH v5 04/19] KVM:x86: Refresh CPUID on write to guest MSR_IA32_XSS Date: Thu, 3 Aug 2023 00:27:17 -0400 Message-Id: <20230803042732.88515-5-weijiang.yang@intel.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20230803042732.88515-1-weijiang.yang@intel.com> References: <20230803042732.88515-1-weijiang.yang@intel.com> MIME-Version: 1.0 X-Spam-Status: No, score=-0.5 required=5.0 tests=BAYES_00,DATE_IN_PAST_03_06, DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1773195024411908710 X-GMAIL-MSGID: 1773195024411908710 Update CPUID(EAX=0DH,ECX=1) when the guest's XSS is modified. CPUID(EAX=0DH,ECX=1).EBX reports required storage size of all enabled xstate features in XCR0 | XSS. Guest can allocate sufficient xsave buffer based on the info. Note, KVM does not yet support any XSS based features, i.e. supported_xss is guaranteed to be zero at this time. Co-developed-by: Zhang Yi Z Signed-off-by: Zhang Yi Z Signed-off-by: Yang Weijiang Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/cpuid.c | 20 ++++++++++++++++++-- arch/x86/kvm/x86.c | 8 +++++--- 3 files changed, 24 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 28bd38303d70..20bbcd95511f 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -804,6 +804,7 @@ struct kvm_vcpu_arch { u64 xcr0; u64 guest_supported_xcr0; + u64 guest_supported_xss; struct kvm_pio_request pio; void *pio_data; diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 7f4d13383cf2..0338316b827c 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -249,6 +249,17 @@ static u64 cpuid_get_supported_xcr0(struct kvm_cpuid_entry2 *entries, int nent) return (best->eax | ((u64)best->edx << 32)) & kvm_caps.supported_xcr0; } +static u64 cpuid_get_supported_xss(struct kvm_cpuid_entry2 *entries, int nent) +{ + struct kvm_cpuid_entry2 *best; + + best = cpuid_entry2_find(entries, nent, 0xd, 1); + if (!best) + return 0; + + return (best->ecx | ((u64)best->edx << 32)) & kvm_caps.supported_xss; +} + static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *entries, int nent) { @@ -276,8 +287,11 @@ static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_e best = cpuid_entry2_find(entries, nent, 0xD, 1); if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) || - cpuid_entry_has(best, X86_FEATURE_XSAVEC))) - best->ebx = xstate_required_size(vcpu->arch.xcr0, true); + cpuid_entry_has(best, X86_FEATURE_XSAVEC))) { + u64 xstate = vcpu->arch.xcr0 | vcpu->arch.ia32_xss; + + best->ebx = xstate_required_size(xstate, true); + } best = __kvm_find_kvm_cpuid_features(vcpu, entries, nent); if (kvm_hlt_in_guest(vcpu->kvm) && best && @@ -325,6 +339,8 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) vcpu->arch.guest_supported_xcr0 = cpuid_get_supported_xcr0(vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent); + vcpu->arch.guest_supported_xss = + cpuid_get_supported_xss(vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent); /* * FP+SSE can always be saved/restored via KVM_{G,S}ET_XSAVE, even if diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0b9033551d8c..5d6d6fa33e5b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3780,10 +3780,12 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) * IA32_XSS[bit 8]. Guests have to use RDMSR/WRMSR rather than * XSAVES/XRSTORS to save/restore PT MSRs. */ - if (data & ~kvm_caps.supported_xss) + if (data & ~vcpu->arch.guest_supported_xss) return 1; - vcpu->arch.ia32_xss = data; - kvm_update_cpuid_runtime(vcpu); + if (vcpu->arch.ia32_xss != data) { + vcpu->arch.ia32_xss = data; + kvm_update_cpuid_runtime(vcpu); + } break; case MSR_SMI_COUNT: if (!msr_info->host_initiated)