From nobody Sat Feb 7 18:32:57 2026 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 62781C433F5 for ; Tue, 17 May 2022 15:42:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239433AbiEQPm2 (ORCPT ); Tue, 17 May 2022 11:42:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350480AbiEQPlg (ORCPT ); Tue, 17 May 2022 11:41:36 -0400 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE33B3F898; Tue, 17 May 2022 08:41:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1652802095; x=1684338095; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=PEXOfXI4uz6C2S1/YHi/L6djsDKaGD2Ad2yRpTJujp8=; b=FOAjO8h262azEfu/RsEQBdqTznoUQSZSdNE0sGjKZ7P8LhKA3EFygppi g4u0yXjlnb7s5kQnUM0LJNwQ0WgjIserY3N3oO1ZO/OGhW4CGJ977vhtH v2nEmG9ijx3CcjhitW94h12m9hCtS1MwLek8LL8Ith6wNTLnji9obfd/J CJ0iqAnZluaDEkE96TMbW1TXOE6JBq9zXiYUsxwyxnJoErc3ymDmVCgwr GBWxlBqT73WdGpQUj5P5CcKC3Qw4JPeyy8AZ29vznDdHRjvguTSVKqi2h S7Nz4qVyKWcDm2TR84/rGSDcIn7267fCK554/Niu/upVxKCQoOfCWi+Uq g==; X-IronPort-AV: E=McAfee;i="6400,9594,10350"; a="357632098" X-IronPort-AV: E=Sophos;i="5.91,233,1647327600"; d="scan'208";a="357632098" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 May 2022 08:41:33 -0700 X-IronPort-AV: E=Sophos;i="5.91,233,1647327600"; d="scan'208";a="626533564" Received: from embargo.jf.intel.com ([10.165.9.183]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 May 2022 08:41:33 -0700 From: Yang Weijiang To: pbonzini@redhat.com, jmattson@google.com, seanjc@google.com, like.xu.linux@gmail.com, vkuznets@redhat.com, kan.liang@linux.intel.com, wei.w.wang@intel.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Yang Weijiang , Zhang Yi Z Subject: [PATCH v12 04/16] KVM: x86: Refresh CPUID on writes to MSR_IA32_XSS Date: Tue, 17 May 2022 11:40:48 -0400 Message-Id: <20220517154100.29983-5-weijiang.yang@intel.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220517154100.29983-1-weijiang.yang@intel.com> References: <20220517154100.29983-1-weijiang.yang@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Updated CPUID.0xD.0x1, which reports the current required storage size of all features enabled via XCR0 | XSS, when the guest's XSS is modified. 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 --- arch/x86/kvm/cpuid.c | 16 +++++++++++++--- arch/x86/kvm/x86.c | 6 ++++-- 2 files changed, 17 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 8c1a3b2430a8..b88609847188 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -239,9 +239,19 @@ static void __kvm_update_cpuid_runtime(struct kvm_vcpu= *vcpu, struct kvm_cpuid_e best->ebx =3D xstate_required_size(vcpu->arch.xcr0, false); =20 best =3D 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 =3D xstate_required_size(vcpu->arch.xcr0, true); + if (best) { + if (cpuid_entry_has(best, X86_FEATURE_XSAVES) || + cpuid_entry_has(best, X86_FEATURE_XSAVEC)) { + u64 xstate =3D vcpu->arch.xcr0 | vcpu->arch.ia32_xss; + + best->ebx =3D xstate_required_size(xstate, true); + } + + if (!cpuid_entry_has(best, X86_FEATURE_XSAVES)) { + best->ecx =3D 0; + best->edx =3D 0; + } + } =20 best =3D __kvm_find_kvm_cpuid_features(vcpu, entries, nent); if (kvm_hlt_in_guest(vcpu->kvm) && best && diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6dcfedf10734..247c58f5c8af 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3613,8 +3613,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct= msr_data *msr_info) */ if (data & ~supported_xss) return 1; - vcpu->arch.ia32_xss =3D data; - kvm_update_cpuid_runtime(vcpu); + if (vcpu->arch.ia32_xss !=3D data) { + vcpu->arch.ia32_xss =3D data; + kvm_update_cpuid_runtime(vcpu); + } break; case MSR_SMI_COUNT: if (!msr_info->host_initiated) --=20 2.27.0