From nobody Fri Dec 19 19:15:41 2025 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 2BE82C433EF for ; Wed, 16 Feb 2022 10:26:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229599AbiBPK1J (ORCPT ); Wed, 16 Feb 2022 05:27:09 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:49710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232837AbiBPK1D (ORCPT ); Wed, 16 Feb 2022 05:27:03 -0500 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEABE1DE8B4; Wed, 16 Feb 2022 02:26:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1645007211; x=1676543211; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=1ymbzXgybS9Kud6P+so4FG9rzv9+BB+wvBmn0MMJDDs=; b=L/BjI/Nphx69eCSxQw3PJcIsQUVNzMrvJtAyVCwjZFz5cYwTnQb33JK2 jUvcKHyzbxjdjSGLQ1t4cupU8xa1mAaQvlshQMjr5L7/ACirH+2C33DYN gQXTfX3CCTYO5D5lThfbUqO5V934h5ApWSCAABcTxe3zjuFGpiNeIPH9O 9FhSQaYWuEYLGjsyTRKRy/13dZW7CPqqL0pMG4oh6rqFN48VloQPY40Sp HuUbmKH61R3+uV2csVPAG2//JjvCR8DcaL6s6bQTCexWxccIyzp8QAAY4 q+D2Pj6Y1zojDJbZeHVJDFteZBpB+ugoS5JWUdm6oNGux24UYXMaB+/9d A==; X-IronPort-AV: E=McAfee;i="6200,9189,10259"; a="231201148" X-IronPort-AV: E=Sophos;i="5.88,373,1635231600"; d="scan'208";a="231201148" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Feb 2022 02:26:50 -0800 X-IronPort-AV: E=Sophos;i="5.88,373,1635231600"; d="scan'208";a="498708569" Received: from embargo.jf.intel.com ([10.165.9.183]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Feb 2022 02:26:50 -0800 From: Yang Weijiang To: pbonzini@redhat.com, jmattson@google.com, seanjc@google.com, like.xu.linux@gmail.com, vkuznets@redhat.com, wei.w.wang@intel.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Yang Weijiang , Zhang Yi Z Subject: [PATCH v9 02/17] KVM: x86: Refresh CPUID on writes to MSR_IA32_XSS Date: Tue, 15 Feb 2022 16:25:29 -0500 Message-Id: <20220215212544.51666-3-weijiang.yang@intel.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220215212544.51666-1-weijiang.yang@intel.com> References: <20220215212544.51666-1-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/include/asm/kvm_host.h | 1 + arch/x86/kvm/cpuid.c | 21 ++++++++++++++++++--- arch/x86/kvm/x86.c | 8 +++++--- 3 files changed, 24 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_hos= t.h index 6dcccb304775..9d59dfc27e5a 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -704,6 +704,7 @@ struct kvm_vcpu_arch { =20 u64 xcr0; u64 guest_supported_xcr0; + u64 guest_supported_xss; =20 struct kvm_pio_request pio; void *pio_data; diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 494d4d351859..8cd864411a1c 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -239,9 +239,24 @@ 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; + } + vcpu->arch.guest_supported_xss =3D + (((u64)best->edx << 32) | best->ecx) & supported_xss; + + } else { + vcpu->arch.guest_supported_xss =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 b82934c13e30..8397e5bc4ed5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3535,10 +3535,12 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struc= t 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 & ~supported_xss) + if (data & ~vcpu->arch.guest_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