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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 93E04C10DC2 for ; Thu, 30 Nov 2023 18:30:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346766AbjK3Sar (ORCPT ); Thu, 30 Nov 2023 13:30:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235171AbjK3Sah (ORCPT ); Thu, 30 Nov 2023 13:30:37 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4766170F for ; Thu, 30 Nov 2023 10:30:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701369039; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qytGX0MGJcOz7q/36mRvU0A100gsEwbWnP5WfFvyCcQ=; b=ReIdTavSeZV8PhLOrp5oOWoa0s1bH2jahkRof3SR2l+H9CYTJaCmfYt331DBds1T9DcAIE EzCqE4yRsF3qmktwTq/Y/CzDONY9LRz5r46Ph2f9QDZeWVdMx3kzwo8hUxOwRTLMTepVxJ b3l+sml43+/Wtw+0hflCesxv1Cxj+Fw= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-369-WLr-ZhgTO5a2VwKKyzsgtA-1; Thu, 30 Nov 2023 13:30:37 -0500 X-MC-Unique: WLr-ZhgTO5a2VwKKyzsgtA-1 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-40b357e2a01so8643915e9.1 for ; Thu, 30 Nov 2023 10:30:37 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701369036; x=1701973836; h=content-transfer-encoding:mime-version:user-agent:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=qytGX0MGJcOz7q/36mRvU0A100gsEwbWnP5WfFvyCcQ=; b=TxbGyrkcY+vUJrpl2YhxFfDsKOXI+zmAPhlI1pVKSTMlwkoPPOLkb+XtT7T3O8ICMs hxgoE6Ica2rXsNqJ/W9spbXF947umaKcOHb9nicY+ERVIsbzNBdqyhk2K51YFYfdZdRC ERMzbq/0IsF8t/1Uw0bm8YrQY0Tiybp1wEQUR13a7fxuSyKYp9oMa1xnEYM6YIwaNoK1 ugoSuyuJ+fM8/MMH5WZD+AMEfcroh6prh5ZojCdzp4XbgN2kNLeuwVNKq4UzsnedYFEO 92sq9a3Ik1bVZWZ17zmg/SOlgH2pGlI0RSPiCZ0NuChJqxjR4wgwqrMUPBYV32blpCfo m7Mg== X-Gm-Message-State: AOJu0YzNzRMH9BoZZ8nvkqIellUpVlf1N/h3hVcmNZyEXQnZnnKiWQZz bk+q8zftYeqJ/+iAQ2xmbO0DKfqE4YVsCa0gSjj4VRz7IxzYgnbrbatf6g+nsRVfCzDRuyKl/5S Vtp/I+1AKbd/eeGPBn19mf00L9f+wHgoC X-Received: by 2002:a05:600c:a04:b0:40b:4e4e:2b22 with SMTP id z4-20020a05600c0a0400b0040b4e4e2b22mr2029wmp.38.1701369034658; Thu, 30 Nov 2023 10:30:34 -0800 (PST) X-Google-Smtp-Source: AGHT+IEPJcbCU4cufSDQv6f8QUMe1TA4X/6xNTeMQtfmLGplAXuJX2mk3hU8RkAtP5spjMsfxa0lKg== X-Received: by 2002:a17:906:2086:b0:a11:d323:c1bc with SMTP id 6-20020a170906208600b00a11d323c1bcmr57445ejq.19.1701366166815; Thu, 30 Nov 2023 09:42:46 -0800 (PST) Received: from starship ([5.28.147.32]) by smtp.gmail.com with ESMTPSA id d27-20020ac25edb000000b0050933bb416csm214417lfq.74.2023.11.30.09.42.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Nov 2023 09:42:46 -0800 (PST) Message-ID: Subject: Re: [PATCH v7 21/26] KVM: x86: Save and reload SSP to/from SMRAM From: Maxim Levitsky To: Yang Weijiang , seanjc@google.com, pbonzini@redhat.com, dave.hansen@intel.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: peterz@infradead.org, chao.gao@intel.com, rick.p.edgecombe@intel.com, john.allen@amd.com Date: Thu, 30 Nov 2023 19:42:44 +0200 In-Reply-To: <20231124055330.138870-22-weijiang.yang@intel.com> References: <20231124055330.138870-1-weijiang.yang@intel.com> <20231124055330.138870-22-weijiang.yang@intel.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.5 (3.36.5-2.fc32) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2023-11-24 at 00:53 -0500, Yang Weijiang wrote: > Save CET SSP to SMRAM on SMI and reload it on RSM. KVM emulates HW arch > behavior when guest enters/leaves SMM mode,i.e., save registers to SMRAM > at the entry of SMM and reload them at the exit to SMM. Per SDM, SSP is > one of such registers on 64bit Arch, so add the support for SSP. > > Suggested-by: Sean Christopherson > Signed-off-by: Yang Weijiang > --- > arch/x86/kvm/smm.c | 8 ++++++++ > arch/x86/kvm/smm.h | 2 +- > 2 files changed, 9 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/smm.c b/arch/x86/kvm/smm.c > index 45c855389ea7..7aac9c54c353 100644 > --- a/arch/x86/kvm/smm.c > +++ b/arch/x86/kvm/smm.c > @@ -275,6 +275,10 @@ static void enter_smm_save_state_64(struct kvm_vcpu *vcpu, > enter_smm_save_seg_64(vcpu, &smram->gs, VCPU_SREG_GS); > > smram->int_shadow = static_call(kvm_x86_get_interrupt_shadow)(vcpu); > + > + if (guest_can_use(vcpu, X86_FEATURE_SHSTK)) > + KVM_BUG_ON(kvm_msr_read(vcpu, MSR_KVM_SSP, &smram->ssp), > + vcpu->kvm); > } > #endif > > @@ -564,6 +568,10 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, > static_call(kvm_x86_set_interrupt_shadow)(vcpu, 0); > ctxt->interruptibility = (u8)smstate->int_shadow; > > + if (guest_can_use(vcpu, X86_FEATURE_SHSTK)) > + KVM_BUG_ON(kvm_msr_write(vcpu, MSR_KVM_SSP, smstate->ssp), > + vcpu->kvm); > + > return X86EMUL_CONTINUE; > } > #endif > diff --git a/arch/x86/kvm/smm.h b/arch/x86/kvm/smm.h > index a1cf2ac5bd78..1e2a3e18207f 100644 > --- a/arch/x86/kvm/smm.h > +++ b/arch/x86/kvm/smm.h > @@ -116,8 +116,8 @@ struct kvm_smram_state_64 { > u32 smbase; > u32 reserved4[5]; > > - /* ssp and svm_* fields below are not implemented by KVM */ > u64 ssp; > + /* svm_* fields below are not implemented by KVM */ > u64 svm_guest_pat; > u64 svm_host_efer; > u64 svm_host_cr4; My review feedback from the previous patch series still applies, and I don't know why it was not addressed/replied to: I still think that it is worth it to have a check that CET is not enabled in enter_smm_save_state_32 which is called for pure 32 bit guests (guests that don't have X86_FEATURE_LM enabled) Best regards, Maxim Levitsky