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 E06D2C4332F for ; Thu, 2 Nov 2023 18:15:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346721AbjKBSPB (ORCPT ); Thu, 2 Nov 2023 14:15:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59960 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235688AbjKBSOp (ORCPT ); Thu, 2 Nov 2023 14:14:45 -0400 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 C28D2421D for ; Thu, 2 Nov 2023 11:02:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1698948041; 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=9TXakoAWW1FFOLF5UXdw93JMmC9MoRdLwbBdEicJ9T4=; b=b8tSO4DOpiAtp+BQHa2HQxD3sMHcEzp6G0PW+aiS1SbaAzJfItKvbpeOIoCuJNhPl4COfc geMiouJULondgjvcTIcLgz+MwtJhcZVP5Ttf0yCYK3Jk9nSpUz2VfN6+qOvBm1fgp7mFvV Pc5c3G1UACa/UwZY9miOC3prNio+y+0= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-139-v8GvlphcPDuUty5qc59mzw-1; Thu, 02 Nov 2023 14:00:39 -0400 X-MC-Unique: v8GvlphcPDuUty5qc59mzw-1 Received: by mail-wr1-f71.google.com with SMTP id ffacd0b85a97d-32f8c4e9b88so835472f8f.0 for ; Thu, 02 Nov 2023 11:00:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698948039; x=1699552839; 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=9TXakoAWW1FFOLF5UXdw93JMmC9MoRdLwbBdEicJ9T4=; b=AIwPxa41KG8YhS28YTuJbuY5H/PCFxRZKgHTA5pi35EntHysD4ay4OyYeXq80VZ83P O3JPxdlgrK6lRfTL20mn/ANX20jlkCG+VjTJ7XZ+0bQeSTADg5dPHzUu/APor11soELM ZNAglLbeWDtOuvdH22fQ7zWg67/Ij+X5j+sxyAfVNGxEPi38uBeCq5k63r86QdE9tFnp bcNH1WXQxcLWGwRYzfDOH5fQp/imM2XJd6m2hYCCR4VL6MWp8VFLpx33dm+GWxVbuEGG xhUS+w1kNcPKsVPaINXCeIGarIT/O9GYFLrSimd4y6my68lA6qrqGXq+DtTJtuTUnDdF f8pA== X-Gm-Message-State: AOJu0Yyi/nMLmlpjd1sRnbVlorqOH/ymPPWyxvD8akFe4gP9pNPsJwII KiA3cs8909zdKY+wlGmCL7uwRKVMhyIt+h2foOJi0+gSgrMbgrDuT/ZrYUGUI4yBrftdl5HUxoQ 2IoYfsEUpmx/16B7J+PIbrIZs X-Received: by 2002:adf:d1ca:0:b0:32f:89fb:771b with SMTP id b10-20020adfd1ca000000b0032f89fb771bmr298488wrd.4.1698948038782; Thu, 02 Nov 2023 11:00:38 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHQ+PseGXhaGK5KA47SlyvvRQ+IpK7jimMGqL/PtZUrchAkuXB/NyC2l+qCdJkE8Bvk3Naoiw== X-Received: by 2002:adf:d1ca:0:b0:32f:89fb:771b with SMTP id b10-20020adfd1ca000000b0032f89fb771bmr298468wrd.4.1698948038507; Thu, 02 Nov 2023 11:00:38 -0700 (PDT) Received: from starship ([89.237.99.95]) by smtp.gmail.com with ESMTPSA id l10-20020a1c790a000000b004063977eccesm3573161wme.42.2023.11.02.11.00.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Nov 2023 11:00:38 -0700 (PDT) Message-ID: <65781f864b94db127a7a17e52835326a8a6a9ea0.camel@redhat.com> Subject: Re: [PATCH 1/9] KVM: x86: SVM: Emulate reads and writes to shadow stack MSRs From: Maxim Levitsky To: John Allen , kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, pbonzini@redhat.com, weijiang.yang@intel.com, rick.p.edgecombe@intel.com, seanjc@google.com, x86@kernel.org, thomas.lendacky@amd.com, bp@alien8.de Date: Thu, 02 Nov 2023 20:00:36 +0200 In-Reply-To: <20231010200220.897953-2-john.allen@amd.com> References: <20231010200220.897953-1-john.allen@amd.com> <20231010200220.897953-2-john.allen@amd.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 Tue, 2023-10-10 at 20:02 +0000, John Allen wrote: > Set up interception of shadow stack MSRs. In the event that shadow stack > is unsupported on the host or the MSRs are otherwise inaccessible, the > interception code will return an error. In certain circumstances such as > host initiated MSR reads or writes, the interception code will get or > set the requested MSR value. > > Signed-off-by: John Allen > --- > arch/x86/kvm/svm/svm.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index f283eb47f6ac..6a0d225311bc 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -2859,6 +2859,15 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > if (guest_cpuid_is_intel(vcpu)) > msr_info->data |= (u64)svm->sysenter_esp_hi << 32; > break; > + case MSR_IA32_S_CET: > + msr_info->data = svm->vmcb->save.s_cet; > + break; > + case MSR_IA32_INT_SSP_TAB: > + msr_info->data = svm->vmcb->save.isst_addr; > + break; > + case MSR_KVM_SSP: > + msr_info->data = svm->vmcb->save.ssp; > + break; > case MSR_TSC_AUX: > msr_info->data = svm->tsc_aux; > break; > @@ -3085,6 +3094,15 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) > svm->vmcb01.ptr->save.sysenter_esp = (u32)data; > svm->sysenter_esp_hi = guest_cpuid_is_intel(vcpu) ? (data >> 32) : 0; > break; > + case MSR_IA32_S_CET: > + svm->vmcb->save.s_cet = data; > + break; > + case MSR_IA32_INT_SSP_TAB: > + svm->vmcb->save.isst_addr = data; > + break; > + case MSR_KVM_SSP: > + svm->vmcb->save.ssp = data; > + break; > case MSR_TSC_AUX: > /* > * TSC_AUX is usually changed only during boot and never read Looks good, except that if my complaint about turning the fake 'MSR_KVM_SSP' into a first class register with an ioctl to load/save it is accepted, then there will be a new vendor callback to read/write it instead of doing it in svm_get_msr/svm_set_msr. Besides this, Reviewed-by: Maxim Levitsky Best regards, Maxim Levitsky