From patchwork Mon Feb 7 15:28:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 12737427 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4667BC433F5 for ; Mon, 7 Feb 2022 15:29:18 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 03CAB10E127; Mon, 7 Feb 2022 15:29:16 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0486310E2A8 for ; Mon, 7 Feb 2022 15:29:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644247754; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EQ3ltiA1zD8GMi+gBPOuvalM+7bzpftE5TYI4/s1Kfw=; b=Lg918s/tRX60Rc7ZhOApJBtERDG8itGceVDHFniF3Ne21VVWS7TxGBJZeJLgfVtF6VLvu9 qzWP8DIqbXp8Gw6BGfHbrQrOdI7CebFjNChsWY63mHK91nVjQgsnFy07FiVSoqEmjlZR3T LCiVLvy9v6cfxEyIzOdH+x4iaq+fD+M= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-110-A-kc9TDVMy6FspJpOB3tRw-1; Mon, 07 Feb 2022 10:29:11 -0500 X-MC-Unique: A-kc9TDVMy6FspJpOB3tRw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 607DC8710F8; Mon, 7 Feb 2022 15:29:07 +0000 (UTC) Received: from localhost.localdomain (unknown [10.40.192.15]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9C86B84D38; Mon, 7 Feb 2022 15:28:58 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Date: Mon, 7 Feb 2022 17:28:18 +0200 Message-Id: <20220207152847.836777-2-mlevitsk@redhat.com> In-Reply-To: <20220207152847.836777-1-mlevitsk@redhat.com> References: <20220207152847.836777-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Subject: [Intel-gfx] [PATCH 01/30] KVM: x86: SVM: don't passthrough SMAP/SMEP/PKE bits in !NPT && !gCR0.PG case X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Dave Hansen , Wanpeng Li , David Airlie , "Chang S. Bae" , "maintainer:X86 ARCHITECTURE 32-BIT AND 64-BIT" , "open list:X86 ARCHITECTURE 32-BIT AND 64-BIT" , Maxim Levitsky , Tony Luck , "open list:DRM DRIVERS" , Brijesh Singh , Paolo Bonzini , Vitaly Kuznetsov , Jim Mattson , "open list:INTEL GVT-g DRIVERS Intel GPU Virtualization" , "open list:INTEL DRM DRIVERS excluding Poulsbo, Moorestow..., Joerg Roedel , Borislav Petkov , Daniel Vetter , \"H. Peter Anvin\" , Ingo Molnar , Sean Christopherson , Joonas Lahtinen , Pawan Gupta , Thomas Gleixner , stable@vger.kernel.org" , Kan Liang Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" When the guest doesn't enable paging, and NPT/EPT is disabled, we use guest't paging CR3's as KVM's shadow paging pointer and we are technically in direct mode as if we were to use NPT/EPT. In direct mode we create SPTEs with user mode permissions because usually in the direct mode the NPT/EPT doesn't need to restrict access based on guest CPL (there are MBE/GMET extenstions for that but KVM doesn't use them). In this special "use guest paging as direct" mode however, and if CR4.SMAP/CR4.SMEP are enabled, that will make the CPU fault on each access and KVM will enter endless loop of page faults. Since page protection doesn't have any meaning in !PG case, just don't passthrough these bits. The fix is the same as was done for VMX in commit: commit 656ec4a4928a ("KVM: VMX: fix SMEP and SMAP without EPT") This fixes the boot of windows 10 without NPT for good. (Without this patch, BSP boots, but APs were stuck in endless loop of page faults, causing the VM boot with 1 CPU) Signed-off-by: Maxim Levitsky Cc: stable@vger.kernel.org --- arch/x86/kvm/svm/svm.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 975be872cd1a3..995c203a62fd9 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1596,6 +1596,7 @@ void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) { struct vcpu_svm *svm = to_svm(vcpu); u64 hcr0 = cr0; + bool old_paging = is_paging(vcpu); #ifdef CONFIG_X86_64 if (vcpu->arch.efer & EFER_LME && !vcpu->arch.guest_state_protected) { @@ -1612,8 +1613,11 @@ void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) #endif vcpu->arch.cr0 = cr0; - if (!npt_enabled) + if (!npt_enabled) { hcr0 |= X86_CR0_PG | X86_CR0_WP; + if (old_paging != is_paging(vcpu)) + svm_set_cr4(vcpu, kvm_read_cr4(vcpu)); + } /* * re-enable caching here because the QEMU bios @@ -1657,8 +1661,12 @@ void svm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) svm_flush_tlb_current(vcpu); vcpu->arch.cr4 = cr4; - if (!npt_enabled) + if (!npt_enabled) { cr4 |= X86_CR4_PAE; + + if (!is_paging(vcpu)) + cr4 &= ~(X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE); + } cr4 |= host_cr4_mce; to_svm(vcpu)->vmcb->save.cr4 = cr4; vmcb_mark_dirty(to_svm(vcpu)->vmcb, VMCB_CR);