From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-183.mta0.migadu.com (out-183.mta0.migadu.com [91.218.175.183]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 579C6333443; Mon, 15 Dec 2025 19:29:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765826984; cv=none; b=dKk+ekhwQP8SOhHvMY9iXhn/kPUkGKHaPyHyRLLfKYNjVxWrMydfKjc0v4tBwC6IUjJklRj59KZRlRFgZSu9KCaoGw/SGX3unJmSRblcvUiJDlNMC9H4r12866IIrjsLph51asomnedMdgm3JVzlz/dzCgLojzeBKrel/BgpZ5s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765826984; c=relaxed/simple; bh=VArsy5o076aMKwJm/5njXI/zvbCDN7ca2ZZkciGEe78=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=luThC6Buzp18Z/bkm8EXTuRSS7nR71co2YA3j/pqMYuDZcFYDQSqiyJJpZ3bXZ3J2QAJW5vdULOZYpJD0Ls5OaWfKKjJErI1OWF/gu6lG/pYqooKO13w85tpdPRu8ZnqjMYplJ5i9NHE7bXXg2n7YIX4373LnYM1KjlPFihzv+U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=kiF+wlC6; arc=none smtp.client-ip=91.218.175.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="kiF+wlC6" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1765826975; 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=l7zScTR1o0gExk7JzozEx+BVqCR7gtfJ5p90v27YDmY=; b=kiF+wlC60Y4SdMPB6yREIynfbjJs0fIhc4K+4F7/bFX/2ZkrUdF7aEsHCVULCajFFvAMIl lb+Lz32s3Eu3D0QNgLuDI+0Z71X4Y2YVZEqV9dlY7t00Y8UAaizziPRKmHyDrK2BFv0idA FfzJg3Z7aC3UBTT/6j4SUz4xrT7VdJ4= From: Yosry Ahmed To: Paolo Bonzini , Sean Christopherson Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed , stable@vger.kernel.org Subject: [PATCH v3 18/26] KVM: nSVM: Add missing consistency check for EFER, CR0, CR4, and CS Date: Mon, 15 Dec 2025 19:27:13 +0000 Message-ID: <20251215192722.3654335-20-yosry.ahmed@linux.dev> In-Reply-To: <20251215192722.3654335-1-yosry.ahmed@linux.dev> References: <20251215192722.3654335-1-yosry.ahmed@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT According to the APM Volume #2, 15.5, Canonicalization and Consistency Checks (24593—Rev. 3.42—March 2024), the following condition (among others) results in a #VMEXIT with VMEXIT_INVALID (aka SVM_EXIT_ERR): EFER.LME, CR0.PG, CR4.PAE, CS.L, and CS.D are all non-zero. Add the missing consistency check. This is functionally a nop because the nested VMRUN results in SVM_EXIT_ERR in HW, which is forwarded to L1, but KVM makes all consistency checks before a VMRUN is actually attempted. Fixes: 3d6368ef580a ("KVM: SVM: Add VMRUN handler") Cc: stable@vger.kernel.org Signed-off-by: Yosry Ahmed --- arch/x86/kvm/svm/nested.c | 7 +++++++ arch/x86/kvm/svm/svm.h | 1 + 2 files changed, 8 insertions(+) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 5184e5ae8ccf..47d4316b126d 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -382,6 +382,11 @@ static bool nested_vmcb_check_save(struct kvm_vcpu *vcpu, CC(!(save->cr0 & X86_CR0_PE)) || CC(!kvm_vcpu_is_legal_cr3(vcpu, save->cr3))) return false; + + if (CC((save->cr4 & X86_CR4_PAE) && + (save->cs.attrib & SVM_SELECTOR_L_MASK) && + (save->cs.attrib & SVM_SELECTOR_DB_MASK))) + return false; } /* Note, SVM doesn't have any additional restrictions on CR4. */ @@ -458,6 +463,8 @@ static void __nested_copy_vmcb_save_to_cache(struct vmcb_save_area_cached *to, * Copy only fields that are validated, as we need them * to avoid TOC/TOU races. */ + to->cs = from->cs; + to->efer = from->efer; to->cr0 = from->cr0; to->cr3 = from->cr3; diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 9aa60924623f..d0de7d390889 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -139,6 +139,7 @@ struct kvm_vmcb_info { }; struct vmcb_save_area_cached { + struct vmcb_seg cs; u64 efer; u64 cr4; u64 cr3; -- 2.52.0.239.gd5f0c6e74e-goog