From nobody Thu Apr 2 06:31:34 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4376135F5ED; Tue, 3 Mar 2026 00:34:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772498078; cv=none; b=rh4Xe+RNaEgK7suv996zR5px8R/DVxnTAF0NFu5MfaH5HpewIFV/RgNzWoS8ksMwEjOAgIp6Jpi3ZOQkgqGnUzV9q3JvjrLrnzOWlvzzqIEheHKoYpSklxd7jy7+iMPskw9DJjjzBGiuRLCELA5eTG+DFIpzE2nVqaAEib8Lvko= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772498078; c=relaxed/simple; bh=pIwNjczmYnEx1LxueriC9FIL1WKTRkr09sZcduektJA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=hPHMgKzMK9Jh6yggkPVP0kpJdPMSUHDcrvPP16S16F9Wyfq6/+bnAKSUPK6Wg/lma2xfyUVLaRR6z5CSwJnL+enAQDbI9risEXBuNAKsa4WncHcowykwytbxAJzKF0etI7CkfQ8GcvZ9ZbjBeDVIMFBEb9H3yprx5pscW64DyVE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oW9FlGC4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oW9FlGC4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA964C19423; Tue, 3 Mar 2026 00:34:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772498078; bh=pIwNjczmYnEx1LxueriC9FIL1WKTRkr09sZcduektJA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oW9FlGC45PZpaXjlcsBV9FcMpSFQZSxalnO2HaEgzIaaOkPG4Si4VbqvsCt9Ef9s0 p3nKyxbGxl55hlY2yXrL6SpOAtcaztbk2NED1B4m/Lx8ixakAw50N0V6XtXAYSPQnF pOxR/8VyDA2pNOLaVcyh8vyzgCpinZw6pAZEZZmsr6tdmn/HJ07YfdN2Mt5YQUJBzE z7d0bBsS/l3PjmpnqZ9JmWKQWrJLBnE9WOel+5QBsEA9kFMEqYJpPOsVTvyyzlt8Oy +JaUSmrm1qeFUsnAajBUg2XhZJQnPjmkk/jhVUN3u8iXLv6TzCIn/OIPRHIHImgAL+ 6Y18w6a+nSSIQ== From: Yosry Ahmed To: Sean Christopherson Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed , stable@vger.kernel.org Subject: [PATCH v7 16/26] KVM: nSVM: Add missing consistency check for EFER, CR0, CR4, and CS Date: Tue, 3 Mar 2026 00:34:10 +0000 Message-ID: <20260303003421.2185681-17-yosry@kernel.org> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog In-Reply-To: <20260303003421.2185681-1-yosry@kernel.org> References: <20260303003421.2185681-1-yosry@kernel.org> 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: quoted-printable According to the APM Volume #2, 15.5, Canonicalization and Consistency Checks (24593=E2=80=94Rev. 3.42=E2=80=94March 2024), the following conditio= n (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. In the list of consistency checks done when EFER.LME and CR0.PG are set, add a check that CS.L and CS.D are not both set, after the existing check that CR4.PAE is set. 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 | 6 ++++++ arch/x86/kvm/svm/svm.h | 1 + 2 files changed, 7 insertions(+) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 3aaa4f0bb31ab..93b3fab9b415d 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -392,6 +392,10 @@ static bool nested_vmcb_check_save(struct kvm_vcpu *vc= pu, CC(!(save->cr0 & X86_CR0_PE)) || CC(!kvm_vcpu_is_legal_cr3(vcpu, save->cr3))) return false; + + if (CC((save->cs.attrib & SVM_SELECTOR_L_MASK) && + (save->cs.attrib & SVM_SELECTOR_DB_MASK))) + return false; } =20 /* Note, SVM doesn't have any additional restrictions on CR4. */ @@ -487,6 +491,8 @@ static void __nested_copy_vmcb_save_to_cache(struct vmc= b_save_area_cached *to, * Copy only fields that are validated, as we need them * to avoid TOC/TOU races. */ + to->cs =3D from->cs; + to->efer =3D from->efer; to->cr0 =3D from->cr0; to->cr3 =3D from->cr3; diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 7629cb37c9302..0a5d5a4453b7e 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -140,6 +140,7 @@ struct kvm_vmcb_info { }; =20 struct vmcb_save_area_cached { + struct vmcb_seg cs; u64 efer; u64 cr4; u64 cr3; --=20 2.53.0.473.g4a7958ca14-goog