From nobody Sat Feb 7 18:15:36 2026 Received: from out-181.mta0.migadu.com (out-181.mta0.migadu.com [91.218.175.181]) (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 03CF543E9CF for ; Fri, 6 Feb 2026 19:09:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.181 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770404983; cv=none; b=VPd0trjiLuIpCdss+P63DKpUt8MpPO8288xVtXSikouNO7a8Tm63naQhLsuZFuOJkmlScaWzkp31nBTfKpY3fKhv3chdh95gFGJBgRlme4gmqA4CPxAMQhqrCAiUwtUkLmyVKos0b/r2YH51FNhPDm+V0tDd6YlRZ1HyZQ9q/sA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770404983; c=relaxed/simple; bh=myzwwiuhbadCyZSw7HuAVfjih7JweD6SXt48MzjlC4A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=UUaovniVhlLC0B8YVo/lBIwJ1S72tL034kovsx56EFL8RUwFJIQRkEiPRc6XcWbne1HS7Umf3ougPO1CAo9QuKU0pByV5cpeN1RaJrEf5n10y1cDzVfCGoXztdJzv5+X2EDrqtOK4NCsy6umTI5RmYFqINdXKepnJxNNCZV1Ow4= 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=T7Rr8ibF; arc=none smtp.client-ip=91.218.175.181 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="T7Rr8ibF" 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=1770404981; 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=EG5LX6BdhVM8GYyf0Bk/7CQB4mY+IW3H5PUrABCxjTc=; b=T7Rr8ibFR44X8mefM5hzYRIf1QfZ6+9pXzWpwfKhwwuyixKX6SZ2VTGzIxHk8wUak6ldyU ogI9hmYe/L10uOredc20P1gcOjbtzhhOyXCrs0StSHCLVcNk84JWGe2Z/7LV/0zOerjDm7 x44zs1VO0SNT9y+UG3gp+Y2/TajFSpY= 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 v5 19/26] KVM: nSVM: Add missing consistency check for EFER, CR0, CR4, and CS Date: Fri, 6 Feb 2026 19:08:44 +0000 Message-ID: <20260206190851.860662-20-yosry.ahmed@linux.dev> In-Reply-To: <20260206190851.860662-1-yosry.ahmed@linux.dev> References: <20260206190851.860662-1-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: quoted-printable X-Migadu-Flow: FLOW_OUT 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. 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 ca2d1b1b8be6..90942c8c9d9d 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -397,6 +397,11 @@ 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->cr4 & X86_CR4_PAE) && + (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. */ @@ -492,6 +497,8 @@ 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 7629cb37c930..0a5d5a4453b7 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.rc2.204.g2597b5adb4-goog