From nobody Thu Dec 18 00:25:35 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 842EE3557F6; Wed, 17 Dec 2025 10:14:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765966471; cv=none; b=FomvVpI1zssfok5VYO5bPxunqvyAFGNM8VHdFlTLZfIBp/P3hjtPLjVm9rvfXmDqecfHDxXAuIj2uMR916bVDgAYqBZDasT3KZpZhKjygAax8iZaksQ4gpf6i41KfujNiZVOkL2jfQGJdL444HnAI79k7P/sIlUZE/frz7DIeQg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765966471; c=relaxed/simple; bh=rdPt8xNcSUP/UQ/AbU+k+qgPVbeD+q1e322e9EPsXMk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KZKJ9rozFeR00HCUpWNI9h9/WGVzXve9QB95/3YJHq3sdLXFiK7+Y7bToRCQcUqQItjjaCcf8nGXuFhzm+fCEFg3VG3YaoNQaWuoTHQEAgBGuY/DCKKaEFFUThqYSJwK5EE1zjzG1aEeqRHG0PocsudBJEvxrHMyCtiwXKfDUGY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 097FD168F; Wed, 17 Dec 2025 02:14:23 -0800 (PST) Received: from e122027.arm.com (unknown [10.57.45.201]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 731543F73B; Wed, 17 Dec 2025 02:14:26 -0800 (PST) From: Steven Price To: kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Steven Price , Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve Subject: [PATCH v12 34/46] arm64: RMI: Prevent Device mappings for Realms Date: Wed, 17 Dec 2025 10:11:11 +0000 Message-ID: <20251217101125.91098-35-steven.price@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251217101125.91098-1-steven.price@arm.com> References: <20251217101125.91098-1-steven.price@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Physical device assignment is not supported by RMM v1.0, so it doesn't make much sense to allow device mappings within the realm. Prevent them when the guest is a realm. Signed-off-by: Steven Price --- Changes from v6: * Fix the check in user_mem_abort() to prevent all pages that are not guest_memfd() from being mapped into the protected half of the IPA. Changes from v5: * Also prevent accesses in user_mem_abort() --- arch/arm64/kvm/mmu.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index c30d7be27361..e71ef41fb6b1 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1221,6 +1221,10 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr= _t guest_ipa, if (is_protected_kvm_enabled()) return -EPERM; =20 + /* We don't support mapping special pages into a Realm */ + if (kvm_is_realm(kvm)) + return -EPERM; + size +=3D offset_in_page(guest_ipa); guest_ipa &=3D PAGE_MASK; =20 @@ -1955,6 +1959,15 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phy= s_addr_t fault_ipa, return ret; } =20 + /* + * For now we shouldn't be hitting protected addresses because they are + * handled in private_memslot_fault(). In the future this check may be + * relaxed to support e.g. protected devices. + */ + if (vcpu_is_rec(vcpu) && + kvm_gpa_from_fault(kvm, fault_ipa) =3D=3D fault_ipa) + return -EINVAL; + if (nested) adjust_nested_fault_perms(nested, &prot, &writable); =20 --=20 2.43.0