From nobody Wed Dec 17 16:11:09 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 941D233F38B; Wed, 17 Dec 2025 10:12:26 +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=1765966348; cv=none; b=ryb+rcW6RZenQkk83G52pReoVqhC7XBZGC4rY/GY6vf4/wPC6iUboyFNXHs0XXEZhb4Kyoq4gkzhgJLVvbVV4py6zEvlreF0zeq6jsbR1STAFaUkUhvahYFU8zc8TEaKPg7yo+PdTOfD4PKE7OBAFrrCkiO5qcFv1w3hsd0d9sk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765966348; c=relaxed/simple; bh=KO1CwCDk1lTvyTqvVkkXC6wUZTm9F1Clk6BWzpay0es=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qN77c6/2eE+BZVwMMmcQzOHy6KA/I52JUaNkKLVXFCc1d+C57+IgjG2KyEuswQKh8BPUBy6RJf9gKKnw9p+7PJZOEL4gsRsqH2F3B+m/nWs4hJwN0uQ5TehZjcGLzQinrgq7BOS4RraeJjnOzVq2wi8W93SJiu/6CDVb1hk/4oU= 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 D8C211516; Wed, 17 Dec 2025 02:12:18 -0800 (PST) Received: from e122027.arm.com (unknown [10.57.45.201]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F2B303F73B; Wed, 17 Dec 2025 02:12:20 -0800 (PST) From: Steven Price To: kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Suzuki K Poulose , Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , 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 , Steven Price Subject: [PATCH v12 08/46] kvm: arm64: Don't expose unsupported capabilities for realm guests Date: Wed, 17 Dec 2025 10:10:45 +0000 Message-ID: <20251217101125.91098-9-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" From: Suzuki K Poulose RMM v1.0 provides no mechanism for the host to perform debug operations on the guest. So limit the extensions that are visible to an allowlist so that only those capabilities we can support are advertised. Signed-off-by: Suzuki K Poulose Signed-off-by: Steven Price --- Changes since v10: * Add a kvm_realm_ext_allowed() function which limits which extensions are exposed to an allowlist. This removes the need for special casing various extensions. Changes since v7: * Remove the helper functions and inline the kvm_is_realm() check with a ternary operator. * Rewrite the commit message to explain this patch. --- arch/arm64/kvm/arm.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 4ce3ad1d69b0..345d9f56e98e 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -310,6 +310,26 @@ static bool kvm_has_full_ptr_auth(void) (apa + api + apa3) =3D=3D 1); } =20 +static bool kvm_realm_ext_allowed(long ext) +{ + switch (ext) { + case KVM_CAP_IRQCHIP: + case KVM_CAP_ARM_PSCI: + case KVM_CAP_ARM_PSCI_0_2: + case KVM_CAP_NR_VCPUS: + case KVM_CAP_MAX_VCPUS: + case KVM_CAP_MAX_VCPU_ID: + case KVM_CAP_MSI_DEVID: + case KVM_CAP_ARM_VM_IPA_SIZE: + case KVM_CAP_ARM_PMU_V3: + case KVM_CAP_ARM_PTRAUTH_ADDRESS: + case KVM_CAP_ARM_PTRAUTH_GENERIC: + case KVM_CAP_ARM_RMI: + return true; + } + return false; +} + int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) { int r; @@ -317,6 +337,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long = ext) if (kvm && kvm_vm_is_protected(kvm) && !kvm_pvm_ext_allowed(ext)) return 0; =20 + if (kvm && kvm_is_realm(kvm) && !kvm_realm_ext_allowed(ext)) + return 0; + switch (ext) { case KVM_CAP_IRQCHIP: r =3D vgic_present; --=20 2.43.0