From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1C0A5433051; Mon, 5 Oct 2026 09:09:10 +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=1791191351; cv=none; b=EiXLfKQKmRbxH/HuQJLmZLJV93oaYS5Wxy7Kdiy+bzDFHJD6u2qxIt9BjxmR+2Cjkh1cr57d9FmWhPo/AtOE8/SFL0QXmz72ztLuSZfBID6DZX9yJkndrjiclmEhPnSkIGJmzuh+X2dy6OGT5ivH0Nd4hXmXy0FpBOH88Fze/Xs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791191351; c=relaxed/simple; bh=lpi/z5z9I7QN6X4z0f7ezeP7dj+LvQGbCZME+zU+F/k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BlcWgxRGAsdaKpwIcb1rDSEGA5DHA7COn8W8SdiJNkTESvJ17yfE0y5QW/UPQWYRRmiWMTx1QzBBEhTBTvHV9PxlLxySAxa4kwR/L/tgGqnCQE21yGR+pPj+zUU04s3UgTnoNYxpVE55UninOM9jBibZqb5JnRvyT4Fd2oCdUoE= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=QdwfOA5W; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="QdwfOA5W" 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 22DD2152B; Mon, 5 Oct 2026 02:09:06 -0700 (PDT) Received: from ewhatever.cambridge.arm.com (ewhatever.cambridge.arm.com [10.2.197.99]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 852A63F66F; Mon, 5 Oct 2026 02:09:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1791191349; bh=lpi/z5z9I7QN6X4z0f7ezeP7dj+LvQGbCZME+zU+F/k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QdwfOA5W/C4HUeVUSHag9Yf9OtZWgsmNLUrGcHZqLXhW3JbEgr2dNGANFc9t8NgJo cWwTQaWW3RTgcULkQGzdubSJHcC5f2nkpfkTrtRVTIHCF35zeejFRue5MqFdNw6VE7 FNb0AslsIYcU1GqLiFjWSV1Q4bmb/xY+iLmqKEaA= From: Suzuki K Poulose To: kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: maz@kernel.org, will@kernel.org, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, steven.price@arm.com, aneesh.kumar@kernel.org, oupton@kernel.org, gshan@redhat.com, joey.gouly@arm.com, tabba@google.com, yuzenghui@huawei.com, linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com, sdonthineni@nvidia.com, alpergun@google.com, fj0570is@fujitsu.com, WeiLin.Chang@arm.com, lpieralisi@kernel.org, enju.kohei@fujitsu.com, sudeep.holla@arm.com, jonathan.cameron@oss.qualcomm.com, Suzuki K Poulose Subject: [PATCH v22 19/23] KVM: arm64: CCA: Don't expose unsupported capabilities for realm guests Date: Mon, 5 Oct 2026 10:07:50 +0100 Message-ID: <20261005090754.2140522-20-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261005090754.2140522-1-suzuki.poulose@arm.com> References: <20261005090754.2140522-1-suzuki.poulose@arm.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Limit the capabilities that are allowed for Realm VMs. Similarly block the vm_ioctls backed by the capabilities. Repurpose the kvm_pkvm_ioctl_allowed() to support both pKVM and Realm ioctls. Rename the helper to kvm_vm_ioctl_allowed() and move it into arch/arm64/kvm/arm.c. Also add a generic kvm_vm_ext_allowed() to handle pKVM and Realm capability filtering and route them accordingly. Signed-off-by: Suzuki K Poulose --- Changes since v21: - Drop WARN_ON_ONCE() from kvm_vm_ioctl_allowed to synchronise with what is in -rc5 and make the conflict resolution easier. --- arch/arm64/include/asm/kvm_pkvm.h | 19 ------------ arch/arm64/include/asm/kvm_rmi.h | 24 +++++++++++++++ arch/arm64/kvm/arm.c | 49 +++++++++++++++++++++++++++++-- 3 files changed, 70 insertions(+), 22 deletions(-) diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h index 2addc37c500e1..b833abb1be9c7 100644 --- a/arch/arm64/include/asm/kvm_pkvm.h +++ b/arch/arm64/include/asm/kvm_pkvm.h @@ -53,25 +53,6 @@ static inline bool kvm_pkvm_ext_allowed(struct kvm *kvm, long ext) } } -/* - * Check whether the KVM VM IOCTL is allowed in pKVM. - * - * Certain features are allowed only for non-protected VMs in pKVM, which is why - * this takes the VM (kvm) as a parameter. - */ -static inline bool kvm_pkvm_ioctl_allowed(struct kvm *kvm, unsigned int ioctl) -{ - long ext; - int r; - - r = kvm_get_cap_for_kvm_ioctl(ioctl, &ext); - - if (WARN_ON_ONCE(r < 0)) - return false; - - return kvm_pkvm_ext_allowed(kvm, ext); -} - extern struct memblock_region kvm_nvhe_sym(hyp_memory)[]; extern unsigned int kvm_nvhe_sym(hyp_memblock_nr); diff --git a/arch/arm64/include/asm/kvm_rmi.h b/arch/arm64/include/asm/kvm_rmi.h index 44f5c75a27b5b..ea1450e0c8619 100644 --- a/arch/arm64/include/asm/kvm_rmi.h +++ b/arch/arm64/include/asm/kvm_rmi.h @@ -6,6 +6,8 @@ #ifndef __ASM_KVM_RMI_H #define __ASM_KVM_RMI_H +#include + /** * enum realm_state - State of a Realm * @@ -58,4 +60,26 @@ struct realm { void kvm_init_rmi(void); +static inline 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_DEVICE_CTRL: + 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_SVE: + case KVM_CAP_ONE_REG: + case KVM_CAP_ARM_PTRAUTH_ADDRESS: + case KVM_CAP_ARM_PTRAUTH_GENERIC: + case KVM_CAP_SYNC_MMU: + return true; + } + return false; +} + #endif /* __ASM_KVM_RMI_H */ diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 37ef2ba4e43e2..fe707a0c47308 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -136,6 +136,49 @@ int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE; } +static inline bool kvm_vm_ext_allowed(struct kvm *kvm, long ext) +{ + /* + * We could be called with kvm as NULL, so can't use kvm_vm_* for pKVM + * flavors + */ + if (is_protected_kvm_enabled()) + return kvm_pkvm_ext_allowed(kvm, ext); + else if (kvm && kvm_vm_is_realm(kvm)) + return kvm_realm_ext_allowed(ext); + else + return true; +} + +/* + * Check whether the KVM VM IOCTL is allowed. For pKVM and Realm VMs, certain + * ioctls are not allowed. Further, certain features are allowed only for + * non-protected VMs in pKVM. + */ +static inline bool kvm_vm_ioctl_allowed(struct kvm *kvm, unsigned int ioctl) +{ + long ext; + int r; + + /* + * We are guaranteed to be called with a valid kvm instance, as the + * only caller is kvm_arch_vm_ioctl(). Catch any deviations, as we + * rely on the kvm instance below. + */ + if (WARN_ON_ONCE(!kvm)) + return false; + + /* Cover both pKVM host and Realm VMs */ + if (!kvm_vm_hyp_is_distrusting(kvm)) + return true; + + r = kvm_get_cap_for_kvm_ioctl(ioctl, &ext); + if (r < 0) + return false; + + return kvm_vm_ext_allowed(kvm, ext); +} + int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) { @@ -144,7 +187,7 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, if (cap->flags) return -EINVAL; - if (is_protected_kvm_enabled() && !kvm_pkvm_ext_allowed(kvm, cap->cap)) + if (!kvm_vm_ext_allowed(kvm, cap->cap)) return -EINVAL; switch (cap->cap) { @@ -403,7 +446,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) { int r; - if (is_protected_kvm_enabled() && !kvm_pkvm_ext_allowed(kvm, ext)) + if (!kvm_vm_ext_allowed(kvm, ext)) return 0; switch (ext) { @@ -2146,7 +2189,7 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) void __user *argp = (void __user *)arg; struct kvm_device_attr attr; - if (is_protected_kvm_enabled() && !kvm_pkvm_ioctl_allowed(kvm, ioctl)) + if (!kvm_vm_ioctl_allowed(kvm, ioctl)) return -EINVAL; switch (ioctl) { -- 2.43.0