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 0A4E4411FB8; Mon, 3 Aug 2026 13:47:46 +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=1785764868; cv=none; b=oBb910zwZ/xpmqKuAZCbIeSnlsaWmNz+fn+a47RfrgSXFuu6vSMHLKy9+SvadkyoKrZnHg7HqNzTatjaj2lCnVUodCy47sE6vA5Nij97kZtxtVLovHw508AX0l8nFn/5mcnJvfyD+5xGxwLQkD8n9BMYMt1eOuHqSgQxND0zoZU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785764868; c=relaxed/simple; bh=hU5/Y8gLAYSgHVaaIBAsTIEwnwJD0RpetBq00JLKOGU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Owq2nJjq89b1WvcY2A6p8ubsAWE+uXi/Ytl0jT+MWBwLlvEPZJ55q5N8yfLWDfIcRWbpMaFe5GVzTllM3AM98EPv7x8Y4TNNwi8IaZQMm6cGDPzwhJri/zXESfhKY2VcqjErTnIXXvRFgbVFJLfbZNx+15UY+5kpC/w5TI9LFBM= 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=EqPEZkcE; 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="EqPEZkcE" 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 656931476; Mon, 3 Aug 2026 06:47:42 -0700 (PDT) Received: from e122027.cambridge.arm.com (e122027.cambridge.arm.com [10.1.25.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B81D03F66F; Mon, 3 Aug 2026 06:47:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785764866; bh=hU5/Y8gLAYSgHVaaIBAsTIEwnwJD0RpetBq00JLKOGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EqPEZkcECjXMW/VhDiaE+juIi+dG8W9nNkF9DspL9f2NlLZ43EJqeEQim6ialXL4w FlZ1572dutPCpiphYSWqn+cTBE5ZA8q66IxT8CVQCvY+uOj/OyA6HspeF9UpttJ+CB RwogHDCHvHnoka54u8OW8QPpszwgy5yfxCARZVd4= 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 , WeiLin.Chang@arm.com, Lorenzo Pieralisi Subject: [PATCH v16 44/45] KVM: arm64: CCA: Require ICH_HCR_EL2.TDIR for realms Date: Mon, 3 Aug 2026 14:44:00 +0100 Message-ID: <20260803134403.80630-45-steven.price@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260803134403.80630-1-steven.price@arm.com> References: <20260803134403.80630-1-steven.price@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 KVM advertises realm support when the RMM is available, and allows userspace to create a VM with KVM_VM_TYPE_ARM_REALM on that basis. On CPUs that lack ICH_HCR_EL2.TDIR, KVM uses ICH_HCR_EL2.TC for normal guests so that ICC_DIR_EL1 is still trapped via the common GICv3 CPU interface trap. Realms cannot rely on the normal hyp-side trap handling for that fallback, so advertising RMI support on such systems lets userspace create a realm that cannot safely run. Require the finalized ARM64_HAS_ICH_HCR_EL2_TDIR capability when reporting KVM_CAP_ARM_RMI and when accepting KVM_VM_TYPE_ARM_REALM. This leaves normal VM creation unchanged on systems that need the TC workaround. Signed-off-by: Steven Price --- New patch for v16 --- arch/arm64/kvm/arm.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index fd4e13ff17cf..7edc572dd8ab 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -125,6 +125,12 @@ static bool vgic_present, kvm_arm_initialised; static DEFINE_PER_CPU(unsigned char, kvm_hyp_initialized); +static bool kvm_arm_rmi_supported(void) +{ + return static_key_enabled(&kvm_rmi_is_available) && + cpus_have_final_cap(ARM64_HAS_ICH_HCR_EL2_TDIR); +} + bool is_kvm_arm_initialised(void) { return kvm_arm_initialised; @@ -256,7 +262,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) return -EINVAL; if (type & KVM_VM_TYPE_ARM_REALM) { - if (!static_branch_unlikely(&kvm_rmi_is_available)) + if (!kvm_arm_rmi_supported()) return -EINVAL; kvm_set_realm_state(kvm, REALM_STATE_NONE); kvm->arch.is_realm = true; @@ -537,7 +543,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = kvm_supports_cacheable_pfnmap(); break; case KVM_CAP_ARM_RMI: - r = static_key_enabled(&kvm_rmi_is_available); + r = kvm_arm_rmi_supported(); break; default: -- 2.43.0