From patchwork Thu Feb 13 16:14:06 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Price X-Patchwork-Id: 13973622 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A735F283058; Thu, 13 Feb 2025 16:16:40 +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=1739463402; cv=none; b=kEYLukmPb5oPAef7ZeReE0h/cZrJfuPbDGDhsfqGpaoMcf1aSzP68WikOW8xcnVbGZE8zOt7o222CPFE9Yir0e9C3Q7DQ5JkQDYvfY7u6JwRiM6CBpCsYNSNvRv2qn1niSsXoqYQyQqmepFO7gqvj69CxmHEz2v5j3J/EanTH20= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739463402; c=relaxed/simple; bh=5/Wv4roDFR5pN7vczGfekW5rqfIGe4zsbFQv+4bSHIc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UDml4NjbT/sd+lDOFPvuZsYxhRZxP6620QOP/p0IWdSLp4pPzcYPsuOjThn8sB8QCuC9IUQRWHT2C9BBzxjiEorIGtojSJmoO1ZTEK8JgbN0Wx8AtESNRf5+KZl6hq69mUPHCGzEVqyt0MspMlza+5sgLjiVz0y1GmddosayfUo= 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 A441526BA; Thu, 13 Feb 2025 08:17:00 -0800 (PST) Received: from e122027.cambridge.arm.com (e122027.cambridge.arm.com [10.1.32.44]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 875823F6A8; Thu, 13 Feb 2025 08:16:35 -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" Subject: [PATCH v7 26/45] arm64: Don't expose stolen time for realm guests Date: Thu, 13 Feb 2025 16:14:06 +0000 Message-ID: <20250213161426.102987-27-steven.price@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250213161426.102987-1-steven.price@arm.com> References: <20250213161426.102987-1-steven.price@arm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 It doesn't make much sense as a realm guest wouldn't want to trust the host. It will also need some extra work to ensure that KVM will only attempt to write into a shared memory region. So for now just disable it. Reviewed-by: Suzuki K Poulose Signed-off-by: Steven Price Reviewed-by: Gavin Shan --- arch/arm64/kvm/arm.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index a6718dec00c9..79d541c95bfb 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -403,7 +403,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = system_supports_mte(); break; case KVM_CAP_STEAL_TIME: - r = kvm_arm_pvtime_supported(); + if (kvm_is_realm(kvm)) + r = 0; + else + r = kvm_arm_pvtime_supported(); break; case KVM_CAP_ARM_EL1_32BIT: r = cpus_have_final_cap(ARM64_HAS_32BIT_EL1);