From patchwork Fri Oct 4 15:27:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Price X-Patchwork-Id: 13822814 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 08E32CF8850 for ; Fri, 4 Oct 2024 17:09:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jFMn8jucdrTdFa34phKRcxiNF2lkqR8DzgqVwRPgId4=; b=Y+1DxLTgIEyihXCYIUbutcchfJ 3pKefKfTTx6nO3si+TbD2/LxA9vUSc0qfo5lXK084JkmaGV6BqFZ1LhnSOkxLt8IRC519ZkNKvyiN ClTb9qTQiVvt1ybWua5cMqgSqp5YLwKihQ4nFni8mNrmgtfO/idFV0rDXGiZa9n9JNs5OR8YeTY/O ODlianOVNfXCJL4LW2+vjPIf9UZ3ySHeWq1382sRbhRqEK1JrVWL1prTtwGHcI5fnL3XMvqg2Z1Sy HXcwd4lHdDykIMgHfDUI5K8G0ca2hEPXGCHGG3g4VmkmEeTjTztsFMwkxkIifrPVm3antuTkMZrME +FdmcHxg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1swlo5-0000000DPnd-1jlV; Fri, 04 Oct 2024 17:09:33 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1swkG0-0000000D0P6-1g1D for linux-arm-kernel@lists.infradead.org; Fri, 04 Oct 2024 15:30:18 +0000 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 6CF92152B; Fri, 4 Oct 2024 08:30:45 -0700 (PDT) Received: from e122027.cambridge.arm.com (unknown [10.1.25.25]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 06CF23F640; Fri, 4 Oct 2024 08:30:11 -0700 (PDT) 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 v5 26/43] arm64: Don't expose stolen time for realm guests Date: Fri, 4 Oct 2024 16:27:47 +0100 Message-Id: <20241004152804.72508-27-steven.price@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241004152804.72508-1-steven.price@arm.com> References: <20241004152804.72508-1-steven.price@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241004_083016_689769_A08DB3EF X-CRM114-Status: GOOD ( 10.34 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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. Signed-off-by: Steven Price Reviewed-by: Suzuki K Poulose --- 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 075c1b7306ff..bde1e0f23258 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -433,7 +433,10 @@ 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);