From patchwork Wed Aug 21 15:38:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Price X-Patchwork-Id: 13771861 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 1F52FC52D6F for ; Wed, 21 Aug 2024 15:59:04 +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=gY4MGJwpnecas0wfOWoZI8eTYO8WWECju66xC5rCu8I=; b=fbXs2xddFnWon7LLF0d76ac3+d rg9uXgXC+ibTWdKfdmgwV+B4L99J4ibpiL3a5SIOf6oi/zrn5Tp/IUl/OAoaxVOZ9rx6ltKsS4zO1 sYSK+7DwO6Wtk+OohYFVXnta07DLYUIGMIE34/DiOAlV6PYGv/3KoVQtU+v2AUz+W2cYM9+k1GAHM ZhtGdlYCgVGmoyjA24GG5ITCQrIVqMwUC2K8uRvg21s8imLTbw1K37bqWSShIDvwrjXAHEJRfvA3d lpgEblnPjycRDKFejeJp79TTEuijDh8TKz1n2M4J3mDTXJg+DBDWZAGf0ubmSrpiSdiqEhAkxHWpp 2/58XzqQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sgnjW-00000009dcy-2SjZ; Wed, 21 Aug 2024 15:58:50 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sgnRx-00000009XSM-1drb for linux-arm-kernel@lists.infradead.org; Wed, 21 Aug 2024 15:40:42 +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 222D9152B; Wed, 21 Aug 2024 08:41:07 -0700 (PDT) Received: from e122027.cambridge.arm.com (e122027.cambridge.arm.com [10.1.37.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 065403F73B; Wed, 21 Aug 2024 08:40:37 -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 Subject: [PATCH v4 26/43] arm64: Don't expose stolen time for realm guests Date: Wed, 21 Aug 2024 16:38:27 +0100 Message-Id: <20240821153844.60084-27-steven.price@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240821153844.60084-1-steven.price@arm.com> References: <20240821153844.60084-1-steven.price@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240821_084041_494379_C29EAB04 X-CRM114-Status: GOOD ( 10.39 ) 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 --- 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 c57ed4f41bbc..2d7cbd4a2483 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -429,7 +429,10 @@ 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);