From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7FC931EB5D4 for ; Tue, 4 Mar 2025 05:42:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741066954; cv=none; b=oayo301ho9Z2CcsXqbEOXDercpnOTebVAF8Q/xG4i+1Bkeu1IVVQ2Tg5uHypMcrlmfbBp+vJ3Lz4+PXyxv5SXrkkYcktICiO0ku7P/wn2qyP2xKK4UMDu6bQqKB45KCD8RjbrTyrDhrt9MPdntHY7tioXLi1MnpGPWBGxK1QseQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741066954; c=relaxed/simple; bh=NDiYP2H5hYhH1uYD5YWszI9pFiidjNwL9HaA1erSaWE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OCN6GawYfaN465Zj6eblduiqvAO65Vcrq5r7YCCcQPT2N3UEI7uB3cTepK/tTAKJig/Dh+g54/cZbuN7Xdc1VrZwANPZAzRsrNYzPHs96cvqIYbAaPo9YBtcGybZhF4vvtIbBcBvkHQEDX7TfkPF0Fj0q1mO9i0jHMhdd4d/BC0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=EIi4eFhe; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="EIi4eFhe" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741066951; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hbTXak4fZZgmEd0OOFQqdTCiZzdYnXYZunDKpr8m1kE=; b=EIi4eFhepeOjmAxiwmZv7Pd7FJJgu0kNcQzhNCi0eZDZ5wPQ/0Jrngp+r4qsZlXRqI+615 VAWuGZdZiERLFeBnUohek0ArYaDCGfu8xXqx7XBIu8VRaoWLlTQ6JdsAE9gR7PrMGFmdvM mArm4CSmrQ2aXezhSWJg5LYkjEEr0mA= Received: from mail-pj1-f71.google.com (mail-pj1-f71.google.com [209.85.216.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-644-djIJGSKROQCY-MZg6BfVWA-1; Tue, 04 Mar 2025 00:42:20 -0500 X-MC-Unique: djIJGSKROQCY-MZg6BfVWA-1 X-Mimecast-MFC-AGG-ID: djIJGSKROQCY-MZg6BfVWA_1741066939 Received: by mail-pj1-f71.google.com with SMTP id 98e67ed59e1d1-2f816a85facso10110073a91.3 for ; Mon, 03 Mar 2025 21:42:20 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741066939; x=1741671739; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=hbTXak4fZZgmEd0OOFQqdTCiZzdYnXYZunDKpr8m1kE=; b=tPDTRJ8ku4RbpSEp0y7/EW986CuBkqRtF/Lq6MNcU5c7DR/lIEPHnN+7mKgZisFLBb 5K7GVlmeqXCWfB7Xaw9c8SKOPYJPKDxDAauDpwth1vUr6aOGxgVg3IJUexgcZwpr5QPg nGwTBMQzQUX/YQkdhY7FUQff7UxeVBDSYqvLxGi4Xjg6IUp1tx/Th/dVQgWQ6vT9p23R zqLCk5HFJMf6r9xzNAuqide+QO3iIIB9ML9IpY4OkwfH/GBnPFDlUsi/6wfxQ/hPVt3X 0AFnlIfXu4gwW6r46TbI4iM7RBp4+ICF1frBsuYaFHrxV20dg+dUKuyznaKywRyerNFO rwLw== X-Forwarded-Encrypted: i=1; AJvYcCXt/hM0zNENohcw5RVbddtxGQmjCws9Ed4XZbQ8xV9ebqYFrKNV7DWP4J/ugmoVwM+aRc2JWy0=@lists.linux.dev X-Gm-Message-State: AOJu0Yy0prxw9h6dJjurwpW/b9APfbuNazjBY+fMszxphRu7QDf+ZReA kXKs8d2bjoNl5q6dsGYv1p9ypG1bJbm7/eNl2yCQIlSFumlcO8gxILOvi9DfuiBA0oFjZ5TvNlQ MMmXFZ9PWSanrCcB7a/1Gkd9XxKa53/4o2oWOFhY3wkcXtwvilXUGEQ== X-Gm-Gg: ASbGnctt/t3bXoD5f4bPzfmGK1hchcgrYhPyrQcfCFB69QyJdgElvSiknJmykQGEN6d kgxbn2i7MXoXL60JF52VRQi1N8/f2X3bXM3zb6FE9ml8/xy/uMiA1aqhzLr6bjtRpRWKOjdtlYW eGHDq+nU00MPiIxBV4/cNXZv2rjwsgg37pV4ODSqRDHJXkRysHd19KoyfDeKOucW7QPFWYSmSEL L57yDih985ObOAMZMYwjXHldLz1Ji03Jjp8sQOhPLe0OJcXBHgyHsLxLuAj+VQLrcIWWS3wy4V6 If+kxIArHesBU4JdeQ== X-Received: by 2002:a05:6a20:c781:b0:1ee:e8c4:e1b6 with SMTP id adf61e73a8af0-1f2f4e01578mr26530451637.33.1741066939185; Mon, 03 Mar 2025 21:42:19 -0800 (PST) X-Google-Smtp-Source: AGHT+IHurZweDDClFEM+EDFVGKyToeXZSnslvrdiIY31gYPFZM1mfyMjnp3vImA6Ky+0fKgY2QYszg== X-Received: by 2002:a05:6a20:c781:b0:1ee:e8c4:e1b6 with SMTP id adf61e73a8af0-1f2f4e01578mr26530433637.33.1741066938923; Mon, 03 Mar 2025 21:42:18 -0800 (PST) Received: from [192.168.68.55] ([180.233.125.164]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-af075209ba3sm5804806a12.29.2025.03.03.21.42.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 03 Mar 2025 21:42:18 -0800 (PST) Message-ID: Date: Tue, 4 Mar 2025 15:42:10 +1000 Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 26/45] arm64: Don't expose stolen time for realm guests To: Steven Price , kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: 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 , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" References: <20250213161426.102987-1-steven.price@arm.com> <20250213161426.102987-27-steven.price@arm.com> From: Gavin Shan In-Reply-To: <20250213161426.102987-27-steven.price@arm.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: DB8sLz4zlVtpfzOeoz-mTWhWOhvLJYaFI9tu7R9YbiQ_1741066939 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2/14/25 2:14 AM, Steven Price wrote: > 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 > --- > arch/arm64/kvm/arm.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > With Documentation/virt/kvm/api.rst updated: Reviewed-by: Gavin Shan > 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);