From patchwork Fri Jun 28 06:04:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shaoqin Huang X-Patchwork-Id: 13715494 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 D1B9FC2BBCA for ; Fri, 28 Jun 2024 06:05:37 +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: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:In-Reply-To:References:List-Owner; bh=ajvn4ITctkTMolN6abYxpt2/qWjVElb6xUSFcHxU6sg=; b=tE+w5j74KCswhffWBdFSmxV9hv U3lPUkmsJgKV7Cd98RaDexbyf+AqLUz3j6dubAN8+wxNSAv17M8UMMcRp3zdqLaqLJkPtFTXjwfgw JpPwhAMk9zk10Yvlc8MGTYRepfh8ILB313xuqSM7lBSstm5WElT5todDtoP42TZwrHZIbzjvqXZJl +hqsSuOHKPADM/iR/bHcu7aixFaYEeaZBK8TG3UbDSPPMt9JUXi0hJ8xm5zW2ZM7vuV33nJWEDdkS QdyMOhhL+vWU88rT/LKrZncQ4IALGkNc4DRQR49pUCuYLv3zltrJR8Klp3ZC6sdCGW2XHGoxXBmkP kkeZu7ew==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sN4jb-0000000ChXj-4AqK; Fri, 28 Jun 2024 06:05:23 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sN4jQ-0000000ChTA-1z24 for linux-arm-kernel@lists.infradead.org; Fri, 28 Jun 2024 06:05:16 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1719554709; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=ajvn4ITctkTMolN6abYxpt2/qWjVElb6xUSFcHxU6sg=; b=JtdGV2u+8g8Kc1ujLZhReX8T3pOeq5bzZd2uvPD2u5hgxvkPA5Wmtg5s7UdKujzrMqral4 BGE2OIz0LD/vdaCwQ2QYAuvY0jPxy0sJe0XblPYPyTa8ypJgqZigz8qVdulMBNjFt5fxX8 wuRLfcDD4adMQ2NoASldHu99357Vbns= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-554-Uu0m_sE3NF6Jx4ije6529w-1; Fri, 28 Jun 2024 02:05:05 -0400 X-MC-Unique: Uu0m_sE3NF6Jx4ije6529w-1 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5C1E91955DA6; Fri, 28 Jun 2024 06:05:03 +0000 (UTC) Received: from virt-mtcollins-01.lab.eng.rdu2.redhat.com (virt-mtcollins-01.lab.eng.rdu2.redhat.com [10.8.1.196]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 0819419560A3; Fri, 28 Jun 2024 06:04:59 +0000 (UTC) From: Shaoqin Huang To: Oliver Upton , Marc Zyngier , kvmarm@lists.linux.dev Cc: Shaoqin Huang , Catalin Marinas , James Morse , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Paolo Bonzini , Shuah Khan , Suzuki K Poulose , Will Deacon , Zenghui Yu Subject: [PATCH v3 0/2] Allow userspace to change ID_AA64PFR1_EL1 Date: Fri, 28 Jun 2024 02:04:50 -0400 Message-Id: <20240628060454.1936886-1-shahuang@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240627_230512_610739_7B51FAA7 X-CRM114-Status: GOOD ( 17.28 ) 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 Allow userspace to change the guest-visible value of the register with some severe limitation: - No changes to features not virtualized by KVM (MPAM_frac, RAS_frac, SME, RNDP_trap). - No changes to features (CSV2_frac, NMI, MTE_frac, GCS, THE, MTEX, DF2, PFAR) which haven't been added into the ftr_id_aa64pfr1[]. Because the struct arm64_ftr_bits definition for each feature in the ftr_id_aa64pfr1[] is used by arm64_check_features. If they're not existing in the ftr_id_aa64pfr1[], the for loop won't check the if the new_val is safe for those features. For the question why can't those fields be hidden depending on the VM configuration? I don't find there is the related VM configuration, maybe we should add the new VM configuration? I'm not sure I'm right, so if there're any problems please help to point out and I will fix them. Also add the selftest for it. Changelog: ---------- v2 -> v3: * Give more description about why only part of the fields can be writable. * Updated the writable mask by referring the latest ARM spec. v1 -> v2: * Tackling the full register instead of single field. * Changing the patch title and commit message. RFCv1 -> v1: * Fix the compilation error. * Delete the machine specific information and make the description more generable. RFCv1: https://lore.kernel.org/all/20240612023553.127813-1-shahuang@redhat.com/ v1: https://lore.kernel.org/all/20240617075131.1006173-1-shahuang@redhat.com/ v2: https://lore.kernel.org/all/20240618063808.1040085-1-shahuang@redhat.com/ Shaoqin Huang (2): KVM: arm64: Allow userspace to change ID_AA64PFR1_EL1 KVM: selftests: aarch64: Add writable test for ID_AA64PFR1_EL1 arch/arm64/kvm/sys_regs.c | 4 +++- tools/testing/selftests/kvm/aarch64/set_id_regs.c | 8 ++++++++ 2 files changed, 11 insertions(+), 1 deletion(-)