From nobody Fri Dec 19 17:15:17 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 0946447A60 for ; Fri, 28 Jun 2024 06:05:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719554714; cv=none; b=d4HRhnxyyhZdg4Amht9NlkEaytCNq0kyEf0AW2rgYDi5iS0bOK6ztcfZikQckzmZFwG5JdpB2bzMhmAfI9ODq8hQ9DjZuRHNjYtCfzqBEuaoLUzk+ECYKcqdbUwqEH8ywkgr2Ttj74Qk8O9+a70HN9Typ++6lBZre7/R2+Nm/Qg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719554714; c=relaxed/simple; bh=/pX3wzIxmrkatm6Atvy4eoQxDAwEynsnsnpazri5KBk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=hHG7rR8BSawNEZLfIlgARRwQE8i+BgtmxCS2Rb/GifqxXXnx1KXfAp1w45TmfX/LHOWQsOGSvKEePWI23op2SXSXFt573yKrEOos56s3M1aC09A4m+K72YgUme9x7Yv7ccQSCDNgo/N3yOK/c/HqTfbuwnwj+3wduM2aldB3Y1c= 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=RQCyomvj; arc=none smtp.client-ip=170.10.129.124 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="RQCyomvj" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1719554712; 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: in-reply-to:in-reply-to:references:references; bh=I9zn2i4ef/uuSlInb0x78J+Hjt4S8lkHLb69/zw01pU=; b=RQCyomvjsuzKa3zbJGtnL/SR7AkK5PDQsYaF0hLuWa1MlrlTnjDvbp+n0xCtgWJpa26T68 HUIjaKq9T8AcaOo/21NgpPQn85wl1cKorPtYuspTvTNQ9f/eadUMzKDdB+wTGYrXfGo/3u S+kX0tOR0zrQ03ncxzFhKxJDCakUtVg= Received: from mx-prod-mc-04.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-85-vNQFQkwvPM233aWf-atBog-1; Fri, 28 Jun 2024 02:05:07 -0400 X-MC-Unique: vNQFQkwvPM233aWf-atBog-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-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B601119560B1; Fri, 28 Jun 2024 06:05:05 +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 C26321945CB1; Fri, 28 Jun 2024 06:05:03 +0000 (UTC) From: Shaoqin Huang To: Oliver Upton , Marc Zyngier , kvmarm@lists.linux.dev Cc: Shaoqin Huang , James Morse , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 1/2] KVM: arm64: Allow userspace to change ID_AA64PFR1_EL1 Date: Fri, 28 Jun 2024 02:04:51 -0400 Message-Id: <20240628060454.1936886-2-shahuang@redhat.com> In-Reply-To: <20240628060454.1936886-1-shahuang@redhat.com> References: <20240628060454.1936886-1-shahuang@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" 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. --- arch/arm64/kvm/sys_regs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 22b45a15d068..159cded22357 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2306,7 +2306,9 @@ static const struct sys_reg_desc sys_reg_descs[] =3D { ID_AA64PFR0_EL1_GIC | ID_AA64PFR0_EL1_AdvSIMD | ID_AA64PFR0_EL1_FP), }, - ID_SANITISED(ID_AA64PFR1_EL1), + ID_WRITABLE(ID_AA64PFR1_EL1, ID_AA64PFR1_EL1_MTE | + ID_AA64PFR1_EL1_SSBS | + ID_AA64PFR1_EL1_BT), ID_UNALLOCATED(4,2), ID_UNALLOCATED(4,3), ID_WRITABLE(ID_AA64ZFR0_EL1, ~ID_AA64ZFR0_EL1_RES0), --=20 2.40.1