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[170.10.133.124]) by mx.google.com with ESMTPS id 5b1f17b1804b1-42e754271a8si8668135e9.89.2024.09.19.08.05.31 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Sep 2024 08:05:31 -0700 (PDT) Received-SPF: pass (google.com: domain of cohuck@redhat.com designates 170.10.133.124 as permitted sender) client-ip=170.10.133.124; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=JBwG3LZv; spf=pass (google.com: domain of cohuck@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=cohuck@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1726758330; 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: in-reply-to:in-reply-to:references:references; bh=CRBaIT1ZiEL/UGx9VPyJK7064AwhFwjo48bUXISveq8=; b=JBwG3LZvE/HZGQCnvDmvEaVgoNcVRkuSaH8olqwE+Tb4iqzI+QXWbyavP2JR+Fb68bhzsf mNJ4YcT/es9VMyP9kOgH7aRoWNBo0UHo5JIe9RUxo3jki37cj+7IcJPCeF+lmy5EuBxi6V s6AOFMONb0dXe1coM6c5fwn/pPgAQtA= Received: from mx-prod-mc-01.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-112-9YGylzwgNteCDK_4Ujoq1g-1; Thu, 19 Sep 2024 11:05:27 -0400 X-MC-Unique: 9YGylzwgNteCDK_4Ujoq1g-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (unknown [10.30.177.12]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7260E193611E; Thu, 19 Sep 2024 15:05:25 +0000 (UTC) Received: from localhost (unknown [10.39.194.77]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7EB8719560AF; Thu, 19 Sep 2024 15:05:24 +0000 (UTC) From: Cornelia Huck To: Ganapatrao Kulkarni , Gustavo Romero , qemu-arm@nongnu.org, qemu-devel@nongnu.org Cc: peter.maydell@linaro.org, richard.henderson@linaro.org, alex.bennee@linaro.org, darren@os.amperecomputing.com Subject: Re: [PATCH V2] arm/kvm: add support for MTE In-Reply-To: <879f7e65-070a-4d9b-b70f-60576b7b5319@os.amperecomputing.com> Organization: "Red Hat GmbH, Sitz: Werner-von-Siemens-Ring 12, D-85630 Grasbrunn, Handelsregister: Amtsgericht =?utf-8?Q?M=C3=BCnchen=2C?= HRB 153243, =?utf-8?Q?Gesch=C3=A4ftsf=C3=BChrer=3A?= Ryan Barnhart, Charles Cachera, Michael O'Neill, Amy Ross" References: <20240912091616.393685-1-gankulkarni@os.amperecomputing.com> <0faf9a7c-0400-482c-974f-7b70e1d58202@linaro.org> <879f7e65-070a-4d9b-b70f-60576b7b5319@os.amperecomputing.com> User-Agent: Notmuch/0.38.3 (https://notmuchmail.org) Date: Thu, 19 Sep 2024 17:05:21 +0200 Message-ID: <8734lvu1ji.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 X-TUID: HGN6U/GjenKW On Thu, Sep 19 2024, Ganapatrao Kulkarni wrote: > I have modified as below diff to keep TCG if loop as it is and adding if > for KVM case to clear/mask the MTE bits if MTE in KVM mode is not > enabled by user command(if no mte=on). > > Is below diff makes sense? > > diff --git a/target/arm/cpu.c b/target/arm/cpu.c > index a59417aac8..523996576d 100644 > --- a/target/arm/cpu.c > +++ b/target/arm/cpu.c > @@ -2390,15 +2390,20 @@ static void arm_cpu_realizefn(DeviceState *dev, > Error **errp) > > #ifndef CONFIG_USER_ONLY > /* > - * If we do not have tag-memory provided by the TCG > - * nor MTE at KVM enabled, reduce MTE support to > - * instructions enabled at EL0. > + * If we do not have tag-memory provided by the TCG, > + * reduce MTE support to instructions enabled at EL0. > * This matches Cortex-A710 BROADCASTMTE input being LOW. > */ > - if (cpu->tag_memory == NULL && !cpu->kvm_mte) { > + if (tcg_enabled() && cpu->tag_memory == NULL) { > cpu->isar.id_aa64pfr1 = > FIELD_DP64(cpu->isar.id_aa64pfr1, ID_AA64PFR1, MTE, 1); > } > + > + /* Disable MTE, if it is not enabled by the user for KVM mode. > + */ > + if (kvm_enabled() && !cpu->kvm_mte) { > + FIELD_DP64(cpu->isar.id_aa64pfr1, ID_AA64PFR1, MTE, 0); > + } > #endif > } Wouldn't that be a possibly guest-visible change?