From mboxrd@z Thu Jan 1 00:00:00 1970 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 1BCEAFEFB6E for ; Fri, 27 Feb 2026 18:08:03 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jhNkkAkwhMCH2ojVKzEb17U8rjl6Ex5AfW5DMIGvnfY=; b=fVoazlcFGtirG2nmdAnz01At5/ pQvOQ6s/N//aE51Tl5Cax/XMGcB1RQleEzVYxbDa+HZuWkPrHCHC1Jt72yj6/tS4ABilex7VXjR7z RAGv7KbOEhTtqwOOsAeV5z3DzSdnuy1T+Bm1WdrwPgCEcNr/BWYZaO/1bl7oK8rr7UqVDCn4EXpqS pB/NsvP/JXtkwYXpQegWiwgnqqfIAsdB3x6Meo1JI6+qUfknL2XRyBQ1OL78K3MuowZnrDn/+6ArH 62UHvZCbbPNMjv0OE38XbvLXGI4hwECPX1euGzDPzHJyIioKCQDbAPeuEpOPTMNlIMPH09IS55GTO SUh14HPA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vw2Fm-00000008tYN-0bX6; Fri, 27 Feb 2026 18:07:54 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vw2Fj-00000008tXs-0r3V for linux-arm-kernel@lists.infradead.org; Fri, 27 Feb 2026 18:07:52 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 86537419BE; Fri, 27 Feb 2026 18:07:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5FE74C116C6; Fri, 27 Feb 2026 18:07:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772215670; bh=1JaPmS/NjlHcJLGjdFc4aDc/hp52cYihGMOI5f7LB8I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WzsHFuy7pm+FNqHNSbLlMp8LoQC8o4Qo4GqEJGKmeQRt3Awa4nmDwygz2u4p20Gyp mvsxs4hfjGHx7ga/TckwTLTS+qtG/ohlpTTOyX6PgulVPdcR8PvO3JkQosmO1UjxU0 LRlh5yDe9eZqjWqE0VZebK254zyuVbHyBYY7clnE2pp7nsF0YsMn8KTOt+yyQuBaao dvQwauZSsB/EFOr6C2ctGC3XEq/Nlssj1smP8lSmH7KWPmUBFTfw1NmigKk6RP7o1w s6Pc3r54DOJyubKNym8vYmC3/LhuyoT9VcKdchWoBeTXK0pAMzgwE1sYj/8qy9ahuK 9WNamjsEhcJog== Date: Fri, 27 Feb 2026 18:07:44 +0000 From: Will Deacon To: Leo Yan Cc: yabinc@google.com, James Clark , Marc Zyngier , kvmarm@lists.linux.dev, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, Oliver Upton , Suzuki K Poulose , Fuad Tabba Subject: Re: [PATCH] KVM: arm64: Disable TRBE Trace Buffer Unit when running in guest context Message-ID: References: <20260216130959.19317-1-will@kernel.org> <86a4x8bw38.wl-maz@kernel.org> <20260217141917.GA136967@e132581.arm.com> <20260217190121.GB136967@e132581.arm.com> <20260219185800.GD136967@e132581.arm.com> <20260225120956.GD4184494@e132581.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260225120956.GD4184494@e132581.arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260227_100751_264407_A94B7F5E X-CRM114-Status: GOOD ( 16.81 ) 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 On Wed, Feb 25, 2026 at 12:09:56PM +0000, Leo Yan wrote: > [ + Yabin ] > > Thanks for Suzuki's reminding, I should mention that Yabin reported > another lockup issue caused by missing CPU PM support in TRBE driver. > > We have a patch series to fix the issue: > https://lore.kernel.org/linux-arm-kernel/20251119-arm_coresight_path_power_management_improvement-v5-16-f615a301ad0b@arm.com/ Two nits on that series: 1. It seems a bit weird to me for the ETE driver to manage TRFCR but for the TRBE driver to manage the other registers 2. Are you sure you don't need to save/restore the TRBE state when LIMITR.E is clear? Maybe the driver is fine with that, but I'm worried that we could suspend in a half-programmed state and lose some of that configuration. > Besides your fix the translation regime issue, I'd also suggest applying > the CoreSight PM patch series to fix lockup caused by CPU idle. Yes, we definitely need something like that in the android kernel trees. I've previously bodged a hack into the ETE PM notifiers, but if you have backports of your series to 6.12, 6.6 and 6.1 then we should merge them into Android. As it stands, I don't have a TRBE-capable device running mainline. Will