From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98E1A606A31D for ; Tue, 27 Oct 2026 17:29:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=QMkwC+Up; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=JnukGCmU 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-Unsubscribe-Post:List-Owner; bh=BnI1ypDPlmui1Fn2L3S4sqAodoDBEGGvrnjTOR08vd0=; b=QMkwC+UpwFvyrjl3RaR+yYJK4J fNO3JvcGXwZONmHVekKBjim8E4JKZp6cb8iP08Lynow31DpjtXrJu+Ani950d9RBHwQj/HH1GJltX 3grsJmrWN+KI86F/jCnEjfdFaFjxV8hIYAlP0acegAmvRUBNJSmRK/X9WRUTPP8WvQgvDDheTtufB 7Rvka4+6X4Y8+Y7vjYiXRR3dkUpXvo06FtXsDVd/WdmcuLUAjioudzTEtb8sAyR3DWhu15Hxw4ltA gzAtGiP/Wyte7iqMzYedsk3qzml/QMsFLV97DJx54z/J6Wru2qCcXsM2pI3DoU2rvFtY7x2Ukauy9 /hTphzqQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLkze-00000005ShN-3qoi; Tue, 27 Oct 2026 17:29:50 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLkzc-00000005Sh0-2dSX for linux-arm-kernel@lists.infradead.org; Tue, 27 Oct 2026 17:29:49 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 76CB01650; Tue, 27 Oct 2026 10:29:44 -0700 (PDT) Received: from arm.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 03EA93F7B4; Tue, 27 Oct 2026 10:29:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1793122187; bh=Px2Eb/FcnI3Ov0Mt8j5f3nVtsWHdzfl3d+dvv9q4c3w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JnukGCmUw/pTUGbxSJRJln9Shqph1UdbZJ11e8Rw/XWFSYh2PALvpdxDCrDVUdYar LzIMetk442+RLA1OwGDhiPXdCEN11FcDbAV7sW3W6KSaRWtPR5IOK52cwHFsvOA4lN FVsMGnDA/gqePHcu3rFELPNmZ5TUvTU4GXnL+wus= Date: Tue, 27 Oct 2026 17:29:43 +0000 From: Catalin Marinas To: Marc Zyngier Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Steffen Eiden , Joey Gouly , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Fuad Tabba , Will Deacon , Mark Rutland Subject: Re: [PATCH 0/2] KVM: arm64: Reenable MTE on VHE guest exit Message-ID: References: <20261026082305.2515705-1-maz@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261026082305.2515705-1-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261027_102948_708495_C9BEFCE3 X-CRM114-Status: GOOD ( 16.92 ) X-Spam-Score: -4.4 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Mon, Oct 26, 2026 at 08:23:03AM +0000, Marc Zyngier wrote: > Upton taking an exception, the CPU sets PSTATE.TCO to ensure that no > tag fault can be taken while handling the exception. It is SW's job to > eventually clear it when it is safe to do so. > > It appears that when MTE is enabled and that the kernel is running > VHE, nothing eventually clears TCO when we come back from the guest, > so things such as KASAN_HW_TAGS will not work until the next exit to > userspace. > > This series aims at fixing this. This is not a stable candidate, as > KASAN is only a debug option. > > Marc Zyngier (2): > arm64: Add return value to mte_disable_tco_entry() > KVM: arm64: Reenable MTE tag checking on exit from guest when running > VHE > > arch/arm64/include/asm/mte.h | 10 +++++++--- > arch/arm64/kvm/hyp/vhe/switch.c | 7 +++++++ > 2 files changed, 14 insertions(+), 3 deletions(-) For both patches: Reviewed-by: Catalin Marinas