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 6EEEFCCF2DE for ; Mon, 19 Oct 2026 13:21:34 +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:References:In-Reply-To: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:List-Owner; bh=EqlZmIFYpFJ7sMwft3bXitWK6GFw2x/CJJAS4J6nfGc=; b=yweEOGrPQNWxbiXGm3kcrG9O97 EFpXlLo1VKX4f0g+JqgKsQhg/NjaFSTyiKD/IueJsrMkxGnsFKuCjBos1maRGeXOZXKeSCY38mT4u UQb4uMuLNqAqB6vd2Z9yg5sf4/cfQrzFMCKoydBiVCBM9suFicKtPyIEqID9+TWzifvWFiXOjza2T sSP933CpelxuDeO4ev0+y3PX9oZ6KqrHTi6DDKnQXujR6H7JkrwotRZhE51xckS4h+Og2asq+/yGv Iqq/GeKvBh73nP1psbO9ac7cxJDZpy3O3V/ExYRKO8pPFDcbQLT6LrPa9T3pN9If9e3wOq+RUNmEi n//vDI0w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xInIs-00000007UwE-0pbU; Mon, 19 Oct 2026 13:21:26 +0000 Received: from out-170.mta0.migadu.com ([2001:41d0:1004:224b::aa] helo=mta0.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xInIo-00000007UuP-3tcP for linux-arm-kernel@lists.infradead.org; Mon, 19 Oct 2026 13:21:24 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=uakg/74zoXwi1Kx44nvRA0V20527TnJNQegACr4zriI=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792416080; v=1; x=1793020880; b=Ud4Y+iT8DMSfP3LR7ccR+3xIBw1LKp85jWg9o3FHQ8cxKYWCviH6zqigN1nwjNdxxz4ohmf1 AKIt0WHKUtpiUC3G6lMbbgm0HC7vQ7o+vvEhn+ECvuiAbBJ/VEqd/hL8uqjcm1veXXn4MOr+vSx a47kI+czACXm3mYUgJC5znzI= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id b0f93a7c611f8a5d; Mon, 19 Oct 2026 13:21:20 +0000 X-Mizu-Trace-ID: b0f93a7c611f8a5d X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: Joey Gouly , Suzuki K Poulose , Zenghui Yu , Steffen Eiden , Catalin Marinas , Will Deacon , Mark Rutland , Steven Price , Yang Shi , David Hildenbrand , Fuad Tabba , linux-kernel@vger.kernel.org Subject: [PATCH 3/3] KVM: arm64: Sanitise MTE tags when a permission fault installs a mapping Date: Mon, 19 Oct 2026 14:21:03 +0100 Message-ID: <20261019132103.3836646-4-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261019132103.3836646-1-fuad.tabba@linux.dev> References: <20261019132103.3836646-1-fuad.tabba@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261019_062123_118278_15BF1BD7 X-CRM114-Status: GOOD ( 14.13 ) 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 The stage-2 fault path sanitises MTE tags only on translation faults, as a permission fault normally just relaxes an existing leaf. However, when the page is backed by a THP, a permission fault at page granule installs a block whose other pages may never have been mapped or sanitised. Once dirty logging is off, a guest write to a page mapped read-only during logging installs the block, and the guest can read the tags those pages' previous owners left. Sanitise whenever the fault path calls kvm_pgtable_stage2_map() rather than relaxing permissions. If the VMM replaces the VMA after the guest takes a permission fault but before vma_lookup(), that path would map and sanitise memory from the new VMA without checking it. Run the VM_MTE_ALLOWED check in kvm_s2_fault_compute_prot() on permission faults too. Fixes: ea7fc1bb1cd1b ("KVM: arm64: Introduce MTE VM feature") Cc: stable@vger.kernel.org Signed-off-by: Fuad Tabba --- arch/arm64/kvm/mmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 48a08b608ea72..208fcae80f67f 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -2005,7 +2005,7 @@ static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd, if (s2fd->nested) *prot = adjust_nested_exec_perms(kvm, s2fd->nested, *prot); - if (!kvm_s2_fault_is_perm(s2fd) && !s2vi->map_non_cacheable && kvm_has_mte(kvm)) { + if (!s2vi->map_non_cacheable && kvm_has_mte(kvm)) { /* Check the VMM hasn't introduced a new disallowed VMA */ if (!s2vi->mte_allowed) return -EFAULT; @@ -2060,7 +2060,7 @@ static int kvm_s2_fault_map(const struct kvm_s2_fault_desc *s2fd, } } - if (!perm_fault_granule && !s2vi->map_non_cacheable && kvm_has_mte(kvm)) + if (mapping_size != perm_fault_granule && !s2vi->map_non_cacheable && kvm_has_mte(kvm)) sanitise_mte_tags(kvm, pfn, mapping_size); /* -- 2.47.3