From nobody Mon Nov 25 11:51:18 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 56F4F1991C3; Mon, 28 Oct 2024 09:40:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730108447; cv=none; b=npuQzbBEDIhpizGl6pmDs/ymx+0xl5D3R7a8xrBFVWFj4+sPJmTw4NOPN++X+whMBDmnHqmvboIETnWZyezRmFGSK0AxH9HG+qvSerm8LlIDWWWT8cKUEymBqonZEqsfsZGCJDOLIfV+x4RgGK9Vh0AhdM0Bb4k+EO3MgBT29yk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730108447; c=relaxed/simple; bh=z1mUlgIUaANV/bPlzaFct/onP+Qou91QVjn4WHN+xBg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=R9F8/wqY4RqDZ3srHBhDWQOmSsfZjbRrqZ0bSX18RzBLK/qH3MwJiIqiicA0Uw+WROp32Db3LeXMEDqkrlngxXW5B3bXzIaH7Ht9fNxzKfFJb7pLkT5KwjmkBCuCd6xRH/7OEBroyiROFEedlb6apfuMJpGkxmN3N3IuN5C/2H4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=makORikM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="makORikM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 41EA3C4CEE3; Mon, 28 Oct 2024 09:40:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730108446; bh=z1mUlgIUaANV/bPlzaFct/onP+Qou91QVjn4WHN+xBg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=makORikMMp9/UbWQJ3sLJYYmDweBYANAH51dd82Y2lkQOuR/iidUeUDNFZazncjP9 SXlxlDLkTEuXSuJxdvyV3ic8Z8x8fkCuv5P2eGaDWz96MXcgNl1bu+4ps234VH4hFz hojhDqOkIT0MHmmm27Yqe04+In8D8Unw308HCHt3aw71+SxoM2XbzPIpwKzBZYbNDO CkomdyrKrGxLm7fCWIb77ITglUOIe6z6qrVF/clVOowdB2jt3wT1XARtYa/+jYQ3uo UiBKwAvgSnrqo9SM5rouDqir2whDwApOP26Gxoxe6qY9Zh0LMW8iGZjivdTvPpcIfQ 7UQJd5K8abhYg== From: "Aneesh Kumar K.V (Arm)" To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Cc: Suzuki K Poulose , Steven Price , Will Deacon , Catalin Marinas , Marc Zyngier , Mark Rutland , Oliver Upton , Joey Gouly , Zenghui Yu , "Aneesh Kumar K.V (Arm)" Subject: [PATCH 3/4] arm64: mte: update code comments Date: Mon, 28 Oct 2024 15:10:13 +0530 Message-ID: <20241028094014.2596619-4-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241028094014.2596619-1-aneesh.kumar@kernel.org> References: <20241028094014.2596619-1-aneesh.kumar@kernel.org> 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 Content-Type: text/plain; charset="utf-8" commit d77e59a8fccd ("arm64: mte: Lock a page for MTE tag initialisation") updated the locking such the kernel now allows VM_SHARED mapping with MTE. Update the code comment to reflect this. Signed-off-by: Aneesh Kumar K.V (Arm) --- arch/arm64/kvm/mmu.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index a509b63bd4dd..b5824e93cee0 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1390,11 +1390,8 @@ static int get_vma_page_shift(struct vm_area_struct = *vma, unsigned long hva) * able to see the page's tags and therefore they must be initialised firs= t. If * PG_mte_tagged is set, tags have already been initialised. * - * The race in the test/set of the PG_mte_tagged flag is handled by: - * - preventing VM_SHARED mappings in a memslot with MTE preventing two VMs - * racing to santise the same page - * - mmap_lock protects between a VM faulting a page in and the VMM perfor= ming - * an mprotect() to add VM_MTE + * The race in the test/set of the PG_mte_tagged flag is handled by + * using PG_mte_lock and PG_mte_tagged together. */ static void sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn, unsigned long size) @@ -1646,7 +1643,10 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phy= s_addr_t fault_ipa, } =20 if (!fault_is_perm && !device && kvm_has_mte(kvm)) { - /* Check the VMM hasn't introduced a new disallowed VMA */ + /* + * not a permission fault implies a translation fault which + * means mapping the page for the first time + */ if (mte_allowed) { sanitise_mte_tags(kvm, pfn, vma_pagesize); } else { --=20 2.43.0