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 53A54C5DF87 for ; Fri, 21 Aug 2026 06:45:21 +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=US+vjSEcS3cjXw07qmheRFhsDdHEZnGUsdfTV1Oajdo=; b=hXXS0qqg9uYx6Q8hZuOt56WnD5 X/D+AdrRB8Emqz209yXWUphD2s2vJ6HDESmpW5RfnbGJTsp0HFzeb7mrdz1QVI1YfxCgJxLOlwI2l jPwLRrZRjeIq5Iid3joxcDjcez40SkOJC5M891+mecTLv0g1FsI3wKuIcrpq5NXY8IvlNIPTVVI2Q MSz7T0i98krnxiJDDoT5O+IHRdOgLJ/J6DORAv7kbmJtehSxHF87LtIzu29MLbd1xbPDzZy8QiZzA e9dbvrhqJbhIR0RKTxbuLb/yrrFq/sU9UXprH2K7lyBHYSTt7YtBIfql/PCXRuDMd4fkh1BYPVuR6 OjcpIy6g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wxJ01-0000000CeP4-412A; Fri, 21 Aug 2026 06:45:09 +0000 Received: from out-232.mta0.migadu.com ([2001:41d0:1004:224b::e8] helo=mta0.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wxIzu-0000000CeMG-1zib for linux-arm-kernel@lists.infradead.org; Fri, 21 Aug 2026 06:45:05 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=s01m9l8EYn7yXOYXD4CsQkn4QNAqwH/gr7B+G//pUqA=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787294700; v=1; x=1787899500; b=YYBaX/8oFq2LooNBO1OCp7sEYSAVQo7G89Ire0i3o/ERYRddb+mjVw3557Gb165+pqd1byx/ EtKVilFxs5nIvPC+EB7L3RNSX6djfr35a5qUwqo7XTu/Rnrya1E0GeOZhX8TuaUs7mXS49QqX/P sZcV9gcNzXpVoxnQkhKH5Hlc= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: from claudy.lan (37.156.72.212) by smtp.migadu.com with ESMTPS id 22874c4fdda4c102; Fri, 21 Aug 2026 06:45:00 +0000 X-Mizu-Trace-ID: 22874c4fdda4c102 X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton Cc: Eric Auger , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Will Deacon , Sascha Bischoff , Sebastian Ene , Fuad Tabba , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/4] Revert "KVM: arm64: vgic-its: Don't save collections the table cannot hold" Date: Fri, 21 Aug 2026 07:44:43 +0100 Message-Id: <20260821064445.615838-3-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260821064445.615838-1-fuad.tabba@linux.dev> References: <20260821064445.615838-1-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-20260820_234503_691973_BB938DD9 X-CRM114-Status: GOOD ( 10.34 ) 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 This reverts commit 9b10fb74e4b661543d188701bd4d024fc5c18f58. Freeing the collections when GITS_BASER changes removes the state this check rejected: vgic_its_cmd_handle_mapi(), vgic_its_cmd_handle_mapc() and vgic_its_restore_cte() all validate the ID against the current table before allocating, and the table can no longer change under the list. What remains is a collection whose entry is not backed by a memslot, which the write fails on anyway, so the check costs a save userspace should be able to issue reliably and buys nothing. The reverted commit credited the check with bounding the walk as well. It stays bounded without it: collection IDs are unique and each is below the table's capacity, so the list cannot be longer than the table. Suggested-by: Marc Zyngier Link: https://lore.kernel.org/all/87ecg9owwa.wl-maz@kernel.org/ Signed-off-by: Fuad Tabba --- arch/arm64/kvm/vgic/vgic-its.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c index d5ede640812c4..f702ac31b8b1b 100644 --- a/arch/arm64/kvm/vgic/vgic-its.c +++ b/arch/arm64/kvm/vgic/vgic-its.c @@ -2537,9 +2537,6 @@ static int vgic_its_save_collection_table(struct vgic_its *its) max_size = GITS_BASER_NR_PAGES(baser) * SZ_64K; list_for_each_entry(collection, &its->collection_list, coll_list) { - if (!vgic_its_check_id(its, baser, collection->collection_id, NULL)) - return -EINVAL; - ret = vgic_its_save_cte(its, collection, gpa); if (ret) return ret; -- 2.39.5