From patchwork Mon Feb 22 12:36:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 386665 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 825B1C433E0 for ; Mon, 22 Feb 2021 12:51:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 379E664E41 for ; Mon, 22 Feb 2021 12:51:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231675AbhBVMvO (ORCPT ); Mon, 22 Feb 2021 07:51:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:57092 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231419AbhBVMrL (ORCPT ); Mon, 22 Feb 2021 07:47:11 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 518DB64F5D; Mon, 22 Feb 2021 12:42:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613997740; bh=p+oW8OlV44RvJ5tEMAQrHVoWPqjBmbA2LBQUBE50Jaw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rlw/+k5/y40RSomHwfPjJbmFAaSy2PouzjBpSNit/VVSQkzsg1tJO4+ajBJ5GGUFP wLKif9oQz2lyULHDGE5I3mhKywY+8bfiHVhhsPF8MuRk8+XnGwdY+NjIMg3Vg8ID8F f2B0oy9K578w/KB2LRRISd2SMqiS4QMohAPRvaPM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Beulich , Stefano Stabellini , Juergen Gross Subject: [PATCH 4.9 41/49] Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages() Date: Mon, 22 Feb 2021 13:36:39 +0100 Message-Id: <20210222121027.958279402@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210222121022.546148341@linuxfoundation.org> References: <20210222121022.546148341@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jan Beulich commit dbe5283605b3bc12ca45def09cc721a0a5c853a2 upstream. We may not skip setting the field in the unmap structure when GNTMAP_device_map is in use - such an unmap would fail to release the respective resources (a page ref in the hypervisor). Otoh the field doesn't need setting at all when GNTMAP_device_map is not in use. To record the value for unmapping, we also better don't use our local p2m: In particular after a subsequent change it may not have got updated for all the batch elements. Instead it can simply be taken from the respective map's results. We can additionally avoid playing this game altogether for the kernel part of the mappings in (x86) PV mode. This is part of XSA-361. Signed-off-by: Jan Beulich Cc: stable@vger.kernel.org Reviewed-by: Stefano Stabellini Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- drivers/xen/gntdev.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -293,18 +293,25 @@ static int map_grant_pages(struct grant_ * to the kernel linear addresses of the struct pages. * These ptes are completely different from the user ptes dealt * with find_grant_ptes. + * Note that GNTMAP_device_map isn't needed here: The + * dev_bus_addr output field gets consumed only from ->map_ops, + * and by not requesting it when mapping we also avoid needing + * to mirror dev_bus_addr into ->unmap_ops (and holding an extra + * reference to the page in the hypervisor). */ + unsigned int flags = (map->flags & ~GNTMAP_device_map) | + GNTMAP_host_map; + for (i = 0; i < map->count; i++) { unsigned long address = (unsigned long) pfn_to_kaddr(page_to_pfn(map->pages[i])); BUG_ON(PageHighMem(map->pages[i])); - gnttab_set_map_op(&map->kmap_ops[i], address, - map->flags | GNTMAP_host_map, + gnttab_set_map_op(&map->kmap_ops[i], address, flags, map->grants[i].ref, map->grants[i].domid); gnttab_set_unmap_op(&map->kunmap_ops[i], address, - map->flags | GNTMAP_host_map, -1); + flags, -1); } } @@ -320,6 +327,9 @@ static int map_grant_pages(struct grant_ continue; } + if (map->flags & GNTMAP_device_map) + map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr; + map->unmap_ops[i].handle = map->map_ops[i].handle; if (use_ptemod) map->kunmap_ops[i].handle = map->kmap_ops[i].handle;