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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 E4FF6C433E0 for ; Fri, 15 May 2020 20:29:57 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7D80D206D4 for ; Fri, 15 May 2020 20:29:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7D80D206D4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=antioche.eu.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jZgxJ-0004wg-7Z; Fri, 15 May 2020 20:29:17 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jZgxI-0004wb-2I for xen-devel@lists.xenproject.org; Fri, 15 May 2020 20:29:16 +0000 X-Inumbo-ID: bd4474a8-96ea-11ea-b9cf-bc764e2007e4 Received: from chassiron.antioche.eu.org (unknown [2001:41d0:fe9d:1101::1]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id bd4474a8-96ea-11ea-b9cf-bc764e2007e4; Fri, 15 May 2020 20:29:13 +0000 (UTC) Received: from rochebonne.antioche.eu.org (rochebonne [IPv6:2001:41d0:fe9d:1100:221:70ff:fe0c:9885]) by chassiron.antioche.eu.org (8.15.2/8.15.2) with ESMTP id 04FKTCmI028947 for ; Fri, 15 May 2020 22:29:12 +0200 (MEST) Received: by rochebonne.antioche.eu.org (Postfix, from userid 1210) id 6D2D62810; Fri, 15 May 2020 22:29:12 +0200 (CEST) Date: Fri, 15 May 2020 22:29:12 +0200 From: Manuel Bouyer To: xen-devel@lists.xenproject.org Subject: IOCTL_PRIVCMD_MMAPBATCH on Xen 4.13.0 Message-ID: <20200515202912.GA11714@antioche.eu.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.12.1 (2019-06-15) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3 (chassiron.antioche.eu.org [IPv6:2001:41d0:fe9d:1101:0:0:0:1]); Fri, 15 May 2020 22:29:12 +0200 (MEST) X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Hello, NetBSD works as dom0 up to Xen 4.11. I'm trying to get it working on 4.13.0. I added the support for gntdev operations, but I'm stuck with privcmd IOCTL_PRIVCMD_MMAPBATCH. It seems to work fine for PV and PVH domUs, but with HVM domUs, MMU_NORMAL_PT_UPDATE returns -22 (EINVAL) and qemu-dm dumps core (as expected; the page is not mapped). Of course this works fine in 4.11 In the Xen kernel, I tracked it down to arch/x86/mm.c near line 2229, in mod_l1_entry(): /* Translate foreign guest address. */ if ( cmd != MMU_PT_UPDATE_NO_TRANSLATE && paging_mode_translate(pg_dom) ) { p2m_type_t p2mt; p2m_query_t q = l1e_get_flags(nl1e) & _PAGE_RW ? P2M_ALLOC | P2M_UNSHARE : P2M_ALLOC; page = get_page_from_gfn(pg_dom, l1e_get_pfn(nl1e), &p2mt, q); if ( p2m_is_paged(p2mt) ) { if ( page ) put_page(page); p2m_mem_paging_populate(pg_dom, l1e_get_pfn(nl1e)); return -ENOENT; } if ( p2mt == p2m_ram_paging_in && !page ) return -ENOENT; /* Did our attempt to unshare fail? */ if ( (q & P2M_UNSHARE) && p2m_is_shared(p2mt) ) { /* We could not have obtained a page ref. */ ASSERT(!page); /* And mem_sharing_notify has already been called. */ return -ENOMEM; } if ( !page ) { gdprintk(XENLOG_WARNING, "translate but no page\n"); return -EINVAL; } nl1e = l1e_from_page(page, l1e_get_flags(nl1e)); } the gdprintk() I added in the ( !page) case fires, so this is the cause of the EINVAL. Is it expected for a HVM domU ? If so, how should the dom0 code be changed to get it working ? I failed to see where our code is different from linux ... -- Manuel Bouyer NetBSD: 26 ans d'experience feront toujours la difference --