From patchwork Sat Jan 30 02:58:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Andrew Cooper X-Patchwork-Id: 12056749 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=-19.0 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 59D88C4332B for ; Sat, 30 Jan 2021 02:59:36 +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 EEBF064E24 for ; Sat, 30 Jan 2021 02:59:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EEBF064E24 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=citrix.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.78634.143142 (Exim 4.92) (envelope-from ) id 1l5gTj-0000ZM-IS; Sat, 30 Jan 2021 02:59:15 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 78634.143142; Sat, 30 Jan 2021 02:59:15 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l5gTj-0000ZF-Ey; Sat, 30 Jan 2021 02:59:15 +0000 Received: by outflank-mailman (input) for mailman id 78634; Sat, 30 Jan 2021 02:59:13 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l5gTh-0000YI-Rx for xen-devel@lists.xenproject.org; Sat, 30 Jan 2021 02:59:13 +0000 Received: from esa6.hc3370-68.iphmx.com (unknown [216.71.155.175]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 27a26bf1-553e-443e-8540-0c5db081456f; Sat, 30 Jan 2021 02:59:12 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 27a26bf1-553e-443e-8540-0c5db081456f DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1611975552; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=dQKNhP8sDS8/NNw+FPEKxJTqs+cEaD8DbMzBYrGIXcA=; b=bhUxG0Xf2YiOpLFD/3LczxN4mq7/URuKir3bMW8cbsvDCQRJ39qsQUIL pl6xh8Lhu39WbGnU8S4msWCxPnUxc4S/g70dpCnFqRO1H5nGA+FGMMEgN W0M44q6UkQTJQW8F10QTFuDrA5xgaFqYyD90TuQVJfJDISRec7iLaoPmM o=; Authentication-Results: esa6.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none IronPort-SDR: wbRla5J5MEZhyzoROXLITv6uEQUDN5uDsIXrJOjGiflUz9YT0n9KRg6k47+OLQSBApS9e1x8iw k/emv68V8fwyCfl0Ni/hn9n/RQ/17lBUKRrEC7JzuqeJ8o/XzRmhy8DW1sdBwWW78d6CM22+zH JyzrSXPuMrN/qjCvhJRJIDofVop7Nugo/mtLHf6sZYxEZfXY9b8Yzcuc7fVTf1QM0tP8k2tWUh 7Fq6V/Jphwjzm0xsnIdfuUbeAD5q9BAlA5IJn70rueha+NF4A+BaSBoKRDyiR7vuWMinEdtUg8 WFo= X-SBRS: 5.1 X-MesageID: 36399489 X-Ironport-Server: esa6.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.79,387,1602561600"; d="scan'208";a="36399489" From: Andrew Cooper To: Xen-devel CC: Andrew Cooper , George Dunlap , Ian Jackson , Jan Beulich , Stefano Stabellini , Wei Liu , Julien Grall , Paul Durrant , =?utf-8?q?Micha?= =?utf-8?q?=C5=82_Leszczy=C5=84ski?= , Hubert Jasudowicz , Tamas K Lengyel Subject: [PATCH v8 04/16] xen/memory: Improve compat XENMEM_acquire_resource handling Date: Sat, 30 Jan 2021 02:58:40 +0000 Message-ID: <20210130025852.12430-5-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20210130025852.12430-1-andrew.cooper3@citrix.com> References: <20210130025852.12430-1-andrew.cooper3@citrix.com> MIME-Version: 1.0 The frame_list is an input, or an output, depending on whether the calling domain is translated or not. The array does not need marshalling in both directions. Furthermore, the copy-in loop was very inefficient, copying 4 bytes at at time. Rewrite it to copy in all nr_frames at once, and then expand compat_pfn_t to xen_pfn_t in place. Re-position the copy-in loop to simplify continuation support in a future patch, and reduce the scope of certain variables. No change in guest observed behaviour. Signed-off-by: Andrew Cooper Reviewed-by: Paul Durrant --- CC: George Dunlap CC: Ian Jackson CC: Jan Beulich CC: Stefano Stabellini CC: Wei Liu CC: Julien Grall CC: Paul Durrant CC: Michał Leszczyński CC: Hubert Jasudowicz CC: Tamas K Lengyel --- xen/common/compat/memory.c | 65 ++++++++++++++++++++++++++++------------------ 1 file changed, 40 insertions(+), 25 deletions(-) diff --git a/xen/common/compat/memory.c b/xen/common/compat/memory.c index ed92e05b08..834c5e19d1 100644 --- a/xen/common/compat/memory.c +++ b/xen/common/compat/memory.c @@ -55,6 +55,8 @@ static int get_reserved_device_memory(xen_pfn_t start, xen_ulong_t nr, int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) compat) { + struct vcpu *curr = current; + struct domain *currd = curr->domain; int split, op = cmd & MEMOP_CMD_MASK; long rc; unsigned int start_extent = cmd >> MEMOP_EXTENT_SHIFT; @@ -399,7 +401,7 @@ int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) compat) case XENMEM_acquire_resource: { - xen_pfn_t *xen_frame_list; + xen_pfn_t *xen_frame_list = NULL; unsigned int max_nr_frames; if ( copy_from_guest(&cmp.mar, compat, 1) ) @@ -417,28 +419,10 @@ int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) compat) if ( cmp.mar.nr_frames > max_nr_frames ) return -E2BIG; - if ( compat_handle_is_null(cmp.mar.frame_list) ) - xen_frame_list = NULL; - else - { + /* Marshal the frame list in the remainder of the xlat space. */ + if ( !compat_handle_is_null(cmp.mar.frame_list) ) xen_frame_list = (xen_pfn_t *)(nat.mar + 1); - if ( !compat_handle_okay(cmp.mar.frame_list, - cmp.mar.nr_frames) ) - return -EFAULT; - - for ( i = 0; i < cmp.mar.nr_frames; i++ ) - { - compat_pfn_t frame; - - if ( __copy_from_compat_offset( - &frame, cmp.mar.frame_list, i, 1) ) - return -EFAULT; - - xen_frame_list[i] = frame; - } - } - #define XLAT_mem_acquire_resource_HNDL_frame_list(_d_, _s_) \ set_xen_guest_handle((_d_)->frame_list, xen_frame_list) @@ -446,6 +430,31 @@ int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) compat) #undef XLAT_mem_acquire_resource_HNDL_frame_list + if ( xen_frame_list && cmp.mar.nr_frames ) + { + /* + * frame_list is an input for translated guests, and an output + * for untranslated guests. Only copy in for translated guests. + */ + if ( paging_mode_translate(currd) ) + { + compat_pfn_t *compat_frame_list = (void *)xen_frame_list; + + if ( !compat_handle_okay(cmp.mar.frame_list, + cmp.mar.nr_frames) || + __copy_from_compat_offset( + compat_frame_list, cmp.mar.frame_list, + 0, cmp.mar.nr_frames) ) + return -EFAULT; + + /* + * Iterate backwards over compat_frame_list[] expanding + * compat_pfn_t to xen_pfn_t in place. + */ + for ( int x = cmp.mar.nr_frames - 1; x >= 0; --x ) + xen_frame_list[x] = compat_frame_list[x]; + } + } break; } default: @@ -590,8 +599,6 @@ int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) compat) case XENMEM_acquire_resource: { - const xen_pfn_t *xen_frame_list = (xen_pfn_t *)(nat.mar + 1); - compat_pfn_t *compat_frame_list = (compat_pfn_t *)(nat.mar + 1); DEFINE_XEN_GUEST_HANDLE(compat_mem_acquire_resource_t); if ( compat_handle_is_null(cmp.mar.frame_list) ) @@ -601,9 +608,18 @@ int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) compat) compat_mem_acquire_resource_t), nat.mar, nr_frames) ) return -EFAULT; + break; } - else + + /* + * frame_list is an input for translated guests, and an output for + * untranslated guests. Only copy out for untranslated guests. + */ + if ( !paging_mode_translate(currd) ) { + const xen_pfn_t *xen_frame_list = (xen_pfn_t *)(nat.mar + 1); + compat_pfn_t *compat_frame_list = (compat_pfn_t *)(nat.mar + 1); + /* * NOTE: the smaller compat array overwrites the native * array. @@ -625,7 +641,6 @@ int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) compat) cmp.mar.nr_frames) ) return -EFAULT; } - break; }