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=-12.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 4F7A9C2D0E2 for ; Tue, 22 Sep 2020 18:25:28 +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 D20D8239D2 for ; Tue, 22 Sep 2020 18:25:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="FWWzFI87" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D20D8239D2 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 localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kKmya-0008Mp-Kx; Tue, 22 Sep 2020 18:25:16 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kKmyZ-0008GI-7I for xen-devel@lists.xenproject.org; Tue, 22 Sep 2020 18:25:15 +0000 X-Inumbo-ID: e493f973-a6de-481c-b043-9d8af8e6b720 Received: from esa4.hc3370-68.iphmx.com (unknown [216.71.155.144]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id e493f973-a6de-481c-b043-9d8af8e6b720; Tue, 22 Sep 2020 18:25:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1600799106; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=rU4T0b1gOrbQM5IJxlzUlr+qKaU/UBRT7s0tSb1goJY=; b=FWWzFI87tOVq1tJXsTAj/C6PfnaWdfmLVaMf09HzNtAeXZ6ZaRtbt3UP TTX2jONv+6y0k8m84KI7pAEJYQolFVTnXwy+PJzfnXEm3njP1mCZQSNzq 6swKhkpctxyGopmEYM1Wcs0Oo+lRpATpr+31efqcljldLycaQtmArbxxD k=; Authentication-Results: esa4.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none IronPort-SDR: BtEeTIYmEEE0eUHoxJvEe4cCTaaj1CJ0jl3J84aIM+PyauCZuJkj7WWbhF5rosbBTNuFhLB5PU mlpSVoO+WxmRnfol5bW5ToCVpD0WIm7W+a7U/xGC0jGw5YkZkqmH7lCyCHPSh9uwy0rCIME9E+ Avx+J/DTUMcDaSqi5CS01DF4HZMujpWqMgSEFFhsYkW6XEipYLdTOZHbZBQDK40dpVj2ZRCwAG qX5M6jvHU5C8BA0kPNZPzOJRDqZz41av37xpQ90ScgeSiE3G9CL8LJFIhuzKbXF36VQfvNTknt u1c= X-SBRS: 2.7 X-MesageID: 28290906 X-Ironport-Server: esa4.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.77,291,1596513600"; d="scan'208";a="28290906" 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=C5=82=20Leszczy=C5=84ski?= , Hubert Jasudowicz , Tamas K Lengyel Subject: [PATCH v2 07/11] xen/memory: Improve compat XENMEM_acquire_resource handling Date: Tue, 22 Sep 2020 19:24:40 +0100 Message-ID: <20200922182444.12350-8-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20200922182444.12350-1-andrew.cooper3@citrix.com> References: <20200922182444.12350-1-andrew.cooper3@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit 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" 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 --- 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; } -- 2.11.0