From patchwork Tue Jun 27 22:04:42 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefano Stabellini X-Patchwork-Id: 9813179 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 06FCD603D7 for ; Tue, 27 Jun 2017 22:07:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F288F26E16 for ; Tue, 27 Jun 2017 22:07:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E5A9A26E46; Tue, 27 Jun 2017 22:07:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6866A26E16 for ; Tue, 27 Jun 2017 22:07:23 +0000 (UTC) Received: from localhost ([::1]:58368 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dPydm-0000sO-Fx for patchwork-qemu-devel@patchwork.kernel.org; Tue, 27 Jun 2017 18:07:22 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49905) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dPybP-0008E2-Lr for qemu-devel@nongnu.org; Tue, 27 Jun 2017 18:04:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dPybL-0000NG-NC for qemu-devel@nongnu.org; Tue, 27 Jun 2017 18:04:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:40124) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dPybL-0000Mp-Gq for qemu-devel@nongnu.org; Tue, 27 Jun 2017 18:04:51 -0400 Received: from localhost.localdomain (162-198-228-33.lightspeed.wlfrct.sbcglobal.net [162.198.228.33]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 986D122B60; Tue, 27 Jun 2017 22:04:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 986D122B60 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=sstabellini@kernel.org From: Stefano Stabellini To: peter.maydell@linaro.org, stefanha@gmail.com Date: Tue, 27 Jun 2017 15:04:42 -0700 Message-Id: <1498601083-11799-2-git-send-email-sstabellini@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1498601083-11799-1-git-send-email-sstabellini@kernel.org> References: <1498601083-11799-1-git-send-email-sstabellini@kernel.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 198.145.29.99 Subject: [Qemu-devel] [PULL 2/3] xen-disk: only advertize feature-persistent if grant copy is not available X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: sstabellini@kernel.org, qemu-devel@nongnu.org, Paul Durrant , stefanha@redhat.com, anthony.perard@citrix.com, xen-devel@lists.xenproject.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Paul Durrant If grant copy is available then it will always be used in preference to persistent maps. In this case feature-persistent should not be advertized to the frontend, otherwise it may needlessly copy data into persistently granted buffers. Signed-off-by: Paul Durrant Signed-off-by: Stefano Stabellini Reviewed-by: Stefano Stabellini --- hw/block/xen_disk.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c index 9200511..8218741 100644 --- a/hw/block/xen_disk.c +++ b/hw/block/xen_disk.c @@ -1022,11 +1022,18 @@ static int blk_init(struct XenDevice *xendev) blkdev->file_blk = BLOCK_SIZE; + blkdev->feature_grant_copy = + (xengnttab_grant_copy(blkdev->xendev.gnttabdev, 0, NULL) == 0); + + xen_pv_printf(&blkdev->xendev, 3, "grant copy operation %s\n", + blkdev->feature_grant_copy ? "enabled" : "disabled"); + /* fill info * blk_connect supplies sector-size and sectors */ xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1); - xenstore_write_be_int(&blkdev->xendev, "feature-persistent", 1); + xenstore_write_be_int(&blkdev->xendev, "feature-persistent", + !blkdev->feature_grant_copy); xenstore_write_be_int(&blkdev->xendev, "info", info); blk_parse_discard(blkdev); @@ -1201,12 +1208,6 @@ static int blk_connect(struct XenDevice *xendev) xen_be_bind_evtchn(&blkdev->xendev); - blkdev->feature_grant_copy = - (xengnttab_grant_copy(blkdev->xendev.gnttabdev, 0, NULL) == 0); - - xen_pv_printf(&blkdev->xendev, 3, "grant copy operation %s\n", - blkdev->feature_grant_copy ? "enabled" : "disabled"); - xen_pv_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, " "remote port %d, local port %d\n", blkdev->xendev.protocol, blkdev->ring_ref,