From patchwork Mon Jan 11 14:39:38 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kurz X-Patchwork-Id: 565921 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id ECD831402DE for ; Tue, 12 Jan 2016 01:40:10 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932636AbcAKOjv (ORCPT ); Mon, 11 Jan 2016 09:39:51 -0500 Received: from e06smtp15.uk.ibm.com ([195.75.94.111]:53662 "EHLO e06smtp15.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760461AbcAKOjs (ORCPT ); Mon, 11 Jan 2016 09:39:48 -0500 Received: from localhost by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 11 Jan 2016 14:39:45 -0000 Received: from d06dlp02.portsmouth.uk.ibm.com (9.149.20.14) by e06smtp15.uk.ibm.com (192.168.101.145) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Mon, 11 Jan 2016 14:39:43 -0000 X-IBM-Helo: d06dlp02.portsmouth.uk.ibm.com X-IBM-MailFrom: gkurz@linux.vnet.ibm.com X-IBM-RcptTo: kvm@vger.kernel.org; linux-kernel@vger.kernel.org; netdev@vger.kernel.org Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id EB0B0219006C; Mon, 11 Jan 2016 14:39:31 +0000 (GMT) Received: from d06av03.portsmouth.uk.ibm.com (d06av03.portsmouth.uk.ibm.com [9.149.37.213]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u0BEdgMo6357486; Mon, 11 Jan 2016 14:39:43 GMT Received: from d06av03.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av03.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u0BEdf9w019127; Mon, 11 Jan 2016 07:39:42 -0700 Received: from smtp.lab.toulouse-stg.fr.ibm.com (srv01.lab.toulouse-stg.fr.ibm.com [9.101.4.1]) by d06av03.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u0BEdfpA019118; Mon, 11 Jan 2016 07:39:41 -0700 Received: from bahia.huguette.org (sig-9-79-81-64.de.ibm.com [9.79.81.64]) by smtp.lab.toulouse-stg.fr.ibm.com (Postfix) with ESMTP id 44DA7220220; Mon, 11 Jan 2016 15:39:40 +0100 (CET) Subject: [PATCH] vhost: move is_le setup to the backend From: Greg Kurz To: "Michael S. Tsirkin" Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Date: Mon, 11 Jan 2016 15:39:38 +0100 Message-ID: <20160111143509.9601.15143.stgit@bahia.huguette.org> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16011114-0021-0000-0000-0000088B9E5D Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The vq->is_le field is used to fix endianness when accessing the vring via the cpu_to_vhost16() and vhost16_to_cpu() helpers in the following cases: 1) host is big endian and device is modern virtio 2) host has cross-endian support and device is legacy virtio with a different endianness than the host Both cases rely on the VHOST_SET_FEATURES ioctl, but 2) also needs the VHOST_SET_VRING_ENDIAN ioctl to be called by userspace. Since vq->is_le is only needed when the backend is active, it was decided to set it at backend start. This is currently done in vhost_init_used()->vhost_init_is_le() but it obfuscates the core vhost code. This patch moves the is_le setup to a dedicated function that is called from the backend code. Note vhost_net is the only backend that can pass vq->private_data == NULL to vhost_init_used(), hence the "if (sock)" branch. No behaviour change. Reviewed-by: Cornelia Huck Signed-off-by: Greg Kurz --- Hi Michael, This is a cleanup patch I had posted last year: http://patchwork.ozlabs.org/patch/538277/ I am just reposting with Cornelia's R-b. Cheers. -- Greg drivers/vhost/net.c | 6 ++++++ drivers/vhost/scsi.c | 3 +++ drivers/vhost/test.c | 2 ++ drivers/vhost/vhost.c | 12 +++++++----- drivers/vhost/vhost.h | 1 + 5 files changed, 19 insertions(+), 5 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 9eda69e40678..d6319cb2664c 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -917,6 +917,12 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) vhost_net_disable_vq(n, vq); vq->private_data = sock; + + if (sock) + vhost_set_is_le(vq); + else + vq->is_le = virtio_legacy_is_little_endian(); + r = vhost_init_used(vq); if (r) goto err_used; diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 29cfc57d496e..1f4f405ebba8 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -1274,6 +1274,9 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, vq = &vs->vqs[i].vq; mutex_lock(&vq->mutex); vq->private_data = vs_tpg; + + vhost_set_is_le(vq); + vhost_init_used(vq); mutex_unlock(&vq->mutex); } diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c index f2882ac98726..b1c7df502211 100644 --- a/drivers/vhost/test.c +++ b/drivers/vhost/test.c @@ -196,6 +196,8 @@ static long vhost_test_run(struct vhost_test *n, int test) oldpriv = vq->private_data; vq->private_data = priv; + vhost_set_is_le(vq); + r = vhost_init_used(&n->vqs[index]); mutex_unlock(&vq->mutex); diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index ad2146a9ab2d..e688eb801d43 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -113,6 +113,12 @@ static void vhost_init_is_le(struct vhost_virtqueue *vq) } #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */ +void vhost_set_is_le(struct vhost_virtqueue *vq) +{ + vhost_init_is_le(vq); +} +EXPORT_SYMBOL_GPL(vhost_set_is_le); + static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh, poll_table *pt) { @@ -1156,12 +1162,8 @@ int vhost_init_used(struct vhost_virtqueue *vq) { __virtio16 last_used_idx; int r; - if (!vq->private_data) { - vq->is_le = virtio_legacy_is_little_endian(); + if (!vq->private_data) return 0; - } - - vhost_init_is_le(vq); r = vhost_update_used_flags(vq); if (r) diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index d3f767448a72..af5d33797937 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -162,6 +162,7 @@ bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *); int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, unsigned int log_num, u64 len); +void vhost_set_is_le(struct vhost_virtqueue *vq); #define vq_err(vq, fmt, ...) do { \ pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \