Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751214AbaKMFxI (ORCPT ); Thu, 13 Nov 2014 00:53:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:46268 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750787AbaKMFxF (ORCPT ); Thu, 13 Nov 2014 00:53:05 -0500 From: Jason Wang To: rusty@rustcorp.com.au, mst@redhat.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org Cc: netdev@vger.kernel.org, Jason Wang Subject: [PATCH 1/2] virito: introduce methods of fixing device features Date: Thu, 13 Nov 2014 13:52:53 +0800 Message-Id: <1415857974-23326-1-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Buggy host may advertised buggy host features (a usual case is that host advertise a feature whose dependencies were missed). In this case, driver should detect and disable the buggy features by itself. This patch introduces driver specific fix_features() method which is called just before features finalizing to detect and disable buggy features advertised by host. Virtio-net will be the first user. Cc: Rusty Russell Cc: Michael S. Tsirkin Signed-off-by: Jason Wang --- drivers/virtio/virtio.c | 4 ++++ include/linux/virtio.h | 1 + include/linux/virtio_config.h | 12 ++++++++++++ 3 files changed, 17 insertions(+) diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index df598dd..7001d6e 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -181,6 +181,10 @@ static int virtio_dev_probe(struct device *_d) if (device_features & (1 << i)) set_bit(i, dev->features); + /* Fix buggy features advertised by host */ + if (drv->fix_features) + drv->fix_features(dev); + dev->config->finalize_features(dev); err = drv->probe(dev); diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 65261a7..9d01b54 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -142,6 +142,7 @@ struct virtio_driver { void (*scan)(struct virtio_device *dev); void (*remove)(struct virtio_device *dev); void (*config_changed)(struct virtio_device *dev); + void (*fix_features)(struct virtio_device *dev); #ifdef CONFIG_PM int (*freeze)(struct virtio_device *dev); int (*restore)(struct virtio_device *dev); diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 7f4ef66..7bd89ea 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -96,6 +96,18 @@ static inline bool virtio_has_feature(const struct virtio_device *vdev, return test_bit(fbit, vdev->features); } +static inline void virtio_disable_feature(struct virtio_device *vdev, + unsigned int fbit) +{ + BUG_ON(fbit >= VIRTIO_TRANSPORT_F_START); + BUG_ON(vdev->config->get_status(vdev) & + ~(VIRTIO_CONFIG_S_ACKNOWLEDGE | VIRTIO_CONFIG_S_DRIVER)); + + virtio_check_driver_offered_feature(vdev, fbit); + + clear_bit(fbit, vdev->features); +} + static inline struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, vq_callback_t *c, const char *n) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/