Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751743AbbBJGl7 (ORCPT ); Tue, 10 Feb 2015 01:41:59 -0500 Received: from ozlabs.org ([103.22.144.67]:44111 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751699AbbBJGl6 convert rfc822-to-8bit (ORCPT ); Tue, 10 Feb 2015 01:41:58 -0500 From: Rusty Russell To: "lkml" , Cc: "Michael S. Tsirkin" Subject: [PATCH] virtio_pci: use 16-bit accessor for queue_enable. User-Agent: Notmuch/0.17 (http://notmuchmail.org) Emacs/24.3.1 (x86_64-pc-linux-gnu) Date: Tue, 10 Feb 2015 17:05:01 +1030 Message-ID: <87twyuw9yi.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1493 Lines: 38 Since PCI is little endian, 8-bit access might work, but the spec section is very clear on this: 4.1.3.1 Driver Requirements: PCI Device Layout The driver MUST access each field using the “natural” access method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for 16-bit fields and 8-bit accesses for 8-bit fields. Signed-off-by: Rusty Russell diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c index f16e462cb4ef..2aa38e59db2e 100644 --- a/drivers/virtio/virtio_pci_modern.c +++ b/drivers/virtio/virtio_pci_modern.c @@ -294,7 +294,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev, /* Check if queue is either not available or already active. */ num = ioread16(&cfg->queue_size); - if (!num || ioread8(&cfg->queue_enable)) + if (!num || ioread16(&cfg->queue_enable)) return ERR_PTR(-ENOENT); if (num & (num - 1)) { @@ -394,7 +394,7 @@ static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs, */ list_for_each_entry(vq, &vdev->vqs, list) { iowrite16(vq->index, &vp_dev->common->queue_select); - iowrite8(1, &vp_dev->common->queue_enable); + iowrite16(1, &vp_dev->common->queue_enable); } return 0; -- 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/