From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756750Ab2DLFhq (ORCPT ); Thu, 12 Apr 2012 01:37:46 -0400 Received: from ozlabs.org ([203.10.76.45]:41083 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756539Ab2DLFgs (ORCPT ); Thu, 12 Apr 2012 01:36:48 -0400 From: David Gibson To: rusty@rustcorp.com.au, mst@redhat.com Cc: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, paulus@samba.org, qemu-devel@nongnu.org, David Gibson Subject: [PATCH 2/3] virtio_balloon: Fix endian bug Date: Thu, 12 Apr 2012 15:36:34 +1000 Message-Id: <1334208995-29985-3-git-send-email-david@gibson.dropbear.id.au> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1334208995-29985-1-git-send-email-david@gibson.dropbear.id.au> References: <1334208995-29985-1-git-send-email-david@gibson.dropbear.id.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Although virtio config space fields are usually in guest-native endian, the spec for the virtio balloon device explicitly states that both fields in its config space are little-endian. However, the current virtio_balloon driver does not have a suitable endian swap for the 'num_pages' field, although it does have one for the 'actual' field. This patch corrects the bug, adding sparse annotation while we're at it. Signed-off-by: David Gibson --- drivers/virtio/virtio_balloon.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 6c07793..553cc1f 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -238,11 +238,14 @@ static void virtballoon_changed(struct virtio_device *vdev) static inline s64 towards_target(struct virtio_balloon *vb) { - u32 v; + __le32 v; + s64 target; + vb->vdev->config->get(vb->vdev, offsetof(struct virtio_balloon_config, num_pages), &v, sizeof(v)); - return (s64)v - vb->num_pages; + target = le32_to_cpu(v); + return target - vb->num_pages; } static void update_balloon_size(struct virtio_balloon *vb) -- 1.7.9.5