From: Michael S. Tsirkin <mst@redhat.com>
Date: Thu, 4 Dec 2014 17:16:43 +0000 (+0200)
Subject: virtio_ccw: rev 1 devices set VIRTIO_F_VERSION_1
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=4d23676fb645f683b61943de9901d58c1e728a25;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

virtio_ccw: rev 1 devices set VIRTIO_F_VERSION_1

What does it mean if rev 1 device does not set
VIRTIO_F_VERSION_1? E.g. is it native endian?

Let's not even try to drive such devices:
fail attempts to finalize features.
virtio core will detect this and bail out.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 789275fb577f..f9f87ba013c9 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -758,6 +758,13 @@ static int virtio_ccw_finalize_features(struct virtio_device *vdev)
 	struct virtio_feature_desc *features;
 	struct ccw1 *ccw;
 
+	if (vcdev->revision == 1 &&
+	    !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
+		dev_err(&vdev->dev, "virtio: device uses revision 1 "
+			"but does not have VIRTIO_F_VERSION_1\n");
+		return -EINVAL;
+	}
+
 	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
 	if (!ccw)
 		return 0;