Cornelia Huck <cornelia.huck@xxxxxxxxxx> writes:
> On Thu, 21 Mar 2013 18:59:25 +1030
> Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote:
>
>> It seemed like a good idea, but it's actually a pain when we get more
>> than 32 feature bits. Just change it to a u32 for now.
>>
...
> I didn't try this patch, but wouldn't virtio_ccw need something like
> the change below as well?
Ah, yes, when I refreshed this pre-ccw patch, I didn't re-do the grep.
And thanks, this made me look at lguest, too. Which is actually fine,
but now has a misleading comment.
Here'st the net change on top of this patch (I've rolled into the
patch in my git tree).
Thanks,
Rusty.
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index 48bd2ad..6203562 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -137,9 +137,9 @@ static void lg_finalize_features(struct virtio_device *vdev)
vring_transport_features(vdev);
/*
- * The vdev->feature array is a Linux bitmask: this isn't the same as a
- * the simple array of bits used by lguest devices for features. So we
- * do this slow, manual conversion which is completely general.
+ * Since lguest is currently x86-only, we're little-endian. That
+ * means we could just memcpy. But it's not time critical, and in
+ * case someone copies this code, we do it the slow, obvious way.
*/
memset(out_features, 0, desc->feature_len);
bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 3652473..8c564bf 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -440,7 +440,6 @@ static void virtio_ccw_finalize_features(struct virtio_device *vdev)
{
struct virtio_ccw_device *vcdev = to_vc_device(vdev);
struct virtio_feature_desc *features;
- int i;
struct ccw1 *ccw;
ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
@@ -454,19 +453,15 @@ static void virtio_ccw_finalize_features(struct virtio_device *vdev)
/* Give virtio_ring a chance to accept features. */
vring_transport_features(vdev);
- for (i = 0; i < sizeof(*vdev->features) / sizeof(features->features);
- i++) {
- int highbits = i % 2 ? 32 : 0;
- features->index = i;
- features->features = cpu_to_le32(vdev->features[i / 2]
- >> highbits);
- /* Write the feature bits to the host. */
- ccw->cmd_code = CCW_CMD_WRITE_FEAT;
- ccw->flags = 0;
- ccw->count = sizeof(*features);
- ccw->cda = (__u32)(unsigned long)features;
- ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
- }
+ features->index = 0;
+ features->features = cpu_to_le32(vdev->features);
+ /* Write the feature bits to the host. */
+ ccw->cmd_code = CCW_CMD_WRITE_FEAT;
+ ccw->flags = 0;
+ ccw->count = sizeof(*features);
+ ccw->cda = (__u32)(unsigned long)features;
+ ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
+
out_free:
kfree(features);
kfree(ccw);
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