Re: s390 kvm_virtio.c build error

Heiko Carstens
2008-05-04T19:25:51Z

On Sat, May 03, 2008 at 08:47:17PM +0300, Adrian Bunk wrote:
> Commit c45a6816c19dee67b8f725e6646d428901a6dc24
> (virtio: explicit advertisement of driver features)
> and commit e976a2b997fc4ad70ccc53acfe62811c4aaec851
> (s390: KVM guest: virtio device support, and kvm hypercalls)
> don't like each other:
>
> <-- snip -->
>
> ...
> CC drivers/s390/kvm/kvm_virtio.o
> /home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/s390/kvm/kvm_virtio.c:224: error: unknown field 'feature' specified in initializer
> /home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/s390/kvm/kvm_virtio.c:224: warning: initialization from incompatible pointer type
> make[3]: *** [drivers/s390/kvm/kvm_virtio.o] Error 1
>
> <-- snip -->

Hmm... this should help:

---
drivers/s390/kvm/kvm_virtio.c | 40 +++++++++++++++++++++++-----------------
1 file changed, 23 insertions(+), 17 deletions(-)

Index: linux-2.6/drivers/s390/kvm/kvm_virtio.c
===================================================================
--- linux-2.6.orig/drivers/s390/kvm/kvm_virtio.c
+++ linux-2.6/drivers/s390/kvm/kvm_virtio.c
@@ -78,27 +78,32 @@ static unsigned desc_size(const struct k
+ desc->config_len;
}

-/*
- * This tests (and acknowleges) a feature bit.
- */
-static bool kvm_feature(struct virtio_device *vdev, unsigned fbit)
+/* This gets the device's feature bits. */
+static u32 kvm_get_features(struct virtio_device *vdev)
{
+ unsigned int i;
+ u32 features = 0;
struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
- u8 *features;
+ u8 *in_features = kvm_vq_features(desc);

- if (fbit / 8 > desc->feature_len)
- return false;
+ for (i = 0; i < min(desc->feature_len * 8, 32); i++)
+ if (in_features[i / 8] & (1 << (i % 8)))
+ features |= (1 << i);
+ return features;
+}

- features = kvm_vq_features(desc);
- if (!(features[fbit / 8] & (1 << (fbit % 8))))
- return false;
+static void kvm_set_features(struct virtio_device *vdev, u32 features)
+{
+ unsigned int i;
+ struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
+ /* Second half of bitmap is features we accept. */
+ u8 *out_features = kvm_vq_features(desc) + desc->feature_len;

- /*
- * We set the matching bit in the other half of the bitmap to tell the
- * Host we want to use this feature.
- */
- features[desc->feature_len + fbit / 8] |= (1 << (fbit % 8));
- return true;
+ memset(out_features, 0, desc->feature_len);
+ for (i = 0; i < min(desc->feature_len * 8, 32); i++) {
+ if (features & (1 << i))
+ out_features[i / 8] |= (1 << (i % 8));
+ }
}

/*
@@ -221,7 +226,8 @@ static void kvm_del_vq(struct virtqueue
* The config ops structure as defined by virtio config
*/
static struct virtio_config_ops kvm_vq_configspace_ops = {
- .feature = kvm_feature,
+ .get_features = kvm_get_features,
+ .set_features = kvm_set_features,
.get = kvm_get,
.set = kvm_set,
.get_status = kvm_get_status,