1 files changed, 23 insertions, 17 deletions

diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index 47a7e6200b26..9f55ce6f3c78 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -78,27 +78,32 @@ static unsigned desc_size(const struct kvm_device_desc *desc)
                 + 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 *vq)
  * 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,