virtio: Rename set_features to finalize_features

Rather than explicitly handing the features to the lower-level, we just
hand the virtio_device and have it set the features.  This make it clear
that it has the chance to manipulate the features of the device at this
point (and that all feature negotiation is already done).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

4 files changed, 20 insertions, 17 deletions

diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index 1a8de57..54fdc2a 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -98,16 +98,17 @@ static u32 lg_get_features(struct virtio_device *vdev)
 	return features;
 }
 
-static void lg_set_features(struct virtio_device *vdev, u32 features)
+static void lg_finalize_features(struct virtio_device *vdev)
 {
-	unsigned int i;
+	unsigned int i, bits;
 	struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
 	/* Second half of bitmap is features we accept. */
 	u8 *out_features = lg_features(desc) + desc->feature_len;
 
 	memset(out_features, 0, desc->feature_len);
-	for (i = 0; i < min(desc->feature_len * 8, 32); i++) {
-		if (features & (1 << i))
+	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
+	for (i = 0; i < bits; i++) {
+		if (test_bit(i, vdev->features))
 			out_features[i / 8] |= (1 << (i % 8));
 	}
 }
@@ -297,7 +298,7 @@ static void lg_del_vq(struct virtqueue *vq)
 /* The ops structure which hooks everything together. */
 static struct virtio_config_ops lguest_config_ops = {
 	.get_features = lg_get_features,
-	.set_features = lg_set_features,
+	.finalize_features = lg_finalize_features,
 	.get = lg_get,
 	.set = lg_set,
 	.get_status = lg_get_status,
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index d41f234..5953510 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -88,16 +88,17 @@ static u32 kvm_get_features(struct virtio_device *vdev)
 	return features;
 }
 
-static void kvm_set_features(struct virtio_device *vdev, u32 features)
+static void kvm_finalize_features(struct virtio_device *vdev)
 {
-	unsigned int i;
+	unsigned int i, bits;
 	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;
 
 	memset(out_features, 0, desc->feature_len);
-	for (i = 0; i < min(desc->feature_len * 8, 32); i++) {
-		if (features & (1 << i))
+	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
+	for (i = 0; i < bits; i++) {
+		if (test_bit(i, vdev->features))
 			out_features[i / 8] |= (1 << (i % 8));
 	}
 }
@@ -223,7 +224,7 @@ static void kvm_del_vq(struct virtqueue *vq)
  */
 static struct virtio_config_ops kvm_vq_configspace_ops = {
 	.get_features = kvm_get_features,
-	.set_features = kvm_set_features,
+	.finalize_features = kvm_finalize_features,
 	.get = kvm_get,
 	.set = kvm_set,
 	.get_status = kvm_get_status,
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index baf1033..5b78fd0 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -113,7 +113,7 @@ static int virtio_dev_probe(struct device *_d)
 			set_bit(f, dev->features);
 	}
 
-	/* Transport features are always preserved to pass to set_features. */
+	/* Transport features always preserved to pass to finalize_features. */
 	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
 		if (device_features & (1 << i))
 			set_bit(i, dev->features);
@@ -122,8 +122,7 @@ static int virtio_dev_probe(struct device *_d)
 	if (err)
 		add_status(dev, VIRTIO_CONFIG_S_FAILED);
 	else {
-		/* They should never have set feature bits beyond 32 */
-		dev->config->set_features(dev, dev->features[0]);
+		dev->config->finalize_features(dev);
 		add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
 	}
 	return err;
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index eae72363..9855975 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -94,12 +94,14 @@ static u32 vp_get_features(struct virtio_device *vdev)
 	return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
 }
 
-/* virtio config->set_features() implementation */
-static void vp_set_features(struct virtio_device *vdev, u32 features)
+/* virtio config->finalize_features() implementation */
+static void vp_finalize_features(struct virtio_device *vdev)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 
-	iowrite32(features, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
+	/* We only support 32 feature bits. */
+	BUILD_BUG_ON(ARRAY_SIZE(vdev->features) != 1);
+	iowrite32(vdev->features[0], vp_dev->ioaddr+VIRTIO_PCI_GUEST_FEATURES);
 }
 
 /* virtio config->get() implementation */
@@ -297,7 +299,7 @@ static struct virtio_config_ops virtio_pci_config_ops = {
 	.find_vq	= vp_find_vq,
 	.del_vq		= vp_del_vq,
 	.get_features	= vp_get_features,
-	.set_features	= vp_set_features,
+	.finalize_features = vp_finalize_features,
 };
 
 /* the PCI probing function */