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Commit e34f8725 authored by Rusty Russell's avatar Rusty Russell
Browse files

virtio: Add transport feature handling stub for virtio_ring. 



To prepare for virtio_ring transport feature bits, hook in a call in
all the users to manipulate them.  This currently just clears all the
bits, since it doesn't understand any features.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent c624896e

drivers/lguest/lguest_device.c

+3 −0
Original line number Diff line number Diff line
@@ -105,6 +105,9 @@ static void lg_finalize_features(struct virtio_device *vdev) 
	/* Second half of bitmap is features we accept. */

	u8 *out_features = lg_features(desc) + desc->feature_len;



	/* Give virtio_ring a chance to accept features. */

	vring_transport_features(vdev);



	memset(out_features, 0, desc->feature_len);

	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;

	for (i = 0; i < bits; i++) {

drivers/s390/kvm/kvm_virtio.c

+3 −0
Original line number Diff line number Diff line
@@ -95,6 +95,9 @@ static void kvm_finalize_features(struct virtio_device *vdev) 
	/* Second half of bitmap is features we accept. */

	u8 *out_features = kvm_vq_features(desc) + desc->feature_len;



	/* Give virtio_ring a chance to accept features. */

	vring_transport_features(vdev);



	memset(out_features, 0, desc->feature_len);

	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;

	for (i = 0; i < bits; i++) {

drivers/virtio/virtio_pci.c

+3 −0
Original line number Diff line number Diff line
@@ -99,6 +99,9 @@ static void vp_finalize_features(struct virtio_device *vdev) 
{

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);



	/* Give virtio_ring a chance to accept features. */

	vring_transport_features(vdev);



	/* 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);

drivers/virtio/virtio_ring.c

+16 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
 */

#include <linux/virtio.h>

#include <linux/virtio_ring.h>

#include <linux/virtio_config.h>

#include <linux/device.h>



#ifdef DEBUG
@@ -323,4 +324,19 @@ void vring_del_virtqueue(struct virtqueue *vq) 
}

EXPORT_SYMBOL_GPL(vring_del_virtqueue);



/* Manipulates transport-specific feature bits. */

void vring_transport_features(struct virtio_device *vdev)

{

	unsigned int i;



	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) {

		switch (i) {

		default:

			/* We don't understand this bit. */

			clear_bit(i, vdev->features);

		}

	}

}

EXPORT_SYMBOL_GPL(vring_transport_features);



MODULE_LICENSE("GPL");

include/linux/virtio_ring.h

+2 −0
Original line number Diff line number Diff line
@@ -120,6 +120,8 @@ struct virtqueue *vring_new_virtqueue(unsigned int num, 
				      void (*notify)(struct virtqueue *vq),

				      void (*callback)(struct virtqueue *vq));

void vring_del_virtqueue(struct virtqueue *vq);

/* Filter out transport-specific feature bits. */

void vring_transport_features(struct virtio_device *vdev);



irqreturn_t vring_interrupt(int irq, void *_vq);

#endif /* __KERNEL__ */