virtio: Add VirtIO PCI modern (V1) support

Use the existing legacy PCI driver as the basis for shared code
between the legacy and modern PCI drivers. The existing virtio_pci
kernel module will contain both the legacy and modern drivers.

Changes to the virtqueue and each device driver (network, block, etc)
for V1 support come in later commits.

Update the MMIO driver to reflect the VirtIO bus method changes, but
the modern compliance can be improved on later.

Note that the modern PCI driver requires bus_map_resource() to be
implemented, which is not the case on all archs.

The hw.virtio.pci.transitional tunable default value is zero so
transitional devices will continue to be driven via the legacy
driver.

Reviewed by: grehan (mentor)
Differential Revision: https://reviews.freebsd.org/D27856

1 files changed, 7 insertions, 3 deletions

diff --git a/sys/dev/virtio/virtqueue.c b/sys/dev/virtio/virtqueue.c
index e23d4d25c47f..da6e7bf89fd5 100644
--- a/sys/dev/virtio/virtqueue.c
+++ b/sys/dev/virtio/virtqueue.c
@@ -64,6 +64,7 @@ struct virtqueue {
 #define	VIRTQUEUE_FLAG_INDIRECT	 0x0001
 #define	VIRTQUEUE_FLAG_EVENT_IDX 0x0002
 
+	bus_size_t		 vq_notify_offset;
 	int			 vq_alignment;
 	int			 vq_ring_size;
 	void			*vq_ring_mem;
@@ -147,8 +148,9 @@ virtqueue_filter_features(uint64_t features)
 }
 
 int
-virtqueue_alloc(device_t dev, uint16_t queue, uint16_t size, int align,
-    vm_paddr_t highaddr, struct vq_alloc_info *info, struct virtqueue **vqp)
+virtqueue_alloc(device_t dev, uint16_t queue, uint16_t size,
+    bus_size_t notify_offset, int align, vm_paddr_t highaddr,
+    struct vq_alloc_info *info, struct virtqueue **vqp)
 {
 	struct virtqueue *vq;
 	int error;
@@ -184,6 +186,7 @@ virtqueue_alloc(device_t dev, uint16_t queue, uint16_t size, int align,
 	vq->vq_dev = dev;
 	strlcpy(vq->vq_name, info->vqai_name, sizeof(vq->vq_name));
 	vq->vq_queue_index = queue;
+	vq->vq_notify_offset = notify_offset;
 	vq->vq_alignment = align;
 	vq->vq_nentries = size;
 	vq->vq_free_cnt = size;
@@ -820,7 +823,8 @@ static void
 vq_ring_notify_host(struct virtqueue *vq)
 {
 
-	VIRTIO_BUS_NOTIFY_VQ(vq->vq_dev, vq->vq_queue_index);
+	VIRTIO_BUS_NOTIFY_VQ(vq->vq_dev, vq->vq_queue_index,
+	    vq->vq_notify_offset);
 }
 
 static void