From 156b97fa1f4366966b8cb50be6e720a58e50e959 Mon Sep 17 00:00:00 2001
From: Ruslan Bukin <br@FreeBSD.org>
Date: Fri, 12 Dec 2014 11:19:10 +0000
Subject: [PATCH] Add virtio bus 'poll' method allowing us to inform backend we
 are going to poll virtqueue.

Use on BERI soft-core to invalidate cpu caches.

Reviewed by:	bryanv
Sponsored by:	DARPA, AFRL
---
 sys/dev/beri/virtio/virtio_mmio_platform.c | 10 ++++++++++
 sys/dev/virtio/mmio/virtio_mmio.c          | 13 +++++++++++++
 sys/dev/virtio/mmio/virtio_mmio_if.m       |  7 +++++++
 sys/dev/virtio/virtio_bus_if.m             |  5 +++++
 sys/dev/virtio/virtqueue.c                 |  5 ++++-
 5 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/sys/dev/beri/virtio/virtio_mmio_platform.c b/sys/dev/beri/virtio/virtio_mmio_platform.c
index 0c58747d8b5b..86244babc448 100644
--- a/sys/dev/beri/virtio/virtio_mmio_platform.c
+++ b/sys/dev/beri/virtio/virtio_mmio_platform.c
@@ -234,12 +234,22 @@ platform_setup_intr(device_t dev, device_t mmio_dev,
 	return (0);
 }
 
+static int
+platform_poll(device_t dev)
+{
+
+	mips_dcache_wbinv_all();
+
+	return (0);
+}
+
 static device_method_t virtio_mmio_platform_methods[] = {
 	DEVMETHOD(device_probe,		virtio_mmio_platform_probe),
 	DEVMETHOD(device_attach,	virtio_mmio_platform_attach),
 
 	/* virtio_mmio_if.h */
 	DEVMETHOD(virtio_mmio_note,		platform_note),
+	DEVMETHOD(virtio_mmio_poll,		platform_poll),
 	DEVMETHOD(virtio_mmio_setup_intr,	platform_setup_intr),
 	DEVMETHOD_END
 };
diff --git a/sys/dev/virtio/mmio/virtio_mmio.c b/sys/dev/virtio/mmio/virtio_mmio.c
index 5c6a0e18a4af..c41eafc9c0e1 100644
--- a/sys/dev/virtio/mmio/virtio_mmio.c
+++ b/sys/dev/virtio/mmio/virtio_mmio.c
@@ -114,6 +114,7 @@ static int	vtmmio_alloc_virtqueues(device_t, int, int,
 		    struct vq_alloc_info *);
 static int	vtmmio_setup_intr(device_t, enum intr_type);
 static void	vtmmio_stop(device_t);
+static void	vtmmio_poll(device_t);
 static int	vtmmio_reinit(device_t, uint64_t);
 static void	vtmmio_reinit_complete(device_t);
 static void	vtmmio_notify_virtqueue(device_t, uint16_t);
@@ -182,6 +183,7 @@ static device_method_t vtmmio_methods[] = {
 	DEVMETHOD(virtio_bus_alloc_virtqueues,	  vtmmio_alloc_virtqueues),
 	DEVMETHOD(virtio_bus_setup_intr,	  vtmmio_setup_intr),
 	DEVMETHOD(virtio_bus_stop,		  vtmmio_stop),
+	DEVMETHOD(virtio_bus_poll,		  vtmmio_poll),
 	DEVMETHOD(virtio_bus_reinit,		  vtmmio_reinit),
 	DEVMETHOD(virtio_bus_reinit_complete,	  vtmmio_reinit_complete),
 	DEVMETHOD(virtio_bus_notify_vq,		  vtmmio_notify_virtqueue),
@@ -550,6 +552,17 @@ vtmmio_stop(device_t dev)
 	vtmmio_reset(device_get_softc(dev));
 }
 
+static void
+vtmmio_poll(device_t dev)
+{
+	struct vtmmio_softc *sc;
+
+	sc = device_get_softc(dev);
+
+	if (sc->platform != NULL)
+		VIRTIO_MMIO_POLL(sc->platform);
+}
+
 static int
 vtmmio_reinit(device_t dev, uint64_t features)
 {
diff --git a/sys/dev/virtio/mmio/virtio_mmio_if.m b/sys/dev/virtio/mmio/virtio_mmio_if.m
index 8514c307b994..499c619c8e92 100644
--- a/sys/dev/virtio/mmio/virtio_mmio_if.m
+++ b/sys/dev/virtio/mmio/virtio_mmio_if.m
@@ -66,6 +66,13 @@ METHOD int note {
 	int		val;
 } DEFAULT virtio_mmio_note;
 
+#
+# Inform backend we are going to poll virtqueue.
+#
+METHOD int poll {
+	device_t	dev;
+};
+
 #
 # Setup backend-specific interrupts.
 #
diff --git a/sys/dev/virtio/virtio_bus_if.m b/sys/dev/virtio/virtio_bus_if.m
index 74341ffe3751..cbf6069d242f 100644
--- a/sys/dev/virtio/virtio_bus_if.m
+++ b/sys/dev/virtio/virtio_bus_if.m
@@ -87,3 +87,8 @@ METHOD void write_device_config {
 	void		*src;
 	int		len;
 };
+
+METHOD void poll {
+	device_t	dev;
+};
+
diff --git a/sys/dev/virtio/virtqueue.c b/sys/dev/virtio/virtqueue.c
index 94016087f8bf..e25d39e6b5d7 100644
--- a/sys/dev/virtio/virtqueue.c
+++ b/sys/dev/virtio/virtqueue.c
@@ -567,8 +567,11 @@ virtqueue_poll(struct virtqueue *vq, uint32_t *len)
 {
 	void *cookie;
 
-	while ((cookie = virtqueue_dequeue(vq, len)) == NULL)
+	VIRTIO_BUS_POLL(vq->vq_dev);
+	while ((cookie = virtqueue_dequeue(vq, len)) == NULL) {
 		cpu_spinwait();
+		VIRTIO_BUS_POLL(vq->vq_dev);
+	}
 
 	return (cookie);
 }