bus/vmbus: map ring in secondary process

Need to remember primary channel in secondary process.
Then use it to iterate over subchannels in secondary
process mapping setup.

Fixes: 831dba47bd36 ("bus/vmbus: add Hyper-V virtual bus support")
Cc: stable@dpdk.org

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>

drivers/bus/vmbus/linux/vmbus_uio.c

@@ -247,6 +247,49 @@ static int vmbus_uio_map_subchan(const struct rte_vmbus_device *dev,
 	return 0;
 }
 
+int
+vmbus_uio_map_secondary_subchan(const struct rte_vmbus_device *dev,
+				const struct vmbus_channel *chan)
+{
+	const struct vmbus_br *br = &chan->txbr;
+	char ring_path[PATH_MAX];
+	void *mapaddr, *ring_buf;
+	uint32_t ring_size;
+	int fd;
+
+	snprintf(ring_path, sizeof(ring_path),
+		 "%s/%s/channels/%u/ring",
+		 SYSFS_VMBUS_DEVICES, dev->device.name,
+		 chan->relid);
+
+	ring_buf = br->vbr;
+	ring_size = br->dsize + sizeof(struct vmbus_bufring);
+	VMBUS_LOG(INFO, "secondary ring_buf %p size %u",
+		  ring_buf, ring_size);
+
+	fd = open(ring_path, O_RDWR);
+	if (fd < 0) {
+		VMBUS_LOG(ERR, "Cannot open %s: %s",
+			  ring_path, strerror(errno));
+		return -errno;
+	}
+
+	mapaddr = vmbus_map_resource(ring_buf, fd, 0, 2 * ring_size, 0);
+	close(fd);
+
+	if (mapaddr == ring_buf)
+		return 0;
+
+	if (mapaddr == MAP_FAILED)
+		VMBUS_LOG(ERR,
+			  "mmap subchan %u in secondary failed", chan->relid);
+	else
+		VMBUS_LOG(ERR,
+			  "mmap subchan %u in secondary address mismatch",
+			  chan->relid);
+	return -1;
+}
+
 int vmbus_uio_map_rings(struct vmbus_channel *chan)
 {
 	const struct rte_vmbus_device *dev = chan->device;

drivers/bus/vmbus/private.h

@@ -45,6 +45,7 @@ struct mapped_vmbus_resource {
 
 	rte_uuid_t id;
 	int nb_maps;
+	struct vmbus_channel *primary;
 	struct vmbus_map maps[VMBUS_MAX_RESOURCE];
 	char path[PATH_MAX];
 };
@@ -107,6 +108,8 @@ bool vmbus_uio_subchannels_supported(const struct rte_vmbus_device *dev,
 int vmbus_uio_get_subchan(struct vmbus_channel *primary,
 			  struct vmbus_channel **subchan);
 int vmbus_uio_map_rings(struct vmbus_channel *chan);
+int vmbus_uio_map_secondary_subchan(const struct rte_vmbus_device *dev,
+				    const struct vmbus_channel *chan);
 
 void vmbus_br_setup(struct vmbus_br *br, void *buf, unsigned int blen);
 

drivers/bus/vmbus/vmbus_channel.c

@@ -352,12 +352,21 @@ int vmbus_chan_create(const struct rte_vmbus_device *device,
 int rte_vmbus_chan_open(struct rte_vmbus_device *device,
 			struct vmbus_channel **new_chan)
 {
+	struct mapped_vmbus_resource *uio_res;
 	int err;
 
+	uio_res = vmbus_uio_find_resource(device);
+	if (!uio_res) {
+		VMBUS_LOG(ERR, "can't find uio resource");
+		return -EINVAL;
+	}
+
 	err = vmbus_chan_create(device, device->relid, 0,
 				device->monitor_id, new_chan);
-	if (!err)
+	if (!err) {
 		device->primary = *new_chan;
+		uio_res->primary = *new_chan;
+	}
 
 	return err;
 }
@@ -396,11 +405,16 @@ void rte_vmbus_chan_close(struct vmbus_channel *chan)
 	const struct rte_vmbus_device *device = chan->device;
 	struct vmbus_channel *primary = device->primary;
 
-	if (chan != primary)
+	/*
+	 * intentionally leak primary channel because
+	 * secondary may still reference it
+	 */
+	if (chan != primary) {
 		STAILQ_REMOVE(&primary->subchannel_list, chan,
 			      vmbus_channel, next);
+		rte_free(chan);
+	}
 
-	rte_free(chan);
 }
 
 static void vmbus_dump_ring(FILE *f, const char *id, const struct vmbus_br *br)

drivers/bus/vmbus/vmbus_common_uio.c

@@ -27,6 +27,7 @@ static int
 vmbus_uio_map_secondary(struct rte_vmbus_device *dev)
 {
 	int fd, i;
+	struct vmbus_channel *chan;
 	struct mapped_vmbus_resource *uio_res;
 	struct mapped_vmbus_res_list *uio_res_list
 		= RTE_TAILQ_CAST(vmbus_tailq.head, mapped_vmbus_res_list);
@@ -76,6 +77,20 @@ vmbus_uio_map_secondary(struct rte_vmbus_device *dev)
 
 		/* fd is not needed in slave process, close it */
 		close(fd);
+
+		dev->primary = uio_res->primary;
+		if (!dev->primary) {
+			VMBUS_LOG(ERR, "missing primary channel");
+			return -1;
+		}
+
+		STAILQ_FOREACH(chan, &dev->primary->subchannel_list, next) {
+			if (vmbus_uio_map_secondary_subchan(dev, chan) != 0) {
+				VMBUS_LOG(ERR, "cannot map secondary subchan");
+				return -1;
+			}
+		}
+
 		return 0;
 	}