summaryrefslogtreecommitdiffstats
path: root/drivers/bus/vmbus/linux
diff options
context:
space:
mode:
authorLuca Boccassi <luca.boccassi@gmail.com>2018-08-14 18:52:30 +0100
committerLuca Boccassi <luca.boccassi@gmail.com>2018-08-14 18:53:17 +0100
commitb63264c8342e6a1b6971c79550d2af2024b6a4de (patch)
tree83114aac64286fe616506c0b3dfaec2ab86ef835 /drivers/bus/vmbus/linux
parentca33590b6af032bff57d9cc70455660466a654b2 (diff)
New upstream version 18.08upstream/18.08
Change-Id: I32fdf5e5016556d9c0a6d88ddaf1fc468961790a Signed-off-by: Luca Boccassi <luca.boccassi@gmail.com>
Diffstat (limited to 'drivers/bus/vmbus/linux')
-rw-r--r--drivers/bus/vmbus/linux/Makefile3
-rw-r--r--drivers/bus/vmbus/linux/vmbus_bus.c355
-rw-r--r--drivers/bus/vmbus/linux/vmbus_uio.c398
3 files changed, 756 insertions, 0 deletions
diff --git a/drivers/bus/vmbus/linux/Makefile b/drivers/bus/vmbus/linux/Makefile
new file mode 100644
index 00000000..ef0d30b2
--- /dev/null
+++ b/drivers/bus/vmbus/linux/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+SRCS += vmbus_bus.c vmbus_uio.c
diff --git a/drivers/bus/vmbus/linux/vmbus_bus.c b/drivers/bus/vmbus/linux/vmbus_bus.c
new file mode 100644
index 00000000..52d6a3c0
--- /dev/null
+++ b/drivers/bus/vmbus/linux/vmbus_bus.c
@@ -0,0 +1,355 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (c) 2018, Microsoft Corporation.
+ * All Rights Reserved.
+ */
+
+#include <string.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+#include <rte_eal.h>
+#include <rte_uuid.h>
+#include <rte_tailq.h>
+#include <rte_log.h>
+#include <rte_devargs.h>
+#include <rte_memory.h>
+#include <rte_malloc.h>
+#include <rte_bus_vmbus.h>
+
+#include "eal_filesystem.h"
+#include "private.h"
+
+/** Pathname of VMBUS devices directory. */
+#define SYSFS_VMBUS_DEVICES "/sys/bus/vmbus/devices"
+
+extern struct rte_vmbus_bus rte_vmbus_bus;
+
+/* Read sysfs file to get UUID */
+static int
+parse_sysfs_uuid(const char *filename, rte_uuid_t uu)
+{
+ char buf[BUFSIZ];
+ char *cp, *in = buf;
+ FILE *f;
+
+ f = fopen(filename, "r");
+ if (f == NULL) {
+ VMBUS_LOG(ERR, "cannot open sysfs value %s: %s",
+ filename, strerror(errno));
+ return -1;
+ }
+
+ if (fgets(buf, sizeof(buf), f) == NULL) {
+ VMBUS_LOG(ERR, "cannot read sysfs value %s",
+ filename);
+ fclose(f);
+ return -1;
+ }
+ fclose(f);
+
+ cp = strchr(buf, '\n');
+ if (cp)
+ *cp = '\0';
+
+ /* strip { } notation */
+ if (buf[0] == '{') {
+ in = buf + 1;
+ cp = strchr(in, '}');
+ if (cp)
+ *cp = '\0';
+ }
+
+ if (rte_uuid_parse(in, uu) < 0) {
+ VMBUS_LOG(ERR, "%s %s not a valid UUID",
+ filename, buf);
+ return -1;
+ }
+
+ return 0;
+}
+
+static int
+get_sysfs_string(const char *filename, char *buf, size_t buflen)
+{
+ char *cp;
+ FILE *f;
+
+ f = fopen(filename, "r");
+ if (f == NULL) {
+ VMBUS_LOG(ERR, "cannot open sysfs value %s:%s",
+ filename, strerror(errno));
+ return -1;
+ }
+
+ if (fgets(buf, buflen, f) == NULL) {
+ VMBUS_LOG(ERR, "cannot read sysfs value %s",
+ filename);
+ fclose(f);
+ return -1;
+ }
+ fclose(f);
+
+ /* remove trailing newline */
+ cp = memchr(buf, '\n', buflen);
+ if (cp)
+ *cp = '\0';
+
+ return 0;
+}
+
+static int
+vmbus_get_uio_dev(const struct rte_vmbus_device *dev,
+ char *dstbuf, size_t buflen)
+{
+ char dirname[PATH_MAX];
+ unsigned int uio_num;
+ struct dirent *e;
+ DIR *dir;
+
+ /* Assume recent kernel where uio is in uio/uioX */
+ snprintf(dirname, sizeof(dirname),
+ SYSFS_VMBUS_DEVICES "/%s/uio", dev->device.name);
+
+ dir = opendir(dirname);
+ if (dir == NULL)
+ return -1; /* Not a UIO device */
+
+ /* take the first file starting with "uio" */
+ while ((e = readdir(dir)) != NULL) {
+ const int prefix_len = 3;
+ char *endptr;
+
+ if (strncmp(e->d_name, "uio", prefix_len) != 0)
+ continue;
+
+ /* try uio%d */
+ errno = 0;
+ uio_num = strtoull(e->d_name + prefix_len, &endptr, 10);
+ if (errno == 0 && endptr != (e->d_name + prefix_len)) {
+ snprintf(dstbuf, buflen, "%s/uio%u", dirname, uio_num);
+ break;
+ }
+ }
+ closedir(dir);
+
+ if (e == NULL)
+ return -1;
+
+ return uio_num;
+}
+
+/* Check map names with kernel names */
+static const char *map_names[VMBUS_MAX_RESOURCE] = {
+ [HV_TXRX_RING_MAP] = "txrx_rings",
+ [HV_INT_PAGE_MAP] = "int_page",
+ [HV_MON_PAGE_MAP] = "monitor_page",
+ [HV_RECV_BUF_MAP] = "recv:",
+ [HV_SEND_BUF_MAP] = "send:",
+};
+
+
+/* map the resources of a vmbus device in virtual memory */
+int
+rte_vmbus_map_device(struct rte_vmbus_device *dev)
+{
+ char uioname[PATH_MAX], filename[PATH_MAX];
+ char dirname[PATH_MAX], mapname[64];
+ int i;
+
+ dev->uio_num = vmbus_get_uio_dev(dev, uioname, sizeof(uioname));
+ if (dev->uio_num < 0) {
+ VMBUS_LOG(DEBUG, "Not managed by UIO driver, skipped");
+ return 1;
+ }
+
+ /* Extract resource value */
+ for (i = 0; i < VMBUS_MAX_RESOURCE; i++) {
+ struct rte_mem_resource *res = &dev->resource[i];
+ unsigned long len, gpad = 0;
+ char *cp;
+
+ snprintf(dirname, sizeof(dirname),
+ "%s/maps/map%d", uioname, i);
+
+ snprintf(filename, sizeof(filename),
+ "%s/name", dirname);
+
+ if (get_sysfs_string(filename, mapname, sizeof(mapname)) < 0) {
+ VMBUS_LOG(ERR, "could not read %s", filename);
+ return -1;
+ }
+
+ if (strncmp(map_names[i], mapname, strlen(map_names[i])) != 0) {
+ VMBUS_LOG(ERR,
+ "unexpected resource %s (expected %s)",
+ mapname, map_names[i]);
+ return -1;
+ }
+
+ snprintf(filename, sizeof(filename),
+ "%s/size", dirname);
+ if (eal_parse_sysfs_value(filename, &len) < 0) {
+ VMBUS_LOG(ERR,
+ "could not read %s", filename);
+ return -1;
+ }
+ res->len = len;
+
+ /* both send and receive buffers have gpad in name */
+ cp = memchr(mapname, ':', sizeof(mapname));
+ if (cp)
+ gpad = strtoul(cp+1, NULL, 0);
+
+ /* put the GPAD value in physical address */
+ res->phys_addr = gpad;
+ }
+
+ return vmbus_uio_map_resource(dev);
+}
+
+void
+rte_vmbus_unmap_device(struct rte_vmbus_device *dev)
+{
+ vmbus_uio_unmap_resource(dev);
+}
+
+/* Scan one vmbus sysfs entry, and fill the devices list from it. */
+static int
+vmbus_scan_one(const char *name)
+{
+ struct rte_vmbus_device *dev, *dev2;
+ char filename[PATH_MAX];
+ char dirname[PATH_MAX];
+ unsigned long tmp;
+
+ dev = calloc(1, sizeof(*dev));
+ if (dev == NULL)
+ return -1;
+
+ dev->device.name = strdup(name);
+ if (!dev->device.name)
+ goto error;
+
+ /* sysfs base directory
+ * /sys/bus/vmbus/devices/7a08391f-f5a0-4ac0-9802-d13fd964f8df
+ * or on older kernel
+ * /sys/bus/vmbus/devices/vmbus_1
+ */
+ snprintf(dirname, sizeof(dirname), "%s/%s",
+ SYSFS_VMBUS_DEVICES, name);
+
+ /* get device id */
+ snprintf(filename, sizeof(filename), "%s/device_id", dirname);
+ if (parse_sysfs_uuid(filename, dev->device_id) < 0)
+ goto error;
+
+ /* get device class */
+ snprintf(filename, sizeof(filename), "%s/class_id", dirname);
+ if (parse_sysfs_uuid(filename, dev->class_id) < 0)
+ goto error;
+
+ /* get relid */
+ snprintf(filename, sizeof(filename), "%s/id", dirname);
+ if (eal_parse_sysfs_value(filename, &tmp) < 0)
+ goto error;
+ dev->relid = tmp;
+
+ /* get monitor id */
+ snprintf(filename, sizeof(filename), "%s/monitor_id", dirname);
+ if (eal_parse_sysfs_value(filename, &tmp) < 0)
+ goto error;
+ dev->monitor_id = tmp;
+
+ /* get numa node (if present) */
+ snprintf(filename, sizeof(filename), "%s/numa_node",
+ dirname);
+
+ if (access(filename, R_OK) == 0) {
+ if (eal_parse_sysfs_value(filename, &tmp) < 0)
+ goto error;
+ dev->device.numa_node = tmp;
+ } else {
+ /* if no NUMA support, set default to 0 */
+ dev->device.numa_node = SOCKET_ID_ANY;
+ }
+
+ /* device is valid, add in list (sorted) */
+ VMBUS_LOG(DEBUG, "Adding vmbus device %s", name);
+
+ TAILQ_FOREACH(dev2, &rte_vmbus_bus.device_list, next) {
+ int ret;
+
+ ret = rte_uuid_compare(dev->device_id, dev2->device_id);
+ if (ret > 0)
+ continue;
+
+ if (ret < 0) {
+ vmbus_insert_device(dev2, dev);
+ } else { /* already registered */
+ VMBUS_LOG(NOTICE,
+ "%s already registered", name);
+ free(dev);
+ }
+ return 0;
+ }
+
+ vmbus_add_device(dev);
+ return 0;
+error:
+ VMBUS_LOG(DEBUG, "failed");
+
+ free(dev);
+ return -1;
+}
+
+/*
+ * Scan the content of the vmbus, and the devices in the devices list
+ */
+int
+rte_vmbus_scan(void)
+{
+ struct dirent *e;
+ DIR *dir;
+
+ dir = opendir(SYSFS_VMBUS_DEVICES);
+ if (dir == NULL) {
+ if (errno == ENOENT)
+ return 0;
+
+ VMBUS_LOG(ERR, "opendir %s failed: %s",
+ SYSFS_VMBUS_DEVICES, strerror(errno));
+ return -1;
+ }
+
+ while ((e = readdir(dir)) != NULL) {
+ if (e->d_name[0] == '.')
+ continue;
+
+ if (vmbus_scan_one(e->d_name) < 0)
+ goto error;
+ }
+ closedir(dir);
+ return 0;
+
+error:
+ closedir(dir);
+ return -1;
+}
+
+void rte_vmbus_irq_mask(struct rte_vmbus_device *device)
+{
+ vmbus_uio_irq_control(device, 1);
+}
+
+void rte_vmbus_irq_unmask(struct rte_vmbus_device *device)
+{
+ vmbus_uio_irq_control(device, 0);
+}
+
+int rte_vmbus_irq_read(struct rte_vmbus_device *device)
+{
+ return vmbus_uio_irq_read(device);
+}
diff --git a/drivers/bus/vmbus/linux/vmbus_uio.c b/drivers/bus/vmbus/linux/vmbus_uio.c
new file mode 100644
index 00000000..856c6d66
--- /dev/null
+++ b/drivers/bus/vmbus/linux/vmbus_uio.c
@@ -0,0 +1,398 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (c) 2018, Microsoft Corporation.
+ * All Rights Reserved.
+ */
+
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <inttypes.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+#include <rte_log.h>
+#include <rte_bus.h>
+#include <rte_memory.h>
+#include <rte_eal_memconfig.h>
+#include <rte_common.h>
+#include <rte_malloc.h>
+#include <rte_bus_vmbus.h>
+#include <rte_string_fns.h>
+
+#include "private.h"
+
+/** Pathname of VMBUS devices directory. */
+#define SYSFS_VMBUS_DEVICES "/sys/bus/vmbus/devices"
+
+static void *vmbus_map_addr;
+
+/* Control interrupts */
+void vmbus_uio_irq_control(struct rte_vmbus_device *dev, int32_t onoff)
+{
+ if (write(dev->intr_handle.fd, &onoff, sizeof(onoff)) < 0) {
+ VMBUS_LOG(ERR, "cannot write to %d:%s",
+ dev->intr_handle.fd, strerror(errno));
+ }
+}
+
+int vmbus_uio_irq_read(struct rte_vmbus_device *dev)
+{
+ int32_t count;
+ int cc;
+
+ cc = read(dev->intr_handle.fd, &count, sizeof(count));
+ if (cc < (int)sizeof(count)) {
+ if (cc < 0) {
+ VMBUS_LOG(ERR, "IRQ read failed %s",
+ strerror(errno));
+ return -errno;
+ }
+ VMBUS_LOG(ERR, "can't read IRQ count");
+ return -EINVAL;
+ }
+
+ return count;
+}
+
+void
+vmbus_uio_free_resource(struct rte_vmbus_device *dev,
+ struct mapped_vmbus_resource *uio_res)
+{
+ rte_free(uio_res);
+
+ if (dev->intr_handle.uio_cfg_fd >= 0) {
+ close(dev->intr_handle.uio_cfg_fd);
+ dev->intr_handle.uio_cfg_fd = -1;
+ }
+
+ if (dev->intr_handle.fd >= 0) {
+ close(dev->intr_handle.fd);
+ dev->intr_handle.fd = -1;
+ dev->intr_handle.type = RTE_INTR_HANDLE_UNKNOWN;
+ }
+}
+
+int
+vmbus_uio_alloc_resource(struct rte_vmbus_device *dev,
+ struct mapped_vmbus_resource **uio_res)
+{
+ char devname[PATH_MAX]; /* contains the /dev/uioX */
+
+ /* save fd if in primary process */
+ snprintf(devname, sizeof(devname), "/dev/uio%u", dev->uio_num);
+ dev->intr_handle.fd = open(devname, O_RDWR);
+ if (dev->intr_handle.fd < 0) {
+ VMBUS_LOG(ERR, "Cannot open %s: %s",
+ devname, strerror(errno));
+ goto error;
+ }
+ dev->intr_handle.type = RTE_INTR_HANDLE_UIO_INTX;
+
+ /* allocate the mapping details for secondary processes*/
+ *uio_res = rte_zmalloc("UIO_RES", sizeof(**uio_res), 0);
+ if (*uio_res == NULL) {
+ VMBUS_LOG(ERR, "cannot store uio mmap details");
+ goto error;
+ }
+
+ strlcpy((*uio_res)->path, devname, PATH_MAX);
+ rte_uuid_copy((*uio_res)->id, dev->device_id);
+
+ return 0;
+
+error:
+ vmbus_uio_free_resource(dev, *uio_res);
+ return -1;
+}
+
+static int
+find_max_end_va(const struct rte_memseg_list *msl, void *arg)
+{
+ size_t sz = msl->memseg_arr.len * msl->page_sz;
+ void *end_va = RTE_PTR_ADD(msl->base_va, sz);
+ void **max_va = arg;
+
+ if (*max_va < end_va)
+ *max_va = end_va;
+ return 0;
+}
+
+/*
+ * TODO: this should be part of memseg api.
+ * code is duplicated from PCI.
+ */
+static void *
+vmbus_find_max_end_va(void)
+{
+ void *va = NULL;
+
+ rte_memseg_list_walk(find_max_end_va, &va);
+ return va;
+}
+
+int
+vmbus_uio_map_resource_by_index(struct rte_vmbus_device *dev, int idx,
+ struct mapped_vmbus_resource *uio_res,
+ int flags)
+{
+ size_t size = dev->resource[idx].len;
+ struct vmbus_map *maps = uio_res->maps;
+ void *mapaddr;
+ off_t offset;
+ int fd;
+
+ /* devname for mmap */
+ fd = open(uio_res->path, O_RDWR);
+ if (fd < 0) {
+ VMBUS_LOG(ERR, "Cannot open %s: %s",
+ uio_res->path, strerror(errno));
+ return -1;
+ }
+
+ /* try mapping somewhere close to the end of hugepages */
+ if (vmbus_map_addr == NULL)
+ vmbus_map_addr = vmbus_find_max_end_va();
+
+ /* offset is special in uio it indicates which resource */
+ offset = idx * PAGE_SIZE;
+
+ mapaddr = vmbus_map_resource(vmbus_map_addr, fd, offset, size, flags);
+ close(fd);
+
+ if (mapaddr == MAP_FAILED)
+ return -1;
+
+ dev->resource[idx].addr = mapaddr;
+ vmbus_map_addr = RTE_PTR_ADD(mapaddr, size);
+
+ /* Record result of sucessful mapping for use by secondary */
+ maps[idx].addr = mapaddr;
+ maps[idx].size = size;
+
+ return 0;
+}
+
+static int vmbus_uio_map_primary(struct vmbus_channel *chan,
+ void **ring_buf, uint32_t *ring_size)
+{
+ struct mapped_vmbus_resource *uio_res;
+
+ uio_res = vmbus_uio_find_resource(chan->device);
+ if (!uio_res) {
+ VMBUS_LOG(ERR, "can not find resources!");
+ return -ENOMEM;
+ }
+
+ if (uio_res->nb_maps < VMBUS_MAX_RESOURCE) {
+ VMBUS_LOG(ERR, "VMBUS: only %u resources found!",
+ uio_res->nb_maps);
+ return -EINVAL;
+ }
+
+ *ring_size = uio_res->maps[HV_TXRX_RING_MAP].size / 2;
+ *ring_buf = uio_res->maps[HV_TXRX_RING_MAP].addr;
+ return 0;
+}
+
+static int vmbus_uio_map_subchan(const struct rte_vmbus_device *dev,
+ const struct vmbus_channel *chan,
+ void **ring_buf, uint32_t *ring_size)
+{
+ char ring_path[PATH_MAX];
+ size_t file_size;
+ struct stat sb;
+ int fd;
+
+ snprintf(ring_path, sizeof(ring_path),
+ "%s/%s/channels/%u/ring",
+ SYSFS_VMBUS_DEVICES, dev->device.name,
+ chan->relid);
+
+ fd = open(ring_path, O_RDWR);
+ if (fd < 0) {
+ VMBUS_LOG(ERR, "Cannot open %s: %s",
+ ring_path, strerror(errno));
+ return -errno;
+ }
+
+ if (fstat(fd, &sb) < 0) {
+ VMBUS_LOG(ERR, "Cannot state %s: %s",
+ ring_path, strerror(errno));
+ close(fd);
+ return -errno;
+ }
+ file_size = sb.st_size;
+
+ if (file_size == 0 || (file_size & (PAGE_SIZE - 1))) {
+ VMBUS_LOG(ERR, "incorrect size %s: %zu",
+ ring_path, file_size);
+
+ close(fd);
+ return -EINVAL;
+ }
+
+ *ring_size = file_size / 2;
+ *ring_buf = vmbus_map_resource(vmbus_map_addr, fd,
+ 0, sb.st_size, 0);
+ close(fd);
+
+ if (ring_buf == MAP_FAILED)
+ return -EIO;
+
+ vmbus_map_addr = RTE_PTR_ADD(ring_buf, file_size);
+ return 0;
+}
+
+int vmbus_uio_map_rings(struct vmbus_channel *chan)
+{
+ const struct rte_vmbus_device *dev = chan->device;
+ uint32_t ring_size;
+ void *ring_buf;
+ int ret;
+
+ /* Primary channel */
+ if (chan->subchannel_id == 0)
+ ret = vmbus_uio_map_primary(chan, &ring_buf, &ring_size);
+ else
+ ret = vmbus_uio_map_subchan(dev, chan, &ring_buf, &ring_size);
+
+ if (ret)
+ return ret;
+
+ vmbus_br_setup(&chan->txbr, ring_buf, ring_size);
+ vmbus_br_setup(&chan->rxbr, (char *)ring_buf + ring_size, ring_size);
+ return 0;
+}
+
+static int vmbus_uio_sysfs_read(const char *dir, const char *name,
+ unsigned long *val, unsigned long max_range)
+{
+ char path[PATH_MAX];
+ FILE *f;
+ int ret;
+
+ snprintf(path, sizeof(path), "%s/%s", dir, name);
+ f = fopen(path, "r");
+ if (!f) {
+ VMBUS_LOG(ERR, "can't open %s:%s",
+ path, strerror(errno));
+ return -errno;
+ }
+
+ if (fscanf(f, "%lu", val) != 1)
+ ret = -EIO;
+ else if (*val > max_range)
+ ret = -ERANGE;
+ else
+ ret = 0;
+ fclose(f);
+
+ return ret;
+}
+
+static bool vmbus_uio_ring_present(const struct rte_vmbus_device *dev,
+ uint32_t relid)
+{
+ char ring_path[PATH_MAX];
+
+ /* Check if kernel has subchannel sysfs files */
+ snprintf(ring_path, sizeof(ring_path),
+ "%s/%s/channels/%u/ring",
+ SYSFS_VMBUS_DEVICES, dev->device.name, relid);
+
+ return access(ring_path, R_OK|W_OK) == 0;
+}
+
+bool vmbus_uio_subchannels_supported(const struct rte_vmbus_device *dev,
+ const struct vmbus_channel *chan)
+{
+ return vmbus_uio_ring_present(dev, chan->relid);
+}
+
+static bool vmbus_isnew_subchannel(struct vmbus_channel *primary,
+ unsigned long id)
+{
+ const struct vmbus_channel *c;
+
+ STAILQ_FOREACH(c, &primary->subchannel_list, next) {
+ if (c->relid == id)
+ return false;
+ }
+ return true;
+}
+
+int vmbus_uio_get_subchan(struct vmbus_channel *primary,
+ struct vmbus_channel **subchan)
+{
+ const struct rte_vmbus_device *dev = primary->device;
+ char chan_path[PATH_MAX], subchan_path[PATH_MAX];
+ struct dirent *ent;
+ DIR *chan_dir;
+
+ snprintf(chan_path, sizeof(chan_path),
+ "%s/%s/channels",
+ SYSFS_VMBUS_DEVICES, dev->device.name);
+
+ chan_dir = opendir(chan_path);
+ if (!chan_dir) {
+ VMBUS_LOG(ERR, "cannot open %s: %s",
+ chan_path, strerror(errno));
+ return -errno;
+ }
+
+ while ((ent = readdir(chan_dir))) {
+ unsigned long relid, subid, monid;
+ char *endp;
+ int err;
+
+ if (ent->d_name[0] == '.')
+ continue;
+
+ errno = 0;
+ relid = strtoul(ent->d_name, &endp, 0);
+ if (*endp || errno != 0 || relid > UINT16_MAX) {
+ VMBUS_LOG(NOTICE, "not a valid channel relid: %s",
+ ent->d_name);
+ continue;
+ }
+
+ snprintf(subchan_path, sizeof(subchan_path), "%s/%lu",
+ chan_path, relid);
+ err = vmbus_uio_sysfs_read(subchan_path, "subchannel_id",
+ &subid, UINT16_MAX);
+ if (err) {
+ VMBUS_LOG(NOTICE, "invalid subchannel id %lu",
+ subid);
+ closedir(chan_dir);
+ return err;
+ }
+
+ if (subid == 0)
+ continue; /* skip primary channel */
+
+ if (!vmbus_isnew_subchannel(primary, relid))
+ continue;
+
+ if (!vmbus_uio_ring_present(dev, relid))
+ continue; /* Ring may not be ready yet */
+
+ err = vmbus_uio_sysfs_read(subchan_path, "monitor_id",
+ &monid, UINT8_MAX);
+ if (err) {
+ VMBUS_LOG(NOTICE, "invalid monitor id %lu",
+ monid);
+ return err;
+ }
+
+ err = vmbus_chan_create(dev, relid, subid, monid, subchan);
+ if (err) {
+ VMBUS_LOG(NOTICE, "subchannel setup failed");
+ return err;
+ }
+ break;
+ }
+ closedir(chan_dir);
+
+ return (ent == NULL) ? -ENOENT : 0;
+}