uio_hv_generic: support sub-channels
Use sysfs to allow supporting sub-channels. The userspace application makes request to host to create sub-channels and the UIO kernel driver populates the sysfs per-channel directory with a binary attribute file that can be used to read/write ring. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
cf21be919c
commit
37b96a4931
|
@ -132,3 +132,10 @@ KernelVersion: 4.16
|
|||
Contact: Stephen Hemminger <sthemmin@microsoft.com>
|
||||
Description: Monitor bit associated with channel
|
||||
Users: Debugging tools and userspace drivers
|
||||
|
||||
What: /sys/bus/vmbus/devices/vmbus_*/channels/NN/ring
|
||||
Date: January. 2018
|
||||
KernelVersion: 4.16
|
||||
Contact: Stephen Hemminger <sthemmin@microsoft.com>
|
||||
Description: Binary file created by uio_hv_generic for ring buffer
|
||||
Users: Userspace drivers
|
||||
|
|
|
@ -709,6 +709,11 @@ The vmbus device regions are mapped into uio device resources:
|
|||
3) Network receive buffer region
|
||||
4) Network send buffer region
|
||||
|
||||
If a subchannel is created by a request to host, then the uio_hv_generic
|
||||
device driver will create a sysfs binary file for the per-channel ring buffer.
|
||||
For example:
|
||||
/sys/bus/vmbus/devices/3811fe4d-0fa0-4b62-981a-74fc1084c757/channels/21/ring
|
||||
|
||||
Further information
|
||||
===================
|
||||
|
||||
|
|
|
@ -121,6 +121,94 @@ static void hv_uio_rescind(struct vmbus_channel *channel)
|
|||
uio_event_notify(&pdata->info);
|
||||
}
|
||||
|
||||
/*
|
||||
* Handle fault when looking for sub channel ring buffer
|
||||
* Subchannel ring buffer is same as resource 0 which is main ring buffer
|
||||
* This is derived from uio_vma_fault
|
||||
*/
|
||||
static int hv_uio_vma_fault(struct vm_fault *vmf)
|
||||
{
|
||||
struct vm_area_struct *vma = vmf->vma;
|
||||
void *ring_buffer = vma->vm_private_data;
|
||||
struct page *page;
|
||||
void *addr;
|
||||
|
||||
addr = ring_buffer + (vmf->pgoff << PAGE_SHIFT);
|
||||
page = virt_to_page(addr);
|
||||
get_page(page);
|
||||
vmf->page = page;
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct vm_operations_struct hv_uio_vm_ops = {
|
||||
.fault = hv_uio_vma_fault,
|
||||
};
|
||||
|
||||
/* Sysfs API to allow mmap of the ring buffers */
|
||||
static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj,
|
||||
struct bin_attribute *attr,
|
||||
struct vm_area_struct *vma)
|
||||
{
|
||||
struct vmbus_channel *channel
|
||||
= container_of(kobj, struct vmbus_channel, kobj);
|
||||
unsigned long requested_pages, actual_pages;
|
||||
|
||||
if (vma->vm_end < vma->vm_start)
|
||||
return -EINVAL;
|
||||
|
||||
/* only allow 0 for now */
|
||||
if (vma->vm_pgoff > 0)
|
||||
return -EINVAL;
|
||||
|
||||
requested_pages = vma_pages(vma);
|
||||
actual_pages = 2 * HV_RING_SIZE;
|
||||
if (requested_pages > actual_pages)
|
||||
return -EINVAL;
|
||||
|
||||
vma->vm_private_data = channel->ringbuffer_pages;
|
||||
vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
|
||||
vma->vm_ops = &hv_uio_vm_ops;
|
||||
return 0;
|
||||
}
|
||||
|
||||
static struct bin_attribute ring_buffer_bin_attr __ro_after_init = {
|
||||
.attr = {
|
||||
.name = "ring",
|
||||
.mode = 0600,
|
||||
/* size is set at init time */
|
||||
},
|
||||
.mmap = hv_uio_ring_mmap,
|
||||
};
|
||||
|
||||
/* Callback from VMBUS subystem when new channel created. */
|
||||
static void
|
||||
hv_uio_new_channel(struct vmbus_channel *new_sc)
|
||||
{
|
||||
struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
|
||||
struct device *device = &hv_dev->device;
|
||||
struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
|
||||
const size_t ring_bytes = HV_RING_SIZE * PAGE_SIZE;
|
||||
int ret;
|
||||
|
||||
/* Create host communication ring */
|
||||
ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0,
|
||||
hv_uio_channel_cb, pdata);
|
||||
if (ret) {
|
||||
dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
|
||||
return;
|
||||
}
|
||||
|
||||
/* Disable interrupts on sub channel */
|
||||
new_sc->inbound.ring_buffer->interrupt_mask = 1;
|
||||
set_channel_read_mode(new_sc, HV_CALL_ISR);
|
||||
|
||||
ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);
|
||||
if (ret) {
|
||||
dev_err(device, "sysfs create ring bin file failed; %d\n", ret);
|
||||
vmbus_close(new_sc);
|
||||
}
|
||||
}
|
||||
|
||||
static void
|
||||
hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
|
||||
{
|
||||
|
@ -236,6 +324,7 @@ hv_uio_probe(struct hv_device *dev,
|
|||
}
|
||||
|
||||
vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind);
|
||||
vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel);
|
||||
|
||||
hv_set_drvdata(dev, pdata);
|
||||
|
||||
|
|
Loading…
Reference in a new issue