RE: [PATCH 1/1] Drivers: hv: vmbus: Add vendor and device atttributes

[KY Srinivasan <kys@microsoft.com>]

> -----Original Message-----
> From: Greg KH [mailto:gregkh@linuxfoundation.org]
> Sent: Monday, December 21, 2015 1:15 PM
> To: KY Srinivasan <kys@microsoft.com>
> Cc: linux-kernel@vger.kernel.org; devel@linuxdriverproject.org;
> olaf@aepfle.de; apw@canonical.com; vkuznets@redhat.com;
> jasowang@redhat.com
> Subject: Re: [PATCH 1/1] Drivers: hv: vmbus: Add vendor and device
> atttributes
> 
> On Thu, Dec 17, 2015 at 03:51:29PM -0800, K. Y. Srinivasan wrote:
> > Add vendor and device attributes to VMBUS devices. These will be used
> > by Hyper-V tools as well user-level RDMA libraries that will use the
> > vendor/device tuple to discover the RDMA device.
> >
> > Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
> > ---
> >  Documentation/ABI/stable/sysfs-bus-vmbus |   14 ++++++++++++++
> >  drivers/hv/vmbus_drv.c                   |   21 +++++++++++++++++++++
> >  include/linux/hyperv.h                   |    2 ++
> >  3 files changed, 37 insertions(+), 0 deletions(-)
> >
> > diff --git a/Documentation/ABI/stable/sysfs-bus-vmbus
> b/Documentation/ABI/stable/sysfs-bus-vmbus
> > index 636e938..5d0125f 100644
> > --- a/Documentation/ABI/stable/sysfs-bus-vmbus
> > +++ b/Documentation/ABI/stable/sysfs-bus-vmbus
> > @@ -27,3 +27,17 @@ Description:	The mapping of which primary/sub
> channels are bound to which
> >  		Virtual Processors.
> >  		Format: <channel's child_relid:the bound cpu's number>
> >  Users:		tools/hv/lsvmbus
> > +
> > +What:		/sys/bus/vmbus/devices/vmbus_*/device
> 
> Shouldn't that be 'device_id' as 'device' is a symlink in the sysfs
> tree?
We currently have device_id as one of the attributes - this is the instance GUID. We want to add
the 16 bit device attribute to VMBUS devices. 
> 
> > +Date:		Dec. 2015
> > +KernelVersion:	4.5
> > +Contact:	K. Y. Srinivasan <kys@microsoft.com>
> > +Description:	The 16 bit device ID of the device
> > +Users:		tools/hv/lsvmbus and user level RDMA libraries
> > +
> > +What:		/sys/bus/vmbus/devices/vmbus_*/vendor
> 
> 'vendor_id'?
We want to have the device and vendor attributes like the PCI devices have.
> 
> 
> > +Date:		Dec. 2015
> > +KernelVersion:	4.5
> > +Contact:	K. Y. Srinivasan <kys@microsoft.com>
> > +Description:	The 16 bit vendor ID of the device
> > +Users:		tools/hv/lsvmbus and user level RDMA libraries
> > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> > index 328e4c3..3668a95 100644
> > --- a/drivers/hv/vmbus_drv.c
> > +++ b/drivers/hv/vmbus_drv.c
> > @@ -477,6 +477,24 @@ static ssize_t channel_vp_mapping_show(struct
> device *dev,
> >  }
> >  static DEVICE_ATTR_RO(channel_vp_mapping);
> >
> > +static ssize_t vendor_show(struct device *dev,
> > +			   struct device_attribute *dev_attr,
> > +			   char *buf)
> > +{
> > +	struct hv_device *hv_dev = device_to_hv_device(dev);
> > +	return sprintf(buf, "0x%x\n", hv_dev->vendor_id);
> > +}
> > +static DEVICE_ATTR_RO(vendor);
> > +
> > +static ssize_t device_show(struct device *dev,
> > +			   struct device_attribute *dev_attr,
> > +			   char *buf)
> > +{
> > +	struct hv_device *hv_dev = device_to_hv_device(dev);
> > +	return sprintf(buf, "0x%x\n", hv_dev->device_id);
> > +}
> > +static DEVICE_ATTR_RO(device);
> > +
> >  /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device>
> */
> >  static struct attribute *vmbus_attrs[] = {
> >  	&dev_attr_id.attr,
> > @@ -502,6 +520,8 @@ static struct attribute *vmbus_attrs[] = {
> >  	&dev_attr_in_read_bytes_avail.attr,
> >  	&dev_attr_in_write_bytes_avail.attr,
> >  	&dev_attr_channel_vp_mapping.attr,
> > +	&dev_attr_vendor.attr,
> > +	&dev_attr_device.attr,
> >  	NULL,
> >  };
> >  ATTRIBUTE_GROUPS(vmbus);
> > @@ -957,6 +977,7 @@ struct hv_device *vmbus_device_create(const
> uuid_le *type,
> >  	memcpy(&child_device_obj->dev_type, type, sizeof(uuid_le));
> >  	memcpy(&child_device_obj->dev_instance, instance,
> >  	       sizeof(uuid_le));
> > +	child_device_obj->vendor_id = 0x1414; /* MSFT vendor ID */
> 
> So this is always the same value?
The MSFT  PCI Vendor ID is the default value.
> 
> And device_id is never set?  What does it default to?  Why include it in
> this patch if it's never used?
I will add that and resubmit.

Regards,

K. Y