[ofw] open_ca & um_open_ca calls in winverbs

[Leonid Keller]

Right.
WinVerbs doesn't provide a kernel interface for now.
 


________________________________

	From: ofw-bounces at lists.openfabrics.org
[mailto:ofw-bounces at lists.openfabrics.org] On Behalf Of Prasanna Vv
	Sent: Tuesday, September 15, 2009 4:21 PM
	To: ofw at lists.openfabrics.org
	Subject: [ofw] open_ca & um_open_ca calls in winverbs 
	
	
	Hi All,
	
	I request feedback for few queries related to mapping HCA
registers in user space and  kernel space, just for understanding  and
not for any specific purpose such as  RDS etc..
	
	1. I find HCA driver provides 2 verbs call :  'open_ca' and
'um_open_ca'  to get handle to CA. As I  understand , 'open_ca()'
provides HCA access to kernel space
	and 'um_open_ca()' provides HCA access to user space. So in
order to do post_send/post_recv from kernel mode,  HCA handle should be
obtained using 'open_ca()';
	Similarly  'um_open_ca()' provides HCA handle to do
post_send/post_recv from user space. Please let me if you agree  with
the same.
	
	
	2. I observe Winverbs driver call HCA 'um_open_ca(..)' while
opening winverbs device object as below:
	
	WvDeviceInit()
	{
	
	....
	pDevice->pVerbs->um_open_ca(..)
	...
	
	}
	
	So essentially  it looks winverbs does not provide any scope for
kernel mode HCA access and hence do post_send/post_receive from kernel
space. Can it be possible to have  option in create to facilitate both
kernel mode and user mode CA mapping in winverbs driver ? or do you see
any other issues in supporting 'open_ca()' in winverbs driver.
	
	Regards,
	Prasanna
	

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