On 09/04/2012 09:33 PM, Don Dutile wrote:
On 08/30/2012 02:02 AM, Bjorn Helgaas wrote:
[removed cc ksummit-2012-discuss]
On Wed, Aug 29, 2012 at 3:54 PM, Yinghai Lu<yinghai@xxxxxxxxxx> wrote:
On Wed, Aug 29, 2012 at 3:44 PM, Jon Mason<jdmason@xxxxxxxx> wrote:
Hi Bjorn,
One of my team member reported another corner case for SR-IOV. There's
are two NIC cards in the system driven by the same driver, but one supports
SR-IOV and the other doesn't. It runs into trouble if "max_vfs" parameter is
set for the NIC driver.
--Gerry
I believe it was decided that a per-pf sysfs interface would be used
to replace the current module parameter that specifies the number of
vf's. This should enable different numbers of vf's for each physical
device. The driver interface that was discussed would introduce new
function pointers for handlers to setup/teardown the vf's. I believe
this will solve your problem once it has been implemented.
now we have ixgbe.max_vfs=63
so if change to per pci device (PF),
how about having the driver built-in?
what kind of kernel parameters will be passed?
Having the driver built-in won't make a difference.
The model is to have files under sys fs, i.e.,
/sys/bus/pci/devices/0000:03:01.0/[sriov_vf_enable, sriov_vf_disable]
where one echo's the number of vf's one wants to configure for a pf
into the sriov_vf_enable file; if want to disable/deconfigure the vf's,
one echo's a 1 to sriov_vf_disable (all or nothing disable).
the pci core will be able to check & filter that the max num of vf's
is not exceeded. Also looking to add a file like 'sriov_num_vfs' to
indicate max number of vf's a PF supports. Whether the bus configuration
supports it (enough mmio space, enough pci bus nums, etc.) won't be
known until the enable count is written.
I have the code down to create the sysfs files & report the num_vfs.
^^^^ should be 'done' ...
Hope to have the first enable/disable working within another week.
The tough part is to re-factor a pf driver that enables/configures pf;
I'm working with the igb(_main.c) driver right now.
- Don
btw -- what we didn't resolve at summit, and I haven't taken a crack at it yet,
is a method to set the vf-enablement on a per-pf basis at boot time...
-- kernel cmdline (sounds knarly for large PCIe config)
-- /etc/module.d/sriov.conf ?
-- other ?
I don't think we really discussed things at this level, and I
personally don't know enough about the current SR-IOV support to even
know what the possible strategies are. I think it's really up to the
person doing the implementation to figure out what makes sense given
the constraints of the SR-IOV specs and the current Linux support.
Bjorn
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