RE: [PATCH v2] PCI: hv: Allocate MMIO from above 4GB for the config window

[Dexuan Cui]

> > ...
> > This approach could be taken one step further, where vmbus_reserve_fb()
> > *always* reserves 64 MiB starting at the low end of low MMIO space,
> > regardless of the value of "start". The messy code for getting "start"
> > could be dropped entirely, and the dependency on CONFIG_SYSFB goes
> > away. Or maybe still get the value of "start" and "size", and if non-zero
> > just do a sanity check that they are within the fixed 64 MiB reserved area.

My earlier reply yesterday explains why we shouldn't get rid of the
screen.lfb_base. I'm trying to make as few assumptions as possible.

> > Thoughts? To me tweaking vmbus_reserve_fb() is a more
> > straightforward and explicit way to do the reserving, vs. modifying
> > the requested range in the Hyper-V PCI driver.
> 
> Agreed. Let me try to make a new patch for review.

I just posted a patch here:
https://lwn.net/ml/linux-kernel/20260416183529.838321-1-decui%40microsoft.com/
Please review.

The new patch changes the vmbus driver. With it, the previous v2 pci-hyperv patch
 is unnecessary now.

Thanks,
-- Dexuan