Re: [PATCH v8 0/5] PCI: endpoint: BAR subrange mapping support

Niklas Cassel
2026-01-26T19:08:38Z

On Mon, Jan 26, 2026 at 11:26:53PM +0900, Koichiro Den wrote:
> On Fri, Jan 23, 2026 at 03:57:25PM +0100, Niklas Cassel wrote:
> >
> > I guess in worst case, if someone actually complains, I think a nice
> > solution would be do to like you are doing for vntb:
> > https://lore.kernel.org/linux-pci/20260118135440.1958279-34-den@valinux.co.jp/
> >
> > i.e. pci-epf-test could have {barX_size} in configfs, one per BAR,
> > and then the user themselves could configure the BAR sizes that they
> > want to run pci-epf-test with, if the pci-epf-test default sizes are
> > not desirable, before starting the link. (Some tests like e.g. the
> > subrange mapping test should of course fail if there is not a single
> > BAR with BAR size larger than needed to test the feature.)
> >
> > But if I were you, I would just bump the defaults, since the defaults
> > are currently overrided for BAR type FIXED_BAR and RESIZABLE_BAR anyway,
> > and just add the barX_size attributes in configfs if someone complains.
>
> That makes sense. I bumped the default sizes in v10, and if this turns out
> to be a concern for some setups, I'll consider sending a patch to add such
> configfs knobs. Thanks for sharing your thoughts.

FWIW, I think such configfs knobs are nice to have regardless of any new
features or not.

(I have personally changed the hardcoded values locally during testing many
times.)

So I decided to just send a patch that adds such configfs knobs:
https://lore.kernel.org/linux-pci/20260123180747.827357-2-cassel@kernel.org/

Kind regards,
Niklas