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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <aXe7ssERwysqJbT7@ryzen>
Date: Mon, 26 Jan 2026 20:08:34 +0100
From: Niklas Cassel <cassel@...nel.org>
To: Koichiro Den <den@...inux.co.jp>
Cc: Manivannan Sadhasivam <mani@...nel.org>, bhelgaas@...gle.com,
	kwilczynski@...nel.org, frank.li@....com, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8 0/5] PCI: endpoint: BAR subrange mapping support

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