Re: [PATCH v2] firmware: qemu_fw_cfg.c: hold ACPI global lock during device access

On 16/03/2016 17:57, Michael S. Tsirkin wrote:

On Tue, Mar 08, 2016 at 01:30:50PM -0500, Gabriel Somlo wrote:

quoted

Allowing for the future possibility of implementing AML-based
(i.e., firmware-triggered) access to the QEMU fw_cfg device,
acquire the global ACPI lock when accessing the device on behalf
of the guest-side sysfs driver, to prevent any potential race
conditions.

Suggested-by: Michael S. Tsirkin <redacted>
Signed-off-by: Gabriel Somlo <somlo-D+Gtc/HYRWM@public.gmane.org>

So this patch makes sense of course.


Given the recent discussion on QEMU mailing list,
I think there is an additional patch that we need:
filter the files exposed to userspace by "opt/" prefix.

This will ensure that we can change all other fw cfg files
at will without breaking guest scripts.

That makes no sense, all other fw_cfg files are firmware ABI so we
cannot change them anyway.

Paolo