On 29.01.2025 04:22, Marek Marczykowski-Górecki wrote: > On Tue, Jan 28, 2025 at 09:03:15PM -0600, Bjorn Helgaas wrote: >> The report claims the problem only happens with Xen. I'm not a Xen >> person, and I don't know how to find the relevant config accessors. >> The snippets of kernel messages I see at [1] all mention pciback, so >> that's my only clue of where to look. Bottom line, I have no idea >> what the config accessor path is, and maybe we could learn something >> by looking at whatever it is. > > AFAIK there are no separate config accessors under Xen dom0, the default > ones are used. xen-pcifront takes over PCI config space access (and few > more) only in a domU (and only for PV), when PCI passthrough is used. > Here, it didn't went that far... > > But then, Xen may intercept such access [2]. If I read it right, it > should allow all access (is_hardware_domain(dom0)==true, and also the > device is not on ro_map - otherwise reset wouldn't work at all). The other day you mentioned (on Matrix I think) that you observe mmcfg not being used on that system. Am I misremembering? (Since the capability where the control bit lives is an extended one, that capability would neither be read nor modified when mmcfg is unavailable.) Jan
