On Thu, Jul 22, 2021 at 11:47:06AM -0700, Patel, Nirmal wrote:
> On 7/20/2021 3:42 PM, Bjorn Helgaas wrote:
> > On Tue, Jul 20, 2021 at 01:50:09PM -0700, Nirmal Patel wrote:
> >> In order to properly re-initialize the VMD domain during repetitive driver
> >> attachment or reboot tests, ensure that the VMD root ports are re-initialized
> >> to a blank state that can be re-enumerated appropriately by the PCI core.
> >> This is performed by re-initializing all of the bridge windows to ensure
> >> that PCI core enumeration does not detect potentially invalid bridge windows
> >> and misinterpret them as firmware-assigned windows, when they simply may be
> >> invalid bridge window information from a previous boot.
> >> +static void vmd_domain_reset_windows(struct vmd_dev *vmd)
> >> +{
> >> + u8 hdr_type;
> >> + char __iomem *addr;
> >> + int dev_seq;
> >> + u8 functions;
> >> + u8 fn_seq;
> >> + int max_devs = resource_size(&vmd->resources[0]) * 32;
> >> +
> >> + for (dev_seq = 0; dev_seq < max_devs; dev_seq++) {
> >> + addr = VMD_DEVICE_BASE(vmd, dev_seq) + PCI_VENDOR_ID;
> >> + if (readw(addr) != PCI_VENDOR_ID_INTEL)
> >> + continue;
> >> +
> >> + addr = VMD_DEVICE_BASE(vmd, dev_seq) + PCI_HEADER_TYPE;
> >> + hdr_type = readb(addr) & PCI_HEADER_TYPE_MASK;
> >> + if (hdr_type != PCI_HEADER_TYPE_BRIDGE)
> >> + continue;
> >> +
> >> + functions = !!(hdr_type & 0x80) ? 8 : 1;
> >> + for (fn_seq = 0; fn_seq < functions; fn_seq++)
> >> + {
> >
> > Looks quite parallel to vmd_domain_sbr(), except that here we iterate
> > through functions as well. Why does vmd_domain_sbr() not need to
> > iterate through functions?
>
> I am not sure if there is VMD hardware with non zero functions.
I'm not sure either ;) Hopefully you can resolve this one way or the
other. It would be good to either make them the same or add a comment
about why they are different. Otherwise it just looks like a possible
bug.
