PCI: Skip Resizable BAR restore on read error

pci_restore_rebar_state() uses the Resizable BAR Control register to decide
how many BARs to restore (nbars) and which BAR each iteration addresses
(bar_idx).

When a device does not respond, config reads typically return
PCI_ERROR_RESPONSE (~0).  Both fields are 3 bits wide, so nbars and bar_idx
both evaluate to 7, past the spec's valid ranges for both fields.
pci_resource_n() then returns an unrelated resource slot, whose size is
used to derive a nonsensical value written back to the Resizable BAR
Control register.

Bail out if any Resizable BAR Control read returns PCI_ERROR_RESPONSE. No
further BARs are touched, which is safe because a config read that returns
PCI_ERROR_RESPONSE indicates the device is unreachable and restoration is
pointless.

Fixes: d3252ace0bc6 ("PCI: Restore resized BAR state on resume")
Signed-off-by: Marco Nenciarini <mnencia@kcore.it>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/666cac19b5daa0ab0e0ab64454e76b4d24465dbd.1776429882.git.mnencia@kcore.it

0 files changed, 0 insertions, 0 deletions