PCI: fix nit in ROM BAR size probing

When probing for ROM BAR size, we should not change bits 1:10 in this
BAR, because these bits are marked as "reserved for future use" in PCI
spec, so changing them might have side effects.

No such issue for I/O or memory, as there is an implementation note in
PCI spec which explicitly allows writing 0xfffffffff there.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index bb2cc39..9cefc54 100644 (file)
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -165,12 +165,12 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
 {
        u32 l, sz, mask;
 
-       mask = type ? ~PCI_ROM_ADDRESS_ENABLE : ~0;
+       mask = type ? PCI_ROM_ADDRESS_MASK : ~0;
 
        res->name = pci_name(dev);
 
        pci_read_config_dword(dev, pos, &l);
-       pci_write_config_dword(dev, pos, mask);
+       pci_write_config_dword(dev, pos, l | mask);
        pci_read_config_dword(dev, pos, &sz);
        pci_write_config_dword(dev, pos, l);