xen-pciback: relax BAR sizing write value check

Just like done in d2bd05d88d ("xen-pciback: return proper values during
BAR sizing") for the ROM BAR, ordinary ones also shouldn't compare the
written value directly against ~0, but consider the r/o bits at the
bottom (if any).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/xen/xen-pciback/conf_space_header.c b/drivers/xen/xen-pciback/conf_space_header.c
index 5fbfd9cfb6d6..5b3d57fc82d3 100644
--- a/drivers/xen/xen-pciback/conf_space_header.c
+++ b/drivers/xen/xen-pciback/conf_space_header.c
@@ -169,6 +169,9 @@ static int rom_write(struct pci_dev *dev, int offset, u32 value, void *data)
 static int bar_write(struct pci_dev *dev, int offset, u32 value, void *data)
 {
         struct pci_bar_info *bar = data;
+        unsigned int pos = (offset - PCI_BASE_ADDRESS_0) / 4;
+        const struct resource *res = dev->resource;
+        u32 mask;
 
         if (unlikely(!bar)) {
                 pr_warn(DRV_NAME ": driver data not found for %s\n",
@@ -179,7 +182,13 @@ static int bar_write(struct pci_dev *dev, int offset, u32 value, void *data)
         /* A write to obtain the length must happen as a 32-bit write.
          * This does not (yet) support writing individual bytes
          */
-        if (value == ~0)
+        if (res[pos].flags & IORESOURCE_IO)
+                mask = ~PCI_BASE_ADDRESS_IO_MASK;
+        else if (pos && (res[pos - 1].flags & IORESOURCE_MEM_64))
+                mask = 0;
+        else
+                mask = ~PCI_BASE_ADDRESS_MEM_MASK;
+        if ((value | mask) == ~0U)
                 bar->which = 1;
         else {
                 u32 tmpval;