[PATCH 3.13.y-ckt 087/138] xen/pciback: Check PF instead of VF for PCI_COMMAND_MEMORY

From: Kamal Mostafa
Date: Wed Mar 09 2016 - 18:33:48 EST

3.13.11-ckt36 -stable review patch. If anyone has any objections, please let me know.


From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

commit 8d47065f7d1980dde52abb874b301054f3013602 upstream.

Commit 408fb0e5aa7fda0059db282ff58c3b2a4278baa0 (xen/pciback: Don't
allow MSI-X ops if PCI_COMMAND_MEMORY is not set) prevented enabling
MSI-X on passed-through virtual functions, because it checked the VF
for PCI_COMMAND_MEMORY but this is not a valid bit for VFs.

Instead, check the physical function for PCI_COMMAND_MEMORY.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
drivers/xen/xen-pciback/pciback_ops.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/xen-pciback/pciback_ops.c b/drivers/xen/xen-pciback/pciback_ops.c
index f64b7f5..a2da466 100644
--- a/drivers/xen/xen-pciback/pciback_ops.c
+++ b/drivers/xen/xen-pciback/pciback_ops.c
@@ -227,8 +227,9 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev,
* PCI_COMMAND_MEMORY must be enabled, otherwise we may not be able
* to access the BARs where the MSI-X entries reside.
+ * But VF devices are unique in which the PF needs to be checked.
- pci_read_config_word(dev, PCI_COMMAND, &cmd);
+ pci_read_config_word(pci_physfn(dev), PCI_COMMAND, &cmd);
if (dev->msi_enabled || !(cmd & PCI_COMMAND_MEMORY))
return -ENXIO;