Patch "xen/pciback: Check PF instead of VF for PCI_COMMAND_MEMORY" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

xen/pciback: Check PF instead of VF for PCI_COMMAND_MEMORY

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
xen-pciback-check-pf-instead-of-vf-for-pci_command_memory.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Konrad Rzeszutek Wilk <[email protected]>
Date: Thu, 11 Feb 2016 16:10:23 -0500
Subject: xen/pciback: Check PF instead of VF for PCI_COMMAND_MEMORY

From: Konrad Rzeszutek Wilk <[email protected]>

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.

---
 drivers/xen/xen-pciback/pciback_ops.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -227,8 +227,9 @@ int xen_pcibk_enable_msix(struct xen_pci
 	/*
 	 * 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;
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/xen-pciback-save-the-number-of-msi-x-entries-to-be-copied-later.patch queue-4.4/xen-pciback-check-pf-instead-of-vf-for-pci_command_memory.patch queue-4.4/xen-pcifront-fix-mysterious-crashes-when-numa-locality-information-was-extracted.patch