Re: [Xen-devel] [PATCH 1/4] xen/pciback: Check PF instead of VF for PCI_COMMAND_MEMORY
From: Jan Beulich
Date: Fri Feb 12 2016 - 04:20:28 EST
>>> On 11.02.16 at 22:10, <konrad.wilk@xxxxxxxxxx> wrote:
> c/s 408fb0e5aa7fda0059db282ff58c3b2a4278baa0
> "xen/pciback: Don't allow MSI-X ops if PCI_COMMAND_MEMORY is not set."
> would check the device for PCI_COMMAND_MEMORY which is great.
> Except that VF devices are unique - for example they have no
> legacy interrupts, and also any writes to PCI_COMMAND_MEMORY
> are silently ignored (by the hardware).
>
> CC: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
albeit ...
> --- a/drivers/xen/xen-pciback/pciback_ops.c
> +++ b/drivers/xen/xen-pciback/pciback_ops.c
> @@ -213,6 +213,7 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev,
> int i, result;
> struct msix_entry *entries;
> u16 cmd;
> + struct pci_dev *phys_dev;
>
> if (unlikely(verbose_request))
> printk(KERN_DEBUG DRV_NAME ": %s: enable MSI-X\n",
> @@ -227,8 +228,10 @@ 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);
> + phys_dev = pci_physfn(dev);
> + pci_read_config_word(phys_dev, PCI_COMMAND, &cmd);
... I don't think the use of a local variable here is really needed.
Jan