Re: [PATCH 1/5] vfio-pci: Allow PCI IDs to be specified as module options

[Bjorn Helgaas]

On Wed, Mar 04, 2015 at 01:02:43PM -0700, Alex Williamson wrote:
> This copies the same support from pci-stub for exactly the same
> purpose, enabling a set of PCI IDs to be automatically added to the
> driver's dynamic ID table at module load time.  The code here is
> pretty simple and both vfio-pci and pci-stub are fairly unique in
> being meta drivers, capable of attaching to any device, so there's no
> attempt made to generalize the code into pci-core.
> 
> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> ---
>  drivers/vfio/pci/vfio_pci.c |   46 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 46 insertions(+)
> 
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index f8a1863..b3bae4c 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -32,6 +32,10 @@
>  #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@xxxxxxxxxx>"
>  #define DRIVER_DESC     "VFIO PCI - User Level meta-driver"
>  
> +static char ids[1024] __initdata;
> +module_param_string(ids, ids, sizeof(ids), 0);
> +MODULE_PARM_DESC(ids, "Initial PCI IDs to add to the vfio driver, format is \"vendor:device[:subvendor[:subdevice[:class[:class_mask]]]]\" and multiple comma separated entries can be specified");
> +
>  static bool nointxmask;
>  module_param_named(nointxmask, nointxmask, bool, S_IRUGO | S_IWUSR);
>  MODULE_PARM_DESC(nointxmask,
> @@ -1034,6 +1038,46 @@ static void __exit vfio_pci_cleanup(void)
>  	vfio_pci_uninit_perm_bits();
>  }
>  
> +static void __init vfio_pci_fill_ids(void)
> +{
> +	char *p, *id;
> +	int rc;
> +
> +	/* no ids passed actually */
> +	if (ids[0] == '\0')
> +		return;
> +
> +	/* add ids specified in the module parameter */
> +	p = ids;
> +	while ((id = strsep(&p, ","))) {
> +		unsigned int vendor, device, subvendor = PCI_ANY_ID,
> +			subdevice = PCI_ANY_ID, class = 0, class_mask = 0;
> +		int fields;
> +
> +		if (!strlen(id))
> +			continue;
> +
> +		fields = sscanf(id, "%x:%x:%x:%x:%x:%x",
> +				&vendor, &device, &subvendor, &subdevice,
> +				&class, &class_mask);
> +
> +		if (fields < 2) {
> +			pr_warn("vfio-pci: invalid id string \"%s\"\n", id);
> +			continue;
> +		}
> +
> +		pr_info("vfio-pci: add %04X:%04X sub=%04X:%04X cls=%08X/%08X\n",

pci_setup_device() uses "[%04x:%04x] ... class %#08x".  Maybe they should
be the same, at least as far as using upper/lower case, spelling out
"class", and "0x" prefix.  Maybe there's other precedent that you're
following and pci_setup_device() is not?

> +			vendor, device, subvendor, subdevice,
> +			class, class_mask);
> +
> +		rc = pci_add_dynid(&vfio_pci_driver, vendor, device,
> +				   subvendor, subdevice, class, class_mask, 0);
> +		if (rc)
> +			pr_warn("vfio-pci: failed to add dynamic id (%d)\n",
> +				rc);
> +	}
> +}
> +
>  static int __init vfio_pci_init(void)
>  {
>  	int ret;
> @@ -1053,6 +1097,8 @@ static int __init vfio_pci_init(void)
>  	if (ret)
>  		goto out_driver;
>  
> +	vfio_pci_fill_ids();
> +
>  	return 0;
>  
>  out_driver:
> 
> --
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