Messages in this thread |  | | Date | Thu, 27 Jan 2022 10:10:36 -0500 | Subject | Re: [RFC PATCH] s390: vfio-ap: Register the vfio_ap module for the "ap" parent bus | From | Tony Krowiak <> |
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On 1/27/22 05:33, Thomas Huth wrote: > On 14/12/2021 22.28, Tony Krowiak wrote: >> >> >> On 12/13/21 10:44, Harald Freudenberger wrote: >>> On 01.12.21 15:11, Thomas Huth wrote: >>>> The crypto devices that we can use with the vfio_ap module are sitting >>>> on the "ap" bus, not on the "vfio_ap" bus that the module defines >>>> itself. With this change, the vfio_ap module now gets automatically >>>> loaded if a supported crypto adapter is available in the host. >>>> >>>> Signed-off-by: Thomas Huth <thuth@redhat.com> >>>> --- >>>> Note: Marked as "RFC" since I'm not 100% sure about it ... >>>> please review carefully! >>>> >>>> drivers/s390/crypto/vfio_ap_drv.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/s390/crypto/vfio_ap_drv.c >>>> b/drivers/s390/crypto/vfio_ap_drv.c >>>> index 4d2556bc7fe5..5580e40608a4 100644 >>>> --- a/drivers/s390/crypto/vfio_ap_drv.c >>>> +++ b/drivers/s390/crypto/vfio_ap_drv.c >>>> @@ -39,7 +39,7 @@ static struct ap_device_id ap_queue_ids[] = { >>>> { /* end of sibling */ }, >>>> }; >>>> -MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids); >>>> +MODULE_DEVICE_TABLE(ap, ap_queue_ids); >>>> /** >>>> * vfio_ap_queue_dev_probe: >>> I had a chance to check this now. >>> First I have to apologize about the dispute with vfio devices >>> appearing on the ap bus. >>> That's not the case with this patch. As Connie states the >>> MODULE_DEVICE_TABLE() does not >>> change the parent of a device and vfio_ap_drv is a driver for ap >>> devices and thus >>> belongs to the ap bus anyway. >>> So what's left is that with this change the vfio_ap kernel module is >>> automatically loaded >>> when an ap device type 10-13 is recognized by the ap bus. So the >>> intention of the patch >>> is fulfilled. >>> Yet another kernel module which may occupy memory but will never get >>> used by most customers. >>> This may not be a problem but I had a glance at the list of kernel >>> modules loaded on my >>> LPAR with and without the patch and the difference is: >>> ... >>> kvm 512000 1 vfio_ap >>> vfio_ap 28672 0 >>> ... >>> So the vfio_ap module has a dependency to the biggest kernel module >>> ever - kvm. >>> Do I need to say something more? >>> >>> If this dependency is removed then I would not hesitate to accept >>> this patch. However >>> this is up to Tony as he is the maintainer of the vfio ap device >>> driver. >> >> The vfio_ap device driver has a dependency on kvm, it can not be >> removed. >> If the user base for vfio_ap is minimal, then I see no reason why the >> vfio_ap >> module should be automatically loaded when an AP device type 10-13 is >> recognized by the AP bus. The module is needed only to pass through AP >> queue devices to a KVM guest. > > To continue the discussion here - it seems like my patch here won't be > accepted? Shall I send another one instead to remove the bad > MODLE_DEVICE_TABLE from the vfio_ap_drv.c file? > > Thomas
After re-reviewing all of the comments, I am okay with this patch:
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
If there are any other objections, speak now or forever hold your peace:)
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