s390: vfio-ap: disable IRQ in remove callback results in kernel OOPS

Commit Message

Anthony Krowiak Oct. 29, 2019, 10:09 p.m. UTC

From: aekrowia <[e-mail]>

When an AP adapter card is configured off via the SE or the SCLP
Deconfigure Adjunct Processor command and the AP bus subsequently detects
that the adapter card is no longer in the AP configuration, the card
device representing the adapter card as well as each of its associated
AP queue devices will be removed by the AP bus. If one or more of the
affected queue devices is bound to the VFIO AP device driver, its remove
callback will be invoked for each queue to be removed. The remove callback
resets the queue and disables IRQ processing. If interrupt processing was
never enabled for the queue, disabling IRQ processing will fail resulting
in a kernel OOPS.

This patch verifies IRQ processing is enabled before attempting to disable
interrupts for the queue.

Signed-off-by: Tony Krowiak <[e-mail]>
Signed-off-by: aekrowia <[e-mail]>
---
 drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Cornelia Huck Oct. 29, 2019, 10:19 p.m. UTC | #1

On Tue, 29 Oct 2019 18:09:06 -0400
Tony Krowiak <[e-mail]> wrote:

> From: aekrowia <[e-mail]>

Some accident seems to have happened to your git config.

> 
> When an AP adapter card is configured off via the SE or the SCLP
> Deconfigure Adjunct Processor command and the AP bus subsequently detects
> that the adapter card is no longer in the AP configuration, the card
> device representing the adapter card as well as each of its associated
> AP queue devices will be removed by the AP bus. If one or more of the
> affected queue devices is bound to the VFIO AP device driver, its remove
> callback will be invoked for each queue to be removed. The remove callback
> resets the queue and disables IRQ processing. If interrupt processing was
> never enabled for the queue, disabling IRQ processing will fail resulting
> in a kernel OOPS.
> 
> This patch verifies IRQ processing is enabled before attempting to disable
> interrupts for the queue.
> 
> Signed-off-by: Tony Krowiak <[e-mail]>
> Signed-off-by: aekrowia <[e-mail]>
> ---
>  drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
> index be2520cc010b..42d8308fd3a1 100644
> --- a/drivers/s390/crypto/vfio_ap_drv.c
> +++ b/drivers/s390/crypto/vfio_ap_drv.c
> @@ -79,7 +79,8 @@ static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
>  	apid = AP_QID_CARD(q->apqn);
>  	apqi = AP_QID_QUEUE(q->apqn);
>  	vfio_ap_mdev_reset_queue(apid, apqi, 1);
> -	vfio_ap_irq_disable(q);
> +	if (q->saved_isc != VFIO_AP_ISC_INVALID)
> +		vfio_ap_irq_disable(q);

Hm... would it make sense to move that check into vfio_ap_irq_disable()
instead? Or are we sure that in all other cases the irq processing had
been enabled before?

Also, if that oops is reasonably easy to trigger, it would probably
make sense to cc:stable. (Or is this a new problem?)

>  	kfree(q);
>  	mutex_unlock(&matrix_dev->lock);
>  }

Harald Freudenberger Oct. 30, 2019, 7:44 a.m. UTC | #2

On 29.10.19 23:09, Tony Krowiak wrote:
> From: aekrowia <[e-mail]>
>
> When an AP adapter card is configured off via the SE or the SCLP
> Deconfigure Adjunct Processor command and the AP bus subsequently detects
> that the adapter card is no longer in the AP configuration, the card
> device representing the adapter card as well as each of its associated
> AP queue devices will be removed by the AP bus. If one or more of the
> affected queue devices is bound to the VFIO AP device driver, its remove
> callback will be invoked for each queue to be removed. The remove callback
> resets the queue and disables IRQ processing. If interrupt processing was
> never enabled for the queue, disabling IRQ processing will fail resulting
> in a kernel OOPS.
>
> This patch verifies IRQ processing is enabled before attempting to disable
> interrupts for the queue.
>
> Signed-off-by: Tony Krowiak <[e-mail]>
> Signed-off-by: aekrowia <[e-mail]>
> ---
>  drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
> index be2520cc010b..42d8308fd3a1 100644
> --- a/drivers/s390/crypto/vfio_ap_drv.c
> +++ b/drivers/s390/crypto/vfio_ap_drv.c
> @@ -79,7 +79,8 @@ static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
>  	apid = AP_QID_CARD(q->apqn);
>  	apqi = AP_QID_QUEUE(q->apqn);
>  	vfio_ap_mdev_reset_queue(apid, apqi, 1);
> -	vfio_ap_irq_disable(q);
> +	if (q->saved_isc != VFIO_AP_ISC_INVALID)
> +		vfio_ap_irq_disable(q);
>  	kfree(q);
>  	mutex_unlock(&matrix_dev->lock);
>  }
Reset of an APQN does also clear IRQ processing. I don't say that the
resources associated with IRQ handling for the APQN are also cleared.
But when you call PQAP(AQIC) after an PQAP(RAPQ) or PQAP(ZAPQ)
it is superfluous. However, there should not appear any kernel OOPS.
So can you please give me more details about this kernel oops - maybe
I need to add exception handler code to the inline ap_aqic() function.

regards, Harald Freudenberger

Pierre Morel Oct. 30, 2019, 2 p.m. UTC | #3

On 10/30/19 8:44 AM, Harald Freudenberger wrote:
> On 29.10.19 23:09, Tony Krowiak wrote:
>> From: aekrowia <[e-mail]>
>>
>> When an AP adapter card is configured off via the SE or the SCLP
>> Deconfigure Adjunct Processor command and the AP bus subsequently detects
>> that the adapter card is no longer in the AP configuration, the card
>> device representing the adapter card as well as each of its associated
>> AP queue devices will be removed by the AP bus. If one or more of the
>> affected queue devices is bound to the VFIO AP device driver, its remove
>> callback will be invoked for each queue to be removed. The remove callback
>> resets the queue and disables IRQ processing. If interrupt processing was
>> never enabled for the queue, disabling IRQ processing will fail resulting
>> in a kernel OOPS.
>>
>> This patch verifies IRQ processing is enabled before attempting to disable
>> interrupts for the queue.
>>
>> Signed-off-by: Tony Krowiak <[e-mail]>
>> Signed-off-by: aekrowia <[e-mail]>
>> ---
>>   drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
>> index be2520cc010b..42d8308fd3a1 100644
>> --- a/drivers/s390/crypto/vfio_ap_drv.c
>> +++ b/drivers/s390/crypto/vfio_ap_drv.c
>> @@ -79,7 +79,8 @@ static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
>>   	apid = AP_QID_CARD(q->apqn);
>>   	apqi = AP_QID_QUEUE(q->apqn);
>>   	vfio_ap_mdev_reset_queue(apid, apqi, 1);
>> -	vfio_ap_irq_disable(q);
>> +	if (q->saved_isc != VFIO_AP_ISC_INVALID)
>> +		vfio_ap_irq_disable(q);
>>   	kfree(q);
>>   	mutex_unlock(&matrix_dev->lock);
>>   }
> Reset of an APQN does also clear IRQ processing. I don't say that the
> resources associated with IRQ handling for the APQN are also cleared.
> But when you call PQAP(AQIC) after an PQAP(RAPQ) or PQAP(ZAPQ)
> it is superfluous. However, there should not appear any kernel OOPS.
> So can you please give me more details about this kernel oops - maybe
> I need to add exception handler code to the inline ap_aqic() function.
>
> regards, Harald Freudenberger
>

Hi Tony,

wasn't it already solved by the patch 5c4c2126  from Christian ?

Can you send the trace to me please?

Thanks,

Pierre

Anthony Krowiak Oct. 30, 2019, 4:51 p.m. UTC | #4

On 10/30/19 10:00 AM, Pierre Morel wrote:
> 
> 
> 
> On 10/30/19 8:44 AM, Harald Freudenberger wrote:
>> On 29.10.19 23:09, Tony Krowiak wrote:
>>> From: aekrowia <[e-mail]>
>>>
>>> When an AP adapter card is configured off via the SE or the SCLP
>>> Deconfigure Adjunct Processor command and the AP bus subsequently 
>>> detects
>>> that the adapter card is no longer in the AP configuration, the card
>>> device representing the adapter card as well as each of its associated
>>> AP queue devices will be removed by the AP bus. If one or more of the
>>> affected queue devices is bound to the VFIO AP device driver, its remove
>>> callback will be invoked for each queue to be removed. The remove 
>>> callback
>>> resets the queue and disables IRQ processing. If interrupt processing 
>>> was
>>> never enabled for the queue, disabling IRQ processing will fail 
>>> resulting
>>> in a kernel OOPS.
>>>
>>> This patch verifies IRQ processing is enabled before attempting to 
>>> disable
>>> interrupts for the queue.
>>>
>>> Signed-off-by: Tony Krowiak <[e-mail]>
>>> Signed-off-by: aekrowia <[e-mail]>
>>> ---
>>>   drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/s390/crypto/vfio_ap_drv.c 
>>> b/drivers/s390/crypto/vfio_ap_drv.c
>>> index be2520cc010b..42d8308fd3a1 100644
>>> --- a/drivers/s390/crypto/vfio_ap_drv.c
>>> +++ b/drivers/s390/crypto/vfio_ap_drv.c
>>> @@ -79,7 +79,8 @@ static void vfio_ap_queue_dev_remove(struct 
>>> ap_device *apdev)
>>>       apid = AP_QID_CARD(q->apqn);
>>>       apqi = AP_QID_QUEUE(q->apqn);
>>>       vfio_ap_mdev_reset_queue(apid, apqi, 1);
>>> -    vfio_ap_irq_disable(q);
>>> +    if (q->saved_isc != VFIO_AP_ISC_INVALID)
>>> +        vfio_ap_irq_disable(q);
>>>       kfree(q);
>>>       mutex_unlock(&matrix_dev->lock);
>>>   }
>> Reset of an APQN does also clear IRQ processing. I don't say that the
>> resources associated with IRQ handling for the APQN are also cleared.
>> But when you call PQAP(AQIC) after an PQAP(RAPQ) or PQAP(ZAPQ)
>> it is superfluous. However, there should not appear any kernel OOPS.
>> So can you please give me more details about this kernel oops - maybe
>> I need to add exception handler code to the inline ap_aqic() function.
>>
>> regards, Harald Freudenberger
>>
> 
> Hi Tony,
> 
> wasn't it already solved by the patch 5c4c2126  from Christian ?

No, that patch merely sets the 'matrix_mdev' field of the
'struct vfio_ap_queue' to NULL in the vfio_ap_free_aqic_resources()
function. Also, with the latest master branch which has 5c4c2126
installed, the failure occurs.

> 
> Can you send the trace to me please?

[  266.989476] crw_info : CRW reports slct=0, oflw=0, chn=0, rsc=B, 
anc=0, erc=0, rsid=0
[  266.989617] ------------[ cut here ]------------
[  266.989622] vfio_ap_wait_for_irqclear: tapq rc 03: 0504
[  266.989681] WARNING: CPU: 0 PID: 7 at 
drivers/s390/crypto/vfio_ap_ops.c:101 vfio_ap_irq_disable+0x13c/0x1b0 
[vfio_ap]
[  266.989682] Modules linked in: xt_CHECKSUM xt_MASQUERADE tun bridge 
stp llc ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack 
ebtable_nat ip6table_nat ip6table_mangle ip6table_raw ip6table_security 
iptable_nat nf_nat iptable_mangle iptable_raw iptable_security 
nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c ip_set nfnetlink 
ebtable_filter ebtables ip6table_filter ip6_tables sunrpc ghash_s390 
prng aes_s390 des_s390 libdes vfio_ccw sha512_s390 sha1_s390 eadm_sch 
zcrypt_cex4 qeth_l2 crc32_vx_s390 dasd_eckd_mod sha256_s390 qeth 
sha_common dasd_mod ccwgroup qdio pkey zcrypt vfio_ap kvm
[  266.989704] CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.4.0-rc5 #81
[  266.989705] Hardware name: IBM 2964 NE1 749 (LPAR)
[  266.989710] Workqueue: events_long ap_scan_bus
[  266.989711] Krnl PSW : 0704c00180000000 000003ff8007d89c 
(vfio_ap_irq_disable+0x13c/0x1b0 [vfio_ap])
[  266.989714]            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 
PM:0 RI:0 EA:3
[  266.989716] Krnl GPRS: 000000000000000a 0000000000000006 
000000000000002b 0000000000000007
[  266.989717]            0000000000000007 000000007fe06000 
000003ff00000005 0000000000000000
[  266.989718]            0000000100000504 0000000000000003 
00000001f9d27e40 000003e00003bb5c
[  266.989719]            00000001fe765d00 0000000000000504 
000003ff8007d898 000003e00003ba60
[  266.989724] Krnl Code: 000003ff8007d88c: c02000000ce6    larl 
%r2,3ff8007f258
                           000003ff8007d892: c0e5fffff4c7    brasl 
%r14,3ff8007c220
                          #000003ff8007d898: a7f40001        brc 
15,3ff8007d89a
                          >000003ff8007d89c: a7f4ff9d        brc 
15,3ff8007d7d6
                           000003ff8007d8a0: a7100100        tmlh    %r1,256
                           000003ff8007d8a4: a784ff99        brc 
8,3ff8007d7d6
                           000003ff8007d8a8: a7290014        lghi    %r2,20
                           000003ff8007d8ac: c0e5fffff4b0    brasl 
%r14,3ff8007c20c
[  266.989772] Call Trace:
[  266.989777] ([<000003ff8007d898>] vfio_ap_irq_disable+0x138/0x1b0 
[vfio_ap])
[  266.989779]  [<000003ff8007c4d2>] vfio_ap_queue_dev_remove+0x6a/0x90 
[vfio_ap]
[  266.989782]  [<00000000bf0f24f0>] ap_device_remove+0x50/0x110
[  266.989784]  [<00000000beffbaac>] 
device_release_driver_internal+0x114/0x1f0
[  266.989787]  [<00000000beff9c88>] bus_remove_device+0x108/0x190
[  266.989789]  [<00000000beff5418>] device_del+0x178/0x3a0
[  266.989790]  [<00000000beff5670>] device_unregister+0x30/0x90
[  266.989791]  [<00000000bf0f0f04>] 
__ap_queue_devices_with_id_unregister+0x44/0x50
[  266.989793]  [<00000000beff86ea>] bus_for_each_dev+0x82/0xb0
[  266.989794]  [<00000000bf0f2aba>] ap_scan_bus+0x262/0x878
[  266.989798]  [<00000000beb4785c>] process_one_work+0x1e4/0x410
[  266.989800]  [<00000000beb47ca8>] worker_thread+0x220/0x460
[  266.989802]  [<00000000beb4e99a>] kthread+0x12a/0x160
[  266.989805]  [<00000000bf2d8eb0>] ret_from_fork+0x28/0x2c
[  266.989806]  [<00000000bf2d8eb4>] kernel_thread_starter+0x0/0xc
[  266.989807] Last Breaking-Event-Address:
[  266.989809]  [<000003ff8007d898>] vfio_ap_irq_disable+0x138/0x1b0 
[vfio_ap]
[  266.989810] ---[ end trace 59b4020890dbd391 ]---


> 
> Thanks,
> 
> Pierre
> 
> 
>

Pierre Morel Oct. 30, 2019, 6:02 p.m. UTC | #5

On 10/30/19 5:51 PM, Tony Krowiak wrote:
> On 10/30/19 10:00 AM, Pierre Morel wrote:
>>
>>
>>
>> On 10/30/19 8:44 AM, Harald Freudenberger wrote:
>>> On 29.10.19 23:09, Tony Krowiak wrote:
>>>> From: aekrowia <[e-mail]>
>>>>
>>>> When an AP adapter card is configured off via the SE or the SCLP
>>>> Deconfigure Adjunct Processor command and the AP bus subsequently 
>>>> detects
>>>> that the adapter card is no longer in the AP configuration, the card
>>>> device representing the adapter card as well as each of its associated
>>>> AP queue devices will be removed by the AP bus. If one or more of the
>>>> affected queue devices is bound to the VFIO AP device driver, its 
>>>> remove
>>>> callback will be invoked for each queue to be removed. The remove 
>>>> callback
>>>> resets the queue and disables IRQ processing. If interrupt 
>>>> processing was
>>>> never enabled for the queue, disabling IRQ processing will fail 
>>>> resulting
>>>> in a kernel OOPS.
>>>>
>>>> This patch verifies IRQ processing is enabled before attempting to 
>>>> disable
>>>> interrupts for the queue.
>>>>
>>>> Signed-off-by: Tony Krowiak <[e-mail]>
>>>> Signed-off-by: aekrowia <[e-mail]>
>>>> ---
>>>>   drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
>>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/s390/crypto/vfio_ap_drv.c 
>>>> b/drivers/s390/crypto/vfio_ap_drv.c
>>>> index be2520cc010b..42d8308fd3a1 100644
>>>> --- a/drivers/s390/crypto/vfio_ap_drv.c
>>>> +++ b/drivers/s390/crypto/vfio_ap_drv.c
>>>> @@ -79,7 +79,8 @@ static void vfio_ap_queue_dev_remove(struct 
>>>> ap_device *apdev)
>>>>       apid = AP_QID_CARD(q->apqn);
>>>>       apqi = AP_QID_QUEUE(q->apqn);
>>>>       vfio_ap_mdev_reset_queue(apid, apqi, 1);
>>>> -    vfio_ap_irq_disable(q);
>>>> +    if (q->saved_isc != VFIO_AP_ISC_INVALID)
>>>> +        vfio_ap_irq_disable(q);
>>>>       kfree(q);
>>>>       mutex_unlock(&matrix_dev->lock);
>>>>   }
>>> Reset of an APQN does also clear IRQ processing. I don't say that the
>>> resources associated with IRQ handling for the APQN are also cleared.
>>> But when you call PQAP(AQIC) after an PQAP(RAPQ) or PQAP(ZAPQ)
>>> it is superfluous. However, there should not appear any kernel OOPS.
>>> So can you please give me more details about this kernel oops - maybe
>>> I need to add exception handler code to the inline ap_aqic() function.
>>>
>>> regards, Harald Freudenberger
>>>
>>
>> Hi Tony,
>>
>> wasn't it already solved by the patch 5c4c2126  from Christian ?
>
> No, that patch merely sets the 'matrix_mdev' field of the
> 'struct vfio_ap_queue' to NULL in the vfio_ap_free_aqic_resources()
> function. Also, with the latest master branch which has 5c4c2126
> installed, the failure occurs.
>
>>
>> Can you send the trace to me please?
>
> [  266.989476] crw_info : CRW reports slct=0, oflw=0, chn=0, rsc=B, 
> anc=0, erc=0, rsid=0
> [  266.989617] ------------[ cut here ]------------
> [  266.989622] vfio_ap_wait_for_irqclear: tapq rc 03: 0504
> [  266.989681] WARNING: CPU: 0 PID: 7 at 
> drivers/s390/crypto/vfio_ap_ops.c:101 vfio_ap_irq_disable+0x13c/0x1b0 
> [vfio_ap]


Hi Tony,

This is not a oops this is the warning written in 
vfio_ap_wait_for_irqclear() because the AP has been deconfigured.

Note that, IIUC, this (the warning) does not happen for devices bound to 
the vfio_ap driver but not currently assigned to a mediated device.

I do not think we should avoid sending a warning in this case because 
this is not a normal administration good practice to forcefully take an 
AP away like this without smoothly removing the device from the mediated 
device.

Regards,

Pierre


> [ 266.989682] Modules linked in: xt_CHECKSUM xt_MASQUERADE tun bridge 
> stp llc ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack 
> ebtable_nat ip6table_nat ip6table_mangle ip6table_raw 
> ip6table_security iptable_nat nf_nat iptable_mangle iptable_raw 
> iptable_security nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c 
> ip_set nfnetlink ebtable_filter ebtables ip6table_filter ip6_tables 
> sunrpc ghash_s390 prng aes_s390 des_s390 libdes vfio_ccw sha512_s390 
> sha1_s390 eadm_sch zcrypt_cex4 qeth_l2 crc32_vx_s390 dasd_eckd_mod 
> sha256_s390 qeth sha_common dasd_mod ccwgroup qdio pkey zcrypt vfio_ap 
> kvm
> [  266.989704] CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.4.0-rc5 #81
> [  266.989705] Hardware name: IBM 2964 NE1 749 (LPAR)
> [  266.989710] Workqueue: events_long ap_scan_bus
> [  266.989711] Krnl PSW : 0704c00180000000 000003ff8007d89c 
> (vfio_ap_irq_disable+0x13c/0x1b0 [vfio_ap])
> [  266.989714]            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 
> CC:0 PM:0 RI:0 EA:3
> [  266.989716] Krnl GPRS: 000000000000000a 0000000000000006 
> 000000000000002b 0000000000000007
> [  266.989717]            0000000000000007 000000007fe06000 
> 000003ff00000005 0000000000000000
> [  266.989718]            0000000100000504 0000000000000003 
> 00000001f9d27e40 000003e00003bb5c
> [  266.989719]            00000001fe765d00 0000000000000504 
> 000003ff8007d898 000003e00003ba60
> [  266.989724] Krnl Code: 000003ff8007d88c: c02000000ce6    larl 
> %r2,3ff8007f258
>                           000003ff8007d892: c0e5fffff4c7    brasl 
> %r14,3ff8007c220
>                          #000003ff8007d898: a7f40001        brc 
> 15,3ff8007d89a
>                          >000003ff8007d89c: a7f4ff9d        brc 
> 15,3ff8007d7d6
>                           000003ff8007d8a0: a7100100 tmlh    %r1,256
>                           000003ff8007d8a4: a784ff99        brc 
> 8,3ff8007d7d6
>                           000003ff8007d8a8: a7290014 lghi    %r2,20
>                           000003ff8007d8ac: c0e5fffff4b0    brasl 
> %r14,3ff8007c20c
> [  266.989772] Call Trace:
> [  266.989777] ([<000003ff8007d898>] vfio_ap_irq_disable+0x138/0x1b0 
> [vfio_ap])
> [  266.989779]  [<000003ff8007c4d2>] 
> vfio_ap_queue_dev_remove+0x6a/0x90 [vfio_ap]
> [  266.989782]  [<00000000bf0f24f0>] ap_device_remove+0x50/0x110
> [  266.989784]  [<00000000beffbaac>] 
> device_release_driver_internal+0x114/0x1f0
> [  266.989787]  [<00000000beff9c88>] bus_remove_device+0x108/0x190
> [  266.989789]  [<00000000beff5418>] device_del+0x178/0x3a0
> [  266.989790]  [<00000000beff5670>] device_unregister+0x30/0x90
> [  266.989791]  [<00000000bf0f0f04>] 
> __ap_queue_devices_with_id_unregister+0x44/0x50
> [  266.989793]  [<00000000beff86ea>] bus_for_each_dev+0x82/0xb0
> [  266.989794]  [<00000000bf0f2aba>] ap_scan_bus+0x262/0x878
> [  266.989798]  [<00000000beb4785c>] process_one_work+0x1e4/0x410
> [  266.989800]  [<00000000beb47ca8>] worker_thread+0x220/0x460
> [  266.989802]  [<00000000beb4e99a>] kthread+0x12a/0x160
> [  266.989805]  [<00000000bf2d8eb0>] ret_from_fork+0x28/0x2c
> [  266.989806]  [<00000000bf2d8eb4>] kernel_thread_starter+0x0/0xc
> [  266.989807] Last Breaking-Event-Address:
> [  266.989809]  [<000003ff8007d898>] vfio_ap_irq_disable+0x138/0x1b0 
> [vfio_ap]
> [  266.989810] ---[ end trace 59b4020890dbd391 ]---
>
>
>>
>> Thanks,
>>
>> Pierre
>>
>>
>>
>

Anthony Krowiak Oct. 31, 2019, 1:26 p.m. UTC | #6

On 10/30/19 2:02 PM, Pierre Morel wrote:
> 
> On 10/30/19 5:51 PM, Tony Krowiak wrote:
>> On 10/30/19 10:00 AM, Pierre Morel wrote:
>>>
>>>
>>>
>>> On 10/30/19 8:44 AM, Harald Freudenberger wrote:
>>>> On 29.10.19 23:09, Tony Krowiak wrote:
>>>>> From: aekrowia <[e-mail]>
>>>>>
>>>>> When an AP adapter card is configured off via the SE or the SCLP
>>>>> Deconfigure Adjunct Processor command and the AP bus subsequently 
>>>>> detects
>>>>> that the adapter card is no longer in the AP configuration, the card
>>>>> device representing the adapter card as well as each of its associated
>>>>> AP queue devices will be removed by the AP bus. If one or more of the
>>>>> affected queue devices is bound to the VFIO AP device driver, its 
>>>>> remove
>>>>> callback will be invoked for each queue to be removed. The remove 
>>>>> callback
>>>>> resets the queue and disables IRQ processing. If interrupt 
>>>>> processing was
>>>>> never enabled for the queue, disabling IRQ processing will fail 
>>>>> resulting
>>>>> in a kernel OOPS.
>>>>>
>>>>> This patch verifies IRQ processing is enabled before attempting to 
>>>>> disable
>>>>> interrupts for the queue.
>>>>>
>>>>> Signed-off-by: Tony Krowiak <[e-mail]>
>>>>> Signed-off-by: aekrowia <[e-mail]>
>>>>> ---
>>>>>   drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
>>>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/s390/crypto/vfio_ap_drv.c 
>>>>> b/drivers/s390/crypto/vfio_ap_drv.c
>>>>> index be2520cc010b..42d8308fd3a1 100644
>>>>> --- a/drivers/s390/crypto/vfio_ap_drv.c
>>>>> +++ b/drivers/s390/crypto/vfio_ap_drv.c
>>>>> @@ -79,7 +79,8 @@ static void vfio_ap_queue_dev_remove(struct 
>>>>> ap_device *apdev)
>>>>>       apid = AP_QID_CARD(q->apqn);
>>>>>       apqi = AP_QID_QUEUE(q->apqn);
>>>>>       vfio_ap_mdev_reset_queue(apid, apqi, 1);
>>>>> -    vfio_ap_irq_disable(q);
>>>>> +    if (q->saved_isc != VFIO_AP_ISC_INVALID)
>>>>> +        vfio_ap_irq_disable(q);
>>>>>       kfree(q);
>>>>>       mutex_unlock(&matrix_dev->lock);
>>>>>   }
>>>> Reset of an APQN does also clear IRQ processing. I don't say that the
>>>> resources associated with IRQ handling for the APQN are also cleared.
>>>> But when you call PQAP(AQIC) after an PQAP(RAPQ) or PQAP(ZAPQ)
>>>> it is superfluous. However, there should not appear any kernel OOPS.
>>>> So can you please give me more details about this kernel oops - maybe
>>>> I need to add exception handler code to the inline ap_aqic() function.
>>>>
>>>> regards, Harald Freudenberger
>>>>
>>>
>>> Hi Tony,
>>>
>>> wasn't it already solved by the patch 5c4c2126  from Christian ?
>>
>> No, that patch merely sets the 'matrix_mdev' field of the
>> 'struct vfio_ap_queue' to NULL in the vfio_ap_free_aqic_resources()
>> function. Also, with the latest master branch which has 5c4c2126
>> installed, the failure occurs.
>>
>>>
>>> Can you send the trace to me please?
>>
>> [  266.989476] crw_info : CRW reports slct=0, oflw=0, chn=0, rsc=B, 
>> anc=0, erc=0, rsid=0
>> [  266.989617] ------------[ cut here ]------------
>> [  266.989622] vfio_ap_wait_for_irqclear: tapq rc 03: 0504
>> [  266.989681] WARNING: CPU: 0 PID: 7 at 
>> drivers/s390/crypto/vfio_ap_ops.c:101 vfio_ap_irq_disable+0x13c/0x1b0 
>> [vfio_ap]
> 
> 
> Hi Tony,
> 
> This is not a oops this is the warning written in 
> vfio_ap_wait_for_irqclear() because the AP has been deconfigured.

Yes, I was mistaken about that. I had seen an oops earlier from
something else in code on which I was working and mistakenly thought
this was a repeat.

> 
> Note that, IIUC, this (the warning) does not happen for devices bound to 
> the vfio_ap driver but not currently assigned to a mediated device.

That is the case in point, but I suspect it will happen whenever
interrupts are not enabled.

> 
> I do not think we should avoid sending a warning in this case because 
> this is not a normal administration good practice to forcefully take an 
> AP away like this without smoothly removing the device from the mediated 
> device.

The scenario in which I encountered this was when a queue was bound to
the vfio_ap driver but not assigned to a mediated device and the queue
was unbound due to deconfiguration of the adapter from the SE. So, the
queue was not being forcefully taken away from a mediated device. In
other words, this was normal administration.

> 
> Regards,
> 
> Pierre
> 
> 
>> [ 266.989682] Modules linked in: xt_CHECKSUM xt_MASQUERADE tun bridge 
>> stp llc ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack 
>> ebtable_nat ip6table_nat ip6table_mangle ip6table_raw 
>> ip6table_security iptable_nat nf_nat iptable_mangle iptable_raw 
>> iptable_security nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c 
>> ip_set nfnetlink ebtable_filter ebtables ip6table_filter ip6_tables 
>> sunrpc ghash_s390 prng aes_s390 des_s390 libdes vfio_ccw sha512_s390 
>> sha1_s390 eadm_sch zcrypt_cex4 qeth_l2 crc32_vx_s390 dasd_eckd_mod 
>> sha256_s390 qeth sha_common dasd_mod ccwgroup qdio pkey zcrypt vfio_ap 
>> kvm
>> [  266.989704] CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.4.0-rc5 #81
>> [  266.989705] Hardware name: IBM 2964 NE1 749 (LPAR)
>> [  266.989710] Workqueue: events_long ap_scan_bus
>> [  266.989711] Krnl PSW : 0704c00180000000 000003ff8007d89c 
>> (vfio_ap_irq_disable+0x13c/0x1b0 [vfio_ap])
>> [  266.989714]            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 
>> CC:0 PM:0 RI:0 EA:3
>> [  266.989716] Krnl GPRS: 000000000000000a 0000000000000006 
>> 000000000000002b 0000000000000007
>> [  266.989717]            0000000000000007 000000007fe06000 
>> 000003ff00000005 0000000000000000
>> [  266.989718]            0000000100000504 0000000000000003 
>> 00000001f9d27e40 000003e00003bb5c
>> [  266.989719]            00000001fe765d00 0000000000000504 
>> 000003ff8007d898 000003e00003ba60
>> [  266.989724] Krnl Code: 000003ff8007d88c: c02000000ce6    larl 
>> %r2,3ff8007f258
>>                           000003ff8007d892: c0e5fffff4c7    brasl 
>> %r14,3ff8007c220
>>                          #000003ff8007d898: a7f40001        brc 
>> 15,3ff8007d89a
>>                          >000003ff8007d89c: a7f4ff9d        brc 
>> 15,3ff8007d7d6
>>                           000003ff8007d8a0: a7100100 tmlh    %r1,256
>>                           000003ff8007d8a4: a784ff99        brc 
>> 8,3ff8007d7d6
>>                           000003ff8007d8a8: a7290014 lghi    %r2,20
>>                           000003ff8007d8ac: c0e5fffff4b0    brasl 
>> %r14,3ff8007c20c
>> [  266.989772] Call Trace:
>> [  266.989777] ([<000003ff8007d898>] vfio_ap_irq_disable+0x138/0x1b0 
>> [vfio_ap])
>> [  266.989779]  [<000003ff8007c4d2>] 
>> vfio_ap_queue_dev_remove+0x6a/0x90 [vfio_ap]
>> [  266.989782]  [<00000000bf0f24f0>] ap_device_remove+0x50/0x110
>> [  266.989784]  [<00000000beffbaac>] 
>> device_release_driver_internal+0x114/0x1f0
>> [  266.989787]  [<00000000beff9c88>] bus_remove_device+0x108/0x190
>> [  266.989789]  [<00000000beff5418>] device_del+0x178/0x3a0
>> [  266.989790]  [<00000000beff5670>] device_unregister+0x30/0x90
>> [  266.989791]  [<00000000bf0f0f04>] 
>> __ap_queue_devices_with_id_unregister+0x44/0x50
>> [  266.989793]  [<00000000beff86ea>] bus_for_each_dev+0x82/0xb0
>> [  266.989794]  [<00000000bf0f2aba>] ap_scan_bus+0x262/0x878
>> [  266.989798]  [<00000000beb4785c>] process_one_work+0x1e4/0x410
>> [  266.989800]  [<00000000beb47ca8>] worker_thread+0x220/0x460
>> [  266.989802]  [<00000000beb4e99a>] kthread+0x12a/0x160
>> [  266.989805]  [<00000000bf2d8eb0>] ret_from_fork+0x28/0x2c
>> [  266.989806]  [<00000000bf2d8eb4>] kernel_thread_starter+0x0/0xc
>> [  266.989807] Last Breaking-Event-Address:
>> [  266.989809]  [<000003ff8007d898>] vfio_ap_irq_disable+0x138/0x1b0 
>> [vfio_ap]
>> [  266.989810] ---[ end trace 59b4020890dbd391 ]---
>>
>>
>>>
>>> Thanks,
>>>
>>> Pierre
>>>
>>>
>>>
>>

Anthony Krowiak Nov. 1, 2019, 8:04 p.m. UTC | #7

On 10/30/19 2:02 PM, Pierre Morel wrote:
> 
> On 10/30/19 5:51 PM, Tony Krowiak wrote:
>> On 10/30/19 10:00 AM, Pierre Morel wrote:
>>>
>>>
>>>
>>> On 10/30/19 8:44 AM, Harald Freudenberger wrote:
>>>> On 29.10.19 23:09, Tony Krowiak wrote:
>>>>> From: aekrowia <[e-mail]>
>>>>>
>>>>> When an AP adapter card is configured off via the SE or the SCLP
>>>>> Deconfigure Adjunct Processor command and the AP bus subsequently 
>>>>> detects
>>>>> that the adapter card is no longer in the AP configuration, the card
>>>>> device representing the adapter card as well as each of its associated
>>>>> AP queue devices will be removed by the AP bus. If one or more of the
>>>>> affected queue devices is bound to the VFIO AP device driver, its 
>>>>> remove
>>>>> callback will be invoked for each queue to be removed. The remove 
>>>>> callback
>>>>> resets the queue and disables IRQ processing. If interrupt 
>>>>> processing was
>>>>> never enabled for the queue, disabling IRQ processing will fail 
>>>>> resulting
>>>>> in a kernel OOPS.
>>>>>
>>>>> This patch verifies IRQ processing is enabled before attempting to 
>>>>> disable
>>>>> interrupts for the queue.
>>>>>
>>>>> Signed-off-by: Tony Krowiak <[e-mail]>
>>>>> Signed-off-by: aekrowia <[e-mail]>
>>>>> ---
>>>>>   drivers/s390/crypto/vfio_ap_drv.c | 3 ++-
>>>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/s390/crypto/vfio_ap_drv.c 
>>>>> b/drivers/s390/crypto/vfio_ap_drv.c
>>>>> index be2520cc010b..42d8308fd3a1 100644
>>>>> --- a/drivers/s390/crypto/vfio_ap_drv.c
>>>>> +++ b/drivers/s390/crypto/vfio_ap_drv.c
>>>>> @@ -79,7 +79,8 @@ static void vfio_ap_queue_dev_remove(struct 
>>>>> ap_device *apdev)
>>>>>       apid = AP_QID_CARD(q->apqn);
>>>>>       apqi = AP_QID_QUEUE(q->apqn);
>>>>>       vfio_ap_mdev_reset_queue(apid, apqi, 1);
>>>>> -    vfio_ap_irq_disable(q);
>>>>> +    if (q->saved_isc != VFIO_AP_ISC_INVALID)
>>>>> +        vfio_ap_irq_disable(q);
>>>>>       kfree(q);
>>>>>       mutex_unlock(&matrix_dev->lock);
>>>>>   }
>>>> Reset of an APQN does also clear IRQ processing. I don't say that the
>>>> resources associated with IRQ handling for the APQN are also cleared.
>>>> But when you call PQAP(AQIC) after an PQAP(RAPQ) or PQAP(ZAPQ)
>>>> it is superfluous. However, there should not appear any kernel OOPS.
>>>> So can you please give me more details about this kernel oops - maybe
>>>> I need to add exception handler code to the inline ap_aqic() function.
>>>>
>>>> regards, Harald Freudenberger
>>>>
>>>
>>> Hi Tony,
>>>
>>> wasn't it already solved by the patch 5c4c2126  from Christian ?
>>
>> No, that patch merely sets the 'matrix_mdev' field of the
>> 'struct vfio_ap_queue' to NULL in the vfio_ap_free_aqic_resources()
>> function. Also, with the latest master branch which has 5c4c2126
>> installed, the failure occurs.
>>
>>>
>>> Can you send the trace to me please?
>>
>> [  266.989476] crw_info : CRW reports slct=0, oflw=0, chn=0, rsc=B, 
>> anc=0, erc=0, rsid=0
>> [  266.989617] ------------[ cut here ]------------
>> [  266.989622] vfio_ap_wait_for_irqclear: tapq rc 03: 0504
>> [  266.989681] WARNING: CPU: 0 PID: 7 at 
>> drivers/s390/crypto/vfio_ap_ops.c:101 vfio_ap_irq_disable+0x13c/0x1b0 
>> [vfio_ap]
> 
> 
> Hi Tony,
> 
> This is not a oops this is the warning written in 
> vfio_ap_wait_for_irqclear() because the AP has been deconfigured.
> 
> Note that, IIUC, this (the warning) does not happen for devices bound to 
> the vfio_ap driver but not currently assigned to a mediated device.
> 
> I do not think we should avoid sending a warning in this case because 
> this is not a normal administration good practice to forcefully take an 
> AP away like this without smoothly removing the device from the mediated 
> device.
> 
> Regards,
> 
> Pierre

After further review, I see this warning is actually issued as a
WARN_ONCE in the vfio_ap_wait_for_irqclear() function when the
PQAP(TAPQ) returns with response code 3, AP adapter deconfigured.
I wasn't aware that the WARN_ONCE macro put out a stack trace.
That doesn't negate the fact that it makes no sense to disable
interrupts if they are not enabled, nor does it make sense to
disable interrrupts subsequent to a reset because the reset will
disable interrupts. For now, this patch can be ignored pending
further review of these issues.

> 
> 
>> [ 266.989682] Modules linked in: xt_CHECKSUM xt_MASQUERADE tun bridge 
>> stp llc ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack 
>> ebtable_nat ip6table_nat ip6table_mangle ip6table_raw 
>> ip6table_security iptable_nat nf_nat iptable_mangle iptable_raw 
>> iptable_security nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c 
>> ip_set nfnetlink ebtable_filter ebtables ip6table_filter ip6_tables 
>> sunrpc ghash_s390 prng aes_s390 des_s390 libdes vfio_ccw sha512_s390 
>> sha1_s390 eadm_sch zcrypt_cex4 qeth_l2 crc32_vx_s390 dasd_eckd_mod 
>> sha256_s390 qeth sha_common dasd_mod ccwgroup qdio pkey zcrypt vfio_ap 
>> kvm
>> [  266.989704] CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.4.0-rc5 #81
>> [  266.989705] Hardware name: IBM 2964 NE1 749 (LPAR)
>> [  266.989710] Workqueue: events_long ap_scan_bus
>> [  266.989711] Krnl PSW : 0704c00180000000 000003ff8007d89c 
>> (vfio_ap_irq_disable+0x13c/0x1b0 [vfio_ap])
>> [  266.989714]            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 
>> CC:0 PM:0 RI:0 EA:3
>> [  266.989716] Krnl GPRS: 000000000000000a 0000000000000006 
>> 000000000000002b 0000000000000007
>> [  266.989717]            0000000000000007 000000007fe06000 
>> 000003ff00000005 0000000000000000
>> [  266.989718]            0000000100000504 0000000000000003 
>> 00000001f9d27e40 000003e00003bb5c
>> [  266.989719]            00000001fe765d00 0000000000000504 
>> 000003ff8007d898 000003e00003ba60
>> [  266.989724] Krnl Code: 000003ff8007d88c: c02000000ce6    larl 
>> %r2,3ff8007f258
>>                           000003ff8007d892: c0e5fffff4c7    brasl 
>> %r14,3ff8007c220
>>                          #000003ff8007d898: a7f40001        brc 
>> 15,3ff8007d89a
>>                          >000003ff8007d89c: a7f4ff9d        brc 
>> 15,3ff8007d7d6
>>                           000003ff8007d8a0: a7100100 tmlh    %r1,256
>>                           000003ff8007d8a4: a784ff99        brc 
>> 8,3ff8007d7d6
>>                           000003ff8007d8a8: a7290014 lghi    %r2,20
>>                           000003ff8007d8ac: c0e5fffff4b0    brasl 
>> %r14,3ff8007c20c
>> [  266.989772] Call Trace:
>> [  266.989777] ([<000003ff8007d898>] vfio_ap_irq_disable+0x138/0x1b0 
>> [vfio_ap])
>> [  266.989779]  [<000003ff8007c4d2>] 
>> vfio_ap_queue_dev_remove+0x6a/0x90 [vfio_ap]
>> [  266.989782]  [<00000000bf0f24f0>] ap_device_remove+0x50/0x110
>> [  266.989784]  [<00000000beffbaac>] 
>> device_release_driver_internal+0x114/0x1f0
>> [  266.989787]  [<00000000beff9c88>] bus_remove_device+0x108/0x190
>> [  266.989789]  [<00000000beff5418>] device_del+0x178/0x3a0
>> [  266.989790]  [<00000000beff5670>] device_unregister+0x30/0x90
>> [  266.989791]  [<00000000bf0f0f04>] 
>> __ap_queue_devices_with_id_unregister+0x44/0x50
>> [  266.989793]  [<00000000beff86ea>] bus_for_each_dev+0x82/0xb0
>> [  266.989794]  [<00000000bf0f2aba>] ap_scan_bus+0x262/0x878
>> [  266.989798]  [<00000000beb4785c>] process_one_work+0x1e4/0x410
>> [  266.989800]  [<00000000beb47ca8>] worker_thread+0x220/0x460
>> [  266.989802]  [<00000000beb4e99a>] kthread+0x12a/0x160
>> [  266.989805]  [<00000000bf2d8eb0>] ret_from_fork+0x28/0x2c
>> [  266.989806]  [<00000000bf2d8eb4>] kernel_thread_starter+0x0/0xc
>> [  266.989807] Last Breaking-Event-Address:
>> [  266.989809]  [<000003ff8007d898>] vfio_ap_irq_disable+0x138/0x1b0 
>> [vfio_ap]
>> [  266.989810] ---[ end trace 59b4020890dbd391 ]---
>>
>>
>>>
>>> Thanks,
>>>
>>> Pierre
>>>
>>>
>>>
>>

Patch

diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index be2520cc010b..42d8308fd3a1 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -79,7 +79,8 @@  static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
 	apid = AP_QID_CARD(q->apqn);
 	apqi = AP_QID_QUEUE(q->apqn);
 	vfio_ap_mdev_reset_queue(apid, apqi, 1);
-	vfio_ap_irq_disable(q);
+	if (q->saved_isc != VFIO_AP_ISC_INVALID)
+		vfio_ap_irq_disable(q);
 	kfree(q);
 	mutex_unlock(&matrix_dev->lock);
 }