I see, thanks for the detail information.
Normally when CP is hang, the hiq access to unmap the queue will
failed before driver call to the hqd_destroy. I think driver should
add the code to check the return value and directly finish the
pre_reset in this case . If the hiq does not hang but kiq hang. We
can use the same logic in hqd_destroy function, return in first
access failure instead go further. With this change we probably
can move the pre_reset function back to normal .
Felix, do you have any concerns or comments for the change.
Regards
Shaoyun.liu
------------------------------------------------------------------------
*From:* Liu, Monk <Monk.Liu@xxxxxxx>
*Sent:* December 19, 2019 1:13:24 AM
*To:* Liu, Shaoyun <Shaoyun.Liu@xxxxxxx>;
amd-gfx@xxxxxxxxxxxxxxxxxxxxx <amd-gfx@xxxxxxxxxxxxxxxxxxxxx>
*Subject:* RE: [PATCH 2/2] drm/amdgpu: fix KIQ ring test fail in
TDR of SRIOV
>>> I would like to check why we need a special sequences for sriov
on this pre_reset. If possible, make it the same as bare metal mode
sounds better solution.
Because before VF FLR calling function would lead to register
access through KIQ, which will not complete because KIQ/GFX
already hang by that time
>>> I don't remember any register access by amdkfd_pre_reset
call, please let me know if this assumption is wrong .
Please check “void pm_uninit(struct packet_manager *pm)” which is
invoked inside of amdkfd_pre_reset() :
It will call uninitialized() in kfd_kernel_queue.c file
And then go to the path of “kq->mqd_mgr->destroy_mqd(…)”
And finally it calls “static int kgd_hqd_destroy(…)” in
amdgpu_amdkfd_gfx_v10.c
539 {
540 struct amdgpu_device *adev = get_amdgpu_device(kgd);
541 enum hqd_dequeue_request_type type;
542 unsigned long end_jiffies;
543 uint32_t temp;
544 struct v10_compute_mqd *m = get_mqd(mqd);
545
546 #if 0
547 unsigned long flags;
548 int retry;
549 #endif
550
551 acquire_queue(kgd, pipe_id, queue_id); //this introduce
register access via KIQ
552
553 if (m->cp_hqd_vmid == 0)
554 WREG32_FIELD15(GC, 0, RLC_CP_SCHEDULERS, scheduler1,
0); //this introduce register access via KIQ
555
556 switch (reset_type) {
557 case KFD_PREEMPT_TYPE_WAVEFRONT_DRAIN:
558 type = DRAIN_PIPE;
559 break;
560 case KFD_PREEMPT_TYPE_WAVEFRONT_RESET:
561 type = RESET_WAVES;
562 break;
563 default:
564 type = DRAIN_PIPE;
565 break;
566 }
624 WREG32(SOC15_REG_OFFSET(GC, 0, mmCP_HQD_DEQUEUE_REQUEST),
type); //this introduce register access via KIQ
625
626 end_jiffies = (utimeout * HZ / 1000) + jiffies;
627 while (true) {
628 temp = RREG32(SOC15_REG_OFFSET(GC, 0,
mmCP_HQD_ACTIVE)); //this introduce register access via KIQ
629 if (!(temp & CP_HQD_ACTIVE__ACTIVE_MASK))
630 break;
631 if (time_after(jiffies, end_jiffies)) {
632 pr_err("cp queue preemption time out.\n");
633 release_queue(kgd);
634 return -ETIME;
635 }
636 usleep_range(500, 1000);
637 }
638
639 release_queue(kgd);
640 return 0;
If we use the sequence from bare-metal, all above highlighted
register access will not work because KIQ/GFX already died by that
time which means the amdkfd_pre_reset() is actually not working as
expected.
_____________________________________
Monk Liu|GPU Virtualization Team |AMD
sig-cloud-gpu
*From:* Liu, Shaoyun <Shaoyun.Liu@xxxxxxx>
*Sent:* Thursday, December 19, 2019 12:30 PM
*To:* Liu, Monk <Monk.Liu@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx
*Subject:* Re: [PATCH 2/2] drm/amdgpu: fix KIQ ring test fail in
TDR of SRIOV
I don't remember any register access by amdkfd_pre_reset call,
please let me know if this assumption is wrong .
This function will use hiq to access CP, in case CP already hang,
we might not able to get the response from hw and will got a
timeout. I think kfd internal should handle this. Felix already
have some comments on that.
I would like to check why we need a special sequences for sriov on
this pre_reset. If possible, make it the same as bare metal mode
sounds better solution.
Regards
Shaoyun.liu
------------------------------------------------------------------------
*From:*Liu, Monk <Monk.Liu@xxxxxxx <mailto:Monk.Liu@xxxxxxx>>
*Sent:* December 18, 2019 10:52:47 PM
*To:* Liu, Shaoyun <Shaoyun.Liu@xxxxxxx
<mailto:Shaoyun.Liu@xxxxxxx>>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx
<mailto:amd-gfx@xxxxxxxxxxxxxxxxxxxxx>
<amd-gfx@xxxxxxxxxxxxxxxxxxxxx <mailto:amd-gfx@xxxxxxxxxxxxxxxxxxxxx>>
*Subject:* RE: [PATCH 2/2] drm/amdgpu: fix KIQ ring test fail in
TDR of SRIOV
Oh, by the way
>>> Do we know the root cause why this function would ruin MEC ?
Only we call this function right after VF FLR will ruin MEC and
lead to following KIQ ring test fail , and on bare-metal it is
called before gpu rest , so that's why on bare-metal we don't have
this issue
But the reason we cannot call it before VF FLR on SRIOV case was
already stated in this thread
Thanks
_____________________________________
Monk Liu|GPU Virtualization Team |AMD
-----Original Message-----
From: Liu, Monk
Sent: Thursday, December 19, 2019 11:49 AM
To: shaoyunl <shaoyun.liu@xxxxxxx <mailto:shaoyun.liu@xxxxxxx>>;
amd-gfx@xxxxxxxxxxxxxxxxxxxxx <mailto:amd-gfx@xxxxxxxxxxxxxxxxxxxxx>
Subject: RE: [PATCH 2/2] drm/amdgpu: fix KIQ ring test fail in TDR
of SRIOV
Hi Shaoyun
>>> Do we know the root cause why this function would ruin MEC ?
From the logic, I think this function should be called before FLR
since we need to disable the user queue submission first.
Right now I don't know which detail step lead to KIQ ring test
fail, I totally agree with you that this func should be called
before VF FLR, but we cannot do it and the reason is described in
The comment:
> if we do pre_reset() before VF FLR, it would go KIQ way to do
register
> access and stuck there, because KIQ probably won't work by that time
> (e.g. you already made GFX hang)
>>> I remembered the function should use hiq to communicate with HW
, shouldn't use kiq to access HW registerm, has this been changed ?
Tis function use WREG32/RREG32 to do register access, like all
other functions in KMD, and WREG32/RREG32 will let KIQ to do the
register access If we are under dynamic SRIOV mode (means we are
SRIOV VF and isn't under full exclusive mode)
You see that if you call this func before EVENT_5 (event 5 triggers
VF FLR) then it will run under dynamic mode and KIQ will handle the
register access, which is not an option Since ME/MEC probably
already hang ( if we are testing quark on gfx/compute rings)
Do you have a good suggestion ?
thanks
_____________________________________
Monk Liu|GPU Virtualization Team |AMD
-----Original Message-----
From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx
<mailto:amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx>> On Behalf Of shaoyunl
Sent: Tuesday, December 17, 2019 11:38 PM
To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
<mailto:amd-gfx@xxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [PATCH 2/2] drm/amdgpu: fix KIQ ring test fail in TDR
of SRIOV
I think amdkfd side depends on this call to stop the user queue,
without this call, the user queue can submit to HW during the reset
which could cause hang again ...
Do we know the root cause why this function would ruin MEC ? From
the logic, I think this function should be called before FLR since
we need to disable the user queue submission first.
I remembered the function should use hiq to communicate with HW ,
shouldn't use kiq to access HW registerm, has this been changed ?
Regards
shaoyun.liu
On 2019-12-17 5:19 a.m., Monk Liu wrote:
> issues:
> MEC is ruined by the amdkfd_pre_reset after VF FLR done
>
> fix:
> amdkfd_pre_reset() would ruin MEC after hypervisor finished the VF
> FLR, the correct sequence is do amdkfd_pre_reset before VF FLR but
> there is a limitation to block this sequence:
> if we do pre_reset() before VF FLR, it would go KIQ way to do
register
> access and stuck there, because KIQ probably won't work by that time
> (e.g. you already made GFX hang)
>
> so the best way right now is to simply remove it.
>
> Signed-off-by: Monk Liu <Monk.Liu@xxxxxxx <mailto:Monk.Liu@xxxxxxx>>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 605cef6..ae962b9 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -3672,8 +3672,6 @@ static int amdgpu_device_reset_sriov(struct
amdgpu_device *adev,
> if (r)
> return r;
>
> - amdgpu_amdkfd_pre_reset(adev);
> -
> /* Resume IP prior to SMC */
> r = amdgpu_device_ip_reinit_early_sriov(adev);
> if (r)
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