Re: [PATCH] drm/amdkfd: fix address watch clearing bug for gfx v9.4.2

[Felix Kuehling <felix.kuehling@xxxxxxx>]

I think Jon is suggesting that the UNMAP_QUEUES command should clear the 
address watch registers. Requesting such a change from the the HWS team 
may take a long time.

That said, when was this workaround implemented and reviewed? Did I 
review it as part of Jon's debugger upstreaming patch series? Or did 
this come later? This patch only enables the workaround for v9.4.2.

Regards,
  Felix


On 2023-08-10 17:52, Eric Huang wrote:
> The problem is the queue is suspended before clearing address watch 
> call in KFD, there is not queue preemption and queue resume after 
> clearing call, and the test ends. So there is not chance to send 
> MAP_PROCESS to HWS. At this point FW has nothing to do. We have 
> several test FWs from Tej, none of them works, so I recalled the 
> kernel debug log and found out the problem.
>
> GFX11 has different scheduler, when calling clear address watch, KFD 
> directly sends the MES_MISC_OP_SET_SHADER_DEBUGGER to MES, it doesn't 
> consider if the queue is suspended. So GFX11 doesn't have this issue.
>
> Regards,
> Eric
>
> On 2023-08-10 17:27, Kim, Jonathan wrote:
> > [AMD Official Use Only - General]
> >
> > This is a strange solution because the MEC should set watch controls 
> > as non-valid automatically on queue preemption to avoid this kind of 
> > issue in the first place by design.  MAP_PROCESS on resume will take 
> > whatever the driver requests.
> > GFX11 has no issue with letting the HWS do this.
> >
> > Are we sure we're not working around some HWS bug?
> >
> > Thanks,
> >
> > Jon
> >
> > > -----Original Message-----
> > > From: Kuehling, Felix <Felix.Kuehling@xxxxxxx>
> > > Sent: Thursday, August 10, 2023 5:03 PM
> > > To: Huang, JinHuiEric <JinHuiEric.Huang@xxxxxxx>; amd-
> > > gfx@xxxxxxxxxxxxxxxxxxxxx
> > > Cc: Kim, Jonathan <Jonathan.Kim@xxxxxxx>
> > > Subject: Re: [PATCH] drm/amdkfd: fix address watch clearing bug for 
> > > gfx v9.4.2
> > >
> > > I think amdgpu_amdkfd_gc_9_4_3.c needs a similar fix. But maybe a bit
> > > different because it needs to support multiple XCCs.
> > >
> > > That said, this patch is
> > >
> > > Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
> > >
> > >
> > > On 2023-08-10 16:47, Eric Huang wrote:
> > > > KFD currently relies on MEC FW to clear tcp watch control
> > > > register by sending MAP_PROCESS packet with 0 of field
> > > > tcp_watch_cntl to HWS, but if the queue is suspended, the
> > > > packet will not be sent and the previous value will be
> > > > left on the register, that will affect the following apps.
> > > > So the solution is to clear the register as gfx v9 in KFD.
> > > >
> > > > Signed-off-by: Eric Huang <jinhuieric.huang@xxxxxxx>
> > > > ---
> > > >    drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_aldebaran.c | 8 +-------
> > > >    1 file changed, 1 insertion(+), 7 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_aldebaran.c
> > > b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_aldebaran.c
> > > > index e2fed6edbdd0..aff08321e976 100644
> > > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_aldebaran.c
> > > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_aldebaran.c
> > > > @@ -163,12 +163,6 @@ static uint32_t
> > > kgd_gfx_aldebaran_set_address_watch(
> > > >      return watch_address_cntl;
> > > >    }
> > > >
> > > > -static uint32_t kgd_gfx_aldebaran_clear_address_watch(struct
> > > amdgpu_device *adev,
> > > > - uint32_t watch_id)
> > > > -{
> > > > -   return 0;
> > > > -}
> > > > -
> > > >    const struct kfd2kgd_calls aldebaran_kfd2kgd = {
> > > >      .program_sh_mem_settings =
> > > kgd_gfx_v9_program_sh_mem_settings,
> > > >      .set_pasid_vmid_mapping = kgd_gfx_v9_set_pasid_vmid_mapping,
> > > > @@ -193,7 +187,7 @@ const struct kfd2kgd_calls aldebaran_kfd2kgd = {
> > > >      .set_wave_launch_trap_override =
> > > kgd_aldebaran_set_wave_launch_trap_override,
> > > >      .set_wave_launch_mode = kgd_aldebaran_set_wave_launch_mode,
> > > >      .set_address_watch = kgd_gfx_aldebaran_set_address_watch,
> > > > -   .clear_address_watch = kgd_gfx_aldebaran_clear_address_watch,
> > > > +   .clear_address_watch = kgd_gfx_v9_clear_address_watch,
> > > >      .get_iq_wait_times = kgd_gfx_v9_get_iq_wait_times,
> > > >      .build_grace_period_packet_info =
> > > kgd_gfx_v9_build_grace_period_packet_info,
> > > >      .program_trap_handler_settings =
> > > kgd_gfx_v9_program_trap_handler_settings,