Re: [PATCH] drm/amdgpu: cache in more vm fault information

[Christian König]

Am 06.03.24 um 16:13 schrieb Khatri, Sunil:
> On 3/6/2024 8:34 PM, Christian König wrote:
> > Am 06.03.24 um 15:29 schrieb Alex Deucher:
> > > On Wed, Mar 6, 2024 at 8:04 AM Khatri, Sunil <sukhatri@xxxxxxx> wrote:
> > > > On 3/6/2024 6:12 PM, Christian König wrote:
> > > > > Am 06.03.24 um 11:40 schrieb Khatri, Sunil:
> > > > > > On 3/6/2024 3:37 PM, Christian König wrote:
> > > > > > > Am 06.03.24 um 10:04 schrieb Sunil Khatri:
> > > > > > > > When an  page fault interrupt is raised there
> > > > > > > > is a lot more information that is useful for
> > > > > > > > developers to analyse the pagefault.
> > > > > > > Well actually those information are not that interesting because
> > > > > > > they are hw generation specific.
> > > > > > >
> > > > > > > You should probably rather use the decoded strings here, e.g. hub,
> > > > > > > client, xcc_id, node_id etc...
> > > > > > >
> > > > > > > See gmc_v9_0_process_interrupt() an example.
> > > > > > > I saw this v9 does provide more information than what v10 and v11
> > > > > > > provide like node_id and fault from which die but thats again very
> > > > > > > specific to IP_VERSION(9, 4, 3)) i dont know why thats information
> > > > > > > is not there in v10 and v11.
> > > > > > I agree to your point but, as of now during a pagefault we are
> > > > > > dumping this information which is useful like which client
> > > > > > has generated an interrupt and for which src and other information
> > > > > > like address. So i think to provide the similar information in the
> > > > > > devcoredump.
> > > > > >
> > > > > > Currently we do not have all this information from either job or vm
> > > > > > being derived from the job during a reset. We surely could add more
> > > > > > relevant information later on as per request but this information is
> > > > > > useful as
> > > > > > eventually its developers only who would use the dump file provided
> > > > > > by customer to debug.
> > > > > >
> > > > > > Below is the information that i dump in devcore and i feel that is
> > > > > > good information but new information could be added which could be
> > > > > > picked later.
> > > > > >
> > > > > > > Page fault information
> > > > > > > [gfxhub] page fault (src_id:0 ring:24 vmid:3 pasid:32773)
> > > > > > > in page starting at address 0x0000000000000000 from client 0x1b 
> > > > > > > (UTCL2)
> > > > > This is a perfect example what I mean. You record in the patch is the
> > > > > client_id, but this is is basically meaningless unless you have 
> > > > > access
> > > > > to the AMD internal hw documentation.
> > > > >
> > > > > What you really need is the client in decoded form, in this case
> > > > > UTCL2. You can keep the client_id additionally, but the decoded 
> > > > > client
> > > > > string is mandatory to have I think.
> > > > >
> > > > > Sure i am capturing that information as i am trying to minimise the
> > > > > memory interaction to minimum as we are still in interrupt context
> > > > > here that why i recorded the integer information compared to decoding
> > > > and writing strings there itself but to postpone till we dump.
> > > >
> > > > Like decoding to the gfxhub/mmhub based on vmhub/vmid_src and client
> > > > string from client id. So are we good to go with the information with
> > > > the above information of sharing details in devcoredump using the
> > > > additional information from pagefault cached.
> > > I think amdgpu_vm_fault_info() has everything you need already (vmhub,
> > > status, and addr).  client_id and src_id are just tokens in the
> > > interrupt cookie so we know which IP to route the interrupt to. We
> > > know what they will be because otherwise we'd be in the interrupt
> > > handler for a different IP.  I don't think ring_id has any useful
> > > information in this context and vmid and pasid are probably not too
> > > useful because they are just tokens to associate the fault with a
> > > process.  It would be better to have the process name.
>
> Just to share context here Alex, i am preparing this for devcoredump, 
> my intention was to replicate the information which in KMD we are 
> sharing in Dmesg for page faults. If assuming we do not add client id 
> specially we would not be able to share enough information in 
> devcoredump.
> It would be just address and hub(gfxhub/mmhub) and i think that is 
> partial information as src id and client id and ip block shares good 
> information.
>
> For process related information we are capturing that information part 
> of dump from existing functionality.
> **** AMDGPU Device Coredump ****
> version: 1
> kernel: 6.7.0-amd-staging-drm-next
> module: amdgpu
> time: 45.084775181
> process_name: soft_recovery_p PID: 1780
>
> Ring timed out details
> IP Type: 0 Ring Name: gfx_0.0.0
>
> Page fault information
> [gfxhub] page fault (src_id:0 ring:24 vmid:3 pasid:32773)
> in page starting at address 0x0000000000000000 from client 0x1b (UTCL2)
> VRAM is lost due to GPU reset!
>
> Regards
> Sunil
>
> > The decoded client name would be really useful I think since the 
> > fault handled is a catch all and handles a whole bunch of different 
> > clients.
> >
> > But that should be ideally passed in as const string instead of the 
> > hw generation specific client_id.
> >
> > As long as it's only a pointer we also don't run into the trouble 
> > that we need to allocate memory for it.
>
> I agree but i prefer adding the client id and decoding it in 
> devcorecump using soc15_ih_clientid_name[fault_info->client_id]) is 
> better else we have to do an sprintf this string to fault_info in irq 
> context which is writing more bytes to memory i guess compared to an 
> integer:)

Well I totally agree that we shouldn't fiddle to much in the interrupt 
handler, but exactly what you suggest here won't work.

The client_id is hw generation specific, so the only one who has that is 
the hw generation specific fault handler. Just compare the defines here:

https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c#L83

and here:

https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/amd/amdgpu/gfxhub_v11_5_0.c#L38

Regards,
Christian.

> We can argue on values like pasid and vmid and ring id to be taken off 
> if they are totally not useful.
>
> Regards
> Sunil
>
> > Christian.
> >
> > > Alex
> > >
> > > > regards
> > > > sunil
> > > >
> > > > > Regards,
> > > > > Christian.
> > > > >
> > > > > > Regards
> > > > > > Sunil Khatri
> > > > > >
> > > > > > > Regards,
> > > > > > > Christian.
> > > > > > >
> > > > > > > > Add all such information in the last cached
> > > > > > > > pagefault from an interrupt handler.
> > > > > > > >
> > > > > > > > Signed-off-by: Sunil Khatri <sunil.khatri@xxxxxxx>
> > > > > > > > ---
> > > > > > > >    drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 9 +++++++--
> > > > > > > >    drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 7 ++++++-
> > > > > > > >    drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c | 2 +-
> > > > > > > >    drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c | 2 +-
> > > > > > > >    drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c  | 2 +-
> > > > > > > >    drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c  | 2 +-
> > > > > > > >    drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c  | 2 +-
> > > > > > > >    7 files changed, 18 insertions(+), 8 deletions(-)
> > > > > > > >
> > > > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > > > > > > > b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > > > > > > > index 4299ce386322..b77e8e28769d 100644
> > > > > > > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > > > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > > > > > > > @@ -2905,7 +2905,7 @@ void amdgpu_debugfs_vm_bo_info(struct
> > > > > > > > amdgpu_vm *vm, struct seq_file *m)
> > > > > > > >     * Cache the fault info for later use by userspace in 
> > > > > > > > debugging.
> > > > > > > >     */
> > > > > > > >    void amdgpu_vm_update_fault_cache(struct amdgpu_device *adev,
> > > > > > > > -                  unsigned int pasid,
> > > > > > > > +                  struct amdgpu_iv_entry *entry,
> > > > > > > >                      uint64_t addr,
> > > > > > > >                      uint32_t status,
> > > > > > > >                      unsigned int vmhub)
> > > > > > > > @@ -2915,7 +2915,7 @@ void amdgpu_vm_update_fault_cache(struct
> > > > > > > > amdgpu_device *adev,
> > > > > > > > xa_lock_irqsave(&adev->vm_manager.pasids, flags);
> > > > > > > >    -    vm = xa_load(&adev->vm_manager.pasids, pasid);
> > > > > > > > +    vm = xa_load(&adev->vm_manager.pasids, entry->pasid);
> > > > > > > >        /* Don't update the fault cache if status is 0.  In the 
> > > > > > > > multiple
> > > > > > > >         * fault case, subsequent faults will return a 0 status 
> > > > > > > > which is
> > > > > > > >         * useless for userspace and replaces the useful fault
> > > > > > > > status, so
> > > > > > > > @@ -2924,6 +2924,11 @@ void amdgpu_vm_update_fault_cache(struct
> > > > > > > > amdgpu_device *adev,
> > > > > > > >        if (vm && status) {
> > > > > > > >            vm->fault_info.addr = addr;
> > > > > > > >            vm->fault_info.status = status;
> > > > > > > > +        vm->fault_info.client_id = entry->client_id;
> > > > > > > > +        vm->fault_info.src_id = entry->src_id;
> > > > > > > > +        vm->fault_info.vmid = entry->vmid;
> > > > > > > > +        vm->fault_info.pasid = entry->pasid;
> > > > > > > > +        vm->fault_info.ring_id = entry->ring_id;
> > > > > > > >            if (AMDGPU_IS_GFXHUB(vmhub)) {
> > > > > > > >                vm->fault_info.vmhub = AMDGPU_VMHUB_TYPE_GFX;
> > > > > > > >                vm->fault_info.vmhub |=
> > > > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> > > > > > > > b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> > > > > > > > index 047ec1930d12..c7782a89bdb5 100644
> > > > > > > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> > > > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> > > > > > > > @@ -286,6 +286,11 @@ struct amdgpu_vm_fault_info {
> > > > > > > >        uint32_t    status;
> > > > > > > >        /* which vmhub? gfxhub, mmhub, etc. */
> > > > > > > >        unsigned int    vmhub;
> > > > > > > > +    unsigned int    client_id;
> > > > > > > > +    unsigned int    src_id;
> > > > > > > > +    unsigned int    ring_id;
> > > > > > > > +    unsigned int    pasid;
> > > > > > > > +    unsigned int    vmid;
> > > > > > > >    };
> > > > > > > >      struct amdgpu_vm {
> > > > > > > > @@ -605,7 +610,7 @@ static inline void
> > > > > > > > amdgpu_vm_eviction_unlock(struct amdgpu_vm *vm)
> > > > > > > >    }
> > > > > > > >      void amdgpu_vm_update_fault_cache(struct amdgpu_device *adev,
> > > > > > > > -                  unsigned int pasid,
> > > > > > > > +                  struct amdgpu_iv_entry *entry,
> > > > > > > >                      uint64_t addr,
> > > > > > > >                      uint32_t status,
> > > > > > > >                      unsigned int vmhub);
> > > > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> > > > > > > > b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> > > > > > > > index d933e19e0cf5..6b177ce8db0e 100644
> > > > > > > > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> > > > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> > > > > > > > @@ -150,7 +150,7 @@ static int gmc_v10_0_process_interrupt(struct
> > > > > > > > amdgpu_device *adev,
> > > > > > > >            status = RREG32(hub->vm_l2_pro_fault_status);
> > > > > > > >            WREG32_P(hub->vm_l2_pro_fault_cntl, 1, ~1);
> > > > > > > >    -        amdgpu_vm_update_fault_cache(adev, entry->pasid, addr,
> > > > > > > > status,
> > > > > > > > +        amdgpu_vm_update_fault_cache(adev, entry, addr, status,
> > > > > > > >                             entry->vmid_src ? AMDGPU_MMHUB0(0) :
> > > > > > > > AMDGPU_GFXHUB(0));
> > > > > > > >        }
> > > > > > > >    diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c
> > > > > > > > b/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c
> > > > > > > > index 527dc917e049..bcf254856a3e 100644
> > > > > > > > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c
> > > > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v11_0.c
> > > > > > > > @@ -121,7 +121,7 @@ static int gmc_v11_0_process_interrupt(struct
> > > > > > > > amdgpu_device *adev,
> > > > > > > >            status = RREG32(hub->vm_l2_pro_fault_status);
> > > > > > > >            WREG32_P(hub->vm_l2_pro_fault_cntl, 1, ~1);
> > > > > > > >    -        amdgpu_vm_update_fault_cache(adev, entry->pasid, addr,
> > > > > > > > status,
> > > > > > > > +        amdgpu_vm_update_fault_cache(adev, entry, addr, status,
> > > > > > > >                             entry->vmid_src ? AMDGPU_MMHUB0(0) :
> > > > > > > > AMDGPU_GFXHUB(0));
> > > > > > > >        }
> > > > > > > >    diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> > > > > > > > b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> > > > > > > > index 3da7b6a2b00d..e9517ebbe1fd 100644
> > > > > > > > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> > > > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> > > > > > > > @@ -1270,7 +1270,7 @@ static int gmc_v7_0_process_interrupt(struct
> > > > > > > > amdgpu_device *adev,
> > > > > > > >        if (!addr && !status)
> > > > > > > >            return 0;
> > > > > > > >    -    amdgpu_vm_update_fault_cache(adev, entry->pasid,
> > > > > > > > +    amdgpu_vm_update_fault_cache(adev, entry,
> > > > > > > >                         ((u64)addr) << AMDGPU_GPU_PAGE_SHIFT,
> > > > > > > > status, AMDGPU_GFXHUB(0));
> > > > > > > >          if (amdgpu_vm_fault_stop == AMDGPU_VM_FAULT_STOP_FIRST)
> > > > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> > > > > > > > b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> > > > > > > > index d20e5f20ee31..a271bf832312 100644
> > > > > > > > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> > > > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> > > > > > > > @@ -1438,7 +1438,7 @@ static int gmc_v8_0_process_interrupt(struct
> > > > > > > > amdgpu_device *adev,
> > > > > > > >        if (!addr && !status)
> > > > > > > >            return 0;
> > > > > > > >    -    amdgpu_vm_update_fault_cache(adev, entry->pasid,
> > > > > > > > +    amdgpu_vm_update_fault_cache(adev, entry,
> > > > > > > >                         ((u64)addr) << AMDGPU_GPU_PAGE_SHIFT,
> > > > > > > > status, AMDGPU_GFXHUB(0));
> > > > > > > >          if (amdgpu_vm_fault_stop == AMDGPU_VM_FAULT_STOP_FIRST)
> > > > > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> > > > > > > > b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> > > > > > > > index 47b63a4ce68b..dc9fb1fb9540 100644
> > > > > > > > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> > > > > > > > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> > > > > > > > @@ -666,7 +666,7 @@ static int gmc_v9_0_process_interrupt(struct
> > > > > > > > amdgpu_device *adev,
> > > > > > > >        rw = REG_GET_FIELD(status, 
> > > > > > > > VM_L2_PROTECTION_FAULT_STATUS, RW);
> > > > > > > >        WREG32_P(hub->vm_l2_pro_fault_cntl, 1, ~1);
> > > > > > > >    -    amdgpu_vm_update_fault_cache(adev, entry->pasid, addr,
> > > > > > > > status, vmhub);
> > > > > > > > +    amdgpu_vm_update_fault_cache(adev, entry, addr, status, 
> > > > > > > > vmhub);
> > > > > > > >          dev_err(adev->dev,
> > > > > > > >            "VM_L2_PROTECTION_FAULT_STATUS:0x%08X\n",