Re: [PATCH] drm/amdgpu: move VM PTE MTYPE override to per-PTE granularity

[Philip Yang <yangp@amd.com>]

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On 2026-04-17 10:04, Christian König wrote:
> On 4/17/26 15:50, Philip Yang wrote:
>> Refactor the NUMA-aware MTYPE override for VM page table entries:
>>
>> - Move the override_vm_pte_flags call from the centralized
>>    amdgpu_vm_pte_update_flags() into the individual CPU and SDMA update
>>    backends, enabling per-PTE MTYPE override including for scattered
>>    pages (pages_addr path).
>>
>> - Move APU, IP version, and direct-mapped eligibility checks from
>>    runtime (gmc_v9_0_override_vm_pte_flags) to init time
>>    (gmc_v9_0_set_gmc_funcs), selecting between gmc_funcs structs with
>>    and without the override function pointer to avoid repeated runtime
>>    checks on every PTE update.
>>
>> - Guard allow_override on whether gmc_funcs->override_vm_pte_flags is
>>    actually implemented.
>>
>> - Move amdgpu_device_check_iommu_direct_map() earlier in device init
>>    so ram_is_direct_mapped is available when gmc_funcs are selected
>>    during IP early init.
>>
>> Signed-off-by: Philip Yang<Philip.Yang@amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c  |  5 ++-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c      |  2 +-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h      |  4 +-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c  | 11 ++++-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c   |  9 ----
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c | 11 ++++-
>>   drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c       | 50 ++++++++++++---------
>>   7 files changed, 55 insertions(+), 37 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> index bc7e96b58d3f..b139475f65cb 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> @@ -3860,6 +3860,9 @@ int amdgpu_device_init(struct amdgpu_device *adev,
>>   	 * completed before the need for a different level is detected.
>>   	 */
>>   	amdgpu_set_init_level(adev, AMDGPU_INIT_LEVEL_DEFAULT);
>> +
>> +	amdgpu_device_check_iommu_direct_map(adev);
>> +
>>   	/* early init functions */
>>   	r = amdgpu_device_ip_early_init(adev);
>>   	if (r)
>> @@ -4117,8 +4120,6 @@ int amdgpu_device_init(struct amdgpu_device *adev,
>>   	if (px)
>>   		vga_switcheroo_init_domain_pm_ops(adev->dev, &adev->vga_pm_domain);
>>   
>> -	amdgpu_device_check_iommu_direct_map(adev);
>> -
> That should probably be a separate patch.
ok
>
>>   	adev->pm_nb.notifier_call = amdgpu_device_pm_notifier;
>>   	r = register_pm_notifier(&adev->pm_nb);
>>   	if (r)
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> index 63156289ae7f..853204b5bd73 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> @@ -1163,7 +1163,7 @@ int amdgpu_vm_update_range(struct amdgpu_device *adev, struct amdgpu_vm *vm,
>>   	params.pages_addr = pages_addr;
>>   	params.unlocked = unlocked;
>>   	params.needs_flush = flush_tlb;
>> -	params.allow_override = allow_override;
>> +	params.allow_override = allow_override && adev->gmc.gmc_funcs->override_vm_pte_flags;
> Prerequisite check first please!
adev->gmc.gmc_funcs->override_vm_pte_flags is not NULL only if all 
prerequisites are true.
>
> And we should probably rename params.allow_override as well. Maybe something like override_pte_flags similar to the name of the callback?
will rename to params->override_pte_flags, don't change allow_override 
parameter of function amdgpu_vm_update_range
>
>>   	INIT_LIST_HEAD(&params.tlb_flush_waitlist);
>>   
>>   	amdgpu_vm_eviction_lock(vm);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> index f33ea7f8509b..326522917131 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> @@ -296,8 +296,8 @@ struct amdgpu_vm_update_params {
>>   	bool needs_flush;
>>   
>>   	/**
>> -	 * @allow_override: true for memory that is not uncached: allows MTYPE
>> -	 * to be overridden for NUMA local memory.
>> +	 * @allow_override: true for memory that is not uncached and gmc override function is
>> +	 * implemented to allow MTYPE to be overridden for NUMA local memory.
>>   	 */
>>   	bool allow_override;
>>   
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c
>> index f078db3fef79..fa5d4ac2ef39 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c
>> @@ -88,12 +88,21 @@ static int amdgpu_vm_cpu_update(struct amdgpu_vm_update_params *p,
>>   
>>   	trace_amdgpu_vm_set_ptes(pe, addr, count, incr, flags, p->immediate);
>>   
>> +	if (!p->pages_addr && p->allow_override)
>> +		amdgpu_gmc_override_vm_pte_flags(p->adev, p->vm, addr, &flags);
>> +
>>   	for (i = 0; i < count; i++) {
>> +		u64 oflags = flags;
>> +
>>   		value = p->pages_addr ?
>>   			amdgpu_vm_map_gart(p->pages_addr, addr) :
>>   			addr;
>> +
>> +		if (p->pages_addr && p->allow_override)
>> +			amdgpu_gmc_override_vm_pte_flags(p->adev, p->vm, value, &oflags);
>> +
>>   		amdgpu_gmc_set_pte_pde(p->adev, (void *)(uintptr_t)pe,
>> -				       i, value, flags);
>> +				       i, value, oflags);
>>   		addr += incr;
>>   	}
>>   	return 0;
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
>> index 31a437ce9570..883cc275f354 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
>> @@ -707,15 +707,6 @@ static void amdgpu_vm_pte_update_flags(struct amdgpu_vm_update_params *params,
>>   	if (level == AMDGPU_VM_PTB)
>>   		amdgpu_vm_pte_update_noretry_flags(adev, &flags);
>>   
>> -	/* APUs mapping system memory may need different MTYPEs on different
>> -	 * NUMA nodes. Only do this for contiguous ranges that can be assumed
>> -	 * to be on the same NUMA node.
>> -	 */
>> -	if ((flags & AMDGPU_PTE_SYSTEM) && (adev->flags & AMD_IS_APU) &&
>> -	    adev->gmc.gmc_funcs->override_vm_pte_flags &&
>> -	    num_possible_nodes() > 1 && !params->pages_addr && params->allow_override)
>> -		amdgpu_gmc_override_vm_pte_flags(adev, params->vm, addr, &flags);
>> -
>>   	params->vm->update_funcs->update(params, pt, pe, addr, count, incr,
>>   					 flags);
>>   }
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
>> index 36805dcfa159..37f0c0027075 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
>> @@ -257,6 +257,9 @@ static int amdgpu_vm_sdma_update(struct amdgpu_vm_update_params *p,
>>   		}
>>   
>>   		if (!p->pages_addr) {
>> +			if (p->allow_override)
>> +				amdgpu_gmc_override_vm_pte_flags(p->adev, p->vm, addr, &flags);
>> +
>>   			/* set page commands needed */
>>   			amdgpu_vm_sdma_set_ptes(p, bo, pe, addr, count,
>>   						incr, flags);
>> @@ -275,8 +278,14 @@ static int amdgpu_vm_sdma_update(struct amdgpu_vm_update_params *p,
>>   		p->num_dw_left -= nptes * 2;
>>   		pte = (uint64_t *)&(p->job->ibs->ptr[p->num_dw_left]);
>>   		for (i = 0; i < nptes; ++i, addr += incr) {
>> +			u64 oflags = flags;
>> +
>>   			pte[i] = amdgpu_vm_map_gart(p->pages_addr, addr);
>> -			pte[i] |= flags;
>> +
>> +			if (p->allow_override)
>> +				amdgpu_gmc_override_vm_pte_flags(p->adev, p->vm, pte[i], &oflags);
>> +
>> +			pte[i] |= oflags;
>>   		}
>>   
>>   		amdgpu_vm_sdma_copy_ptes(p, bo, pe, nptes);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> index e7b78027002b..479611e269b8 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
>> @@ -1204,21 +1204,6 @@ static void gmc_v9_0_override_vm_pte_flags(struct amdgpu_device *adev,
>>   {
>>   	int local_node, nid;
>>   
>> -	/* Only GFX 9.4.3 APUs associate GPUs with NUMA nodes. Local system
>> -	 * memory can use more efficient MTYPEs.
>> -	 */
>> -	if (!(adev->flags & AMD_IS_APU) ||
>> -	    amdgpu_ip_version(adev, GC_HWIP, 0) != IP_VERSION(9, 4, 3))
>> -		return;
>> -
>> -	/* Only direct-mapped memory allows us to determine the NUMA node from
>> -	 * the DMA address.
>> -	 */
>> -	if (!adev->ram_is_direct_mapped) {
>> -		dev_dbg_ratelimited(adev->dev, "RAM is not direct mapped\n");
>> -		return;
>> -	}
>> -
>>   	/* MTYPE_NC is the same default and can be overridden.
>>   	 * MTYPE_UC will be present if the memory is extended-coherent
>>   	 * and can also be overridden.
>> @@ -1231,11 +1216,7 @@ static void gmc_v9_0_override_vm_pte_flags(struct amdgpu_device *adev,
>>   		return;
>>   	}
>>   
>> -	/* FIXME: Only supported on native mode for now. For carve-out, the
>> -	 * NUMA affinity of the GPU/VM needs to come from the PCI info because
>> -	 * memory partitions are not associated with different NUMA nodes.
>> -	 */
>> -	if (adev->gmc.is_app_apu && vm->mem_id >= 0) {
>> +	if (vm->mem_id >= 0) {
>>   		local_node = adev->gmc.mem_partitions[vm->mem_id].numa.node;
>>   	} else {
>>   		dev_dbg_ratelimited(adev->dev, "Only native mode APU is supported.\n");
>> @@ -1328,6 +1309,19 @@ static bool gmc_v9_0_need_reset_on_init(struct amdgpu_device *adev)
>>   }
>>   
>>   static const struct amdgpu_gmc_funcs gmc_v9_0_gmc_funcs = {
>> +	.flush_gpu_tlb = gmc_v9_0_flush_gpu_tlb,
>> +	.flush_gpu_tlb_pasid = gmc_v9_0_flush_gpu_tlb_pasid,
>> +	.emit_flush_gpu_tlb = gmc_v9_0_emit_flush_gpu_tlb,
>> +	.emit_pasid_mapping = gmc_v9_0_emit_pasid_mapping,
>> +	.get_vm_pde = gmc_v9_0_get_vm_pde,
>> +	.get_vm_pte = gmc_v9_0_get_vm_pte,
>> +	.get_vbios_fb_size = gmc_v9_0_get_vbios_fb_size,
>> +	.query_mem_partition_mode = &amdgpu_gmc_query_memory_partition,
>> +	.request_mem_partition_mode = &amdgpu_gmc_request_memory_partition,
>> +	.need_reset_on_init = &gmc_v9_0_need_reset_on_init,
>> +};
>> +
>> +static const struct amdgpu_gmc_funcs gmc_v9_0_gmc_override_funcs = {
>>   	.flush_gpu_tlb = gmc_v9_0_flush_gpu_tlb,
>>   	.flush_gpu_tlb_pasid = gmc_v9_0_flush_gpu_tlb_pasid,
>>   	.emit_flush_gpu_tlb = gmc_v9_0_emit_flush_gpu_tlb,
>> @@ -1343,7 +1337,21 @@ static const struct amdgpu_gmc_funcs gmc_v9_0_gmc_funcs = {
>>   
>>   static void gmc_v9_0_set_gmc_funcs(struct amdgpu_device *adev)
>>   {
>> -	adev->gmc.gmc_funcs = &gmc_v9_0_gmc_funcs;
>> +	/* Only GFX 9.4.3 APUs associate GPUs with NUMA nodes, local system
>> +	 * memory can use more efficient MTYPEs.
>> +	 *
>> +	 * APUs mapping system memory may need different MTYPEs on different
>> +	 * NUMA nodes.
>> +	 *
>> +	 * Only direct-mapped memory allows us to determine the NUMA node from
>> +	 * the DMA address.
>> +	 */
>> +	if ((adev->gmc.is_app_apu && num_possible_nodes() > 1) &&
>> +	    amdgpu_ip_version(adev, GC_HWIP, 0) == IP_VERSION(9, 4, 3) &&
>> +	    adev->ram_is_direct_mapped)
>> +		adev->gmc.gmc_funcs = &gmc_v9_0_gmc_override_funcs;
>> +	else
>> +		adev->gmc.gmc_funcs = &gmc_v9_0_gmc_funcs;
> I think a flag in adev->gmc would probably do as well, no need to duplicate the call table.
will remove the duplicated const call table, add flag 
adev->gmc.override_pte instead.

Regards,
Philip
>
> Regards,
> Christian.
>
>>   }
>>   
>>   static void gmc_v9_0_set_umc_funcs(struct amdgpu_device *adev)

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