[PATCH v9 1/2] drm/amdgpu: implement TLB flush fence
Sharma, Shashank
shashank.sharma at amd.com
Mon Mar 18 19:01:07 UTC 2024
On 18/03/2024 18:30, Joshi, Mukul wrote:
> [AMD Official Use Only - General]
>
>> -----Original Message-----
>> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of
>> Shashank Sharma
>> Sent: Monday, March 18, 2024 12:12 PM
>> To: amd-gfx at lists.freedesktop.org
>> Cc: Koenig, Christian <Christian.Koenig at amd.com>; Kuehling, Felix
>> <Felix.Kuehling at amd.com>; Bhardwaj, Rajneesh
>> <Rajneesh.Bhardwaj at amd.com>; Deucher, Alexander
>> <Alexander.Deucher at amd.com>; Sharma, Shashank
>> <Shashank.Sharma at amd.com>
>> Subject: [PATCH v9 1/2] drm/amdgpu: implement TLB flush fence
>>
>> Caution: This message originated from an External Source. Use proper caution
>> when opening attachments, clicking links, or responding.
>>
>>
>> From: Christian Koenig <christian.koenig at amd.com>
>>
>> The problem is that when (for example) 4k pages are replaced with a single 2M
>> page we need to wait for change to be flushed out by invalidating the TLB
>> before the PT can be freed.
>>
>> Solve this by moving the TLB flush into a DMA-fence object which can be used
>> to delay the freeing of the PT BOs until it is signaled.
>>
>> V2: (Shashank)
>> - rebase
>> - set dma_fence_error only in case of error
>> - add tlb_flush fence only when PT/PD BO is locked (Felix)
>> - use vm->pasid when f is NULL (Mukul)
>>
>> V4: - add a wait for (f->dependency) in tlb_fence_work (Christian)
>> - move the misplaced fence_create call to the end (Philip)
>>
>> V5: - free the f->dependency properly
>>
>> V6: (Shashank)
>> - light code movement, moved all the clean-up in previous patch
>> - introduce params.needs_flush and its usage in this patch
>> - rebase without TLB HW sequence patch
>>
>> V7:
>> - Keep the vm->last_update_fence and tlb_cb code until
>> we can fix the HW sequencing (Christian)
>> - Move all the tlb_fence related code in a separate function so that
>> its easier to read and review
>>
>> V9: Addressed review comments from Christian
>> - start PT update only when we have callback memory allocated
>>
>> Cc: Christian Koenig <christian.koenig at amd.com>
>> Cc: Felix Kuehling <Felix.Kuehling at amd.com>
>> Cc: Rajneesh Bhardwaj <rajneesh.bhardwaj at amd.com>
>> Cc: Alex Deucher <alexander.deucher at amd.com>
>> Acked-by: Felix Kuehling <Felix.Kuehling at amd.com>
>> Acked-by: Rajneesh Bhardwaj <rajneesh.bhardwaj at amd.com>
>> Tested-by: Rajneesh Bhardwaj <rajneesh.bhardwaj at amd.com>
>> Reviewed-by: Shashank Sharma <shashank.sharma at amd.com>
>> Signed-off-by: Christian Koenig <christian.koenig at amd.com>
>> Signed-off-by: Shashank Sharma <shashank.sharma at amd.com>
>> ---
>> drivers/gpu/drm/amd/amdgpu/Makefile | 3 +-
>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 64 +++++++---
>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 8 +-
>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c | 4 +-
>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c | 2 +-
>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c | 4 +
>> .../gpu/drm/amd/amdgpu/amdgpu_vm_tlb_fence.c | 112
>> ++++++++++++++++++
>> 7 files changed, 175 insertions(+), 22 deletions(-) create mode 100644
>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm_tlb_fence.c
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile
>> b/drivers/gpu/drm/amd/amdgpu/Makefile
>> index 4536c8ad0e11..f24f11ac3e92 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/Makefile
>> +++ b/drivers/gpu/drm/amd/amdgpu/Makefile
>> @@ -70,7 +70,8 @@ amdgpu-y += amdgpu_device.o
>> amdgpu_doorbell_mgr.o amdgpu_kms.o \
>> amdgpu_cs.o amdgpu_bios.o amdgpu_benchmark.o \
>> atombios_dp.o amdgpu_afmt.o amdgpu_trace_points.o \
>> atombios_encoders.o amdgpu_sa.o atombios_i2c.o \
>> - amdgpu_dma_buf.o amdgpu_vm.o amdgpu_vm_pt.o amdgpu_ib.o
>> amdgpu_pll.o \
>> + amdgpu_dma_buf.o amdgpu_vm.o amdgpu_vm_pt.o
>> amdgpu_vm_tlb_fence.o \
>> + amdgpu_ib.o amdgpu_pll.o \
>> amdgpu_ucode.o amdgpu_bo_list.o amdgpu_ctx.o amdgpu_sync.o \
>> amdgpu_gtt_mgr.o amdgpu_preempt_mgr.o amdgpu_vram_mgr.o
>> amdgpu_virt.o \
>> amdgpu_atomfirmware.o amdgpu_vf_error.o amdgpu_sched.o \ diff --git
>> a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> index 81fb3465e197..104bf600c85f 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> @@ -885,6 +885,44 @@ static void amdgpu_vm_tlb_seq_cb(struct
>> dma_fence *fence,
>> kfree(tlb_cb);
>> }
>>
>> +/**
>> + * amdgpu_vm_tlb_flush - prepare TLB flush
>> + *
>> + * @params: parameters for update
>> + * @fence: input fence to sync TLB flush with
>> + * @tlb_cb: the callback structure
>> + *
>> + * Increments the tlb sequence to make sure that future CS execute a VM
>> flush.
>> + */
>> +static void
>> +amdgpu_vm_tlb_flush(struct amdgpu_vm_update_params *params,
>> + struct dma_fence **fence,
>> + struct amdgpu_vm_tlb_seq_struct *tlb_cb) {
>> + struct amdgpu_vm *vm = params->vm;
>> +
>> + if (!fence || !*fence)
>> + return;
>> +
>> + tlb_cb->vm = vm;
>> + if (!dma_fence_add_callback(*fence, &tlb_cb->cb,
>> + amdgpu_vm_tlb_seq_cb)) {
>> + dma_fence_put(vm->last_tlb_flush);
>> + vm->last_tlb_flush = dma_fence_get(*fence);
>> + } else {
>> + amdgpu_vm_tlb_seq_cb(NULL, &tlb_cb->cb);
>> + }
>> +
>> + /* Prepare a TLB flush fence to be attached to PTs */
>> + if (!params->unlocked && vm->is_compute_context) {
>> + amdgpu_vm_tlb_fence_create(params->adev, vm, fence);
>> +
>> + /* Makes sure no PD/PT is freed before the flush */
>> + dma_resv_add_fence(vm->root.bo->tbo.base.resv, *fence,
>> + DMA_RESV_USAGE_BOOKKEEP);
>> + }
>> +}
>> +
>> /**
>> * amdgpu_vm_update_range - update a range in the vm page table
>> *
>> @@ -916,8 +954,8 @@ int amdgpu_vm_update_range(struct
>> amdgpu_device *adev, struct amdgpu_vm *vm,
>> struct ttm_resource *res, dma_addr_t *pages_addr,
>> struct dma_fence **fence) {
>> - struct amdgpu_vm_update_params params;
>> struct amdgpu_vm_tlb_seq_struct *tlb_cb;
>> + struct amdgpu_vm_update_params params;
>> struct amdgpu_res_cursor cursor;
>> enum amdgpu_sync_mode sync_mode;
>> int r, idx;
>> @@ -926,10 +964,8 @@ int amdgpu_vm_update_range(struct
>> amdgpu_device *adev, struct amdgpu_vm *vm,
>> return -ENODEV;
>>
>> tlb_cb = kmalloc(sizeof(*tlb_cb), GFP_KERNEL);
>> - if (!tlb_cb) {
>> - r = -ENOMEM;
>> - goto error_unlock;
>> - }
>> + if (!tlb_cb)
>> + return -ENOMEM;
>>
> Do you not need to call drm_dev_exit() if this tlb_cb allocation fails?
Yep, I missed that while restoring the goto in V8, will fix that.
- Shashank
>
> Regards,
> Mukul
>
>> /* Vega20+XGMI where PTEs get inadvertently cached in L2 texture cache,
>> * heavy-weight flush TLB unconditionally.
>> @@ -948,6 +984,7 @@ int amdgpu_vm_update_range(struct
>> amdgpu_device *adev, struct amdgpu_vm *vm,
>> params.immediate = immediate;
>> params.pages_addr = pages_addr;
>> params.unlocked = unlocked;
>> + params.needs_flush = flush_tlb;
>> params.allow_override = allow_override;
>>
>> /* Implicitly sync to command submissions in the same VM before @@ -
>> 1031,24 +1068,16 @@ int amdgpu_vm_update_range(struct amdgpu_device
>> *adev, struct amdgpu_vm *vm,
>> }
>>
>> r = vm->update_funcs->commit(¶ms, fence);
>> + if (r)
>> + goto error_free;
>>
>> - if (flush_tlb || params.table_freed) {
>> - tlb_cb->vm = vm;
>> - if (fence && *fence &&
>> - !dma_fence_add_callback(*fence, &tlb_cb->cb,
>> - amdgpu_vm_tlb_seq_cb)) {
>> - dma_fence_put(vm->last_tlb_flush);
>> - vm->last_tlb_flush = dma_fence_get(*fence);
>> - } else {
>> - amdgpu_vm_tlb_seq_cb(NULL, &tlb_cb->cb);
>> - }
>> + if (params.needs_flush) {
>> + amdgpu_vm_tlb_flush(¶ms, fence, tlb_cb);
>> tlb_cb = NULL;
>> }
>>
>> error_free:
>> kfree(tlb_cb);
>> -
>> -error_unlock:
>> amdgpu_vm_eviction_unlock(vm);
>> drm_dev_exit(idx);
>> return r;
>> @@ -2391,6 +2420,7 @@ int amdgpu_vm_init(struct amdgpu_device *adev,
>> struct amdgpu_vm *vm,
>>
>> mutex_init(&vm->eviction_lock);
>> vm->evicting = false;
>> + vm->tlb_fence_context = dma_fence_context_alloc(1);
>>
>> r = amdgpu_vm_pt_create(adev, vm, adev->vm_manager.root_level,
>> false, &root, xcp_id); diff --git
>> a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> index 8efa8422f4f7..b0a4fe683352 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> @@ -257,9 +257,9 @@ struct amdgpu_vm_update_params {
>> unsigned int num_dw_left;
>>
>> /**
>> - * @table_freed: return true if page table is freed when updating
>> + * @needs_flush: true whenever we need to invalidate the TLB
>> */
>> - bool table_freed;
>> + bool needs_flush;
>>
>> /**
>> * @allow_override: true for memory that is not uncached: allows MTYPE
>> @@ -342,6 +342,7 @@ struct amdgpu_vm {
>> atomic64_t tlb_seq;
>> struct dma_fence *last_tlb_flush;
>> atomic64_t kfd_last_flushed_seq;
>> + uint64_t tlb_fence_context;
>>
>> /* How many times we had to re-generate the page tables */
>> uint64_t generation;
>> @@ -611,5 +612,8 @@ void amdgpu_vm_update_fault_cache(struct
>> amdgpu_device *adev,
>> uint64_t addr,
>> uint32_t status,
>> unsigned int vmhub);
>> +void amdgpu_vm_tlb_fence_create(struct amdgpu_device *adev,
>> + struct amdgpu_vm *vm,
>> + struct dma_fence **fence);
>>
>> #endif
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c
>> index 6e31621452de..3895bd7d176a 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c
>> @@ -108,7 +108,9 @@ static int amdgpu_vm_cpu_update(struct
>> amdgpu_vm_update_params *p, static int amdgpu_vm_cpu_commit(struct
>> amdgpu_vm_update_params *p,
>> struct dma_fence **fence) {
>> - /* Flush HDP */
>> + if (p->needs_flush)
>> + atomic64_inc(&p->vm->tlb_seq);
>> +
>> mb();
>> amdgpu_device_flush_hdp(p->adev, NULL);
>> 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 124389a6bf48..601df0ce8290 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
>> @@ -972,7 +972,7 @@ int amdgpu_vm_ptes_update(struct
>> amdgpu_vm_update_params *params,
>> while (cursor.pfn < frag_start) {
>> /* Make sure previous mapping is freed */
>> if (cursor.entry->bo) {
>> - params->table_freed = true;
>> + params->needs_flush = true;
>> amdgpu_vm_pt_free_dfs(adev, params->vm,
>> &cursor,
>> params->unlocked); diff --git
>> a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
>> index 349416e176a1..66e8a016126b 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
>> @@ -126,6 +126,10 @@ static int amdgpu_vm_sdma_commit(struct
>> amdgpu_vm_update_params *p,
>>
>> WARN_ON(ib->length_dw == 0);
>> amdgpu_ring_pad_ib(ring, ib);
>> +
>> + if (p->needs_flush)
>> + atomic64_inc(&p->vm->tlb_seq);
>> +
>> WARN_ON(ib->length_dw > p->num_dw_left);
>> f = amdgpu_job_submit(p->job);
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_tlb_fence.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_tlb_fence.c
>> new file mode 100644
>> index 000000000000..51cddfa3f1e8
>> --- /dev/null
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_tlb_fence.c
>> @@ -0,0 +1,112 @@
>> +// SPDX-License-Identifier: GPL-2.0 OR MIT
>> +/*
>> + * Copyright 2023 Advanced Micro Devices, Inc.
>> + *
>> + * Permission is hereby granted, free of charge, to any person
>> +obtaining a
>> + * copy of this software and associated documentation files (the
>> +"Software"),
>> + * to deal in the Software without restriction, including without
>> +limitation
>> + * the rights to use, copy, modify, merge, publish, distribute,
>> +sublicense,
>> + * and/or sell copies of the Software, and to permit persons to whom
>> +the
>> + * Software is furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be
>> +included in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
>> +EXPRESS OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
>> +MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO
>> EVENT
>> +SHALL
>> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM,
>> +DAMAGES OR
>> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
>> +OTHERWISE,
>> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
>> THE USE
>> +OR
>> + * OTHER DEALINGS IN THE SOFTWARE.
>> + */
>> +
>> +#include <linux/dma-fence.h>
>> +#include <linux/workqueue.h>
>> +
>> +#include "amdgpu.h"
>> +#include "amdgpu_vm.h"
>> +#include "amdgpu_gmc.h"
>> +
>> +struct amdgpu_tlb_fence {
>> + struct dma_fence base;
>> + struct amdgpu_device *adev;
>> + struct dma_fence *dependency;
>> + struct work_struct work;
>> + spinlock_t lock;
>> + uint16_t pasid;
>> +
>> +};
>> +
>> +static const char *amdgpu_tlb_fence_get_driver_name(struct dma_fence
>> +*fence) {
>> + return "amdgpu tlb fence";
>> +}
>> +
>> +static const char *amdgpu_tlb_fence_get_timeline_name(struct dma_fence
>> +*f) {
>> + return "amdgpu tlb timeline";
>> +}
>> +
>> +static void amdgpu_tlb_fence_work(struct work_struct *work) {
>> + struct amdgpu_tlb_fence *f = container_of(work, typeof(*f), work);
>> + int r;
>> +
>> + if (f->dependency) {
>> + dma_fence_wait(f->dependency, false);
>> + dma_fence_put(f->dependency);
>> + f->dependency = NULL;
>> + }
>> +
>> + r = amdgpu_gmc_flush_gpu_tlb_pasid(f->adev, f->pasid, 2, true, 0);
>> + if (r) {
>> + dev_err(f->adev->dev, "TLB flush failed for PASID %d.\n",
>> + f->pasid);
>> + dma_fence_set_error(&f->base, r);
>> + }
>> +
>> + dma_fence_signal(&f->base);
>> + dma_fence_put(&f->base);
>> +}
>> +
>> +static const struct dma_fence_ops amdgpu_tlb_fence_ops = {
>> + .use_64bit_seqno = true,
>> + .get_driver_name = amdgpu_tlb_fence_get_driver_name,
>> + .get_timeline_name = amdgpu_tlb_fence_get_timeline_name
>> +};
>> +
>> +void amdgpu_vm_tlb_fence_create(struct amdgpu_device *adev, struct
>> amdgpu_vm *vm,
>> + struct dma_fence **fence) {
>> + struct amdgpu_tlb_fence *f;
>> +
>> + f = kmalloc(sizeof(*f), GFP_KERNEL);
>> + if (!f) {
>> + /*
>> + * We can't fail since the PDEs and PTEs are already updated, so
>> + * just block for the dependency and execute the TLB flush
>> + */
>> + if (*fence)
>> + dma_fence_wait(*fence, false);
>> +
>> + amdgpu_gmc_flush_gpu_tlb_pasid(adev, vm->pasid, 2, true, 0);
>> + *fence = dma_fence_get_stub();
>> + return;
>> + }
>> +
>> + f->adev = adev;
>> + f->dependency = *fence;
>> + f->pasid = vm->pasid;
>> + INIT_WORK(&f->work, amdgpu_tlb_fence_work);
>> + spin_lock_init(&f->lock);
>> +
>> + dma_fence_init(&f->base, &amdgpu_tlb_fence_ops, &f->lock,
>> + vm->tlb_fence_context,
>> + atomic64_read(&vm->tlb_seq));
>> +
>> + /* TODO: We probably need a separate wq here */
>> + dma_fence_get(&f->base);
>> + schedule_work(&f->work);
>> +
>> + *fence = &f->base;
>> +}
>> --
>> 2.43.2
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