Re: [PATCH 17/35] drm/amdkfd: register HMM device private zone

On Wed, Jan 06, 2021 at 10:01:09PM -0500, Felix Kuehling wrote:

From: Philip Yang Philip.Yang@amd.com

Register vram memory as MEMORY_DEVICE_PRIVATE type resource, to allocate vram backing pages for page migration.

Signed-off-by: Philip Yang Philip.Yang@amd.com Signed-off-by: Felix Kuehling Felix.Kuehling@amd.com

So maybe I'm getting this all wrong, but I think that the current ttm fault code relies on devmap pte entries (especially for hugepte entries) to stop get_user_pages. But this only works if the pte happens to not point at a range with devmap pages.

This patch here changes that, and so probably breaks this devmap pte hack ttm is using?

If I'm not wrong here then I think we need to first fix up the ttm code to not use the devmap hack anymore, before a ttm based driver can register a dev_pagemap. Also adding Thomas since that just came up in another discussion. -Daniel

---

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c | 3 + drivers/gpu/drm/amd/amdkfd/Makefile | 3 +- drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 101 +++++++++++++++++++++ drivers/gpu/drm/amd/amdkfd/kfd_migrate.h | 48 ++++++++++ drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 3 + 5 files changed, 157 insertions(+), 1 deletion(-) create mode 100644 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c create mode 100644 drivers/gpu/drm/amd/amdkfd/kfd_migrate.h

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c index db96d69eb45e..562bb5b69137 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c @@ -30,6 +30,7 @@ #include <linux/dma-buf.h> #include "amdgpu_xgmi.h" #include <uapi/linux/kfd_ioctl.h> +#include "kfd_migrate.h"

/* Total memory size in system memory and all GPU VRAM. Used to

• estimate worst case amount of memory to reserve for page tables

@@ -170,12 +171,14 @@ void amdgpu_amdkfd_device_init(struct amdgpu_device *adev) }

          kgd2kfd_device_init(adev->kfd.dev, adev_to_drm(adev), &gpu_resources);

•         svm_migrate_init(adev);
  }
  

}

void amdgpu_amdkfd_device_fini(struct amdgpu_device *adev) { if (adev->kfd.dev) {

•         svm_migrate_fini(adev);
          kgd2kfd_device_exit(adev->kfd.dev);
          adev->kfd.dev = NULL;
  }
  

diff --git a/drivers/gpu/drm/amd/amdkfd/Makefile b/drivers/gpu/drm/amd/amdkfd/Makefile index 387ce0217d35..a93301dbc464 100644 --- a/drivers/gpu/drm/amd/amdkfd/Makefile +++ b/drivers/gpu/drm/amd/amdkfd/Makefile @@ -55,7 +55,8 @@ AMDKFD_FILES := $(AMDKFD_PATH)/kfd_module.o \ $(AMDKFD_PATH)/kfd_dbgmgr.o \ $(AMDKFD_PATH)/kfd_smi_events.o \ $(AMDKFD_PATH)/kfd_crat.o \

•         $(AMDKFD_PATH)/kfd_svm.o
  

•         $(AMDKFD_PATH)/kfd_svm.o \
  

•         $(AMDKFD_PATH)/kfd_migrate.o
  
  

ifneq ($(CONFIG_AMD_IOMMU_V2),) AMDKFD_FILES += $(AMDKFD_PATH)/kfd_iommu.o diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c new file mode 100644 index 000000000000..1950b86f1562 --- /dev/null +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c @@ -0,0 +1,101 @@ +/*

• • Copyright 2020 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/types.h> +#include <linux/hmm.h> +#include <linux/dma-direction.h> +#include <linux/dma-mapping.h> +#include "amdgpu_sync.h" +#include "amdgpu_object.h" +#include "amdgpu_vm.h" +#include "amdgpu_mn.h" +#include "kfd_priv.h" +#include "kfd_svm.h" +#include "kfd_migrate.h"

+static void svm_migrate_page_free(struct page *page) +{ +}

+/**

• • svm_migrate_to_ram - CPU page fault handler
• • @vmf: CPU vm fault vma, address
• • Context: vm fault handler, mm->mmap_sem is taken
• • Return:
• • 0 - OK
• • VM_FAULT_SIGBUS - notice application to have SIGBUS page fault
• */

+static vm_fault_t svm_migrate_to_ram(struct vm_fault *vmf) +{

• return VM_FAULT_SIGBUS;
  

+}

+static const struct dev_pagemap_ops svm_migrate_pgmap_ops = {

• .page_free              = svm_migrate_page_free,
  

• .migrate_to_ram         = svm_migrate_to_ram,
  

+};

+int svm_migrate_init(struct amdgpu_device *adev) +{

• struct kfd_dev *kfddev = adev->kfd.dev;
  

• struct dev_pagemap *pgmap;
  

• struct resource *res;
  

• unsigned long size;
  

• void *r;
  

• /* Page migration works on Vega10 or newer */
  

• if (kfddev->device_info->asic_family < CHIP_VEGA10)
  

•         return -EINVAL;
  

• pgmap = &kfddev->pgmap;
  

• memset(pgmap, 0, sizeof(*pgmap));
  

• /* TODO: register all vram to HMM for now.
  

•  * should remove reserved size
  

•  */
  

• size = ALIGN(adev->gmc.real_vram_size, 2ULL << 20);
  

• res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
  

• if (IS_ERR(res))
  

•         return -ENOMEM;
  

• pgmap->type = MEMORY_DEVICE_PRIVATE;
  

• pgmap->res = *res;
  

• pgmap->ops = &svm_migrate_pgmap_ops;
  

• pgmap->owner = adev;
  

• pgmap->flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
  

• r = devm_memremap_pages(adev->dev, pgmap);
  

• if (IS_ERR(r)) {
  

•         pr_err("failed to register HMM device memory\n");
  

•         return PTR_ERR(r);
  

• }
  

• pr_info("HMM registered %ldMB device memory\n", size >> 20);
  

• return 0;
  

+}

+void svm_migrate_fini(struct amdgpu_device *adev) +{

• memunmap_pages(&adev->kfd.dev->pgmap);
  

+} diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.h b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.h new file mode 100644 index 000000000000..98ab685d3e17 --- /dev/null +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.h @@ -0,0 +1,48 @@ +/*

• • Copyright 2020 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.
• */

+#ifndef KFD_MIGRATE_H_ +#define KFD_MIGRATE_H_

+#include <linux/rwsem.h> +#include <linux/list.h> +#include <linux/mutex.h> +#include <linux/sched/mm.h> +#include <linux/hmm.h> +#include "kfd_priv.h" +#include "kfd_svm.h"

+#if defined(CONFIG_DEVICE_PRIVATE) +int svm_migrate_init(struct amdgpu_device *adev); +void svm_migrate_fini(struct amdgpu_device *adev);

+#else +static inline int svm_migrate_init(struct amdgpu_device *adev) +{

• DRM_WARN_ONCE("DEVICE_PRIVATE kernel config option is not enabled, "
  

•               "add CONFIG_DEVICE_PRIVATE=y in config file to fix\n");
  

• return -ENODEV;
  

+} +static inline void svm_migrate_fini(struct amdgpu_device *adev) {} +#endif +#endif /* KFD_MIGRATE_H_ */ diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h index 7a4b4b6dcf32..d5367e770b39 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h @@ -317,6 +317,9 @@ struct kfd_dev { unsigned int max_doorbell_slices;

  int noretry;

• /* HMM page migration MEMORY_DEVICE_PRIVATE mapping */
  

• struct dev_pagemap pgmap;
  

};

enum kfd_mempool {

2.29.2

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-- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch