Re: [PATCH v4 23/33] drm/xe: Add drm_pagemap ops to SVM

[Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>]

On 1/30/25 12:54 PM, Matthew Auld wrote:
> On 29/01/2025 19:52, Matthew Brost wrote:
>> From: Thomas Hellström <thomas.hellstrom@linux.intel.com>
>>
>> Add support for mapping device pages to Xe SVM by attaching drm_pagemap
>> to a memory region, which is then linked to a GPU SVM devmem allocation.
>> This enables GPU SVM to derive the device page address.
>>
>> v3:
>>   - Better commit message (Thomas)
>>   - New drm_pagemap.h location
>>
>> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
>> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
>> Reviewed-by: Matthew Brost <matthew.brost@intel.com>
>> ---
>>   drivers/gpu/drm/xe/xe_device_types.h |  6 ++++++
>>   drivers/gpu/drm/xe/xe_svm.c          | 31 ++++++++++++++++++++++++++++
>>   2 files changed, 37 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/ 
>> xe/xe_device_types.h
>> index da5bf145324b..eb3702db5c17 100644
>> --- a/drivers/gpu/drm/xe/xe_device_types.h
>> +++ b/drivers/gpu/drm/xe/xe_device_types.h
>> @@ -10,6 +10,7 @@
>>   #include <drm/drm_device.h>
>>   #include <drm/drm_file.h>
>> +#include <drm/drm_pagemap.h>
>>   #include <drm/ttm/ttm_device.h>
>>   #include "xe_devcoredump_types.h"
>> @@ -106,6 +107,11 @@ struct xe_mem_region {
>>       void __iomem *mapping;
>>       /** @pagemap: Used to remap device memory as ZONE_DEVICE */
>>       struct dev_pagemap pagemap;
>> +    /**
>> +     * @dpagemap: The struct drm_pagemap of the ZONE_DEVICE memory
>> +     * pages of this tile.
>> +     */
>> +    struct drm_pagemap dpagemap;
>>       /**
>>        * @hpa_base: base host physical address
>>        *
>> diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
>> index 985ac20c5b07..869a155fc9f7 100644
>> --- a/drivers/gpu/drm/xe/xe_svm.c
>> +++ b/drivers/gpu/drm/xe/xe_svm.c
>> @@ -450,6 +450,33 @@ bool xe_svm_has_mapping(struct xe_vm *vm, u64 
>> start, u64 end)
>>   }
>>   #if IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR)
>> +static struct drm_pagemap_dma_addr
>> +xe_drm_pagemap_map_dma(struct drm_pagemap *dpagemap,
>> +               struct device *dev,
>> +               struct page *page,
>> +               unsigned int order,
>> +               enum dma_data_direction dir)
>> +{
>> +    struct device *pgmap_dev = dpagemap->dev;
>> +    enum drm_interconnect_protocol prot;
>> +    dma_addr_t addr;
>> +
>> +    if (pgmap_dev == dev) {
>> +        addr = xe_mem_region_page_to_dpa(page_to_mr(page), page);
>> +        prot = XE_INTERCONNECT_VRAM;
>> +    } else {
>> +        addr = DMA_MAPPING_ERROR;
>> +        prot = 0;
>> +    }
>> +
>> +    return drm_pagemap_dma_addr_encode(addr, prot, order, dir);
>> +}
>> +
>> +static const struct drm_pagemap_ops xe_drm_pagemap_ops = {
>> +    .map_dma = xe_drm_pagemap_map_dma,
>> +};
>> +
>> +>>>>>>> 133db8ade5f0 (drm/xe: Add drm_pagemap ops to SVM)
> 
> Some leftover rebase damage here?
> 
FYI, when applying this series to the latest drm-tip for testing, the 
line did not cause problems for auto-merging on my side. I applied the 
patch with “git am -3 ”.
>>   /**
>>    * xe_devm_add: Remap and provide memmap backing for device memory
>>    * @tile: tile that the memory region belongs to
>> @@ -482,6 +509,10 @@ int xe_devm_add(struct xe_tile *tile, struct 
>> xe_mem_region *mr)
>>       mr->pagemap.ops = drm_gpusvm_pagemap_ops_get();
>>       mr->pagemap.owner = xe_svm_devm_owner(xe);
>>       addr = devm_memremap_pages(dev, &mr->pagemap);
>> +
>> +    mr->dpagemap.dev = dev;
>> +    mr->dpagemap.ops = &xe_drm_pagemap_ops;
>> +
>>       if (IS_ERR(addr)) {
>>           devm_release_mem_region(dev, res->start, resource_size(res));
>>           ret = PTR_ERR(addr);
>