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

[Matthew Brost <matthew.brost@intel.com>]

On Thu, Jan 30, 2025 at 03:24:13PM +0200, Gwan-gyeong Mun wrote:
> 
> 
> 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?
> > 

Yep.

> 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 ”.

Patch 29 deletes this line so the series as whole compiles and runs.

Will fixup this patch.

Matt

> > >   /**
> > >    * 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);
> > 
>