drm/xe/madvise: Update migration policy based on preferred location

When the user sets the valid devmem_fd as a preferred location, GPU fault
will trigger migration to tile of device associated with devmem_fd.

If the user sets an invalid devmem_fd the preferred location is current
placement(smem) only.

v2(Matthew Brost)
- Default should be faulting tile
- remove devmem_fd used as region

v3 (Matthew Brost)
- Add migration_policy
- Fix return condition
- fix migrate condition

v4
-Rebase

v5
- Add check for userptr and bo based vmas

Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20250821173104.3030148-11-himal.prasad.ghimiray@intel.com
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
index c660ccb21945acd6367c6729c0371e626e68b9a7..19585a3d9f69eb3359789a9d94ceacb22d85fc56 100644 (file)
--- a/drivers/gpu/drm/xe/xe_svm.c
+++ b/drivers/gpu/drm/xe/xe_svm.c
@@ -806,6 +806,7 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
        };
        struct xe_svm_range *range;
        struct dma_fence *fence;
+       struct drm_pagemap *dpagemap;
        struct xe_tile *tile = gt_to_tile(gt);
        int migrate_try_count = ctx.devmem_only ? 3 : 1;
        ktime_t end = 0;
@@ -835,8 +836,14 @@ retry:
 
        range_debug(range, "PAGE FAULT");
 
+       dpagemap = xe_vma_resolve_pagemap(vma, tile);
        if (--migrate_try_count >= 0 &&
-           xe_svm_range_needs_migrate_to_vram(range, vma, IS_DGFX(vm->xe))) {
+           xe_svm_range_needs_migrate_to_vram(range, vma, !!dpagemap || ctx.devmem_only)) {
+               /* TODO : For multi-device dpagemap will be used to find the
+                * remote tile and remote device. Will need to modify
+                * xe_svm_alloc_vram to use dpagemap for future multi-device
+                * support.
+                */
                err = xe_svm_alloc_vram(tile, range, &ctx);
                ctx.timeslice_ms <<= 1; /* Double timeslice if we have to retry */
                if (err) {
@@ -1100,6 +1107,37 @@ static struct drm_pagemap *tile_local_pagemap(struct xe_tile *tile)
        return &tile->mem.vram->dpagemap;
 }
 
+/**
+ * xe_vma_resolve_pagemap - Resolve the appropriate DRM pagemap for a VMA
+ * @vma: Pointer to the xe_vma structure containing memory attributes
+ * @tile: Pointer to the xe_tile structure used as fallback for VRAM mapping
+ *
+ * This function determines the correct DRM pagemap to use for a given VMA.
+ * It first checks if a valid devmem_fd is provided in the VMA's preferred
+ * location. If the devmem_fd is negative, it returns NULL, indicating no
+ * pagemap is available and smem to be used as preferred location.
+ * If the devmem_fd is equal to the default faulting
+ * GT identifier, it returns the VRAM pagemap associated with the tile.
+ *
+ * Future support for multi-device configurations may use drm_pagemap_from_fd()
+ * to resolve pagemaps from arbitrary file descriptors.
+ *
+ * Return: A pointer to the resolved drm_pagemap, or NULL if none is applicable.
+ */
+struct drm_pagemap *xe_vma_resolve_pagemap(struct xe_vma *vma, struct xe_tile *tile)
+{
+       s32 fd = (s32)vma->attr.preferred_loc.devmem_fd;
+
+       if (fd == DRM_XE_PREFERRED_LOC_DEFAULT_SYSTEM)
+               return NULL;
+
+       if (fd == DRM_XE_PREFERRED_LOC_DEFAULT_DEVICE)
+               return IS_DGFX(tile_to_xe(tile)) ? tile_local_pagemap(tile) : NULL;
+
+       /* TODO: Support multi-device with drm_pagemap_from_fd(fd) */
+       return NULL;
+}
+
 /**
  * xe_svm_alloc_vram()- Allocate device memory pages for range,
  * migrating existing data.
@@ -1212,6 +1250,11 @@ int xe_devm_add(struct xe_tile *tile, struct xe_vram_region *vr)
 {
        return 0;
 }
+
+struct drm_pagemap *xe_vma_resolve_pagemap(struct xe_vma *vma, struct xe_tile *tile)
+{
+       return NULL;
+}
 #endif
 
 /**

diff --git a/drivers/gpu/drm/xe/xe_svm.h b/drivers/gpu/drm/xe/xe_svm.h
index 046a9c4e95c24a2c61b4055cf1cf83b8544370af..9d6a8840a8b76c4a5bbaad96dbb8bf7acaa8b7aa 100644 (file)
--- a/drivers/gpu/drm/xe/xe_svm.h
+++ b/drivers/gpu/drm/xe/xe_svm.h
@@ -94,6 +94,8 @@ void xe_svm_unmap_address_range(struct xe_vm *vm, u64 start, u64 end);
 
 u8 xe_svm_ranges_zap_ptes_in_range(struct xe_vm *vm, u64 start, u64 end);
 
+struct drm_pagemap *xe_vma_resolve_pagemap(struct xe_vma *vma, struct xe_tile *tile);
+
 /**
  * xe_svm_range_has_dma_mapping() - SVM range has DMA mapping
  * @range: SVM range
@@ -318,6 +320,12 @@ u8 xe_svm_ranges_zap_ptes_in_range(struct xe_vm *vm, u64 start, u64 end)
        return 0;
 }
 
+static inline
+struct drm_pagemap *xe_vma_resolve_pagemap(struct xe_vma *vma, struct xe_tile *tile)
+{
+       return NULL;
+}
+
 #define xe_svm_assert_in_notifier(...) do {} while (0)
 #define xe_svm_range_has_dma_mapping(...) false
 

diff --git a/drivers/gpu/drm/xe/xe_vm_madvise.c b/drivers/gpu/drm/xe/xe_vm_madvise.c
index 95258bb6a8eef252946ff8e6f30e3600a95369cb..b5fc1eedf0957d325d83d8df9df1e4e065cb5a8d 100644 (file)
--- a/drivers/gpu/drm/xe/xe_vm_madvise.c
+++ b/drivers/gpu/drm/xe/xe_vm_madvise.c
@@ -78,7 +78,23 @@ static void madvise_preferred_mem_loc(struct xe_device *xe, struct xe_vm *vm,
                                      struct xe_vma **vmas, int num_vmas,
                                      struct drm_xe_madvise *op)
 {
-       /* Implementation pending */
+       int i;
+
+       xe_assert(vm->xe, op->type == DRM_XE_MEM_RANGE_ATTR_PREFERRED_LOC);
+
+       for (i = 0; i < num_vmas; i++) {
+               /*TODO: Extend attributes to bo based vmas */
+               if (!xe_vma_is_cpu_addr_mirror(vmas[i]))
+                       continue;
+
+               vmas[i]->attr.preferred_loc.devmem_fd = op->preferred_mem_loc.devmem_fd;
+
+               /* Till multi-device support is not added migration_policy
+                * is of no use and can be ignored.
+                */
+               vmas[i]->attr.preferred_loc.migration_policy =
+                                               op->preferred_mem_loc.migration_policy;
+       }
 }
 
 static void madvise_atomic(struct xe_device *xe, struct xe_vm *vm,
@@ -184,6 +200,12 @@ static bool madvise_args_are_sane(struct xe_device *xe, const struct drm_xe_madv
 
        switch (args->type) {
        case DRM_XE_MEM_RANGE_ATTR_PREFERRED_LOC:
+       {
+               s32 fd = (s32)args->preferred_mem_loc.devmem_fd;
+
+               if (XE_IOCTL_DBG(xe, fd < DRM_XE_PREFERRED_LOC_DEFAULT_SYSTEM))
+                       return false;
+
                if (XE_IOCTL_DBG(xe, args->preferred_mem_loc.migration_policy >
                                     DRM_XE_MIGRATE_ONLY_SYSTEM_PAGES))
                        return false;
@@ -194,6 +216,7 @@ static bool madvise_args_are_sane(struct xe_device *xe, const struct drm_xe_madv
                if (XE_IOCTL_DBG(xe, args->atomic.reserved))
                        return false;
                break;
+       }
        case DRM_XE_MEM_RANGE_ATTR_ATOMIC:
                if (XE_IOCTL_DBG(xe, args->atomic.val > DRM_XE_ATOMIC_CPU))
                        return false;