[PATCH v4 04/13] drm/amdkfd: add SPM support for SVM

[Alex Sierra]

When CPU is connected throug XGMI, it has coherent
access to VRAM resource. In this case that resource
is taken from a table in the device gmc aperture base.
This resource is used along with the device type, which could
be DEVICE_PRIVATE or DEVICE_GENERIC to create the device
page map region.

Signed-off-by: Alex Sierra <alex.sie...@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehl...@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index 21b86c35a4f2..3e9315354ce4 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -916,6 +916,7 @@ int svm_migrate_init(struct amdgpu_device *adev)
        struct resource *res;
        unsigned long size;
        void *r;
+       bool xgmi_connected_to_cpu = adev->gmc.xgmi.connected_to_cpu;
 
        /* Page migration works on Vega10 or newer */
        if (kfddev->device_info->asic_family < CHIP_VEGA10)
@@ -928,17 +929,22 @@ int svm_migrate_init(struct amdgpu_device *adev)
         * 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 (xgmi_connected_to_cpu)
+               res = lookup_resource(&iomem_resource, adev->gmc.aper_base);
+       else
+               res = devm_request_free_mem_region(adev->dev, &iomem_resource, 
size);
+
        if (IS_ERR(res))
                return -ENOMEM;
 
-       pgmap->type = MEMORY_DEVICE_PRIVATE;
        pgmap->nr_range = 1;
        pgmap->range.start = res->start;
        pgmap->range.end = res->end;
+       pgmap->type = xgmi_connected_to_cpu ?
+                               MEMORY_DEVICE_GENERIC : MEMORY_DEVICE_PRIVATE;
        pgmap->ops = &svm_migrate_pgmap_ops;
        pgmap->owner = SVM_ADEV_PGMAP_OWNER(adev);
-       pgmap->flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
+       pgmap->flags = 0;
        r = devm_memremap_pages(adev->dev, pgmap);
        if (IS_ERR(r)) {
                pr_err("failed to register HMM device memory\n");
@@ -962,6 +968,7 @@ void svm_migrate_fini(struct amdgpu_device *adev)
        struct dev_pagemap *pgmap = &adev->kfd.dev->pgmap;
 
        devm_memunmap_pages(adev->dev, pgmap);
-       devm_release_mem_region(adev->dev, pgmap->range.start,
-                               pgmap->range.end - pgmap->range.start + 1);
+       if (pgmap->type == MEMORY_DEVICE_PRIVATE)
+               devm_release_mem_region(adev->dev, pgmap->range.start,
+                                       pgmap->range.end - pgmap->range.start + 
1);
 }
-- 
2.32.0