Re: [PATCH v4 04/10] drm/amdkfd: add SPM support for SVM

[Alistair Popple]

On Thursday, 27 January 2022 2:09:43 PM AEDT Alex Sierra wrote:

[...]

> @@ -984,3 +990,4 @@ int svm_migrate_init(struct amdgpu_device *adev)
>  
>   return 0;
>  }
> +
> 

git-am complained about this when I applied the series. Given you have to
rebase anyway it would be worth fixing this.

[PATCH v4 04/10] 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_COHERENT to create the device
page map region.

Signed-off-by: Alex Sierra 
Reviewed-by: Felix Kuehling 
---
v7:
Remove lookup_resource call, so export symbol for this function
is not longer required. Patch dropped "kernel: resource:
lookup_resource as exported symbol"
---
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 29 +++-
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index aeade32ec298..9e36fe8aea0f 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -935,7 +935,7 @@ int svm_migrate_init(struct amdgpu_device *adev)
 {
struct kfd_dev *kfddev = adev->kfd.dev;
struct dev_pagemap *pgmap;
-   struct resource *res;
+   struct resource *res = NULL;
unsigned long size;
void *r;
 
@@ -950,28 +950,34 @@ 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, _resource, size);
-   if (IS_ERR(res))
-   return -ENOMEM;
+   if (adev->gmc.xgmi.connected_to_cpu) {
+   pgmap->range.start = adev->gmc.aper_base;
+   pgmap->range.end = adev->gmc.aper_base + adev->gmc.aper_size - 
1;
+   pgmap->type = MEMORY_DEVICE_COHERENT;
+   } else {
+   res = devm_request_free_mem_region(adev->dev, _resource, 
size);
+   if (IS_ERR(res))
+   return -ENOMEM;
+   pgmap->range.start = res->start;
+   pgmap->range.end = res->end;
+   pgmap->type = MEMORY_DEVICE_PRIVATE;
+   }
 
-   pgmap->type = MEMORY_DEVICE_PRIVATE;
pgmap->nr_range = 1;
-   pgmap->range.start = res->start;
-   pgmap->range.end = res->end;
pgmap->ops = _migrate_pgmap_ops;
pgmap->owner = SVM_ADEV_PGMAP_OWNER(adev);
-   pgmap->flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
-
+   pgmap->flags = 0;
/* Device manager releases device-specific resources, memory region and
 * pgmap when driver disconnects from device.
 */
r = devm_memremap_pages(adev->dev, pgmap);
if (IS_ERR(r)) {
pr_err("failed to register HMM device memory\n");
-
/* Disable SVM support capability */
pgmap->type = 0;
-   devm_release_mem_region(adev->dev, res->start, 
resource_size(res));
+   if (pgmap->type == MEMORY_DEVICE_PRIVATE)
+   devm_release_mem_region(adev->dev, res->start,
+   res->end - res->start + 1);
return PTR_ERR(r);
}
 
@@ -984,3 +990,4 @@ int svm_migrate_init(struct amdgpu_device *adev)
 
return 0;
 }
+
-- 
2.32.0