On 30.09.2022 17:25, Matthew Auld wrote:
It looks like we need this for local-memory, if we want to use ptrace.
Something more is still needed if we want to handle non-mappable memory,
which looks quite annoying.
References: https://gitlab.freedesktop.org/drm/intel/-/issues/6989
Signed-off-by: Matthew Auld <[email protected]>
Cc: Nirmoy Das <[email protected]>
Reviewed-by: Andrzej Hajda <[email protected]>
Regards
Andrzej
---
drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 43 +++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 3dc6acfcf4ec..4f533e0c92b4 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -699,6 +699,48 @@ static unsigned long i915_ttm_io_mem_pfn(struct
ttm_buffer_object *bo,
return ((base + sg_dma_address(sg)) >> PAGE_SHIFT) + ofs;
}
+static int i915_ttm_access_memory(struct ttm_buffer_object *bo,
+ unsigned long offset, void *buf,
+ int len, int write)
+{
+ unsigned long page = offset >> PAGE_SHIFT;
+ unsigned long bytes_left = len;
+ int ret;
+
+ /*
+ * TODO: For now just let it fail if the resource is non-mappable,
+ * otherwise we need to perform the memcpy from the gpu here, without
+ * interfering with the object (like moving the entire thing).
+ */
+
+ offset -= page << PAGE_SHIFT;
+ do {
+ unsigned long bytes = min(bytes_left, PAGE_SIZE - offset);
+ struct ttm_bo_kmap_obj map;
+ void __iomem *ptr;
+ bool is_iomem;
+
+ ret = ttm_bo_kmap(bo, page, 1, &map);
+ if (ret)
+ return ret;
+
+ ptr = ttm_kmap_obj_virtual(&map, &is_iomem) + offset;
+ WARN_ON_ONCE(!is_iomem);
+ if (write)
+ memcpy_toio(ptr, buf, bytes);
+ else
+ memcpy_fromio(buf, ptr, bytes);
+ ttm_bo_kunmap(&map);
+
+ page++;
+ buf += bytes;
+ bytes_left -= bytes;
+ offset = 0;
+ } while (bytes_left);
+
+ return len;
+}
+
/*
* All callbacks need to take care not to downcast a struct ttm_buffer_object
* without checking its subclass, since it might be a TTM ghost object.
@@ -715,6 +757,7 @@ static struct ttm_device_funcs i915_ttm_bo_driver = {
.delete_mem_notify = i915_ttm_delete_mem_notify,
.io_mem_reserve = i915_ttm_io_mem_reserve,
.io_mem_pfn = i915_ttm_io_mem_pfn,
+ .access_memory = i915_ttm_access_memory,
};
/**
