On 18/10/2024 17:25, Matthew Brost wrote:
On Fri, Oct 18, 2024 at 10:08:06AM +0100, Matthew Auld wrote:
On 18/10/2024 00:39, Matthew Brost wrote:
Non-contiguous VRAM cannot be mapped in Xe nor can non-visible VRAM
easily be accessed. Add ttm_bo_access, which is similar to
ttm_bo_vm_access, to access such memory.
Is the plan to roll this out also to object error capture and clear color
access? Those places seem to be using ttm vmap/kmap which only seems to work
with contiguous VRAM, but in those cases we are mapping userspace objects
which are potentially not contiguous so I assume that stuff is also quite
broken atm?
I quickly sent this out without checking the error capture code, but
that seems to be broken but no one is complaining? Seems odd.
It looks like we are also missing some IGTs for the vma dumpable stuff.
Let me look into this a bit more before posting a proper series. Will
also update the error capture if needed.
Visible VRAM access is only supported at the momement but a follow up
can add GPU access to non-visible VRAM.
Suggested-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
---
drivers/gpu/drm/ttm/ttm_bo_vm.c | 20 +++++++++-----
drivers/gpu/drm/xe/xe_bo.c | 48 +++++++++++++++++++++++++++++++++
include/drm/ttm/ttm_bo.h | 2 ++
3 files changed, 64 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index 2c699ed1963a..b53cc064da44 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -405,13 +405,9 @@ static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
return len;
}
-int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
- void *buf, int len, int write)
+int ttm_bo_access(struct ttm_buffer_object *bo, unsigned long offset,
+ void *buf, int len, int write)
{
- struct ttm_buffer_object *bo = vma->vm_private_data;
- unsigned long offset = (addr) - vma->vm_start +
- ((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node))
- << PAGE_SHIFT);
int ret;
if (len < 1 || (offset + len) > bo->base.size)
@@ -439,6 +435,18 @@ int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
return ret;
}
+EXPORT_SYMBOL(ttm_bo_access);
+
+int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
+ void *buf, int len, int write)
+{
+ struct ttm_buffer_object *bo = vma->vm_private_data;
+ unsigned long offset = (addr) - vma->vm_start +
+ ((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node))
+ << PAGE_SHIFT);
+
+ return ttm_bo_access(bo, offset, buf, len, write);
+}
EXPORT_SYMBOL(ttm_bo_vm_access);
static const struct vm_operations_struct ttm_bo_vm_ops = {
diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index 5b232f2951b1..267f3b03a6d0 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -1111,6 +1111,53 @@ static void xe_ttm_bo_swap_notify(struct ttm_buffer_object *ttm_bo)
}
}
+static int xe_ttm_access_memory(struct ttm_buffer_object *ttm_bo,
+ unsigned long offset, void *buf, int len,
+ int write)
+{
+ struct xe_bo *bo = ttm_to_xe_bo(ttm_bo);
+ struct xe_device *xe = ttm_to_xe_device(ttm_bo->bdev);
+ struct iosys_map vmap;
+ struct xe_res_cursor cursor;
+ struct xe_mem_region *vram;
+ void __iomem *virtual;
+ int bytes_left = len;
+
+ xe_bo_assert_held(bo);
I think we need rpm somewhere? Although bo lock might make this tricky.
Do we? OFC if we interact with hardware we should but also if hardware
is powered off a BO shouldn't be in VRAM.
There is also d3hot which doesn't kick stuff out to system memory, but
VRAM is still inaccessible in that mode.
Maybe do a get_if_awake and bail otherwise?
Matt
+
+ if (!mem_type_is_vram(ttm_bo->resource->mem_type))
+ return -EIO;
+
+ /* FIXME: Use GPU for non-visible VRAM */
+ if (!(bo->flags & XE_BO_FLAG_NEEDS_CPU_ACCESS))
+ return -EINVAL;
+
+ vram = res_to_mem_region(ttm_bo->resource);
+ xe_res_first(ttm_bo->resource, offset & ~PAGE_MASK, 0, &cursor);
+
+ do {
+ int wcount = PAGE_SIZE - (offset & PAGE_MASK) > bytes_left ?
+ bytes_left : PAGE_SIZE - (offset & PAGE_MASK);
+
+ virtual = (u8 __force *)vram->mapping + cursor.start;
+
+ iosys_map_set_vaddr_iomem(&vmap, (void __iomem *)virtual);
+ if (write)
+ xe_map_memcpy_to(xe, &vmap, offset & PAGE_MASK, buf,
+ wcount);
+ else
+ xe_map_memcpy_from(xe, buf, &vmap, offset & PAGE_MASK,
+ wcount);
+
+ offset += wcount;
+ buf += wcount;
+ bytes_left -= wcount;
+ xe_res_next(&cursor, PAGE_SIZE);
+ } while (bytes_left);
+
+ return len;
+}
+
const struct ttm_device_funcs xe_ttm_funcs = {
.ttm_tt_create = xe_ttm_tt_create,
.ttm_tt_populate = xe_ttm_tt_populate,
@@ -1120,6 +1167,7 @@ const struct ttm_device_funcs xe_ttm_funcs = {
.move = xe_bo_move,
.io_mem_reserve = xe_ttm_io_mem_reserve,
.io_mem_pfn = xe_ttm_io_mem_pfn,
+ .access_memory = xe_ttm_access_memory,
.release_notify = xe_ttm_bo_release_notify,
.eviction_valuable = ttm_bo_eviction_valuable,
.delete_mem_notify = xe_ttm_bo_delete_mem_notify,
diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h
index 5804408815be..8ea11cd8df39 100644
--- a/include/drm/ttm/ttm_bo.h
+++ b/include/drm/ttm/ttm_bo.h
@@ -421,6 +421,8 @@ void ttm_bo_unpin(struct ttm_buffer_object *bo);
int ttm_bo_evict_first(struct ttm_device *bdev,
struct ttm_resource_manager *man,
struct ttm_operation_ctx *ctx);
+int ttm_bo_access(struct ttm_buffer_object *bo, unsigned long offset,
+ void *buf, int len, int write);
vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo,
struct vm_fault *vmf);
vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
