[Intel-xe] [PATCH v4 02/31] drm/xe: Introduce xe_tile

Ofir Bitton obitton at habana.ai
Tue Jun 13 17:41:04 UTC 2023


Hey, sorry for jumping in so late, few comments, not a must, we can 
refactor this later.

On 01/06/2023 3:03, Matt Roper wrote:
> Create a new xe_tile structure to begin separating the concept of "tile"
> from "GT."  A tile is effectively a complete GPU, and a GT is just one
> part of that.  On platforms like MTL, there's only a single full GPU
> (tile) which has its IP blocks provided by two GTs.  In contrast, a
> "multi-tile" platform like PVC is basically multiple complete GPUs
> packed behind a single PCI device.
> 
> For now, just create xe_tile as a simple wrapper around xe_gt.  The
> items in xe_gt that are truly tied to the tile rather than the GT will
> be moved in future patches.  Support for multiple GTs per tile (i.e.,
> the MTL standalone media case) will also be re-introduced in a future
> patch.
> 
> v2:
>   - Fix kunit test build
>   - Move hunk from next patch to use local tile variable rather than
>     direct xe->tiles[id] accesses.  (Lucas)
>   - Mention compute in kerneldoc.  (Rodrigo)
> 
> Reviewed-by: Lucas De Marchi <lucas.demarchi at intel.com>
> Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
> ---
>   drivers/gpu/drm/xe/tests/xe_bo.c       |  2 +-
>   drivers/gpu/drm/xe/tests/xe_rtp_test.c |  6 ++--
>   drivers/gpu/drm/xe/xe_device.h         | 11 +++++--
>   drivers/gpu/drm/xe/xe_device_types.h   | 40 ++++++++++++++++++++++++--
>   drivers/gpu/drm/xe/xe_gt_types.h       | 15 ++++++----
>   drivers/gpu/drm/xe/xe_mmio.c           | 13 +++++----
>   drivers/gpu/drm/xe/xe_pci.c            |  7 ++++-
>   drivers/gpu/drm/xe/xe_vm.c             |  2 +-
>   drivers/gpu/drm/xe/xe_vm_types.h       |  8 +++---
>   9 files changed, 78 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/tests/xe_bo.c b/drivers/gpu/drm/xe/tests/xe_bo.c
> index 9bd381e5b7a6..6075f12a1962 100644
> --- a/drivers/gpu/drm/xe/tests/xe_bo.c
> +++ b/drivers/gpu/drm/xe/tests/xe_bo.c
> @@ -174,7 +174,7 @@ static int evict_test_run_gt(struct xe_device *xe, struct xe_gt *gt, struct kuni
>   	struct xe_bo *bo, *external;
>   	unsigned int bo_flags = XE_BO_CREATE_USER_BIT |
>   		XE_BO_CREATE_VRAM_IF_DGFX(gt);
> -	struct xe_vm *vm = xe_migrate_get_vm(xe->gt[0].migrate);
> +	struct xe_vm *vm = xe_migrate_get_vm(xe_device_get_root_tile(xe)->primary_gt.migrate);
>   	struct ww_acquire_ctx ww;
>   	int err, i;
>   
> diff --git a/drivers/gpu/drm/xe/tests/xe_rtp_test.c b/drivers/gpu/drm/xe/tests/xe_rtp_test.c
> index ab6f7a47db50..45f2614f91ec 100644
> --- a/drivers/gpu/drm/xe/tests/xe_rtp_test.c
> +++ b/drivers/gpu/drm/xe/tests/xe_rtp_test.c
> @@ -13,6 +13,7 @@
>   
>   #include "regs/xe_gt_regs.h"
>   #include "regs/xe_reg_defs.h"
> +#include "xe_device.h"
>   #include "xe_device_types.h"
>   #include "xe_pci_test.h"
>   #include "xe_reg_sr.h"
> @@ -236,9 +237,10 @@ static void xe_rtp_process_tests(struct kunit *test)
>   {
>   	const struct rtp_test_case *param = test->param_value;
>   	struct xe_device *xe = test->priv;
> -	struct xe_reg_sr *reg_sr = &xe->gt[0].reg_sr;
> +	struct xe_gt *gt = &xe_device_get_root_tile(xe)->primary_gt;
> +	struct xe_reg_sr *reg_sr = &gt->reg_sr;
>   	const struct xe_reg_sr_entry *sre, *sr_entry = NULL;
> -	struct xe_rtp_process_ctx ctx = XE_RTP_PROCESS_CTX_INITIALIZER(&xe->gt[0]);
> +	struct xe_rtp_process_ctx ctx = XE_RTP_PROCESS_CTX_INITIALIZER(gt);
>   	unsigned long idx, count = 0;
>   
>   	xe_reg_sr_init(reg_sr, "xe_rtp_tests", xe);
> diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
> index cbae480a2092..f7acaf51a1fc 100644
> --- a/drivers/gpu/drm/xe/xe_device.h
> +++ b/drivers/gpu/drm/xe/xe_device.h
> @@ -48,12 +48,17 @@ static inline struct xe_file *to_xe_file(const struct drm_file *file)
>   	return file->driver_priv;
>   }
>   
> +static inline struct xe_tile *xe_device_get_root_tile(struct xe_device *xe)
> +{
> +	return &xe->tiles[0];
> +}
> +
>   static inline struct xe_gt *xe_device_get_gt(struct xe_device *xe, u8 gt_id)
>   {
>   	struct xe_gt *gt;
>   
> -	XE_BUG_ON(gt_id > XE_MAX_GT);
> -	gt = xe->gt + gt_id;
> +	XE_BUG_ON(gt_id > XE_MAX_TILES_PER_DEVICE);

Wouldn't it be robust to check (gt_id > xe->info.tile_count) ?

> +	gt = &xe->tiles[gt_id].primary_gt;
>   	XE_BUG_ON(gt->info.id != gt_id);
>   	XE_BUG_ON(gt->info.type == XE_GT_TYPE_UNINITIALIZED);
>   
> @@ -65,7 +70,7 @@ static inline struct xe_gt *xe_device_get_gt(struct xe_device *xe, u8 gt_id)
>    */
>   static inline struct xe_gt *to_gt(struct xe_device *xe)
>   {
> -	return xe->gt;
> +	return &xe_device_get_root_tile(xe)->primary_gt;
>   }
>   
>   static inline bool xe_device_guc_submission_enabled(struct xe_device *xe)
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
> index 51c16d207780..396ee281e499 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -35,7 +35,7 @@
>   
>   #define XE_GT0		0
>   #define XE_GT1		1
> -#define XE_MAX_GT	(XE_GT1 + 1)
> +#define XE_MAX_TILES_PER_DEVICE	(XE_GT1 + 1)

This define will change each time we increase tile count.
I suggest removing this define and use dynamic allocations everywhere 
according to 'tile_count.
Another (worst) option is to use some higher maximum (32?) and 
initialize only the relevant elements in each array that uses this define.

>   
>   #define XE_MAX_ASID	(BIT(20))
>   
> @@ -49,6 +49,40 @@
>   	 (_xe)->info.step.graphics >= (min_step) &&			\
>   	 (_xe)->info.step.graphics < (max_step))
>   
> +#define tile_to_xe(tile__)								\
> +	_Generic(tile__,								\
> +		 const struct xe_tile *: (const struct xe_device *)((tile__)->xe),	\
> +		 struct xe_tile *: (tile__)->xe)
> +
> +/**
> + * struct xe_tile - hardware tile structure
> + *
> + * From a driver perspective, a "tile" is effectively a complete GPU, containing
> + * an SGunit, 1-2 GTs, and (for discrete platforms) VRAM.
> + *
> + * Multi-tile platforms effectively bundle multiple GPUs behind a single PCI
> + * device and designate one "root" tile as being responsible for external PCI
> + * communication.  PCI BAR0 exposes the GGTT and MMIO register space for each
> + * tile in a stacked layout, and PCI BAR2 exposes the local memory associated
> + * with each tile similarly.  Device-wide interrupts can be enabled/disabled
> + * at the root tile, and the MSTR_TILE_INTR register will report which tiles
> + * have interrupts that need servicing.
> + */
> +struct xe_tile {
> +	/** @xe: Backpointer to tile's PCI device */
> +	struct xe_device *xe;
> +
> +	/** @id: ID of the tile */
> +	u8 id;
> +
> +	/**
> +	 * @primary_gt: Primary GT
> +	 */
> +	struct xe_gt primary_gt;
> +
> +	/* TODO: Add media GT here */
> +};
> +
>   /**
>    * struct xe_device - Top level struct of XE device
>    */
> @@ -256,8 +290,8 @@ struct xe_device {
>   	/** @ordered_wq: used to serialize compute mode resume */
>   	struct workqueue_struct *ordered_wq;
>   
> -	/** @gt: graphics tile */
> -	struct xe_gt gt[XE_MAX_GT];
> +	/** @tiles: device tiles */
> +	struct xe_tile tiles[XE_MAX_TILES_PER_DEVICE];
>   
>   	/**
>   	 * @mem_access: keep track of memory access in the device, possibly
> diff --git a/drivers/gpu/drm/xe/xe_gt_types.h b/drivers/gpu/drm/xe/xe_gt_types.h
> index 093d650c35f4..456e3e447a2e 100644
> --- a/drivers/gpu/drm/xe/xe_gt_types.h
> +++ b/drivers/gpu/drm/xe/xe_gt_types.h
> @@ -77,12 +77,17 @@ enum xe_steering_type {
>   };
>   
>   /**
> - * struct xe_gt - Top level struct of a graphics tile
> + * struct xe_gt - A "Graphics Technology" unit of the GPU
>    *
> - * A graphics tile may be a physical split (duplicate pieces of silicon,
> - * different GGTT + VRAM) or a virtual split (shared GGTT + VRAM). Either way
> - * this structure encapsulates of everything a GT is (MMIO, VRAM, memory
> - * management, microcontrols, and a hardware set of engines).
> + * A GT ("Graphics Technology") is the subset of a GPU primarily responsible
> + * for implementing the graphics, compute, and/or media IP.  It encapsulates
> + * the hardware engines, programmable execution units, and GuC.   Each GT has
> + * its own handling of power management (RC6+forcewake) and multicast register
> + * steering.
> + *
> + * A GPU/tile may have a single GT that supplies all graphics, compute, and
> + * media functionality, or the graphics/compute and media may be split into
> + * separate GTs within a tile.
>    */
>   struct xe_gt {
>   	/** @xe: backpointer to XE device */
> diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c
> index ef2353eef6fe..9bc5715e9ebe 100644
> --- a/drivers/gpu/drm/xe/xe_mmio.c
> +++ b/drivers/gpu/drm/xe/xe_mmio.c
> @@ -438,6 +438,7 @@ int xe_mmio_ioctl(struct drm_device *dev, void *data,
>   		  struct drm_file *file)
>   {
>   	struct xe_device *xe = to_xe_device(dev);
> +	struct xe_gt *gt = xe_device_get_gt(xe, 0);

Better to have some define for '0' for example 'XE_ROOT_GT_ID'.

Ofir

>   	struct drm_xe_mmio *args = data;
>   	unsigned int bits_flag, bytes;
>   	struct xe_reg reg;
> @@ -480,7 +481,7 @@ int xe_mmio_ioctl(struct drm_device *dev, void *data,
>   	 */
>   	reg = XE_REG(args->addr);
>   
> -	xe_force_wake_get(gt_to_fw(&xe->gt[0]), XE_FORCEWAKE_ALL);
> +	xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
>   
>   	if (args->flags & DRM_XE_MMIO_WRITE) {
>   		switch (bits_flag) {
> @@ -489,10 +490,10 @@ int xe_mmio_ioctl(struct drm_device *dev, void *data,
>   				ret = -EINVAL;
>   				goto exit;
>   			}
> -			xe_mmio_write32(to_gt(xe), reg, args->value);
> +			xe_mmio_write32(gt, reg, args->value);
>   			break;
>   		case DRM_XE_MMIO_64BIT:
> -			xe_mmio_write64(to_gt(xe), reg, args->value);
> +			xe_mmio_write64(gt, reg, args->value);
>   			break;
>   		default:
>   			drm_dbg(&xe->drm, "Invalid MMIO bit size");
> @@ -507,10 +508,10 @@ int xe_mmio_ioctl(struct drm_device *dev, void *data,
>   	if (args->flags & DRM_XE_MMIO_READ) {
>   		switch (bits_flag) {
>   		case DRM_XE_MMIO_32BIT:
> -			args->value = xe_mmio_read32(to_gt(xe), reg);
> +			args->value = xe_mmio_read32(gt, reg);
>   			break;
>   		case DRM_XE_MMIO_64BIT:
> -			args->value = xe_mmio_read64(to_gt(xe), reg);
> +			args->value = xe_mmio_read64(gt, reg);
>   			break;
>   		default:
>   			drm_dbg(&xe->drm, "Invalid MMIO bit size");
> @@ -522,7 +523,7 @@ int xe_mmio_ioctl(struct drm_device *dev, void *data,
>   	}
>   
>   exit:
> -	xe_force_wake_put(gt_to_fw(&xe->gt[0]), XE_FORCEWAKE_ALL);
> +	xe_force_wake_put(gt_to_fw(gt), XE_FORCEWAKE_ALL);
>   
>   	return ret;
>   }
> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
> index 6f0c4203fca3..0ecf875e4fb4 100644
> --- a/drivers/gpu/drm/xe/xe_pci.c
> +++ b/drivers/gpu/drm/xe/xe_pci.c
> @@ -496,6 +496,7 @@ static int xe_info_init(struct xe_device *xe,
>   	const struct xe_graphics_desc *graphics_desc = NULL;
>   	const struct xe_media_desc *media_desc = NULL;
>   	u32 graphics_gmdid_revid = 0, media_gmdid_revid = 0;
> +	struct xe_tile *tile;
>   	struct xe_gt *gt;
>   	u8 id;
>   
> @@ -558,7 +559,11 @@ static int xe_info_init(struct xe_device *xe,
>   	xe->info.tile_count = 1 + graphics_desc->max_remote_tiles;
>   
>   	for (id = 0; id < xe->info.tile_count; ++id) {
> -		gt = xe->gt + id;
> +		tile = &xe->tiles[id];
> +		tile->xe = xe;
> +		tile->id = id;
> +
> +		gt = &tile->primary_gt;
>   		gt->info.id = id;
>   		gt->xe = xe;
>   
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index dd1335e12d4c..87416b8bb878 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -3389,7 +3389,7 @@ int xe_vm_invalidate_vma(struct xe_vma *vma)
>   	struct xe_device *xe = vma->vm->xe;
>   	struct xe_gt *gt;
>   	u32 gt_needs_invalidate = 0;
> -	int seqno[XE_MAX_GT];
> +	int seqno[XE_MAX_TILES_PER_DEVICE];
>   	u8 id;
>   	int ret;
>   
> diff --git a/drivers/gpu/drm/xe/xe_vm_types.h b/drivers/gpu/drm/xe/xe_vm_types.h
> index fada7896867f..203ba9d946b8 100644
> --- a/drivers/gpu/drm/xe/xe_vm_types.h
> +++ b/drivers/gpu/drm/xe/xe_vm_types.h
> @@ -159,7 +159,7 @@ struct xe_vm {
>   	struct kref refcount;
>   
>   	/* engine used for (un)binding vma's */
> -	struct xe_engine *eng[XE_MAX_GT];
> +	struct xe_engine *eng[XE_MAX_TILES_PER_DEVICE];
>   
>   	/** Protects @rebind_list and the page-table structures */
>   	struct dma_resv resv;
> @@ -167,9 +167,9 @@ struct xe_vm {
>   	u64 size;
>   	struct rb_root vmas;
>   
> -	struct xe_pt *pt_root[XE_MAX_GT];
> -	struct xe_bo *scratch_bo[XE_MAX_GT];
> -	struct xe_pt *scratch_pt[XE_MAX_GT][XE_VM_MAX_LEVEL];
> +	struct xe_pt *pt_root[XE_MAX_TILES_PER_DEVICE];
> +	struct xe_bo *scratch_bo[XE_MAX_TILES_PER_DEVICE];
> +	struct xe_pt *scratch_pt[XE_MAX_TILES_PER_DEVICE][XE_VM_MAX_LEVEL];
>   
>   	/** @flags: flags for this VM, statically setup a creation time */
>   #define XE_VM_FLAGS_64K			BIT(0)



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