kernel.git/include/drm/ttm/ttm_tt.h, branch linux-rolling-stable

drm/ttm: Remove the struct ttm_backup abstraction

2025-05-06T08:57:27Z

The abstraction was previously added to support separate ttm_backup implementations. However with the current implementation casting from a struct file to a struct ttm_backup, we run into trouble since struct file may have randomized the layout and gcc complains. Remove the struct ttm_backup abstraction Cc: dri-devel@lists.freedesktop.org Cc: Matthew Brost Cc: Dave Airlie Cc: Christian König Cc: Matthew Auld Cc: Al Viro Reported-by: Kees Cook Closes: https://lore.kernel.org/dri-devel/9c8dbbafdaf9f3f089da2cde5a772d69579b3795.camel@linux.intel.com/T/#mb153ab9216cb813b92bdeb36f391ad4808c2ba29 Suggested-by: Christian König Fixes: 70d645deac98 ("drm/ttm: Add helpers for shrinking") Signed-off-by: Thomas Hellström Reviewed-by: Christian König Link: https://lore.kernel.org/r/20250502130014.3156-1-thomas.hellstrom@linux.intel.com

drm/ttm: Add helpers for shrinking

2025-03-05T16:08:59Z

Add a number of helpers for shrinking that access core TTM and core MM functionality in a way that make them unsuitable for driver open-coding. v11: - New patch (split off from previous) and additional helpers. v13: - Adapt to ttm_backup interface change. - Take resource off LRU when backed up. Signed-off-by: Thomas Hellström Reviewed-by: Matthew Brost Acked-by: Dave Airlie Acked-by: Christian König Link: https://lore.kernel.org/intel-xe/20250305092220.123405-6-thomas.hellstrom@linux.intel.com

drm/ttm/pool, drm/ttm/tt: Provide a helper to shrink pages

2025-03-05T16:08:59Z

Provide a helper to shrink ttm_tt page-vectors on a per-page basis. A ttm_backup backend could then in theory get away with allocating a single temporary page for each struct ttm_tt. This is accomplished by splitting larger pages before trying to back them up. In the future we could allow ttm_backup to handle backing up large pages as well, but currently there's no benefit in doing that, since the shmem backup backend would have to split those anyway to avoid allocating too much temporary memory, and if the backend instead inserts pages into the swap-cache, those are split on reclaim by the core. Due to potential backup- and recover errors, allow partially swapped out struct ttm_tt's, although mark them as swapped out stopping them from being swapped out a second time. More details in the ttm_pool.c DOC section. v2: - A couple of cleanups and error fixes in ttm_pool_back_up_tt. - s/back_up/backup/ - Add a writeback parameter to the exported interface. v8: - Use a struct for flags for readability (Matt Brost) - Address misc other review comments (Matt Brost) v9: - Update the kerneldoc for the ttm_tt::backup field. v10: - Rebase. v13: - Rebase on ttm_backup interface change. Update kerneldoc. - Rebase and adjust ttm_tt_is_swapped(). v15: - Rebase on ttm_backup return value change. - Rebase on previous restructuring of ttm_pool_alloc() - Rework the ttm_pool backup interface (Christian König) - Remove cond_resched() (Christian König) - Get rid of the need to allocate an intermediate page array when restoring a multi-order page (Christian König) - Update documentation. Cc: Christian König Cc: Somalapuram Amaranath Cc: Matthew Brost Cc: Signed-off-by: Thomas Hellström Reviewed-by: Matthew Brost Acked-by: Christian Koenig Link: https://lore.kernel.org/intel-xe/20250305092220.123405-3-thomas.hellstrom@linux.intel.com

drm/ttm: Move swapped objects off the manager's LRU list

2024-10-09T11:41:30Z

Resources of swapped objects remains on the TTM_PL_SYSTEM manager's LRU list, which is bad for the LRU walk efficiency. Rename the device-wide "pinned" list to "unevictable" and move also resources of swapped-out objects to that list. An alternative would be to create an "UNEVICTABLE" priority to be able to keep the pinned- and swapped objects on their respective manager's LRU without affecting the LRU walk efficiency. v2: - Remove a bogus WARN_ON (Christian König) - Update ttm_resource_[add|del] bulk move (Christian König) - Fix TTM KUNIT tests (Intel CI) v3: - Check for non-NULL bo->resource in ttm_bo_populate(). v4: - Don't move to LRU tail during swapout until the resource is properly swapped or there was a swapout failure. (Intel Ci) - Add a newline after checkpatch check. v5: - Introduce ttm_resource_is_swapped() to avoid a corner-case where a newly created resource was considered swapped. (Intel CI) v6: - Move an assert. Cc: Christian König Cc: Matthew Brost Cc: Signed-off-by: Thomas Hellström Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20240911121859.85387-2-thomas.hellstrom@linux.intel.com

drm/ttm: Make sure the mapped tt pages are decrypted when needed

2024-01-26T19:10:52Z

Some drivers require the mapped tt pages to be decrypted. In an ideal world this would have been handled by the dma layer, but the TTM page fault handling would have to be rewritten to able to do that. A side-effect of the TTM page fault handling is using a dma allocation per order (via ttm_pool_alloc_page) which makes it impossible to just trivially use dma_mmap_attrs. As a result ttm has to be very careful about trying to make its pgprot for the mapped tt pages match what the dma layer thinks it is. At the ttm layer it's possible to deduce the requirement to have tt pages decrypted by checking whether coherent dma allocations have been requested and the system is running with confidential computing technologies. This approach isn't ideal but keeping TTM matching DMAs expectations for the page properties is in general fragile, unfortunately proper fix would require a rewrite of TTM's page fault handling. Fixes vmwgfx with SEV enabled. v2: Explicitly include cc_platform.h v3: Use CC_ATTR_GUEST_MEM_ENCRYPT instead of CC_ATTR_MEM_ENCRYPT to limit the scope to guests and log when memory decryption is enabled. Signed-off-by: Zack Rusin Fixes: 3bf3710e3718 ("drm/ttm: Add a generic TTM memcpy move for page-based iomem") Reviewed-by: Thomas Hellström Acked-by: Christian König Cc: Huang Rui Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Cc: # v5.14+ Link: https://patchwork.freedesktop.org/patch/msgid/20230926040359.3040017-1-zack@kde.org

drm/ttm: Helper function to get TTM mem limit

2023-06-09T13:24:43Z

Add a helper function to get TTM memory limit. This is needed by KFD to set its own internal memory limits. Signed-off-by: Mukul Joshi Reviewed-by: Christian König Signed-off-by: Alex Deucher

drm/ttm: Use the BIT macro for the TTM_TT_FLAGs

2023-03-09T13:18:53Z

New code is recommended to use the BIT macro instead of the explicit shifts. Change the older defines so that we can keep the style consistent with upcoming changes. v2: - Also change the value of the _PRIV_POPULATED bit (Christian König) Signed-off-by: Thomas Hellström Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20230307144621.10748-4-thomas.hellstrom@linux.intel.com

drm/ttm: fix undefined behavior in bit shift for TTM_TT_FLAG_PRIV_POPULATED

2022-11-02T09:23:07Z

Shifting signed 32-bit value by 31 bits is undefined, so changing significant bit to unsigned. The UBSAN warning calltrace like below: UBSAN: shift-out-of-bounds in ./include/drm/ttm/ttm_tt.h:122:26 left shift of 1 by 31 places cannot be represented in type 'int' Call Trace: dump_stack_lvl+0x7d/0xa5 dump_stack+0x15/0x1b ubsan_epilogue+0xe/0x4e __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c ttm_bo_move_memcpy+0x3b4/0x460 [ttm] bo_driver_move+0x32/0x40 [drm_vram_helper] ttm_bo_handle_move_mem+0x118/0x200 [ttm] ttm_bo_validate+0xfa/0x220 [ttm] drm_gem_vram_pin_locked+0x70/0x1b0 [drm_vram_helper] drm_gem_vram_pin+0x48/0xb0 [drm_vram_helper] drm_gem_vram_plane_helper_prepare_fb+0x53/0xe0 [drm_vram_helper] drm_gem_vram_simple_display_pipe_prepare_fb+0x26/0x30 [drm_vram_helper] drm_simple_kms_plane_prepare_fb+0x4d/0xe0 [drm_kms_helper] drm_atomic_helper_prepare_planes+0xda/0x210 [drm_kms_helper] drm_atomic_helper_commit+0xc3/0x1e0 [drm_kms_helper] drm_atomic_commit+0x9c/0x160 [drm] drm_client_modeset_commit_atomic+0x33a/0x380 [drm] drm_client_modeset_commit_locked+0x77/0x220 [drm] drm_client_modeset_commit+0x31/0x60 [drm] __drm_fb_helper_restore_fbdev_mode_unlocked+0xa7/0x170 [drm_kms_helper] drm_fb_helper_set_par+0x51/0x90 [drm_kms_helper] fbcon_init+0x316/0x790 visual_init+0x113/0x1d0 do_bind_con_driver+0x2a3/0x5c0 do_take_over_console+0xa9/0x270 do_fbcon_takeover+0xa1/0x170 do_fb_registered+0x2a8/0x340 fbcon_fb_registered+0x47/0xe0 register_framebuffer+0x294/0x4a0 __drm_fb_helper_initial_config_and_unlock+0x43c/0x880 [drm_kms_helper] drm_fb_helper_initial_config+0x52/0x80 [drm_kms_helper] drm_fbdev_client_hotplug+0x156/0x1b0 [drm_kms_helper] drm_fbdev_generic_setup+0xfc/0x290 [drm_kms_helper] bochs_pci_probe+0x6ca/0x772 [bochs] local_pci_probe+0x4d/0xb0 pci_device_probe+0x119/0x320 really_probe+0x181/0x550 __driver_probe_device+0xc6/0x220 driver_probe_device+0x32/0x100 __driver_attach+0x195/0x200 bus_for_each_dev+0xbb/0x120 driver_attach+0x27/0x30 bus_add_driver+0x22e/0x2f0 driver_register+0xa9/0x190 __pci_register_driver+0x90/0xa0 bochs_pci_driver_init+0x52/0x1000 [bochs] do_one_initcall+0x76/0x430 do_init_module+0x61/0x28a load_module+0x1f82/0x2e50 __do_sys_finit_module+0xf8/0x190 __x64_sys_finit_module+0x23/0x30 do_syscall_64+0x58/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: 3312be8f6fc8 ("drm/ttm: move populated state into page flags") Signed-off-by: Gaosheng Cui Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20221031113350.4180975-1-cuigaosheng1@huawei.com Signed-off-by: Christian König

drm/ttm: Add a parameter to add extra pages into ttm_tt

2022-04-02T02:52:48Z

Add a parameter called "extra_pages" for ttm_tt_init, to indicate that driver needs extra pages in ttm_tt. v2: Used imperative wording [Thomas and Christian] Signed-off-by: Ramalingam C cc: Christian Koenig cc: Hellstrom Thomas Reviewed-by: Thomas Hellstrom Reviewed-by: Christian Konig Reviewed-by: Nirmoy Das Link: https://patchwork.freedesktop.org/patch/msgid/20220401123751.27771-8-ramalingam.c@intel.com

drm/ttm: add TTM_TT_FLAG_EXTERNAL_MAPPABLE

2021-09-29T14:18:43Z

In commit: commit 667a50db0477d47fdff01c666f5ee1ce26b5264c Author: Thomas Hellstrom Date: Fri Jan 3 11:17:18 2014 +0100 drm/ttm: Refuse to fault (prime-) imported pages we introduced the restriction that imported pages should not be directly mappable through TTM(this also extends to userptr). In the next patch we want to introduce a shmem_tt backend, which should follow all the existing rules with TTM_PAGE_FLAG_EXTERNAL, since it will need to handle swapping itself, but with the above mapping restriction lifted. v2(Christian): - Don't OR together EXTERNAL and EXTERNAL_MAPPABLE in the definition of EXTERNAL_MAPPABLE, just leave it the caller to handle this correctly, otherwise we might encounter subtle issues. Signed-off-by: Matthew Auld Cc: Thomas Hellström Cc: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20210929132629.353541-3-matthew.auld@intel.com Signed-off-by: Christian König