kernel/linux.git/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c, branch v6.12.80

drm/amdgpu: Skip loading SDMA_RS64 in VF

2026-03-04T12:21:02+00:00

[ Upstream commit 39c21b81112321cbe1267b02c77ecd2161ce19aa ] VFs use the PF SDMA ucode and are unable to load SDMA_RS64. Signed-off-by: YuBiao Wang Signed-off-by: Victor Skvortsov Reviewed-by: Gavin Wan Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amdgpu: Fix NULL pointer dereference in VRAM logic for APU devices

2025-11-24T09:35:47+00:00

[ Upstream commit 883f309add55060233bf11c1ea6947140372920f ] Previously, APU platforms (and other scenarios with uninitialized VRAM managers) triggered a NULL pointer dereference in `ttm_resource_manager_usage()`. The root cause is not that the `struct ttm_resource_manager *man` pointer itself is NULL, but that `man->bdev` (the backing device pointer within the manager) remains uninitialized (NULL) on APUs—since APUs lack dedicated VRAM and do not fully set up VRAM manager structures. When `ttm_resource_manager_usage()` attempts to acquire `man->bdev->lru_lock`, it dereferences the NULL `man->bdev`, leading to a kernel OOPS. 1. **amdgpu_cs.c**: Extend the existing bandwidth control check in `amdgpu_cs_get_threshold_for_moves()` to include a check for `ttm_resource_manager_used()`. If the manager is not used (uninitialized `bdev`), return 0 for migration thresholds immediately—skipping VRAM-specific logic that would trigger the NULL dereference. 2. **amdgpu_kms.c**: Update the `AMDGPU_INFO_VRAM_USAGE` ioctl and memory info reporting to use a conditional: if the manager is used, return the real VRAM usage; otherwise, return 0. This avoids accessing `man->bdev` when it is NULL. 3. **amdgpu_virt.c**: Modify the vf2pf (virtual function to physical function) data write path. Use `ttm_resource_manager_used()` to check validity: if the manager is usable, calculate `fb_usage` from VRAM usage; otherwise, set `fb_usage` to 0 (APUs have no discrete framebuffer to report). This approach is more robust than APU-specific checks because it: - Works for all scenarios where the VRAM manager is uninitialized (not just APUs), - Aligns with TTM's design by using its native helper function, - Preserves correct behavior for discrete GPUs (which have fully initialized `man->bdev` and pass the `ttm_resource_manager_used()` check). v4: use ttm_resource_manager_used(&adev->mman.vram_mgr.manager) instead of checking the adev->gmc.is_app_apu flag (Christian) Reviewed-by: Christian König Suggested-by: Lijo Lazar Signed-off-by: Jesse Zhang Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amdgpu: Replace Mutex with Spinlock for RLCG register access to avoid Priority Inversion in SRIOV

2025-07-17T16:37:01+00:00

commit dc0297f3198bd60108ccbd167ee5d9fa4af31ed0 upstream. RLCG Register Access is a way for virtual functions to safely access GPU registers in a virtualized environment., including TLB flushes and register reads. When multiple threads or VFs try to access the same registers simultaneously, it can lead to race conditions. By using the RLCG interface, the driver can serialize access to the registers. This means that only one thread can access the registers at a time, preventing conflicts and ensuring that operations are performed correctly. Additionally, when a low-priority task holds a mutex that a high-priority task needs, ie., If a thread holding a spinlock tries to acquire a mutex, it can lead to priority inversion. register access in amdgpu_virt_rlcg_reg_rw especially in a fast code path is critical. The call stack shows that the function amdgpu_virt_rlcg_reg_rw is being called, which attempts to acquire the mutex. This function is invoked from amdgpu_sriov_wreg, which in turn is called from gmc_v11_0_flush_gpu_tlb. The [ BUG: Invalid wait context ] indicates that a thread is trying to acquire a mutex while it is in a context that does not allow it to sleep (like holding a spinlock). Fixes the below: [ 253.013423] ============================= [ 253.013434] [ BUG: Invalid wait context ] [ 253.013446] 6.12.0-amdstaging-drm-next-lol-050225 #14 Tainted: G U OE [ 253.013464] ----------------------------- [ 253.013475] kworker/0:1/10 is trying to lock: [ 253.013487] ffff9f30542e3cf8 (&adev->virt.rlcg_reg_lock){+.+.}-{3:3}, at: amdgpu_virt_rlcg_reg_rw+0xf6/0x330 [amdgpu] [ 253.013815] other info that might help us debug this: [ 253.013827] context-{4:4} [ 253.013835] 3 locks held by kworker/0:1/10: [ 253.013847] #0: ffff9f3040050f58 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x3f5/0x680 [ 253.013877] #1: ffffb789c008be40 ((work_completion)(&wfc.work)){+.+.}-{0:0}, at: process_one_work+0x1d6/0x680 [ 253.013905] #2: ffff9f3054281838 (&adev->gmc.invalidate_lock){+.+.}-{2:2}, at: gmc_v11_0_flush_gpu_tlb+0x198/0x4f0 [amdgpu] [ 253.014154] stack backtrace: [ 253.014164] CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Tainted: G U OE 6.12.0-amdstaging-drm-next-lol-050225 #14 [ 253.014189] Tainted: [U]=USER, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE [ 253.014203] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 11/18/2024 [ 253.014224] Workqueue: events work_for_cpu_fn [ 253.014241] Call Trace: [ 253.014250] [ 253.014260] dump_stack_lvl+0x9b/0xf0 [ 253.014275] dump_stack+0x10/0x20 [ 253.014287] __lock_acquire+0xa47/0x2810 [ 253.014303] ? srso_alias_return_thunk+0x5/0xfbef5 [ 253.014321] lock_acquire+0xd1/0x300 [ 253.014333] ? amdgpu_virt_rlcg_reg_rw+0xf6/0x330 [amdgpu] [ 253.014562] ? __lock_acquire+0xa6b/0x2810 [ 253.014578] __mutex_lock+0x85/0xe20 [ 253.014591] ? amdgpu_virt_rlcg_reg_rw+0xf6/0x330 [amdgpu] [ 253.014782] ? sched_clock_noinstr+0x9/0x10 [ 253.014795] ? srso_alias_return_thunk+0x5/0xfbef5 [ 253.014808] ? local_clock_noinstr+0xe/0xc0 [ 253.014822] ? amdgpu_virt_rlcg_reg_rw+0xf6/0x330 [amdgpu] [ 253.015012] ? srso_alias_return_thunk+0x5/0xfbef5 [ 253.015029] mutex_lock_nested+0x1b/0x30 [ 253.015044] ? mutex_lock_nested+0x1b/0x30 [ 253.015057] amdgpu_virt_rlcg_reg_rw+0xf6/0x330 [amdgpu] [ 253.015249] amdgpu_sriov_wreg+0xc5/0xd0 [amdgpu] [ 253.015435] gmc_v11_0_flush_gpu_tlb+0x44b/0x4f0 [amdgpu] [ 253.015667] gfx_v11_0_hw_init+0x499/0x29c0 [amdgpu] [ 253.015901] ? __pfx_smu_v13_0_update_pcie_parameters+0x10/0x10 [amdgpu] [ 253.016159] ? srso_alias_return_thunk+0x5/0xfbef5 [ 253.016173] ? smu_hw_init+0x18d/0x300 [amdgpu] [ 253.016403] amdgpu_device_init+0x29ad/0x36a0 [amdgpu] [ 253.016614] amdgpu_driver_load_kms+0x1a/0xc0 [amdgpu] [ 253.017057] amdgpu_pci_probe+0x1c2/0x660 [amdgpu] [ 253.017493] local_pci_probe+0x4b/0xb0 [ 253.017746] work_for_cpu_fn+0x1a/0x30 [ 253.017995] process_one_work+0x21e/0x680 [ 253.018248] worker_thread+0x190/0x330 [ 253.018500] ? __pfx_worker_thread+0x10/0x10 [ 253.018746] kthread+0xe7/0x120 [ 253.018988] ? __pfx_kthread+0x10/0x10 [ 253.019231] ret_from_fork+0x3c/0x60 [ 253.019468] ? __pfx_kthread+0x10/0x10 [ 253.019701] ret_from_fork_asm+0x1a/0x30 [ 253.019939] v2: s/spin_trylock/spin_lock_irqsave to be safe (Christian). Fixes: e864180ee49b ("drm/amdgpu: Add lock around VF RLCG interface") Cc: lin cao Cc: Jingwen Chen Cc: Victor Skvortsov Cc: Zhigang Luo Cc: Christian König Cc: Alex Deucher Signed-off-by: Srinivasan Shanmugam Suggested-by: Alex Deucher Reviewed-by: Christian König Signed-off-by: Alex Deucher [ Minor context change fixed. ] Signed-off-by: Wenshan Lan Signed-off-by: Greg Kroah-Hartman

drm/amdgpu: Disable dpm_enabled flag while VF is in reset

2024-08-13T16:12:52+00:00

VFs do not perform HW fini/suspend in FLR, so the dpm_enabled is incorrectly kept enabled. Add interface to disable it in virt_pre_reset call. v2: Made implementation generic for all asics v3: Re-order conditionals so PP_MP1_STATE_FLR is only evaluated on VF Signed-off-by: Victor Skvortsov Reviewed-by: Lijo Lazar Signed-off-by: Alex Deucher

drm/amdgpu/mes: add multiple mes ring instances support

2024-08-13T14:29:25+00:00

Add multiple mes ring instances in mes structure to support multiple mes pipes. Signed-off-by: Jack Xiao Acked-by: Alex Deucher Reviewed-by: Hawking Zhang Signed-off-by: Alex Deucher

drm/amdgpu: Set no_hw_access when VF request full GPU fails

2024-07-08T20:46:56+00:00

[Why] If VF request full GPU access and the request failed, the VF driver can get stuck accessing registers for an extended period during the unload of KMS. [How] Set no_hw_access flag when VF request for full GPU access fails This prevents further hardware access attempts, avoiding the prolonged stuck state. Signed-off-by: Yifan Zha Acked-by: Alex Deucher Signed-off-by: Alex Deucher

drm/amdgpu: process RAS fatal error MB notification

2024-06-27T21:31:37+00:00

For RAS error scenario, VF guest driver will check mailbox and set fed flag to avoid unnecessary HW accesses. additionally, poll for reset completion message first to avoid accidentally spamming multiple reset requests to host. v2: add another mailbox check for handling case where kfd detects timeout first v3: set host_flr bit and use wait_for_reset Signed-off-by: Vignesh Chander Reviewed-by: Zhigang Luo Signed-off-by: Alex Deucher

drm/amdgpu: fix sriov host flr handler

2024-06-14T20:15:58+00:00

We send back the ready to reset message before we stop anything. This is wrong. Move it to when we are actually ready for the FLR to happen. In the current state since we take tens of seconds to stop everything, it is very likely that host would give up waiting and reset the GPU before we send ready, so it would be the same as before. But this gets rid of the hack with reset_domain locking and also let us tell how slow ready to reset actually is from the host. The ready to reset speed can be improved later. Signed-off-by: Yunxiang Li Acked-by: Christian König Reviewed-by: Emily Deng Signed-off-by: Alex Deucher

drm/amdgpu: add skip_hw_access checks for sriov

2024-06-14T20:15:58+00:00

Accessing registers via host is missing the check for skip_hw_access and the lockdep check that comes with it. Signed-off-by: Yunxiang Li Reviewed-by: Christian König Signed-off-by: Alex Deucher

drm/amdgpu: fix failure mapping legacy queue when FLR

2024-06-05T15:25:14+00:00

Flag "mes.ring.shced.ready" will be set as true after mes hw init and set as false when mes hw fini to avoid duplicate initialization. But hw fini will not be called when function level reset, which will cause mes hw init be skipped during FLR, which will leads to mapping legacy queue fail. Set this flag as false when post reset will fix this issue. Signed-off-by: Lin.Cao Acked-by: Alex Deucher Signed-off-by: Alex Deucher