From: Matthew Brost Date: Fri, 7 Jun 2024 01:52:12 +0000 (-0700) Subject: drm/xe: Rework GPU page fault handling X-Git-Tag: v6.11-rc1~141^2~16^2~99 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3d420e9fa84866cb3b98b6baa05d682850ef2952;p=thirdparty%2Fkernel%2Flinux.git drm/xe: Rework GPU page fault handling Add helper function to implement VMA (user binding) page faults, remove unnecessary userptr.invalidate_link list del operation, retry on memory pressure, remove unnecessary xe_vma_userptr_check_repin after rebinding, remove unnecessary TLB invalidation, and always use vm->lock in write mode. Changes help facilitate SVM page faults. Signed-off-by: Matthew Brost Reviewed-by: Nirmoy Das Reviewed-by: Jagmeet Randhawa Link: https://patchwork.freedesktop.org/patch/msgid/20240607015212.2190106-1-matthew.brost@intel.com --- diff --git a/drivers/gpu/drm/xe/xe_gt_pagefault.c b/drivers/gpu/drm/xe/xe_gt_pagefault.c index 040dd142c49c3..eaf68f0135c19 100644 --- a/drivers/gpu/drm/xe/xe_gt_pagefault.c +++ b/drivers/gpu/drm/xe/xe_gt_pagefault.c @@ -125,126 +125,108 @@ static int xe_pf_begin(struct drm_exec *exec, struct xe_vma *vma, return 0; } -static int handle_pagefault(struct xe_gt *gt, struct pagefault *pf) +static int handle_vma_pagefault(struct xe_tile *tile, struct pagefault *pf, + struct xe_vma *vma) { - struct xe_device *xe = gt_to_xe(gt); - struct xe_tile *tile = gt_to_tile(gt); + struct xe_vm *vm = xe_vma_vm(vma); struct drm_exec exec; - struct xe_vm *vm; - struct xe_vma *vma = NULL; struct dma_fence *fence; - bool write_locked; - int ret = 0; + ktime_t end = 0; + int err; bool atomic; - /* SW isn't expected to handle TRTT faults */ - if (pf->trva_fault) - return -EFAULT; - - /* ASID to VM */ - mutex_lock(&xe->usm.lock); - vm = xa_load(&xe->usm.asid_to_vm, pf->asid); - if (vm && xe_vm_in_fault_mode(vm)) - xe_vm_get(vm); - else - vm = NULL; - mutex_unlock(&xe->usm.lock); - if (!vm) - return -EINVAL; - -retry_userptr: - /* - * TODO: Avoid exclusive lock if VM doesn't have userptrs, or - * start out read-locked? - */ - down_write(&vm->lock); - write_locked = true; - vma = lookup_vma(vm, pf->page_addr); - if (!vma) { - ret = -EINVAL; - goto unlock_vm; - } - - if (!xe_vma_is_userptr(vma) || - !xe_vma_userptr_check_repin(to_userptr_vma(vma))) { - downgrade_write(&vm->lock); - write_locked = false; - } - trace_xe_vma_pagefault(vma); - atomic = access_is_atomic(pf->access_type); /* Check if VMA is valid */ if (vma_is_valid(tile, vma) && !atomic) - goto unlock_vm; - - /* TODO: Validate fault */ + return 0; - if (xe_vma_is_userptr(vma) && write_locked) { +retry_userptr: + if (xe_vma_is_userptr(vma) && + xe_vma_userptr_check_repin(to_userptr_vma(vma))) { struct xe_userptr_vma *uvma = to_userptr_vma(vma); - spin_lock(&vm->userptr.invalidated_lock); - list_del_init(&uvma->userptr.invalidate_link); - spin_unlock(&vm->userptr.invalidated_lock); - - ret = xe_vma_userptr_pin_pages(uvma); - if (ret) - goto unlock_vm; - - downgrade_write(&vm->lock); - write_locked = false; + err = xe_vma_userptr_pin_pages(uvma); + if (err) + return err; } /* Lock VM and BOs dma-resv */ drm_exec_init(&exec, 0, 0); drm_exec_until_all_locked(&exec) { - ret = xe_pf_begin(&exec, vma, atomic, tile->id); + err = xe_pf_begin(&exec, vma, atomic, tile->id); drm_exec_retry_on_contention(&exec); - if (ret) + if (xe_vm_validate_should_retry(&exec, err, &end)) + err = -EAGAIN; + if (err) goto unlock_dma_resv; /* Bind VMA only to the GT that has faulted */ trace_xe_vma_pf_bind(vma); fence = xe_vma_rebind(vm, vma, BIT(tile->id)); if (IS_ERR(fence)) { - ret = PTR_ERR(fence); + err = PTR_ERR(fence); + if (xe_vm_validate_should_retry(&exec, err, &end)) + err = -EAGAIN; goto unlock_dma_resv; } } - /* - * XXX: Should we drop the lock before waiting? This only helps if doing - * GPU binds which is currently only done if we have to wait for more - * than 10ms on a move. - */ dma_fence_wait(fence, false); dma_fence_put(fence); - - if (xe_vma_is_userptr(vma)) - ret = xe_vma_userptr_check_repin(to_userptr_vma(vma)); vma->tile_invalidated &= ~BIT(tile->id); unlock_dma_resv: drm_exec_fini(&exec); -unlock_vm: - if (!ret) - vm->usm.last_fault_vma = vma; - if (write_locked) - up_write(&vm->lock); - else - up_read(&vm->lock); - if (ret == -EAGAIN) + if (err == -EAGAIN) goto retry_userptr; - if (!ret) { - ret = xe_gt_tlb_invalidation_vma(gt, NULL, vma); - if (ret >= 0) - ret = 0; + return err; +} + +static int handle_pagefault(struct xe_gt *gt, struct pagefault *pf) +{ + struct xe_device *xe = gt_to_xe(gt); + struct xe_tile *tile = gt_to_tile(gt); + struct xe_vm *vm; + struct xe_vma *vma = NULL; + int err; + + /* SW isn't expected to handle TRTT faults */ + if (pf->trva_fault) + return -EFAULT; + + /* ASID to VM */ + mutex_lock(&xe->usm.lock); + vm = xa_load(&xe->usm.asid_to_vm, pf->asid); + if (vm && xe_vm_in_fault_mode(vm)) + xe_vm_get(vm); + else + vm = NULL; + mutex_unlock(&xe->usm.lock); + if (!vm) + return -EINVAL; + + /* + * TODO: Change to read lock? Using write lock for simplicity. + */ + down_write(&vm->lock); + vma = lookup_vma(vm, pf->page_addr); + if (!vma) { + err = -EINVAL; + goto unlock_vm; } + + err = handle_vma_pagefault(tile, pf, vma); + +unlock_vm: + if (!err) + vm->usm.last_fault_vma = vma; + up_write(&vm->lock); xe_vm_put(vm); - return ret; + return err; } static int send_pagefault_reply(struct xe_guc *guc,