From fb544b8445080c6488a58c01022550adc0873283 Mon Sep 17 00:00:00 2001 From: Matthew Brost Date: Fri, 31 Oct 2025 09:54:14 -0700 Subject: [PATCH] drm/xe: Implement xe_pagefault_queue_work Implement a worker that services page faults, using the same implementation as in xe_gt_pagefault.c. v2: - Rebase on exhaustive eviction changes - Include engine instance in debug prints (Stuart) Signed-off-by: Matthew Brost Reviewed-by: Stuart Summers Reviewed-by: Lucas De Marchi Tested-by: Francois Dugast Link: https://patch.msgid.link/20251031165416.2871503-6-matthew.brost@intel.com --- drivers/gpu/drm/xe/xe_pagefault.c | 235 +++++++++++++++++++++++++++++- 1 file changed, 234 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/xe/xe_pagefault.c b/drivers/gpu/drm/xe/xe_pagefault.c index 7b2ac01a558eb..fe3e401450129 100644 --- a/drivers/gpu/drm/xe/xe_pagefault.c +++ b/drivers/gpu/drm/xe/xe_pagefault.c @@ -5,12 +5,20 @@ #include +#include #include +#include "xe_bo.h" #include "xe_device.h" +#include "xe_gt_printk.h" #include "xe_gt_types.h" +#include "xe_gt_stats.h" +#include "xe_hw_engine.h" #include "xe_pagefault.h" #include "xe_pagefault_types.h" +#include "xe_svm.h" +#include "xe_trace_bo.h" +#include "xe_vm.h" /** * DOC: Xe page faults @@ -37,9 +45,234 @@ static int xe_pagefault_entry_size(void) return roundup_pow_of_two(sizeof(struct xe_pagefault)); } +static int xe_pagefault_begin(struct drm_exec *exec, struct xe_vma *vma, + struct xe_vram_region *vram, bool need_vram_move) +{ + struct xe_bo *bo = xe_vma_bo(vma); + struct xe_vm *vm = xe_vma_vm(vma); + int err; + + err = xe_vm_lock_vma(exec, vma); + if (err) + return err; + + if (!bo) + return 0; + + return need_vram_move ? xe_bo_migrate(bo, vram->placement, NULL, exec) : + xe_bo_validate(bo, vm, true, exec); +} + +static int xe_pagefault_handle_vma(struct xe_gt *gt, struct xe_vma *vma, + bool atomic) +{ + struct xe_vm *vm = xe_vma_vm(vma); + struct xe_tile *tile = gt_to_tile(gt); + struct xe_validation_ctx ctx; + struct drm_exec exec; + struct dma_fence *fence; + int err, needs_vram; + + lockdep_assert_held_write(&vm->lock); + + needs_vram = xe_vma_need_vram_for_atomic(vm->xe, vma, atomic); + if (needs_vram < 0 || (needs_vram && xe_vma_is_userptr(vma))) + return needs_vram < 0 ? needs_vram : -EACCES; + + xe_gt_stats_incr(gt, XE_GT_STATS_ID_VMA_PAGEFAULT_COUNT, 1); + xe_gt_stats_incr(gt, XE_GT_STATS_ID_VMA_PAGEFAULT_KB, + xe_vma_size(vma) / SZ_1K); + + trace_xe_vma_pagefault(vma); + + /* Check if VMA is valid, opportunistic check only */ + if (xe_vm_has_valid_gpu_mapping(tile, vma->tile_present, + vma->tile_invalidated) && !atomic) + return 0; + +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); + + err = xe_vma_userptr_pin_pages(uvma); + if (err) + return err; + } + + /* Lock VM and BOs dma-resv */ + xe_validation_ctx_init(&ctx, &vm->xe->val, &exec, (struct xe_val_flags) {}); + drm_exec_init(&exec, 0, 0); + drm_exec_until_all_locked(&exec) { + err = xe_pagefault_begin(&exec, vma, tile->mem.vram, + needs_vram == 1); + drm_exec_retry_on_contention(&exec); + xe_validation_retry_on_oom(&ctx, &err); + if (err) + goto unlock_dma_resv; + + /* Bind VMA only to the GT that has faulted */ + trace_xe_vma_pf_bind(vma); + xe_vm_set_validation_exec(vm, &exec); + fence = xe_vma_rebind(vm, vma, BIT(tile->id)); + xe_vm_set_validation_exec(vm, NULL); + if (IS_ERR(fence)) { + err = PTR_ERR(fence); + xe_validation_retry_on_oom(&ctx, &err); + goto unlock_dma_resv; + } + } + + dma_fence_wait(fence, false); + dma_fence_put(fence); + +unlock_dma_resv: + xe_validation_ctx_fini(&ctx); + if (err == -EAGAIN) + goto retry_userptr; + + return err; +} + +static bool +xe_pagefault_access_is_atomic(enum xe_pagefault_access_type access_type) +{ + return access_type == XE_PAGEFAULT_ACCESS_TYPE_ATOMIC; +} + +static struct xe_vm *xe_pagefault_asid_to_vm(struct xe_device *xe, u32 asid) +{ + struct xe_vm *vm; + + down_read(&xe->usm.lock); + vm = xa_load(&xe->usm.asid_to_vm, asid); + if (vm && xe_vm_in_fault_mode(vm)) + xe_vm_get(vm); + else + vm = ERR_PTR(-EINVAL); + up_read(&xe->usm.lock); + + return vm; +} + +static int xe_pagefault_service(struct xe_pagefault *pf) +{ + struct xe_gt *gt = pf->gt; + struct xe_device *xe = gt_to_xe(gt); + struct xe_vm *vm; + struct xe_vma *vma = NULL; + int err; + bool atomic; + + /* Producer flagged this fault to be nacked */ + if (pf->consumer.fault_level == XE_PAGEFAULT_LEVEL_NACK) + return -EFAULT; + + vm = xe_pagefault_asid_to_vm(xe, pf->consumer.asid); + if (IS_ERR(vm)) + return PTR_ERR(vm); + + /* + * TODO: Change to read lock? Using write lock for simplicity. + */ + down_write(&vm->lock); + + if (xe_vm_is_closed(vm)) { + err = -ENOENT; + goto unlock_vm; + } + + vma = xe_vm_find_vma_by_addr(vm, pf->consumer.page_addr); + if (!vma) { + err = -EINVAL; + goto unlock_vm; + } + + atomic = xe_pagefault_access_is_atomic(pf->consumer.access_type); + + if (xe_vma_is_cpu_addr_mirror(vma)) + err = xe_svm_handle_pagefault(vm, vma, gt, + pf->consumer.page_addr, atomic); + else + err = xe_pagefault_handle_vma(gt, vma, atomic); + +unlock_vm: + if (!err) + vm->usm.last_fault_vma = vma; + up_write(&vm->lock); + xe_vm_put(vm); + + return err; +} + +static bool xe_pagefault_queue_pop(struct xe_pagefault_queue *pf_queue, + struct xe_pagefault *pf) +{ + bool found_fault = false; + + spin_lock_irq(&pf_queue->lock); + if (pf_queue->tail != pf_queue->head) { + memcpy(pf, pf_queue->data + pf_queue->tail, sizeof(*pf)); + pf_queue->tail = (pf_queue->tail + xe_pagefault_entry_size()) % + pf_queue->size; + found_fault = true; + } + spin_unlock_irq(&pf_queue->lock); + + return found_fault; +} + +static void xe_pagefault_print(struct xe_pagefault *pf) +{ + xe_gt_dbg(pf->gt, "\n\tASID: %d\n" + "\tFaulted Address: 0x%08x%08x\n" + "\tFaultType: %d\n" + "\tAccessType: %d\n" + "\tFaultLevel: %d\n" + "\tEngineClass: %d %s\n" + "\tEngineInstance: %d\n", + pf->consumer.asid, + upper_32_bits(pf->consumer.page_addr), + lower_32_bits(pf->consumer.page_addr), + pf->consumer.fault_type, + pf->consumer.access_type, + pf->consumer.fault_level, + pf->consumer.engine_class, + xe_hw_engine_class_to_str(pf->consumer.engine_class), + pf->consumer.engine_instance); +} + static void xe_pagefault_queue_work(struct work_struct *w) { - /* TODO: Implement */ + struct xe_pagefault_queue *pf_queue = + container_of(w, typeof(*pf_queue), worker); + struct xe_pagefault pf; + unsigned long threshold; + +#define USM_QUEUE_MAX_RUNTIME_MS 20 + threshold = jiffies + msecs_to_jiffies(USM_QUEUE_MAX_RUNTIME_MS); + + while (xe_pagefault_queue_pop(pf_queue, &pf)) { + int err; + + if (!pf.gt) /* Fault squashed during reset */ + continue; + + err = xe_pagefault_service(&pf); + if (err) { + xe_pagefault_print(&pf); + xe_gt_dbg(pf.gt, "Fault response: Unsuccessful %pe\n", + ERR_PTR(err)); + } + + pf.producer.ops->ack_fault(&pf, err); + + if (time_after(jiffies, threshold)) { + queue_work(gt_to_xe(pf.gt)->usm.pf_wq, w); + break; + } + } +#undef USM_QUEUE_MAX_RUNTIME_MS } static int xe_pagefault_queue_init(struct xe_device *xe, -- 2.47.3