drm/amdkfd: Add CWSR support

This hardware feature allows the GPU to preempt shader execution in
the middle of a compute wave, save the state and restore it later
to resume execution.

Memory for saving the state is allocated per queue in user mode and
the address and size passed to the create_queue ioctl. The size
depends on the number of waves that can be in flight simultaneously
on a given ASIC.

Signed-off-by: Shaoyun.liu <shaoyun.liu@amd.com>
Signed-off-by: Yong Zhao <yong.zhao@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

@@ -117,7 +117,7 @@ static int kfd_open(struct inode *inode, struct file *filep)
 		return -EPERM;
 	}
 
-	process = kfd_create_process(current);
+	process = kfd_create_process(filep);
 	if (IS_ERR(process))
 		return PTR_ERR(process);
 
@@ -206,6 +206,7 @@ static int set_queue_properties_from_user(struct queue_properties *q_properties,
 	q_properties->ctx_save_restore_area_address =
 			args->ctx_save_restore_address;
 	q_properties->ctx_save_restore_area_size = args->ctx_save_restore_size;
+	q_properties->ctl_stack_size = args->ctl_stack_size;
 	if (args->queue_type == KFD_IOC_QUEUE_TYPE_COMPUTE ||
 		args->queue_type == KFD_IOC_QUEUE_TYPE_COMPUTE_AQL)
 		q_properties->type = KFD_QUEUE_TYPE_COMPUTE;
@@ -1088,6 +1089,10 @@ static int kfd_mmap(struct file *filp, struct vm_area_struct *vma)
 			KFD_MMAP_EVENTS_MASK) {
 		vma->vm_pgoff = vma->vm_pgoff ^ KFD_MMAP_EVENTS_MASK;
 		return kfd_event_mmap(process, vma);
+	} else if ((vma->vm_pgoff & KFD_MMAP_RESERVED_MEM_MASK) ==
+			KFD_MMAP_RESERVED_MEM_MASK) {
+		vma->vm_pgoff = vma->vm_pgoff ^ KFD_MMAP_RESERVED_MEM_MASK;
+		return kfd_reserved_mem_mmap(process, vma);
 	}
 
 	return -EFAULT;

drivers/gpu/drm/amd/amdkfd/kfd_device.c

@@ -27,6 +27,7 @@
 #include "kfd_priv.h"
 #include "kfd_device_queue_manager.h"
 #include "kfd_pm4_headers_vi.h"
+#include "cwsr_trap_handler_gfx8.asm"
 
 #define MQD_SIZE_ALIGNED 768
 
@@ -38,7 +39,8 @@ static const struct kfd_device_info kaveri_device_info = {
 	.ih_ring_entry_size = 4 * sizeof(uint32_t),
 	.event_interrupt_class = &event_interrupt_class_cik,
 	.num_of_watch_points = 4,
-	.mqd_size_aligned = MQD_SIZE_ALIGNED
+	.mqd_size_aligned = MQD_SIZE_ALIGNED,
+	.supports_cwsr = false,
 };
 
 static const struct kfd_device_info carrizo_device_info = {
@@ -49,7 +51,8 @@ static const struct kfd_device_info carrizo_device_info = {
 	.ih_ring_entry_size = 4 * sizeof(uint32_t),
 	.event_interrupt_class = &event_interrupt_class_cik,
 	.num_of_watch_points = 4,
-	.mqd_size_aligned = MQD_SIZE_ALIGNED
+	.mqd_size_aligned = MQD_SIZE_ALIGNED,
+	.supports_cwsr = true,
 };
 
 struct kfd_deviceid {
@@ -212,6 +215,17 @@ static int iommu_invalid_ppr_cb(struct pci_dev *pdev, int pasid,
 	return AMD_IOMMU_INV_PRI_RSP_INVALID;
 }
 
+static void kfd_cwsr_init(struct kfd_dev *kfd)
+{
+	if (cwsr_enable && kfd->device_info->supports_cwsr) {
+		BUILD_BUG_ON(sizeof(cwsr_trap_gfx8_hex) > PAGE_SIZE);
+
+		kfd->cwsr_isa = cwsr_trap_gfx8_hex;
+		kfd->cwsr_isa_size = sizeof(cwsr_trap_gfx8_hex);
+		kfd->cwsr_enabled = true;
+	}
+}
+
 bool kgd2kfd_device_init(struct kfd_dev *kfd,
 			 const struct kgd2kfd_shared_resources *gpu_resources)
 {
@@ -286,6 +300,8 @@ bool kgd2kfd_device_init(struct kfd_dev *kfd,
 		goto device_iommu_pasid_error;
 	}
 
+	kfd_cwsr_init(kfd);
+
 	if (kfd_resume(kfd))
 		goto kfd_resume_error;
 

drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c

@@ -173,6 +173,9 @@ static int create_queue_nocpsch(struct device_queue_manager *dqm,
 	*allocated_vmid = qpd->vmid;
 	q->properties.vmid = qpd->vmid;
 
+	q->properties.tba_addr = qpd->tba_addr;
+	q->properties.tma_addr = qpd->tma_addr;
+
 	if (q->properties.type == KFD_QUEUE_TYPE_COMPUTE)
 		retval = create_compute_queue_nocpsch(dqm, q, qpd);
 	else if (q->properties.type == KFD_QUEUE_TYPE_SDMA)
@@ -846,6 +849,9 @@ static int create_queue_cpsch(struct device_queue_manager *dqm, struct queue *q,
 	}
 
 	dqm->asic_ops.init_sdma_vm(dqm, q, qpd);
+
+	q->properties.tba_addr = qpd->tba_addr;
+	q->properties.tma_addr = qpd->tma_addr;
 	retval = mqd->init_mqd(mqd, &q->mqd, &q->mqd_mem_obj,
 				&q->gart_mqd_addr, &q->properties);
 	if (retval)

drivers/gpu/drm/amd/amdkfd/kfd_module.c

@@ -50,6 +50,10 @@ module_param(sched_policy, int, 0444);
 MODULE_PARM_DESC(sched_policy,
 	"Scheduling policy (0 = HWS (Default), 1 = HWS without over-subscription, 2 = Non-HWS (Used for debugging only)");
 
+int cwsr_enable = 1;
+module_param(cwsr_enable, int, 0444);
+MODULE_PARM_DESC(cwsr_enable, "CWSR enable (0 = Off, 1 = On (Default))");
+
 int max_num_of_queues_per_device = KFD_MAX_NUM_OF_QUEUES_PER_DEVICE_DEFAULT;
 module_param(max_num_of_queues_per_device, int, 0444);
 MODULE_PARM_DESC(max_num_of_queues_per_device,

drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_vi.c

@@ -89,6 +89,28 @@ static int init_mqd(struct mqd_manager *mm, void **mqd,
 	if (q->format == KFD_QUEUE_FORMAT_AQL)
 		m->cp_hqd_iq_rptr = 1;
 
+	if (q->tba_addr) {
+		m->compute_tba_lo = lower_32_bits(q->tba_addr >> 8);
+		m->compute_tba_hi = upper_32_bits(q->tba_addr >> 8);
+		m->compute_tma_lo = lower_32_bits(q->tma_addr >> 8);
+		m->compute_tma_hi = upper_32_bits(q->tma_addr >> 8);
+		m->compute_pgm_rsrc2 |=
+			(1 << COMPUTE_PGM_RSRC2__TRAP_PRESENT__SHIFT);
+	}
+
+	if (mm->dev->cwsr_enabled && q->ctx_save_restore_area_address) {
+		m->cp_hqd_persistent_state |=
+			(1 << CP_HQD_PERSISTENT_STATE__QSWITCH_MODE__SHIFT);
+		m->cp_hqd_ctx_save_base_addr_lo =
+			lower_32_bits(q->ctx_save_restore_area_address);
+		m->cp_hqd_ctx_save_base_addr_hi =
+			upper_32_bits(q->ctx_save_restore_area_address);
+		m->cp_hqd_ctx_save_size = q->ctx_save_restore_area_size;
+		m->cp_hqd_cntl_stack_size = q->ctl_stack_size;
+		m->cp_hqd_cntl_stack_offset = q->ctl_stack_size;
+		m->cp_hqd_wg_state_offset = q->ctl_stack_size;
+	}
+
 	*mqd = m;
 	if (gart_addr)
 		*gart_addr = addr;
@@ -167,6 +189,11 @@ static int __update_mqd(struct mqd_manager *mm, void *mqd,
 				2 << CP_HQD_PQ_CONTROL__SLOT_BASED_WPTR__SHIFT;
 	}
 
+	if (mm->dev->cwsr_enabled && q->ctx_save_restore_area_address)
+		m->cp_hqd_ctx_save_control =
+			atc_bit << CP_HQD_CTX_SAVE_CONTROL__ATC__SHIFT |
+			mtype << CP_HQD_CTX_SAVE_CONTROL__MTYPE__SHIFT;
+
 	q->is_active = (q->queue_size > 0 &&
 			q->queue_address != 0 &&
 			q->queue_percent > 0);

drivers/gpu/drm/amd/amdkfd/kfd_priv.h

@@ -41,6 +41,7 @@
 
 #define KFD_MMAP_DOORBELL_MASK 0x8000000000000
 #define KFD_MMAP_EVENTS_MASK 0x4000000000000
+#define KFD_MMAP_RESERVED_MEM_MASK 0x2000000000000
 
 /*
  * When working with cp scheduler we should assign the HIQ manually or via
@@ -62,6 +63,15 @@
 #define KFD_MAX_NUM_OF_PROCESSES 512
 #define KFD_MAX_NUM_OF_QUEUES_PER_PROCESS 1024
 
+/*
+ * Size of the per-process TBA+TMA buffer: 2 pages
+ *
+ * The first page is the TBA used for the CWSR ISA code. The second
+ * page is used as TMA for daisy changing a user-mode trap handler.
+ */
+#define KFD_CWSR_TBA_TMA_SIZE (PAGE_SIZE * 2)
+#define KFD_CWSR_TMA_OFFSET PAGE_SIZE
+
 /*
  * Kernel module parameter to specify maximum number of supported queues per
  * device
@@ -78,6 +88,8 @@ extern int max_num_of_queues_per_device;
 /* Kernel module parameter to specify the scheduling policy */
 extern int sched_policy;
 
+extern int cwsr_enable;
+
 /*
  * Kernel module parameter to specify whether to send sigterm to HSA process on
  * unhandled exception
@@ -131,6 +143,7 @@ struct kfd_device_info {
 	size_t ih_ring_entry_size;
 	uint8_t num_of_watch_points;
 	uint16_t mqd_size_aligned;
+	bool supports_cwsr;
 };
 
 struct kfd_mem_obj {
@@ -200,6 +213,11 @@ struct kfd_dev {
 
 	/* Debug manager */
 	struct kfd_dbgmgr           *dbgmgr;
+
+	/* CWSR */
+	bool cwsr_enabled;
+	const void *cwsr_isa;
+	unsigned int cwsr_isa_size;
 };
 
 /* KGD2KFD callbacks */
@@ -332,6 +350,9 @@ struct queue_properties {
 	uint32_t eop_ring_buffer_size;
 	uint64_t ctx_save_restore_area_address;
 	uint32_t ctx_save_restore_area_size;
+	uint32_t ctl_stack_size;
+	uint64_t tba_addr;
+	uint64_t tma_addr;
 };
 
 /**
@@ -439,6 +460,11 @@ struct qcm_process_device {
 	uint32_t num_gws;
 	uint32_t num_oac;
 	uint32_t sh_hidden_private_base;
+
+	/* CWSR memory */
+	void *cwsr_kaddr;
+	uint64_t tba_addr;
+	uint64_t tma_addr;
 };
 
 
@@ -563,7 +589,7 @@ struct amdkfd_ioctl_desc {
 
 void kfd_process_create_wq(void);
 void kfd_process_destroy_wq(void);
-struct kfd_process *kfd_create_process(const struct task_struct *);
+struct kfd_process *kfd_create_process(struct file *filep);
 struct kfd_process *kfd_get_process(const struct task_struct *);
 struct kfd_process *kfd_lookup_process_by_pasid(unsigned int pasid);
 
@@ -577,6 +603,9 @@ struct kfd_process_device *kfd_get_process_device_data(struct kfd_dev *dev,
 struct kfd_process_device *kfd_create_process_device_data(struct kfd_dev *dev,
 							struct kfd_process *p);
 
+int kfd_reserved_mem_mmap(struct kfd_process *process,
+			  struct vm_area_struct *vma);
+
 /* Process device data iterator */
 struct kfd_process_device *kfd_get_first_process_device_data(
 							struct kfd_process *p);

drivers/gpu/drm/amd/amdkfd/kfd_process.c

@@ -28,6 +28,7 @@
 #include <linux/amd-iommu.h>
 #include <linux/notifier.h>
 #include <linux/compat.h>
+#include <linux/mman.h>
 
 struct mm_struct;
 
@@ -53,6 +54,8 @@ struct kfd_process_release_work {
 
 static struct kfd_process *find_process(const struct task_struct *thread);
 static struct kfd_process *create_process(const struct task_struct *thread);
+static int kfd_process_init_cwsr(struct kfd_process *p, struct file *filep);
+
 
 void kfd_process_create_wq(void)
 {
@@ -68,9 +71,10 @@ void kfd_process_destroy_wq(void)
 	}
 }
 
-struct kfd_process *kfd_create_process(const struct task_struct *thread)
+struct kfd_process *kfd_create_process(struct file *filep)
 {
 	struct kfd_process *process;
+	struct task_struct *thread = current;
 
 	if (!thread->mm)
 		return ERR_PTR(-EINVAL);
@@ -101,6 +105,8 @@ struct kfd_process *kfd_create_process(const struct task_struct *thread)
 
 	up_write(&thread->mm->mmap_sem);
 
+	kfd_process_init_cwsr(process, filep);
+
 	return process;
 }
 
@@ -168,6 +174,11 @@ static void kfd_process_wq_release(struct work_struct *work)
 			amd_iommu_unbind_pasid(pdd->dev->pdev, p->pasid);
 
 		list_del(&pdd->per_device_list);
+
+		if (pdd->qpd.cwsr_kaddr)
+			free_pages((unsigned long)pdd->qpd.cwsr_kaddr,
+				get_order(KFD_CWSR_TBA_TMA_SIZE));
+
 		kfree(pdd);
 	}
 
@@ -260,6 +271,46 @@ static const struct mmu_notifier_ops kfd_process_mmu_notifier_ops = {
 	.release = kfd_process_notifier_release,
 };
 
+static int kfd_process_init_cwsr(struct kfd_process *p, struct file *filep)
+{
+	int err = 0;
+	unsigned long  offset;
+	struct kfd_process_device *temp, *pdd = NULL;
+	struct kfd_dev *dev = NULL;
+	struct qcm_process_device *qpd = NULL;
+
+	mutex_lock(&p->mutex);
+	list_for_each_entry_safe(pdd, temp, &p->per_device_data,
+				per_device_list) {
+		dev = pdd->dev;
+		qpd = &pdd->qpd;
+		if (!dev->cwsr_enabled || qpd->cwsr_kaddr)
+			continue;
+		offset = (dev->id | KFD_MMAP_RESERVED_MEM_MASK) << PAGE_SHIFT;
+		qpd->tba_addr = (int64_t)vm_mmap(filep, 0,
+			KFD_CWSR_TBA_TMA_SIZE, PROT_READ | PROT_EXEC,
+			MAP_SHARED, offset);
+
+		if (IS_ERR_VALUE(qpd->tba_addr)) {
+			pr_err("Failure to set tba address. error -%d.\n",
+				(int)qpd->tba_addr);
+			err = qpd->tba_addr;
+			qpd->tba_addr = 0;
+			qpd->cwsr_kaddr = NULL;
+			goto out;
+		}
+
+		memcpy(qpd->cwsr_kaddr, dev->cwsr_isa, dev->cwsr_isa_size);
+
+		qpd->tma_addr = qpd->tba_addr + KFD_CWSR_TMA_OFFSET;
+		pr_debug("set tba :0x%llx, tma:0x%llx, cwsr_kaddr:%p for pqm.\n",
+			qpd->tba_addr, qpd->tma_addr, qpd->cwsr_kaddr);
+	}
+out:
+	mutex_unlock(&p->mutex);
+	return err;
+}
+
 static struct kfd_process *create_process(const struct task_struct *thread)
 {
 	struct kfd_process *process;
@@ -535,3 +586,37 @@ struct kfd_process *kfd_lookup_process_by_pasid(unsigned int pasid)
 
 	return p;
 }
+
+int kfd_reserved_mem_mmap(struct kfd_process *process,
+			  struct vm_area_struct *vma)
+{
+	struct kfd_dev *dev = kfd_device_by_id(vma->vm_pgoff);
+	struct kfd_process_device *pdd;
+	struct qcm_process_device *qpd;
+
+	if (!dev)
+		return -EINVAL;
+	if ((vma->vm_end - vma->vm_start) != KFD_CWSR_TBA_TMA_SIZE) {
+		pr_err("Incorrect CWSR mapping size.\n");
+		return -EINVAL;
+	}
+
+	pdd = kfd_get_process_device_data(dev, process);
+	if (!pdd)
+		return -EINVAL;
+	qpd = &pdd->qpd;
+
+	qpd->cwsr_kaddr = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+					get_order(KFD_CWSR_TBA_TMA_SIZE));
+	if (!qpd->cwsr_kaddr) {
+		pr_err("Error allocating per process CWSR buffer.\n");
+		return -ENOMEM;
+	}
+
+	vma->vm_flags |= VM_IO | VM_DONTCOPY | VM_DONTEXPAND
+		| VM_NORESERVE | VM_DONTDUMP | VM_PFNMAP;
+	/* Mapping pages to user process */
+	return remap_pfn_range(vma, vma->vm_start,
+			       PFN_DOWN(__pa(qpd->cwsr_kaddr)),
+			       KFD_CWSR_TBA_TMA_SIZE, vma->vm_page_prot);
+}

include/uapi/linux/kfd_ioctl.h

@@ -58,7 +58,8 @@ struct kfd_ioctl_create_queue_args {
 	__u64 eop_buffer_address;	/* to KFD */
 	__u64 eop_buffer_size;	/* to KFD */
 	__u64 ctx_save_restore_address; /* to KFD */
-	__u64 ctx_save_restore_size;	/* to KFD */
+	__u32 ctx_save_restore_size;	/* to KFD */
+	__u32 ctl_stack_size;		/* to KFD */
 };
 
 struct kfd_ioctl_destroy_queue_args {