text: /*
   * Copyright 2018 Advanced Micro Devices, Inc.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
   * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   * OTHER DEALINGS IN THE SOFTWARE.
   */
  
  #include <linux/kconfig.h>
  
  #if IS_REACHABLE(CONFIG_AMD_IOMMU_V2)
  
  #include <linux/printk.h>
  #include <linux/device.h>
  #include <linux/slab.h>
  #include <linux/pci.h>
  #include <linux/amd-iommu.h>
  #include "kfd_priv.h"
  #include "kfd_dbgmgr.h"
  #include "kfd_topology.h"
  #include "kfd_iommu.h"
  
  static const u32 required_iommu_flags = AMD_IOMMU_DEVICE_FLAG_ATS_SUP |
  					AMD_IOMMU_DEVICE_FLAG_PRI_SUP |
  					AMD_IOMMU_DEVICE_FLAG_PASID_SUP;
  
  /** kfd_iommu_check_device - Check whether IOMMU is available for device
   */
  int kfd_iommu_check_device(struct kfd_dev *kfd)
  {
  	struct amd_iommu_device_info iommu_info;
  	int err;
  
  	if (!kfd->use_iommu_v2)
  		return -ENODEV;
  
  	iommu_info.flags = 0;
  	err = amd_iommu_device_info(kfd->pdev, &iommu_info);
  	if (err)
  		return err;
  
  	if ((iommu_info.flags & required_iommu_flags) != required_iommu_flags)
  		return -ENODEV;
  
  	return 0;
  }
  
  /** kfd_iommu_device_init - Initialize IOMMU for device
   */
  int kfd_iommu_device_init(struct kfd_dev *kfd)
  {
  	struct amd_iommu_device_info iommu_info;
  	unsigned int pasid_limit;
  	int err;
  
  	if (!kfd->use_iommu_v2)
  		return 0;
  
  	iommu_info.flags = 0;
  	err = amd_iommu_device_info(kfd->pdev, &iommu_info);
  	if (err < 0) {
  		dev_err(kfd_device,
  			"error getting iommu info. is the iommu enabled?\n");
  		return -ENODEV;
  	}
  
  	if ((iommu_info.flags & required_iommu_flags) != required_iommu_flags) {
  		dev_err(kfd_device,
  			"error required iommu flags ats %i, pri %i, pasid %i\n",
  		       (iommu_info.flags & AMD_IOMMU_DEVICE_FLAG_ATS_SUP) != 0,
  		       (iommu_info.flags & AMD_IOMMU_DEVICE_FLAG_PRI_SUP) != 0,
  		       (iommu_info.flags & AMD_IOMMU_DEVICE_FLAG_PASID_SUP)
  									!= 0);
  		return -ENODEV;
  	}
  
  	pasid_limit = min_t(unsigned int,
  			(unsigned int)(1 << kfd->device_info.max_pasid_bits),
  			iommu_info.max_pasids);
  
  	if (!kfd_set_pasid_limit(pasid_limit)) {
  		dev_err(kfd_device, "error setting pasid limit\n");
  		return -EBUSY;
  	}
  
  	return 0;
  }
  
  /** kfd_iommu_bind_process_to_device - Have the IOMMU bind a process
   *
   * Binds the given process to the given device using its PASID. This
   * enables IOMMUv2 address translation for the process on the device.
   *
   * This function assumes that the process mutex is held.
   */
  int kfd_iommu_bind_process_to_device(struct kfd_process_device *pdd)
  {
  	struct kfd_dev *dev = pdd->dev;
  	struct kfd_process *p = pdd->process;
  	int err;
  
  	if (!dev->use_iommu_v2 || pdd->bound == PDD_BOUND)
  		return 0;
  
  	if (unlikely(pdd->bound == PDD_BOUND_SUSPENDED)) {
  		pr_err("Binding PDD_BOUND_SUSPENDED pdd is unexpected!\n");
  		return -EINVAL;
  	}
  
  	err = amd_iommu_bind_pasid(dev->pdev, p->pasid, p->lead_thread);
  	if (!err)
  		pdd->bound = PDD_BOUND;
  
  	return err;
  }
  
  /** kfd_iommu_unbind_process - Unbind process from all devices
   *
   * This removes all IOMMU device bindings of the process. To be used
   * before process termination.
   */
  void kfd_iommu_unbind_process(struct kfd_process *p)
  {
  	int i;
  
  	for (i = 0; i < p->n_pdds; i++)
  		if (p->pdds[i]->bound == PDD_BOUND)
  			amd_iommu_unbind_pasid(p->pdds[i]->dev->pdev, p->pasid);
  }
  
  /* Callback for process shutdown invoked by the IOMMU driver */
  static void iommu_pasid_shutdown_callback(struct pci_dev *pdev, u32 pasid)
  {
  	struct kfd_dev *dev = kfd_device_by_pci_dev(pdev);
  	struct kfd_process *p;
  	struct kfd_process_device *pdd;
  
  	if (!dev)
  		return;
  
  	/*
  	 * Look for the process that matches the pasid. If there is no such
  	 * process, we either released it in amdkfd's own notifier, or there
  	 * is a bug. Unfortunately, there is no way to tell...
  	 */
  	p = kfd_lookup_process_by_pasid(pasid);
  	if (!p)
  		return;
  
  	pr_debug("Unbinding process 0x%x from IOMMU\n", pasid);
  
  	mutex_lock(kfd_get_dbgmgr_mutex());
  
  	if (dev->dbgmgr && dev->dbgmgr->pasid == p->pasid) {
  		if (!kfd_dbgmgr_unregister(dev->dbgmgr, p)) {
  			kfd_dbgmgr_destroy(dev->dbgmgr);
  			dev->dbgmgr = NULL;
  		}
  	}
  
  	mutex_unlock(kfd_get_dbgmgr_mutex());
  
  	mutex_lock(&p->mutex);
  
  	pdd = kfd_get_process_device_data(dev, p);
  	if (pdd)
  		/* For GPU relying on IOMMU, we need to dequeue here
  		 * when PASID is still bound.
  		 */
  		kfd_process_dequeue_from_device(pdd);
  
  	mutex_unlock(&p->mutex);
  
  	kfd_unref_process(p);
  }
  
  /* This function called by IOMMU driver on PPR failure */
  static int iommu_invalid_ppr_cb(struct pci_dev *pdev, u32 pasid,
  				unsigned long address, u16 flags)
  {
  	struct kfd_dev *dev;
  
  	dev_warn_ratelimited(kfd_device,
  			"Invalid PPR device %x:%x.%x pasid 0x%x address 0x%lX flags 0x%X",
  			pdev->bus->number,
  			PCI_SLOT(pdev->devfn),
  			PCI_FUNC(pdev->devfn),
  			pasid,
  			address,
  			flags);
  
  	dev = kfd_device_by_pci_dev(pdev);
  	if (!WARN_ON(!dev))
  		kfd_signal_iommu_event(dev, pasid, address,
  			flags & PPR_FAULT_WRITE, flags & PPR_FAULT_EXEC);
  
  	return AMD_IOMMU_INV_PRI_RSP_INVALID;
  }
  
  /*
   * Bind processes do the device that have been temporarily unbound
   * (PDD_BOUND_SUSPENDED) in kfd_unbind_processes_from_device.
   */
  static int kfd_bind_processes_to_device(struct kfd_dev *kfd)
  {
  	struct kfd_process_device *pdd;
  	struct kfd_process *p;
  	unsigned int temp;
  	int err = 0;
  
  	int idx = srcu_read_lock(&kfd_processes_srcu);
  
  	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
  		mutex_lock(&p->mutex);
  		pdd = kfd_get_process_device_data(kfd, p);
  
  		if (WARN_ON(!pdd) || pdd->bound != PDD_BOUND_SUSPENDED) {
  			mutex_unlock(&p->mutex);
  			continue;
  		}
  
  		err = amd_iommu_bind_pasid(kfd->pdev, p->pasid,
  				p->lead_thread);
  		if (err < 0) {
  			pr_err("Unexpected pasid 0x%x binding failure\n",
  					p->pasid);
  			mutex_unlock(&p->mutex);
  			break;
  		}
  
  		pdd->bound = PDD_BOUND;
  		mutex_unlock(&p->mutex);
  	}
  
  	srcu_read_unlock(&kfd_processes_srcu, idx);
  
  	return err;
  }
  
  /*
   * Mark currently bound processes as PDD_BOUND_SUSPENDED. These
   * processes will be restored to PDD_BOUND state in
   * kfd_bind_processes_to_device.
   */
  static void kfd_unbind_processes_from_device(struct kfd_dev *kfd)
  {
  	struct kfd_process_device *pdd;
  	struct kfd_process *p;
  	unsigned int temp;
  
  	int idx = srcu_read_lock(&kfd_processes_srcu);
  
  	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
  		mutex_lock(&p->mutex);
  		pdd = kfd_get_process_device_data(kfd, p);
  
  		if (WARN_ON(!pdd)) {
  			mutex_unlock(&p->mutex);
  			continue;
  		}
  
  		if (pdd->bound == PDD_BOUND)
  			pdd->bound = PDD_BOUND_SUSPENDED;
  		mutex_unlock(&p->mutex);
  	}
  
  	srcu_read_unlock(&kfd_processes_srcu, idx);
  }
  
  /** kfd_iommu_suspend - Prepare IOMMU for suspend
   *
   * This unbinds processes from the device and disables the IOMMU for
   * the device.
   */
  void kfd_iommu_suspend(struct kfd_dev *kfd)
  {
  	if (!kfd->use_iommu_v2)
  		return;
  
  	kfd_unbind_processes_from_device(kfd);
  
  	amd_iommu_set_invalidate_ctx_cb(kfd->pdev, NULL);
  	amd_iommu_set_invalid_ppr_cb(kfd->pdev, NULL);
  	amd_iommu_free_device(kfd->pdev);
  }
  
  /** kfd_iommu_resume - Restore IOMMU after resume
   *
   * This reinitializes the IOMMU for the device and re-binds previously
   * suspended processes to the device.
   */
  int kfd_iommu_resume(struct kfd_dev *kfd)
  {
  	unsigned int pasid_limit;
  	int err;
  
  	if (!kfd->use_iommu_v2)
  		return 0;
  
  	pasid_limit = kfd_get_pasid_limit();
  
  	err = amd_iommu_init_device(kfd->pdev, pasid_limit);
  	if (err)
  		return -ENXIO;
  
  	amd_iommu_set_invalidate_ctx_cb(kfd->pdev,
  					iommu_pasid_shutdown_callback);
  	amd_iommu_set_invalid_ppr_cb(kfd->pdev,
  				     iommu_invalid_ppr_cb);
  
  	err = kfd_bind_processes_to_device(kfd);
  	if (err) {
  		amd_iommu_set_invalidate_ctx_cb(kfd->pdev, NULL);
  		amd_iommu_set_invalid_ppr_cb(kfd->pdev, NULL);
  		amd_iommu_free_device(kfd->pdev);
  		return err;
  	}
  
  	return 0;
  }
  
  /** kfd_iommu_add_perf_counters - Add IOMMU performance counters to topology
   */
  int kfd_iommu_add_perf_counters(struct kfd_topology_device *kdev)
  {
  	struct kfd_perf_properties *props;
  
  	if (!(kdev->node_props.capability & HSA_CAP_ATS_PRESENT))
  		return 0;
  
  	if (!amd_iommu_pc_supported())
  		return 0;
  
  	props = kfd_alloc_struct(props);
  	if (!props)
  		return -ENOMEM;
  	strcpy(props->block_name, "iommu");
  	props->max_concurrent = amd_iommu_pc_get_max_banks(0) *
  		amd_iommu_pc_get_max_counters(0); /* assume one iommu */
  	list_add_tail(&props->list, &kdev->perf_props);
  
  	return 0;
  }
  
  #endif
  