// Copyright 2018 The Fuchsia Authors
//
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT

#ifndef ZIRCON_KERNEL_DEV_IOMMU_INTEL_DEVICE_CONTEXT_H_
#define ZIRCON_KERNEL_DEV_IOMMU_INTEL_DEVICE_CONTEXT_H_

#include <fbl/intrusive_double_list.h>
#include <fbl/macros.h>
#include <fbl/vector.h>
#include <ktl/unique_ptr.h>
#include <region-alloc/region-alloc.h>
#include <vm/vm_object.h>

#include "hw.h"
#include "second_level_pt.h"

namespace intel_iommu {

class IommuImpl;

class DeviceContext : public fbl::DoublyLinkedListable<ktl::unique_ptr<DeviceContext>> {
 public:
  ~DeviceContext();

  // Create a new DeviceContext representing the given BDF.  It is a fatal error
  // to try to create a context for a BDF that already has one.
  static zx_status_t Create(ds::Bdf bdf, uint32_t domain_id, IommuImpl* parent,
                            volatile ds::ExtendedContextEntry* context_entry,
                            ktl::unique_ptr<DeviceContext>* device);
  static zx_status_t Create(ds::Bdf bdf, uint32_t domain_id, IommuImpl* parent,
                            volatile ds::ContextEntry* context_entry,
                            ktl::unique_ptr<DeviceContext>* device);

  // Check if this DeviceContext is for the given BDF
  bool is_bdf(ds::Bdf bdf) const { return bdf_ == bdf; }

  uint32_t domain_id() const { return domain_id_; }

  uint64_t minimum_contiguity() const;
  uint64_t aspace_size() const;

  // Use the second-level translation table to map the host pages in the given
  // range on |vmo| to the guest's address |*virt_paddr|.  |size| is in bytes.
  // |mapped_len| may be larger than |size|, if |size| was not page-aligned.
  //
  // If |map_contiguous| is false, this function may return a partial mapping,
  // in which case |mapped_len| will indicate how many bytes were actually mapped.
  //
  // If |map_contiguous| is true, this function will never return a partial
  // mapping, and |mapped_len| should be equal to |size|.
  zx_status_t SecondLevelMap(const fbl::RefPtr<VmObject>& vmo, uint64_t offset, size_t size,
                             uint32_t perms, bool map_contiguous, paddr_t* virt_paddr,
                             size_t* mapped_len);
  zx_status_t SecondLevelUnmap(paddr_t virt_paddr, size_t size);

  // Use the second-level translation table to identity-map the given range of
  // host pages.
  zx_status_t SecondLevelMapIdentity(paddr_t base, size_t size, uint32_t perms);

  // Removes all mappings from the device context. This is only intended to be done just prior to
  // destruction as we need to perform unmapping whilst holding the parent lock.
  void SecondLevelUnmapAllLocked();

 private:
  DeviceContext(ds::Bdf bdf, uint32_t domain_id, IommuImpl* parent,
                volatile ds::ExtendedContextEntry* context_entry);
  DeviceContext(ds::Bdf bdf, uint32_t domain_id, IommuImpl* parent,
                volatile ds::ContextEntry* context_entry);

  DISALLOW_COPY_ASSIGN_AND_MOVE(DeviceContext);

  // Shared initialization code for the two public Create() methods
  zx_status_t InitCommon();

  // Map a VMO which may consist of discontiguous physical pages. If
  // |map_contiguous| is true, this must either map the whole requested range
  // contiguously, or fail. If |map_contiguous| is false, it may return
  // success with a partial mapping.
  zx_status_t SecondLevelMapDiscontiguous(const fbl::RefPtr<VmObject>& vmo, uint64_t offset,
                                          size_t size, uint flags, bool map_contiguous,
                                          paddr_t* virt_paddr, size_t* mapped_len);

  // Map a VMO which consists of contiguous physical pages. Currently we assume
  // that all contiguous VMOs should be mapped as a contiguous range, so this
  // function will not return a partial mapping.
  zx_status_t SecondLevelMapContiguous(const fbl::RefPtr<VmObject>& vmo, uint64_t offset,
                                       size_t size, uint flags, paddr_t* virt_paddr,
                                       size_t* mapped_len);

  IommuImpl* const parent_;
  union {
    volatile ds::ExtendedContextEntry* const extended_context_entry_;
    volatile ds::ContextEntry* const context_entry_;
  };

  // Page tables used for translating requests-without-PASID and for nested
  // translation of requests-with-PASID.
  SecondLevelPageTable second_level_pt_;
  RegionAllocator region_alloc_;
  // TODO(fxbug.dev/33017) Use a better data structure for these.  If the
  // region nodes were intrusive, we wouldn't need to have a
  // resizable array for this and we could have cheaper removal.  We
  // can fix this up when it's a problem though.
  //
  fbl::Vector<RegionAllocator::Region::UPtr> allocated_regions_;

  const ds::Bdf bdf_;
  const bool extended_;
  const uint32_t domain_id_;
};

}  // namespace intel_iommu

#endif  // ZIRCON_KERNEL_DEV_IOMMU_INTEL_DEVICE_CONTEXT_H_