Cody Schuffelen | 134ff03 | 2019-11-22 00:25:32 -0800 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2018 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include "host/commands/run_cvd/vsoc_shared_memory.h" |
| 18 | |
| 19 | #include <unistd.h> |
| 20 | |
| 21 | #include <map> |
| 22 | #include <vector> |
| 23 | |
| 24 | #include "common/libs/fs/shared_fd.h" |
| 25 | #include "common/libs/utils/size_utils.h" |
| 26 | #include "common/vsoc/lib/vsoc_memory.h" |
| 27 | #include "glog/logging.h" |
| 28 | |
| 29 | #include "uapi/vsoc_shm.h" |
| 30 | |
| 31 | namespace vsoc { |
| 32 | |
| 33 | namespace { |
| 34 | |
| 35 | uint32_t OffsetOfRegionData(const VSoCRegionLayout& layout) { |
| 36 | uint32_t offset = 0; |
| 37 | // Signal tables |
| 38 | offset += |
| 39 | (1 << layout.guest_to_host_signal_table_log_size()) * sizeof(uint32_t); |
| 40 | offset += |
| 41 | (1 << layout.host_to_guest_signal_table_log_size()) * sizeof(uint32_t); |
| 42 | // Interrup signals |
| 43 | offset += 2 * sizeof(uint32_t); |
| 44 | return offset; |
| 45 | } |
| 46 | |
| 47 | struct VSoCRegionAllocator { |
| 48 | const VSoCRegionLayout* region_layout; |
| 49 | uint32_t begin_offset; |
| 50 | uint32_t region_size; |
| 51 | |
| 52 | VSoCRegionAllocator(const VSoCRegionLayout& layout, uint32_t offset, |
| 53 | uint32_t requested_layout_increase = 0) |
| 54 | : region_layout(&layout), |
| 55 | begin_offset(offset), |
| 56 | region_size(cvd::AlignToPageSize(OffsetOfRegionData(layout) + |
| 57 | layout.layout_size() + |
| 58 | requested_layout_increase)) {} |
| 59 | }; |
| 60 | |
| 61 | // Writes a region's signal table layout to shared memory. Returns the region |
| 62 | // offset of free memory after the table and interrupt signaled word. |
| 63 | uint32_t WriteSignalTableDescription(vsoc_signal_table_layout* layout, |
| 64 | uint32_t offset, int log_size) { |
| 65 | layout->num_nodes_lg2 = log_size; |
| 66 | // First the signal table |
| 67 | layout->futex_uaddr_table_offset = offset; |
| 68 | offset += (1 << log_size) * sizeof(uint32_t); |
| 69 | // Then the interrupt signaled word |
| 70 | layout->interrupt_signalled_offset = offset; |
| 71 | offset += sizeof(uint32_t); |
| 72 | return offset; |
| 73 | } |
| 74 | |
| 75 | // Writes a region's layout description to shared memory |
| 76 | void WriteRegionDescription(vsoc_device_region* shmem_region_desc, |
| 77 | const VSoCRegionAllocator& allocator) { |
| 78 | // Region versions are deprecated, write some sensible value |
| 79 | shmem_region_desc->current_version = 0; |
| 80 | shmem_region_desc->min_compatible_version = 0; |
| 81 | |
| 82 | shmem_region_desc->region_begin_offset = allocator.begin_offset; |
| 83 | shmem_region_desc->region_end_offset = |
| 84 | allocator.begin_offset + allocator.region_size; |
| 85 | shmem_region_desc->offset_of_region_data = |
| 86 | OffsetOfRegionData(*allocator.region_layout); |
| 87 | strncpy(shmem_region_desc->device_name, |
| 88 | allocator.region_layout->region_name(), VSOC_DEVICE_NAME_SZ - 1); |
| 89 | shmem_region_desc->device_name[VSOC_DEVICE_NAME_SZ - 1] = '\0'; |
| 90 | // Guest to host signal table at the beginning of the region |
| 91 | uint32_t offset = 0; |
| 92 | offset = WriteSignalTableDescription( |
| 93 | &shmem_region_desc->guest_to_host_signal_table, offset, |
| 94 | allocator.region_layout->guest_to_host_signal_table_log_size()); |
| 95 | // Host to guest signal table right after |
| 96 | offset = WriteSignalTableDescription( |
| 97 | &shmem_region_desc->host_to_guest_signal_table, offset, |
| 98 | allocator.region_layout->host_to_guest_signal_table_log_size()); |
| 99 | // Double check that the region metadata does not collide with the data |
| 100 | if (offset > shmem_region_desc->offset_of_region_data) { |
| 101 | LOG(FATAL) << "Error: Offset of region data too small (is " |
| 102 | << shmem_region_desc->offset_of_region_data << " should be " |
| 103 | << offset << " ) for region " |
| 104 | << allocator.region_layout->region_name() << ". This is a bug"; |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | void WriteLayout(void* shared_memory, |
| 109 | const std::vector<VSoCRegionAllocator>& allocators, |
| 110 | uint32_t file_size) { |
| 111 | // Device header |
| 112 | static_assert(CURRENT_VSOC_LAYOUT_MAJOR_VERSION == 2, |
| 113 | "Region layout code must be updated"); |
| 114 | auto header = reinterpret_cast<vsoc_shm_layout_descriptor*>(shared_memory); |
| 115 | header->major_version = CURRENT_VSOC_LAYOUT_MAJOR_VERSION; |
| 116 | header->minor_version = CURRENT_VSOC_LAYOUT_MINOR_VERSION; |
| 117 | header->size = file_size; |
| 118 | header->region_count = allocators.size(); |
| 119 | |
| 120 | std::map<std::string, size_t> region_idx_by_name; |
| 121 | for (size_t idx = 0; idx < allocators.size(); ++idx) { |
| 122 | region_idx_by_name[allocators[idx].region_layout->region_name()] = idx; |
| 123 | } |
| 124 | |
| 125 | // Region descriptions go right after the layout descriptor |
| 126 | header->vsoc_region_desc_offset = sizeof(vsoc_shm_layout_descriptor); |
| 127 | auto region_descriptions = reinterpret_cast<vsoc_device_region*>(header + 1); |
| 128 | for (size_t idx = 0; idx < allocators.size(); ++idx) { |
| 129 | auto shmem_region_desc = ®ion_descriptions[idx]; |
| 130 | const auto& region = *allocators[idx].region_layout; |
| 131 | WriteRegionDescription(shmem_region_desc, allocators[idx]); |
| 132 | // Handle managed_by links |
| 133 | if (region.managed_by()) { |
| 134 | auto manager_idx = region_idx_by_name.at(region.managed_by()); |
| 135 | if (manager_idx == VSOC_REGION_WHOLE) { |
| 136 | LOG(FATAL) << "Region '" << region.region_name() << "' has owner " |
| 137 | << region.managed_by() << " with index " << manager_idx |
| 138 | << " which is the default value for regions without an " |
| 139 | "owner. Choose a different region to be at index " |
| 140 | << manager_idx |
| 141 | << ", make sure the chosen region is NOT the owner of any " |
| 142 | "other region"; |
| 143 | } |
| 144 | shmem_region_desc->managed_by = manager_idx; |
| 145 | } else { |
| 146 | shmem_region_desc->managed_by = VSOC_REGION_WHOLE; |
| 147 | } |
| 148 | } |
| 149 | } |
| 150 | } // namespace |
| 151 | |
| 152 | void CreateSharedMemoryFile( |
| 153 | const std::string& path, |
| 154 | const std::map<std::string, uint32_t>& layout_increases) { |
| 155 | // TODO(ender): Lock the file after creation and check lock status upon second |
| 156 | // execution attempt instead of throwing an error. |
| 157 | LOG_IF(WARNING, unlink(path.c_str()) == 0) |
| 158 | << "Removed existing instance of " << path |
| 159 | << ". We currently don't know if another instance of daemon is running"; |
| 160 | auto shared_mem_fd = cvd::SharedFD::Open( |
| 161 | path.c_str(), O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR); |
| 162 | LOG_IF(FATAL, !shared_mem_fd->IsOpen()) |
| 163 | << "Error in creating shared_memory file: " << shared_mem_fd->StrError(); |
| 164 | |
| 165 | auto region_layouts = VSoCMemoryLayout::Get()->GetRegions(); |
| 166 | std::vector<VSoCRegionAllocator> allocators; |
| 167 | uint32_t file_size = |
| 168 | cvd::AlignToPageSize(sizeof(vsoc_shm_layout_descriptor) + |
| 169 | region_layouts.size() * sizeof(vsoc_device_region)); |
| 170 | for (auto layout : region_layouts) { |
| 171 | allocators.emplace_back(*layout, file_size /* offset */, |
| 172 | layout_increases.count(layout->region_name()) |
| 173 | ? layout_increases.at(layout->region_name()) |
| 174 | : 0); |
| 175 | file_size += allocators.back().region_size; |
| 176 | } |
| 177 | file_size = cvd::RoundUpToNextPowerOf2(file_size); |
| 178 | |
| 179 | int truncate_res = shared_mem_fd->Truncate(file_size); |
| 180 | LOG_IF(FATAL, truncate_res == -1) |
| 181 | << "Error in sizing up the shared memory file: " |
| 182 | << shared_mem_fd->StrError(); |
| 183 | |
| 184 | void* mmap_addr = |
| 185 | shared_mem_fd->Mmap(0, file_size, PROT_READ | PROT_WRITE, MAP_SHARED, 0); |
| 186 | LOG_IF(FATAL, mmap_addr == MAP_FAILED) |
| 187 | << "Error mmaping file: " << strerror(errno); |
| 188 | WriteLayout(mmap_addr, allocators, file_size); |
| 189 | munmap(mmap_addr, file_size); |
| 190 | } |
| 191 | |
| 192 | } // namespace vsoc |