diff options
| -rw-r--r-- | MAINTAINERS | 1 | ||||
| -rw-r--r-- | hw/mem/meson.build | 1 | ||||
| -rw-r--r-- | hw/mem/sparse-mem.c | 151 | ||||
| -rw-r--r-- | include/hw/mem/sparse-mem.h | 19 |
4 files changed, 172 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 0bd720a3d6..2a925e76ea 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2636,6 +2636,7 @@ S: Maintained F: tests/qtest/fuzz/ F: tests/qtest/fuzz-*test.c F: scripts/oss-fuzz/ +F: hw/mem/sparse-mem.c F: docs/devel/fuzzing.rst Register API diff --git a/hw/mem/meson.build b/hw/mem/meson.build index 0d22f2b572..ef79e04678 100644 --- a/hw/mem/meson.build +++ b/hw/mem/meson.build @@ -1,5 +1,6 @@ mem_ss = ss.source_set() mem_ss.add(files('memory-device.c')) +mem_ss.add(when: 'CONFIG_FUZZ', if_true: files('sparse-mem.c')) mem_ss.add(when: 'CONFIG_DIMM', if_true: files('pc-dimm.c')) mem_ss.add(when: 'CONFIG_NPCM7XX', if_true: files('npcm7xx_mc.c')) mem_ss.add(when: 'CONFIG_NVDIMM', if_true: files('nvdimm.c')) diff --git a/hw/mem/sparse-mem.c b/hw/mem/sparse-mem.c new file mode 100644 index 0000000000..a13ac74dd9 --- /dev/null +++ b/hw/mem/sparse-mem.c @@ -0,0 +1,151 @@ +/* + * A sparse memory device. Useful for fuzzing + * + * Copyright Red Hat Inc., 2021 + * + * Authors: + * Alexander Bulekov <alxndr@bu.edu> + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" + +#include "exec/address-spaces.h" +#include "hw/qdev-properties.h" +#include "hw/sysbus.h" +#include "qapi/error.h" +#include "qemu/units.h" +#include "sysemu/qtest.h" +#include "hw/mem/sparse-mem.h" + +#define SPARSE_MEM(obj) OBJECT_CHECK(SparseMemState, (obj), TYPE_SPARSE_MEM) +#define SPARSE_BLOCK_SIZE 0x1000 + +typedef struct SparseMemState { + SysBusDevice parent_obj; + MemoryRegion mmio; + uint64_t baseaddr; + uint64_t length; + uint64_t size_used; + uint64_t maxsize; + GHashTable *mapped; +} SparseMemState; + +typedef struct sparse_mem_block { + uint8_t data[SPARSE_BLOCK_SIZE]; +} sparse_mem_block; + +static uint64_t sparse_mem_read(void *opaque, hwaddr addr, unsigned int size) +{ + SparseMemState *s = opaque; + uint64_t ret = 0; + size_t pfn = addr / SPARSE_BLOCK_SIZE; + size_t offset = addr % SPARSE_BLOCK_SIZE; + sparse_mem_block *block; + + block = g_hash_table_lookup(s->mapped, (void *)pfn); + if (block) { + assert(offset + size <= sizeof(block->data)); + memcpy(&ret, block->data + offset, size); + } + return ret; +} + +static void sparse_mem_write(void *opaque, hwaddr addr, uint64_t v, + unsigned int size) +{ + SparseMemState *s = opaque; + size_t pfn = addr / SPARSE_BLOCK_SIZE; + size_t offset = addr % SPARSE_BLOCK_SIZE; + sparse_mem_block *block; + + if (!g_hash_table_lookup(s->mapped, (void *)pfn) && + s->size_used + SPARSE_BLOCK_SIZE < s->maxsize && v) { + g_hash_table_insert(s->mapped, (void *)pfn, + g_new0(sparse_mem_block, 1)); + s->size_used += sizeof(block->data); + } + block = g_hash_table_lookup(s->mapped, (void *)pfn); + if (!block) { + return; + } + + assert(offset + size <= sizeof(block->data)); + + memcpy(block->data + offset, &v, size); + +} + +static const MemoryRegionOps sparse_mem_ops = { + .read = sparse_mem_read, + .write = sparse_mem_write, + .endianness = DEVICE_LITTLE_ENDIAN, + .valid = { + .min_access_size = 1, + .max_access_size = 8, + .unaligned = false, + }, +}; + +static Property sparse_mem_properties[] = { + /* The base address of the memory */ + DEFINE_PROP_UINT64("baseaddr", SparseMemState, baseaddr, 0x0), + /* The length of the sparse memory region */ + DEFINE_PROP_UINT64("length", SparseMemState, length, UINT64_MAX), + /* Max amount of actual memory that can be used to back the sparse memory */ + DEFINE_PROP_UINT64("maxsize", SparseMemState, maxsize, 10 * MiB), + DEFINE_PROP_END_OF_LIST(), +}; + +MemoryRegion *sparse_mem_init(uint64_t addr, uint64_t length) +{ + DeviceState *dev; + + dev = qdev_new(TYPE_SPARSE_MEM); + qdev_prop_set_uint64(dev, "baseaddr", addr); + qdev_prop_set_uint64(dev, "length", length); + sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal); + sysbus_mmio_map_overlap(SYS_BUS_DEVICE(dev), 0, addr, -10000); + return &SPARSE_MEM(dev)->mmio; +} + +static void sparse_mem_realize(DeviceState *dev, Error **errp) +{ + SparseMemState *s = SPARSE_MEM(dev); + SysBusDevice *sbd = SYS_BUS_DEVICE(dev); + + if (!qtest_enabled()) { + error_setg(errp, "sparse_mem device should only be used " + "for testing with QTest"); + return; + } + + assert(s->baseaddr + s->length > s->baseaddr); + + s->mapped = g_hash_table_new(NULL, NULL); + memory_region_init_io(&s->mmio, OBJECT(s), &sparse_mem_ops, s, + "sparse-mem", s->length); + sysbus_init_mmio(sbd, &s->mmio); +} + +static void sparse_mem_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + device_class_set_props(dc, sparse_mem_properties); + + dc->desc = "Sparse Memory Device"; + dc->realize = sparse_mem_realize; +} + +static const TypeInfo sparse_mem_types[] = { + { + .name = TYPE_SPARSE_MEM, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(SparseMemState), + .class_init = sparse_mem_class_init, + }, +}; +DEFINE_TYPES(sparse_mem_types); diff --git a/include/hw/mem/sparse-mem.h b/include/hw/mem/sparse-mem.h new file mode 100644 index 0000000000..f9863b154b --- /dev/null +++ b/include/hw/mem/sparse-mem.h @@ -0,0 +1,19 @@ +/* + * A sparse memory device. Useful for fuzzing + * + * Copyright Red Hat Inc., 2021 + * + * Authors: + * Alexander Bulekov <alxndr@bu.edu> + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#ifndef SPARSE_MEM_H +#define SPARSE_MEM_H +#define TYPE_SPARSE_MEM "sparse-mem" + +MemoryRegion *sparse_mem_init(uint64_t addr, uint64_t length); + +#endif |