From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> Introduce a memory region type that can reserve I/O space. Such regions are useful for modeling I/O that is only handled outside of QEMU, i.e. in the context of an accelerator like KVM. Any access to such a region from QEMU is a bug, but could theoretically be triggered by guest code (DMA to reserved region). So only warning about such events once, then ignore them. Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> --- memory.c | 36 ++++++++++++++++++++++++++++++++++++ memory.h | 16 ++++++++++++++++ 2 files changed, 52 insertions(+), 0 deletions(-) diff --git a/memory.c b/memory.c index 6201a37..68e5cdf 100644 --- a/memory.c +++ b/memory.c @@ -1049,6 +1049,42 @@ void memory_region_init_rom_device(MemoryRegion *mr, mr->ram_addr |= cpu_register_io_memory(mr); } +static uint64_t invalid_read(void *opaque, target_phys_addr_t addr, + unsigned size) +{ + MemoryRegion *mr = opaque; + + if (!mr->warning_printed) { + fprintf(stderr, "Invalid read from memory region %s\n", mr->name); + mr->warning_printed = true; + } + return -1U; +} + +static void invalid_write(void *opaque, target_phys_addr_t addr, uint64_t data, + unsigned size) +{ + MemoryRegion *mr = opaque; + + if (!mr->warning_printed) { + fprintf(stderr, "Invalid write to memory region %s\n", mr->name); + mr->warning_printed = true; + } +} + +static const MemoryRegionOps reservation_ops = { + .read = invalid_read, + .write = invalid_write, + .endianness = DEVICE_NATIVE_ENDIAN, +}; + +void memory_region_init_reservation(MemoryRegion *mr, + const char *name, + uint64_t size) +{ + memory_region_init_io(mr, &reservation_ops, mr, name, size); +} + void memory_region_destroy(MemoryRegion *mr) { assert(QTAILQ_EMPTY(&mr->subregions)); diff --git a/memory.h b/memory.h index d48b08b..34c69cf 100644 --- a/memory.h +++ b/memory.h @@ -126,6 +126,7 @@ struct MemoryRegion { bool readonly; /* For RAM regions */ bool enabled; bool rom_device; + bool warning_printed; /* For reservations */ MemoryRegion *alias; target_phys_addr_t alias_offset; unsigned priority; @@ -280,6 +281,21 @@ void memory_region_init_rom_device(MemoryRegion *mr, uint64_t size); /** + * memory_region_init_reservation: Initialize a memory region that reserves + * I/O space. + * + * A reservation region primariy serves debugging purposes. It claims I/O + * space that is not supposed to be handled by QEMU itself. Any access via + * the memory API will cause an abort(). + * + * @mr: the #MemoryRegion to be initialized + * @name: used for debugging; not visible to the user or ABI + * @size: size of the region. + */ +void memory_region_init_reservation(MemoryRegion *mr, + const char *name, + uint64_t size); +/** * memory_region_destroy: Destroy a memory region and reclaim all resources. * * @mr: the region to be destroyed. May not currently be a subregion -- 1.7.6.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html