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 a7e615a..30eb1b9 100644
--- a/memory.c
+++ b/memory.c
@@ -1049,6 +1049,42 @@ void memory_region_init_rom_device(MemoryRegion *mr,
mr->backend_registered = true;
}
+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 fe643ff..4b5645f 100644
--- a/memory.h
+++ b/memory.h
@@ -124,6 +124,7 @@ struct MemoryRegion {
bool readable;
bool readonly; /* For RAM regions */
bool enabled;
+ bool warning_printed; /* For reservations */
MemoryRegion *alias;
target_phys_addr_t alias_offset;
unsigned priority;
@@ -251,6 +252,21 @@ 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
--
1.7.3.4
--
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
