From: KONRAD Frederic <fred.kon...@greensocs.com>
This introduces a special callback which allows to run code from some MMIO
devices.
SysBusDevice with a MemoryRegion which implements the request_ptr callback will
be notified when the guest try to execute code from their offset. Then it will
be able to eg: pre-load some code from an SPI device or ask a pointer from an
external simulator, etc..
When the pointer or the data in it are no longer valid the device has to
invalidate it.
Signed-off-by: KONRAD Frederic <fred.kon...@greensocs.com>
RFC -> V1:
* Use mmio-interface instead of directly creating the subregion.
---
cputlb.c | 7 +++++++
include/exec/memory.h | 35 +++++++++++++++++++++++++++++++
memory.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 99 insertions(+)
diff --git a/cputlb.c b/cputlb.c
index 846341e..9077247 100644
--- a/cputlb.c
+++ b/cputlb.c
@@ -545,6 +545,13 @@ tb_page_addr_t get_page_addr_code(CPUArchState *env,
target_ulong addr)
if (memory_region_is_unassigned(mr)) {
CPUClass *cc = CPU_GET_CLASS(cpu);
+ if (memory_region_request_mmio_ptr(mr, addr)) {
+ /* A MemoryRegion is potentially added so re-run the
+ * get_page_addr_code.
+ */
+ return get_page_addr_code(env, addr);
+ }
+
if (cc->do_unassigned_access) {
cc->do_unassigned_access(cpu, addr, false, true, 0, 4);
} else {
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 987f925..36b0eec 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -120,6 +120,15 @@ struct MemoryRegionOps {
uint64_t data,
unsigned size,
MemTxAttrs attrs);
+ /* Instruction execution pre-callback:
+ * @addr is the address of the access relative to the @mr.
+ * @size is the size of the area returned by the callback.
+ * @offset is the location of the pointer inside @mr.
+ *
+ * Returns a pointer to a location which contains guest code.
+ */
+ void *(*request_ptr)(void *opaque, hwaddr addr, unsigned *size,
+ unsigned *offset);
enum device_endian endianness;
/* Guest-visible constraints: */
@@ -1253,6 +1262,32 @@ void memory_global_dirty_log_stop(void);
void mtree_info(fprintf_function mon_printf, void *f, bool flatview);
/**
+ * memory_region_request_mmio_ptr: request a pointer to an mmio
+ * MemoryRegion. If it is possible map a RAM MemoryRegion with this pointer.
+ * When the device wants to invalidate the pointer it will call
+ * memory_region_invalidate_mmio_ptr.
+ *
+ * @mr: #MemoryRegion to check
+ * @addr: address within that region
+ *
+ * Returns true on success, false otherwise.
+ */
+bool memory_region_request_mmio_ptr(MemoryRegion *mr, hwaddr addr);
+
+/**
+ * memory_region_invalidate_mmio_ptr: invalidate the pointer to an mmio
+ * previously requested.
+ * In the end that means that if something wants to execute from this area it
+ * will need to request the pointer again.
+ *
+ * @mr: #MemoryRegion associated to the pointer.
+ * @addr: address within that region
+ * @size: size of that area.
+ */
+void memory_region_invalidate_mmio_ptr(MemoryRegion *mr, hwaddr offset,
+ unsigned size);
+
+/**
* memory_region_dispatch_read: perform a read directly to the specified
* MemoryRegion.
*
diff --git a/memory.c b/memory.c
index 6c58373..a605250 100644
--- a/memory.c
+++ b/memory.c
@@ -30,6 +30,8 @@
#include "exec/ram_addr.h"
#include "sysemu/kvm.h"
#include "sysemu/sysemu.h"
+#include "hw/misc/mmio_interface.h"
+#include "hw/qdev-properties.h"
//#define DEBUG_UNASSIGNED
@@ -2375,6 +2377,61 @@ void memory_listener_unregister(MemoryListener *listener)
QTAILQ_REMOVE(&listener->address_space->listeners, listener, link_as);
}
+bool memory_region_request_mmio_ptr(MemoryRegion *mr, hwaddr addr)
+{
+ void *host;
+ unsigned size = 0;
+ unsigned offset = 0;
+ Object *new_interface;
+
+ if (!mr || !mr->ops->request_ptr) {
+ return false;
+ }
+
+ /*
+ * Avoid an update if the request_ptr call
+ * memory_region_invalidate_mmio_ptr which seems to be likely when we use
+ * a cache.
+ */
+ memory_region_transaction_begin();
+
+ host = mr->ops->request_ptr(mr->opaque, addr - mr->addr, &size, &offset);
+
+ if (!host || !size) {
+ memory_region_transaction_commit();
+ return false;
+ }
+
+ new_interface = object_new("mmio_interface");
+ qdev_prop_set_uint64(DEVICE(new_interface), "start", offset);
+ qdev_prop_set_uint64(DEVICE(new_interface), "end", offset + size - 1);
+ qdev_prop_set_bit(DEVICE(new_interface), "ro", true);
+ qdev_prop_set_ptr(DEVICE(new_interface), "host_ptr", host);
+ qdev_prop_set_ptr(DEVICE(new_interface), "subregion", mr);
+ object_property_set_bool(OBJECT(new_interface), true, "realized", NULL);
+
+ memory_region_transaction_commit();
+ return true;
+}
+
+void memory_region_invalidate_mmio_ptr(MemoryRegion *mr, hwaddr offset,
+ unsigned size)
+{
+ MemoryRegionSection section = memory_region_find(mr, offset, size);
+
+ if (section.mr != mr) {
+ /* memory_region_find add a ref on section.mr */
+ memory_region_unref(section.mr);
+ if (!MMIO_INTERFACE(section.mr->owner)) {
+ return;
+ }
+ /* We found the interface just drop it. */
+ object_property_set_bool(section.mr->owner, false, "realized", NULL);
+ object_unref(section.mr->owner);
+ object_unparent(section.mr->owner);
+ }
+}
+
void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name)
{
memory_region_ref(root);
--
1.8.3.1
