exec: allow to get a pointer for some mmio memory region

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When the pointer or the data in it are no longer valid the device has to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.

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
This commit is contained in:
KONRAD Frederic 2016-10-19 15:06:49 +02:00 committed by Edgar E. Iglesias
parent 7cc2298c46
commit c935674635
3 changed files with 156 additions and 0 deletions

View file

@ -858,6 +858,16 @@ tb_page_addr_t get_page_addr_code(CPUArchState *env, target_ulong addr)
pd = iotlbentry->addr & ~TARGET_PAGE_MASK;
mr = iotlb_to_region(cpu, pd, iotlbentry->attrs);
if (memory_region_is_unassigned(mr)) {
qemu_mutex_lock_iothread();
if (memory_region_request_mmio_ptr(mr, addr)) {
qemu_mutex_unlock_iothread();
/* A MemoryRegion is potentially added so re-run the
* get_page_addr_code.
*/
return get_page_addr_code(env, addr);
}
qemu_mutex_unlock_iothread();
cpu_unassigned_access(cpu, addr, false, true, 0, 4);
/* The CPU's unassigned access hook might have longjumped out
* with an exception. If it didn't (or there was no hook) then

View file

@ -137,6 +137,15 @@ 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: */
@ -1362,6 +1371,32 @@ 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.

111
memory.c
View file

@ -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
@ -2430,6 +2432,115 @@ void memory_listener_unregister(MemoryListener *listener)
listener->address_space = NULL;
}
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;
}
typedef struct MMIOPtrInvalidate {
MemoryRegion *mr;
hwaddr offset;
unsigned size;
int busy;
int allocated;
} MMIOPtrInvalidate;
#define MAX_MMIO_INVALIDATE 10
static MMIOPtrInvalidate mmio_ptr_invalidate_list[MAX_MMIO_INVALIDATE];
static void memory_region_do_invalidate_mmio_ptr(CPUState *cpu,
run_on_cpu_data data)
{
MMIOPtrInvalidate *invalidate_data = (MMIOPtrInvalidate *)data.host_ptr;
MemoryRegion *mr = invalidate_data->mr;
hwaddr offset = invalidate_data->offset;
unsigned size = invalidate_data->size;
MemoryRegionSection section = memory_region_find(mr, offset, size);
qemu_mutex_lock_iothread();
/* Reset dirty so this doesn't happen later. */
cpu_physical_memory_test_and_clear_dirty(offset, size, 1);
if (section.mr != mr) {
/* memory_region_find add a ref on section.mr */
memory_region_unref(section.mr);
if (MMIO_INTERFACE(section.mr->owner)) {
/* 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);
}
}
qemu_mutex_unlock_iothread();
if (invalidate_data->allocated) {
g_free(invalidate_data);
} else {
invalidate_data->busy = 0;
}
}
void memory_region_invalidate_mmio_ptr(MemoryRegion *mr, hwaddr offset,
unsigned size)
{
size_t i;
MMIOPtrInvalidate *invalidate_data = NULL;
for (i = 0; i < MAX_MMIO_INVALIDATE; i++) {
if (atomic_cmpxchg(&(mmio_ptr_invalidate_list[i].busy), 0, 1) == 0) {
invalidate_data = &mmio_ptr_invalidate_list[i];
break;
}
}
if (!invalidate_data) {
invalidate_data = g_malloc0(sizeof(MMIOPtrInvalidate));
invalidate_data->allocated = 1;
}
invalidate_data->mr = mr;
invalidate_data->offset = offset;
invalidate_data->size = size;
async_safe_run_on_cpu(first_cpu, memory_region_do_invalidate_mmio_ptr,
RUN_ON_CPU_HOST_PTR(invalidate_data));
}
void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name)
{
memory_region_ref(root);