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-rw-r--r--include/hw/boards.h11
-rw-r--r--include/qom/cpu.h7
-rw-r--r--qom/cpu.c16
3 files changed, 33 insertions, 1 deletions
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 3363dd19fd..7f044d101d 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -131,6 +131,16 @@ typedef struct {
* size than the target architecture's minimum. (Attempting to create
* such a CPU will fail.) Note that changing this is a migration
* compatibility break for the machine.
+ * @ignore_memory_transaction_failures:
+ * If this is flag is true then the CPU will ignore memory transaction
+ * failures which should cause the CPU to take an exception due to an
+ * access to an unassigned physical address; the transaction will instead
+ * return zero (for a read) or be ignored (for a write). This should be
+ * set only by legacy board models which rely on the old RAZ/WI behaviour
+ * for handling devices that QEMU does not yet model. New board models
+ * should instead use "unimplemented-device" for all memory ranges where
+ * the guest will attempt to probe for a device that QEMU doesn't
+ * implement and a stub device is required.
*/
struct MachineClass {
/*< private >*/
@@ -171,6 +181,7 @@ struct MachineClass {
bool rom_file_has_mr;
int minimum_page_bits;
bool has_hotpluggable_cpus;
+ bool ignore_memory_transaction_failures;
int numa_mem_align_shift;
void (*numa_auto_assign_ram)(MachineClass *mc, NodeInfo *nodes,
int nb_nodes, ram_addr_t size);
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 08bd868ce4..995a7beeb5 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -312,6 +312,9 @@ struct qemu_work_item;
* @trace_dstate_delayed: Delayed changes to trace_dstate (includes all changes
* to @trace_dstate).
* @trace_dstate: Dynamic tracing state of events for this vCPU (bitmask).
+ * @ignore_memory_transaction_failures: Cached copy of the MachineState
+ * flag of the same name: allows the board to suppress calling of the
+ * CPU do_transaction_failed hook function.
*
* State of one CPU core or thread.
*/
@@ -398,6 +401,8 @@ struct CPUState {
*/
bool throttle_thread_scheduled;
+ bool ignore_memory_transaction_failures;
+
/* Note that this is accessed at the start of every TB via a negative
offset from AREG0. Leave this field at the end so as to make the
(absolute value) offset as small as possible. This reduces code
@@ -864,7 +869,7 @@ static inline void cpu_transaction_failed(CPUState *cpu, hwaddr physaddr,
{
CPUClass *cc = CPU_GET_CLASS(cpu);
- if (cc->do_transaction_failed) {
+ if (!cpu->ignore_memory_transaction_failures && cc->do_transaction_failed) {
cc->do_transaction_failed(cpu, physaddr, addr, size, access_type,
mmu_idx, attrs, response, retaddr);
}
diff --git a/qom/cpu.c b/qom/cpu.c
index deb8880930..dc5392dbeb 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -29,6 +29,7 @@
#include "exec/cpu-common.h"
#include "qemu/error-report.h"
#include "sysemu/sysemu.h"
+#include "hw/boards.h"
#include "hw/qdev-properties.h"
#include "trace-root.h"
@@ -363,6 +364,21 @@ static void cpu_common_parse_features(const char *typename, char *features,
static void cpu_common_realizefn(DeviceState *dev, Error **errp)
{
CPUState *cpu = CPU(dev);
+ Object *machine = qdev_get_machine();
+
+ /* qdev_get_machine() can return something that's not TYPE_MACHINE
+ * if this is one of the user-only emulators; in that case there's
+ * no need to check the ignore_memory_transaction_failures board flag.
+ */
+ if (object_dynamic_cast(machine, TYPE_MACHINE)) {
+ ObjectClass *oc = object_get_class(machine);
+ MachineClass *mc = MACHINE_CLASS(oc);
+
+ if (mc) {
+ cpu->ignore_memory_transaction_failures =
+ mc->ignore_memory_transaction_failures;
+ }
+ }
if (dev->hotplugged) {
cpu_synchronize_post_init(cpu);