[PULL v1 2/3] hw/tpm: gate PPI support on tpm-tis-device behind a device property

[Stefan Berger <stefanb@linux.ibm.com>]

From: Mohammadfaiz Bawa <mbawa@redhat.com>

Add a "ppi" boolean property (default: true) to tpm-tis-device.
When ppi=off the RAMBlock is never registered and the migration
stream omits "tpm-ppi", restoring backward compatibility.

Move sysbus_init_mmio() calls from instance_init to realizefn so
the memory regions are initialized before being registered.  When
ppi=off, the PPI MMIO region is simply not exposed.

Fixes: 46cd2c1050f0 ("hw/tpm: add PPI support to tpm-tis-device for ARM64 virt")
Signed-off-by: Mohammadfaiz Bawa <mbawa@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20260619093140.832136-3-mbawa@redhat.com
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
 hw/tpm/tpm_tis.h        |  1 +
 hw/tpm/tpm_tis_sysbus.c | 18 +++++++++++-------
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/hw/tpm/tpm_tis.h b/hw/tpm/tpm_tis.h
index 1531620bf9..6ac9804050 100644
--- a/hw/tpm/tpm_tis.h
+++ b/hw/tpm/tpm_tis.h
@@ -76,6 +76,7 @@ typedef struct TPMState {
     size_t be_buffer_size;
 
     TPMPPI ppi;
+    bool ppi_enabled;
 } TPMState;
 
 extern const VMStateDescription vmstate_locty;
diff --git a/hw/tpm/tpm_tis_sysbus.c b/hw/tpm/tpm_tis_sysbus.c
index 16bb17874b..a7b0002d82 100644
--- a/hw/tpm/tpm_tis_sysbus.c
+++ b/hw/tpm/tpm_tis_sysbus.c
@@ -94,6 +94,7 @@ static void tpm_tis_sysbus_reset(DeviceState *dev)
 static const Property tpm_tis_sysbus_properties[] = {
     DEFINE_PROP_UINT32("irq", TPMStateSysBus, state.irq_num, TPM_TIS_IRQ),
     DEFINE_PROP_TPMBE("tpmdev", TPMStateSysBus, state.be_driver),
+    DEFINE_PROP_BOOL("ppi", TPMStateSysBus, state.ppi_enabled, true),
 };
 
 static void tpm_tis_sysbus_initfn(Object *obj)
@@ -101,9 +102,7 @@ static void tpm_tis_sysbus_initfn(Object *obj)
     TPMStateSysBus *sbdev = TPM_TIS_SYSBUS(obj);
     TPMState *s = &sbdev->state;
 
-    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
     sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);
-    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->ppi.ram);
 }
 
 static void tpm_tis_sysbus_realizefn(DeviceState *dev, Error **errp)
@@ -122,14 +121,19 @@ static void tpm_tis_sysbus_realizefn(DeviceState *dev, Error **errp)
         return;
     }
 
-    s->ppi.buf = qemu_memalign(host_page_size,
-                               ROUND_UP(TPM_PPI_ADDR_SIZE, host_page_size));
     memory_region_init_io(&s->mmio, OBJECT(dev), &tpm_tis_memory_ops,
                           s, "tpm-tis-mmio",
                           TPM_TIS_NUM_LOCALITIES << TPM_TIS_LOCALITY_SHIFT);
-    memory_region_init_ram_device_ptr(&s->ppi.ram, OBJECT(dev), "tpm-ppi",
-                                      TPM_PPI_ADDR_SIZE, s->ppi.buf);
-    vmstate_register_ram(&s->ppi.ram, dev);
+    sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->mmio);
+
+    if (s->ppi_enabled) {
+        s->ppi.buf = qemu_memalign(host_page_size,
+                                   ROUND_UP(TPM_PPI_ADDR_SIZE, host_page_size));
+        memory_region_init_ram_device_ptr(&s->ppi.ram, OBJECT(dev), "tpm-ppi",
+                                          TPM_PPI_ADDR_SIZE, s->ppi.buf);
+        sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->ppi.ram);
+        vmstate_register_ram(&s->ppi.ram, dev);
+    }
 }
 
 static void tpm_tis_sysbus_class_init(ObjectClass *klass, const void *data)
-- 
2.55.0