hw/riscv: Enable TPM backends

Imply the TPM sysbus devices. This allows users to add TPM devices to
the RISC-V virt board.

This was tested by first creating an emulated TPM device:

    swtpm socket --tpm2 -t -d --tpmstate dir=/tmp/tpm \
        --ctrl type=unixio,path=swtpm-sock

Then launching QEMU with:

    -chardev socket,id=chrtpm,path=swtpm-sock \
    -tpmdev emulator,id=tpm0,chardev=chrtpm \
    -device tpm-tis-device,tpmdev=tpm0

The TPM device can be seen in the memory tree and the generated device
tree.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/942
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-Id: <20220427234146.1130752-7-alistair.francis@opensource.wdc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

2 files changed, 5 insertions, 0 deletions

diff --git a/hw/riscv/Kconfig b/hw/riscv/Kconfig
index da790f5936..79ff61c464 100644
--- a/hw/riscv/Kconfig
+++ b/hw/riscv/Kconfig
@@ -34,6 +34,7 @@ config RISCV_VIRT
     imply PCI_DEVICES
     imply VIRTIO_VGA
     imply TEST_DEVICES
+    imply TPM_TIS_SYSBUS
     select RISCV_NUMA
     select GOLDFISH_RTC
     select MSI_NONBROKEN
diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
index 035c6fb581..3326f4db96 100644
--- a/hw/riscv/virt.c
+++ b/hw/riscv/virt.c
@@ -43,6 +43,7 @@
 #include "sysemu/device_tree.h"
 #include "sysemu/sysemu.h"
 #include "sysemu/kvm.h"
+#include "sysemu/tpm.h"
 #include "hw/pci/pci.h"
 #include "hw/pci-host/gpex.h"
 #include "hw/display/ramfb.h"
@@ -1617,6 +1618,9 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
     hc->plug = virt_machine_device_plug_cb;
 
     machine_class_allow_dynamic_sysbus_dev(mc, TYPE_RAMFB_DEVICE);
+#ifdef CONFIG_TPM
+    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_TPM_TIS_SYSBUS);
+#endif
 
     object_class_property_add_bool(oc, "aclint", virt_get_aclint,
                                    virt_set_aclint);