[RFC 2/2] hw/arm/virt: vTPM support

[Eric Auger <eric.auger@redhat.com>]

Let the TPM TIS device be dynamically instantiable in ARM virt.
A device tree node is dynamically created (TPM via MMIO).

The TPM Physical Presence interface (PPI) is not supported.

To run with the swtmp TPM emulator, the qemu command line must
be augmented with:

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

swtpm/libtpms command line example:

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

Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 hw/arm/Kconfig      |  1 +
 hw/arm/sysbus-fdt.c | 36 ++++++++++++++++++++++++++++++++++++
 hw/arm/virt.c       |  7 +++++++
 3 files changed, 44 insertions(+)

diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
index 3d86691ae0..ce0852f148 100644
--- a/hw/arm/Kconfig
+++ b/hw/arm/Kconfig
@@ -5,6 +5,7 @@ config ARM_VIRT
     imply VFIO_AMD_XGBE
     imply VFIO_PLATFORM
     imply VFIO_XGMAC
+    imply TPM_TIS
     select A15MPCORE
     select ACPI
     select ARM_SMMUV3
diff --git a/hw/arm/sysbus-fdt.c b/hw/arm/sysbus-fdt.c
index 022fc97ecd..d723fad6ba 100644
--- a/hw/arm/sysbus-fdt.c
+++ b/hw/arm/sysbus-fdt.c
@@ -30,6 +30,7 @@
 #include "hw/arm/sysbus-fdt.h"
 #include "qemu/error-report.h"
 #include "sysemu/device_tree.h"
+#include "sysemu/tpm.h"
 #include "hw/platform-bus.h"
 #include "hw/vfio/vfio-platform.h"
 #include "hw/vfio/vfio-calxeda-xgmac.h"
@@ -434,6 +435,40 @@ static bool vfio_platform_match(SysBusDevice *sbdev,
 #define VFIO_PLATFORM_BINDING(compat, add_fn) \
     {TYPE_VFIO_PLATFORM, (compat), (add_fn), vfio_platform_match}
 
+/*
+ * add_tpm_tis_fdt_node: Create a DT node for TPM TIS
+ *
+ * See kernel documentation:
+ * Documentation/devicetree/bindings/security/tpm/tpm_tis_mmio.txt
+ * Optional interrupt for command completion is not exposed
+ */
+static int add_tpm_tis_fdt_node(SysBusDevice *sbdev, void *opaque)
+{
+    PlatformBusFDTData *data = opaque;
+    PlatformBusDevice *pbus = data->pbus;
+    void *fdt = data->fdt;
+    const char *parent_node = data->pbus_node_name;
+    int compat_str_len;
+    char *nodename;
+    uint32_t reg_attr[2];
+    uint64_t mmio_base;
+
+    mmio_base = platform_bus_get_mmio_addr(pbus, sbdev, 0);
+    nodename = g_strdup_printf("%s/tpm_tis@%" PRIx64, parent_node, mmio_base);
+    qemu_fdt_add_subnode(fdt, nodename);
+
+    compat_str_len = strlen("tcg,tpm-tis-mmio") + 1;
+    qemu_fdt_setprop(fdt, nodename, "compatible", "tcg,tpm-tis-mmio",
+                     compat_str_len);
+
+    reg_attr[0] = cpu_to_be32(mmio_base);
+    reg_attr[1] = cpu_to_be32(0x5000);
+    qemu_fdt_setprop(fdt, nodename, "reg", reg_attr, 2 * sizeof(uint32_t));
+
+    g_free(nodename);
+    return 0;
+}
+
 #endif /* CONFIG_LINUX */
 
 static int no_fdt_node(SysBusDevice *sbdev, void *opaque)
@@ -455,6 +490,7 @@ static const BindingEntry bindings[] = {
     TYPE_BINDING(TYPE_VFIO_CALXEDA_XGMAC, add_calxeda_midway_xgmac_fdt_node),
     TYPE_BINDING(TYPE_VFIO_AMD_XGBE, add_amd_xgbe_fdt_node),
     VFIO_PLATFORM_BINDING("amd,xgbe-seattle-v1a", add_amd_xgbe_fdt_node),
+    TYPE_BINDING(TYPE_TPM_TIS, add_tpm_tis_fdt_node),
 #endif
     TYPE_BINDING(TYPE_RAMFB_DEVICE, no_fdt_node),
     TYPE_BINDING("", NULL), /* last element */
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index f788fe27d6..1bb34dfa0b 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -47,6 +47,7 @@
 #include "sysemu/numa.h"
 #include "sysemu/runstate.h"
 #include "sysemu/sysemu.h"
+#include "sysemu/tpm.h"
 #include "sysemu/kvm.h"
 #include "hw/loader.h"
 #include "exec/address-spaces.h"
@@ -2041,6 +2042,7 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
     machine_class_allow_dynamic_sysbus_dev(mc, TYPE_VFIO_AMD_XGBE);
     machine_class_allow_dynamic_sysbus_dev(mc, TYPE_RAMFB_DEVICE);
     machine_class_allow_dynamic_sysbus_dev(mc, TYPE_VFIO_PLATFORM);
+    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_TPM_TIS);
     mc->block_default_type = IF_VIRTIO;
     mc->no_cdrom = 1;
     mc->pci_allow_0_address = true;
@@ -2153,6 +2155,11 @@ type_init(machvirt_machine_init);
 
 static void virt_machine_5_0_options(MachineClass *mc)
 {
+    static GlobalProperty compat[] = {
+        { TYPE_TPM_TIS, "ppi", "false" },
+    };
+
+    compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat));
 }
 DEFINE_VIRT_MACHINE_AS_LATEST(5, 0)
 
-- 
2.20.1