[Qemu-devel] [PATCH v12 4/6] acpi: expose TPM/PPI configuration parameters to firmware via fw_cfg

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

From: Stefan Berger <stefanb@linux.vnet.ibm.com>

To avoid having to hard code the base address of the PPI virtual
memory device we introduce a fw_cfg file etc/tpm/config that holds the
base address of the PPI device, the version of the PPI interface and
the version of the attached TPM.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
[ Marc-André: renamed to etc/tpm/config, made it static, document it ]
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/hw/acpi/tpm.h |  3 +++
 hw/i386/acpi-build.c  | 19 +++++++++++++++++++
 docs/specs/tpm.txt    | 20 ++++++++++++++++++++
 3 files changed, 42 insertions(+)

diff --git a/include/hw/acpi/tpm.h b/include/hw/acpi/tpm.h
index b8796df916..a6109a97fc 100644
--- a/include/hw/acpi/tpm.h
+++ b/include/hw/acpi/tpm.h
@@ -194,4 +194,7 @@ REG32(CRB_DATA_BUFFER, 0x80)
 #define TPM_PPI_ADDR_SIZE           0x400
 #define TPM_PPI_ADDR_BASE           0xFED45000
 
+#define TPM_PPI_VERSION_NONE        0
+#define TPM_PPI_VERSION_1_30        1
+
 #endif /* HW_ACPI_TPM_H */
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index e1ee8ae9e0..c24f68df02 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -119,6 +119,12 @@ typedef struct AcpiBuildPciBusHotplugState {
     bool pcihp_bridge_en;
 } AcpiBuildPciBusHotplugState;
 
+typedef struct FWCfgTPMConfig {
+    uint32_t tpmppi_address;
+    uint8_t tpm_version;
+    uint8_t tpmppi_version;
+} QEMU_PACKED FWCfgTPMConfig;
+
 static void init_common_fadt_data(Object *o, AcpiFadtData *data)
 {
     uint32_t io = object_property_get_uint(o, ACPI_PM_PROP_PM_IO_BASE, NULL);
@@ -2877,6 +2883,8 @@ void acpi_setup(void)
     AcpiBuildTables tables;
     AcpiBuildState *build_state;
     Object *vmgenid_dev;
+    TPMIf *tpm;
+    static FWCfgTPMConfig tpm_config;
 
     if (!pcms->fw_cfg) {
         ACPI_BUILD_DPRINTF("No fw cfg. Bailing out.\n");
@@ -2911,6 +2919,17 @@ void acpi_setup(void)
     fw_cfg_add_file(pcms->fw_cfg, ACPI_BUILD_TPMLOG_FILE,
                     tables.tcpalog->data, acpi_data_len(tables.tcpalog));
 
+    tpm = tpm_find();
+    if (tpm && object_property_get_bool(OBJECT(tpm), "ppi", &error_abort)) {
+        tpm_config = (FWCfgTPMConfig) {
+            .tpmppi_address = cpu_to_le32(TPM_PPI_ADDR_BASE),
+            .tpm_version = tpm_get_version(tpm_find()),
+            .tpmppi_version = TPM_PPI_VERSION_NONE
+        };
+        fw_cfg_add_file(pcms->fw_cfg, "etc/tpm/config",
+                        &tpm_config, sizeof tpm_config);
+    }
+
     vmgenid_dev = find_vmgenid_dev();
     if (vmgenid_dev) {
         vmgenid_add_fw_cfg(VMGENID(vmgenid_dev), pcms->fw_cfg,
diff --git a/docs/specs/tpm.txt b/docs/specs/tpm.txt
index 0e9bbebe1d..a5bdd5f26e 100644
--- a/docs/specs/tpm.txt
+++ b/docs/specs/tpm.txt
@@ -20,6 +20,26 @@ QEMU files related to TPM TIS interface:
  - hw/tpm/tpm_tis.h
 
 
+= fw_cfg interface =
+
+The bios/firmware may read the "etc/tpm/config" fw_cfg entry for
+configuring the guest appropriately.
+
+The entry of 6 bytes has the following content, in little-endian:
+
+    #define TPM_VERSION_UNSPEC          0
+    #define TPM_VERSION_1_2             1
+    #define TPM_VERSION_2_0             2
+
+    #define TPM_PPI_VERSION_NONE        0
+    #define TPM_PPI_VERSION_1_30        1
+
+    struct FWCfgTPMConfig {
+        uint32_t tpmppi_address;         /* PPI memory location */
+        uint8_t tpm_version;             /* TPM version */
+        uint8_t tpmppi_version;          /* PPI version */
+    };
+
 = ACPI Interface =
 
 The TPM device is defined with ACPI ID "PNP0C31". QEMU builds a SSDT and passes
-- 
2.19.0.rc1