Re: [Qemu-devel] [PATCH v5 3/4] acpi: add fw_cfg file for TPM and PPI virtual memory device

[Igor Mammedov]

On Tue, 26 Jun 2018 14:23:42 +0200
Marc-André Lureau <address@hidden> wrote:

> From: Stefan Berger <address@hidden>
> 
> 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 <address@hidden>
> [ Marc-André: renamed to etc/tpm/config, made it static, document it ]
> Signed-off-by: Marc-André Lureau <address@hidden>
> 
> ---
> 
> v4:
>  - add ACPI only if PPI is enabled
> v3:
>  - renamed to etc/tpm/config, made it static, document it
> ---
>  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 c082df7d1d..f79d68a77a 100644
> --- a/include/hw/acpi/tpm.h
> +++ b/include/hw/acpi/tpm.h
> @@ -193,4 +193,7 @@ 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 9bc6d97ea1..d9320845ed 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;
is 32bit enough (what if on ARM or somewhere else area would be above 4Gb)?
to be future proof I'd make it 64bit field so we won't have to change ABI
later on.

> +    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);
> @@ -2873,6 +2879,8 @@ 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");
> @@ -2907,6 +2915,17 @@ void acpi_setup(void)
what about vart-arm machine?
(it also has some TPM stuff but it doesn't use acpi_setup())
maybe add common helper and reuse it for both?


>      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 = cpu_to_le32(tpm_get_version(tpm_find())),
Have it actually been tested on big endian host?

> +            .tpmppi_version = cpu_to_le32(TPM_PPI_VERSION_NONE)
ditto

(that's why I don't welcome packed structures in random places)

how about adding unit-tests to series to make sure that it works
across different hosts that travis builds on and that thing won't
fall apart in future?

> +        };
> +        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 c230c4c93e..2ddb768084 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 use 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