Re: [Qemu-devel] [PATCH v3 2/4] acpi: add fw_cfg file for TPM and PPI virtual memory device

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 15 May 2018 14:14:31 +0200
Marc-André Lureau <marcandre.lureau@redhat.com> wrote:

> 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.
is it related to TPM_PPI_ADDR_BASE added in previous patch?

> 
> 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>
> ---
>  include/hw/acpi/tpm.h |  3 +++
>  hw/i386/acpi-build.c  | 17 +++++++++++++++++
>  docs/specs/tpm.txt    | 20 ++++++++++++++++++++
>  3 files changed, 40 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..f6d447f03a 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);
> @@ -2873,6 +2879,7 @@ void acpi_setup(void)
>      AcpiBuildTables tables;
>      AcpiBuildState *build_state;
>      Object *vmgenid_dev;
> +    static FWCfgTPMConfig tpm_config;
>  
>      if (!pcms->fw_cfg) {
>          ACPI_BUILD_DPRINTF("No fw cfg. Bailing out.\n");
> @@ -2907,6 +2914,16 @@ void acpi_setup(void)
>      fw_cfg_add_file(pcms->fw_cfg, ACPI_BUILD_TPMLOG_FILE,
>                      tables.tcpalog->data, acpi_data_len(tables.tcpalog));
>  
> +    if (tpm_find()) {
> +        tpm_config = (FWCfgTPMConfig) {
> +            .tpmppi_address = cpu_to_le32(TPM_PPI_ADDR_BASE),
> +            .tpm_version = cpu_to_le32(tpm_get_version(tpm_find())),
> +            .tpmppi_version = cpu_to_le32(TPM_PPI_VERSION_NONE)
> +        };
> +        fw_cfg_add_file(pcms->fw_cfg, "etc/tpm/config",
> +                        &tpm_config, sizeof tpm_config);
> +    }
why it's in ACPI part of the code, shouldn't it be a part of device,
could TPM be used without ACPI at all (-noacpi CLI option)?

Wouldn't adding fwcfg entry unconditionally break migration?

> +
>      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