Re: [Qemu-devel] [PATCH v3 3/4] acpi: build TPM Physical Presence interface

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, May 15, 2018 at 02:14:32PM +0200, Marc-André Lureau wrote:
> From: Stefan Berger <stefanb@linux.vnet.ibm.com>
> 
> The TPM Physical Presence interface consists of an ACPI part, a shared
> memory part, and code in the firmware. Users can send messages to the
> firmware by writing a code into the shared memory through invoking the
> ACPI code. When a reboot happens, the firmware looks for the code and
> acts on it by sending sequences of commands to the TPM.
> 
> This patch adds the ACPI code. It is similar to the one in EDK2 but doesn't
> assume that SMIs are necessary to use. It uses a similar datastructure for
> the shared memory as EDK2 does so that EDK2 and SeaBIOS could both make use
> of it. I extended the shared memory data structure with an array of 256
> bytes, one for each code that could be implemented. The array contains
> flags describing the individual codes. This decouples the ACPI implementation
> from the firmware implementation.
> 
> The underlying TCG specification is accessible from the following page.
> 
> https://trustedcomputinggroup.org/tcg-physical-presence-interface-specification/
> 
> This patch implements version 1.30.
> 
> Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
> 
> ---
> 
> v4 (Marc-André):
>  - replace 'DerefOf (FUNC [N])' with a function, to fix Windows ACPI
>     handling.
>  - replace 'return Package (..) {} ' with scoped variables, to fix
>    Windows ACPI handling.
> 
> v3:
>  - add support for PPI to CRB
>  - split up OperationRegion TPPI into two parts, one containing
>    the registers (TPP1) and the other one the flags (TPP2); switched
>    the order of the flags versus registers in the code
>  - adapted ACPI code to small changes to the array of flags where
>    previous flag 0 was removed and now shifting right wasn't always
>    necessary anymore
> 
> v2:
>  - get rid of FAIL variable; function 5 was using it and always
>    returns 0; the value is related to the ACPI function call not
>    a possible failure of the TPM function call.
>  - extend shared memory data structure with per-opcode entries
>    holding flags and use those flags to determine what to return
>    to caller
>  - implement interface version 1.3
> ---
>  include/hw/acpi/tpm.h |  21 +++
>  hw/i386/acpi-build.c  | 294 +++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 314 insertions(+), 1 deletion(-)
> 
> diff --git a/include/hw/acpi/tpm.h b/include/hw/acpi/tpm.h
> index f79d68a77a..fc53f08827 100644
> --- a/include/hw/acpi/tpm.h
> +++ b/include/hw/acpi/tpm.h
> @@ -196,4 +196,25 @@ REG32(CRB_DATA_BUFFER, 0x80)
>  #define TPM_PPI_VERSION_NONE        0
>  #define TPM_PPI_VERSION_1_30        1
>  
> +struct tpm_ppi {

The name violate the coding style.


> +    uint8_t  func[256];      /* 0x000: per TPM function implementation flags;
> +                                       set by BIOS */
> +/* whether function is blocked by BIOS settings; bits 0, 1, 2 */
> +#define TPM_PPI_FUNC_NOT_IMPLEMENTED     (0 << 0)
> +#define TPM_PPI_FUNC_BIOS_ONLY           (1 << 0)
> +#define TPM_PPI_FUNC_BLOCKED             (2 << 0)
> +#define TPM_PPI_FUNC_ALLOWED_USR_REQ     (3 << 0)
> +#define TPM_PPI_FUNC_ALLOWED_USR_NOT_REQ (4 << 0)
> +#define TPM_PPI_FUNC_MASK                (7 << 0)
> +    uint8_t ppin;            /* 0x100 : set by BIOS */

Are you sure it's right? Below ints will all end up misaligned ...

> +    uint32_t ppip;           /* 0x101 : set by ACPI; not used */
> +    uint32_t pprp;           /* 0x105 : response from TPM; set by BIOS */
> +    uint32_t pprq;           /* 0x109 : opcode; set by ACPI */
> +    uint32_t pprm;           /* 0x10d : parameter for opcode; set by ACPI */
> +    uint32_t lppr;           /* 0x111 : last opcode; set by BIOS */
> +    uint32_t fret;           /* 0x115 : set by ACPI; not used */
> +    uint8_t res1[0x40];      /* 0x119 : reserved for future use */
> +    uint8_t next_step;       /* 0x159 : next step after reboot; set by BIOS */
> +} QEMU_PACKED;
> +
>  #endif /* HW_ACPI_TPM_H */

Igor could you pls take a quick look at the rest?

-- 
MST