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

[Marc-André Lureau]

Hi

On Wed, Jun 20, 2018 at 4:08 PM, Michael S. Tsirkin <address@hidden> wrote:
> On Tue, May 15, 2018 at 02:14:32PM +0200, Marc-André Lureau wrote:
>> From: Stefan Berger <address@hidden>
>>
>> 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 <address@hidden>
>>
>> ---
>>
>> 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.

That's easy to change. Stefan could do it on commit if the rest of the
patch is unchanged.
>
>
>> +    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 ...

Hmm. Sadly, we didn't noticed when doing the edk2 part either. If we
change it in qemu, we will have to change it in edk2 as well

>> +    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
>

thanks


-- 
Marc-André Lureau