tis_get_tpm_version() was returning the interface version, which is always
1.2 since tis_probe() would have failed if the interface wasn't TIS.

New version check is based on the tpm2_probe() function from the Linux
tpm_tis driver.

Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
Tested-by: Stephen Douthit <stephend@silicom-usa.com>
---
 src/hw/tpm_drivers.c | 21 +++++++++++++++------
 src/std/tcg.h        |  1 +
 src/tcgbios.c        |  2 +-
 src/tcgbios.h        |  4 ++++
 4 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
index 789d70a..32c34df 100644
--- a/src/hw/tpm_drivers.c
+++ b/src/hw/tpm_drivers.c
@@ -11,6 +11,7 @@
 #include "config.h" // CONFIG_TPM_TIS_SHA1THRESHOLD
 #include "hw/tpm_drivers.h" // struct tpm_driver
 #include "std/tcg.h" // TCG_RESPONSE_TIMEOUT
+#include "tcgbios.h" // tpm20_getcapability
 #include "output.h" // warn_timeout
 #include "stacks.h" // yield
 #include "string.h" // memcpy
@@ -119,7 +120,7 @@ static u32 tis_probe(void)
     if ((didvid != 0) && (didvid != 0xffffffff))
         rc = 1;
 
-    /* TPM 2 has an interface register */
+    /* Low 32 bits of CRB interface register overlap TIS interface register */
     u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
 
     if ((ifaceid & 0xf) != 0xf) {
@@ -142,13 +143,21 @@ static u32 tis_probe(void)
 
 static TPMVersion tis_get_tpm_version(void)
 {
-    /* TPM 2 has an interface register */
-    u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
+    u8 buffer[128];
+    int ret;
+    struct tpm2_res_getcapability *trg =
+      (struct tpm2_res_getcapability *)&buffer;
+
+    ret = tpm20_getcapability(TPM2_CAP_TPM_PROPERTIES, cpu_to_be32(0x100),
+                              cpu_to_be32(1), &trg->hdr, sizeof(buffer));
+    if (ret == TPM2_RC_INITIALIZE)
+        return TPM_VERSION_2;
+    else if (ret)
+        return TPM_VERSION_NONE;
 
-    if ((ifaceid & 0xf) == 0) {
-        /* TPM 2 */
+    if (cpu_to_be32(trg->hdr.tag) == TPM2_ST_NO_SESSIONS)
         return TPM_VERSION_2;
-    }
+
     return TPM_VERSION_1_2;
 }
 
diff --git a/src/std/tcg.h b/src/std/tcg.h
index 09a92d8..4c07493 100644
--- a/src/std/tcg.h
+++ b/src/std/tcg.h
@@ -357,6 +357,7 @@ struct tpm_res_sha1complete {
 
 /* TPM 2 Capabilities */
 #define TPM2_CAP_PCRS               0x00000005
+#define TPM2_CAP_TPM_PROPERTIES     0x00000006
 
 /* TPM 2 data structures */
 
diff --git a/src/tcgbios.c b/src/tcgbios.c
index 40b3028..b86bf64 100644
--- a/src/tcgbios.c
+++ b/src/tcgbios.c
@@ -381,7 +381,7 @@ tpm_simple_cmd(u8 locty, u32 ordinal
     return ret;
 }
 
-static int
+int
 tpm20_getcapability(u32 capability, u32 property, u32 count,
                     struct tpm_rsp_header *rsp, u32 rsize)
 {
diff --git a/src/tcgbios.h b/src/tcgbios.h
index 32fb941..9fc711a 100644
--- a/src/tcgbios.h
+++ b/src/tcgbios.h
@@ -1,6 +1,7 @@
 #ifndef TCGBIOS_H
 #define TCGBIOS_H
 
+#include "std/tcg.h" // struct tpm_rsp_header
 #include "types.h"
 
 struct bregs;
@@ -15,5 +16,8 @@ void tpm_add_cdrom_catalog(const u8 *addr, u32 length);
 void tpm_option_rom(const void *addr, u32 len);
 int tpm_can_show_menu(void);
 void tpm_menu(void);
+int
+tpm20_getcapability(u32 capability, u32 property, u32 count,
+                    struct tpm_rsp_header *rsp, u32 rsize);
 
 #endif /* TCGBIOS_H */
-- 
2.14.3


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On 02/26/2018 03:37 PM, Stephen Douthit wrote:
> tis_get_tpm_version() was returning the interface version, which is always
> 1.2 since tis_probe() would have failed if the interface wasn't TIS.
>
> New version check is based on the tpm2_probe() function from the Linux
> tpm_tis driver.
>
> Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
> Tested-by: Stephen Douthit <stephend@silicom-usa.com>
> ---
>   src/hw/tpm_drivers.c | 21 +++++++++++++++------
>   src/std/tcg.h        |  1 +
>   src/tcgbios.c        |  2 +-
>   src/tcgbios.h        |  4 ++++
>   4 files changed, 21 insertions(+), 7 deletions(-)
>
> diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
> index 789d70a..32c34df 100644
> --- a/src/hw/tpm_drivers.c
> +++ b/src/hw/tpm_drivers.c
> @@ -11,6 +11,7 @@
>   #include "config.h" // CONFIG_TPM_TIS_SHA1THRESHOLD
>   #include "hw/tpm_drivers.h" // struct tpm_driver
>   #include "std/tcg.h" // TCG_RESPONSE_TIMEOUT
> +#include "tcgbios.h" // tpm20_getcapability
>   #include "output.h" // warn_timeout
>   #include "stacks.h" // yield
>   #include "string.h" // memcpy
> @@ -119,7 +120,7 @@ static u32 tis_probe(void)
>       if ((didvid != 0) && (didvid != 0xffffffff))
>           rc = 1;
>
> -    /* TPM 2 has an interface register */
> +    /* Low 32 bits of CRB interface register overlap TIS interface register */
>       u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));

Since this is tis_probe, I don't think we need to mention the CRB here ...

>
>       if ((ifaceid & 0xf) != 0xf) {
> @@ -142,13 +143,21 @@ static u32 tis_probe(void)
>
>   static TPMVersion tis_get_tpm_version(void)
>   {
> -    /* TPM 2 has an interface register */
> -    u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
> +    u8 buffer[128];
> +    int ret;
> +    struct tpm2_res_getcapability *trg =
> +      (struct tpm2_res_getcapability *)&buffer;
> +
> +    ret = tpm20_getcapability(TPM2_CAP_TPM_PROPERTIES, cpu_to_be32(0x100),
> +                              cpu_to_be32(1), &trg->hdr, sizeof(buffer));
> +    if (ret == TPM2_RC_INITIALIZE)
> +        return TPM_VERSION_2;
> +    else if (ret)
> +        return TPM_VERSION_NONE;
I haven't tried yet, but likely this will not work for TPM 1.2 since it 
will also return an error.

Wouldn't the check for the tag below not be sufficient? We are doing 
something similar in QEMU when probing for the TPM. Here we send TPM 2 
command TPM_CC_ReadClock and check the tag for TPM 2 type and then TPM 
1.2 command TPM_ORD_GetTicks and check for TPM 1.2 tag.

Do you know what value does the InterfaceType show on your TIS? I only 
tested this with QEMU TIS and here we return 0x0 in those 4 bits, which 
means, following specs, 'FIFO interface as defined in PTP for TPM 2.0 is 
active'.

>
> -    if ((ifaceid & 0xf) == 0) {
> -        /* TPM 2 */
> +    if (cpu_to_be32(trg->hdr.tag) == TPM2_ST_NO_SESSIONS)
>           return TPM_VERSION_2;
> -    }
> +
>       return TPM_VERSION_1_2;
>   }
>
> diff --git a/src/std/tcg.h b/src/std/tcg.h
> index 09a92d8..4c07493 100644
> --- a/src/std/tcg.h
> +++ b/src/std/tcg.h
> @@ -357,6 +357,7 @@ struct tpm_res_sha1complete {
>
>   /* TPM 2 Capabilities */
>   #define TPM2_CAP_PCRS               0x00000005
> +#define TPM2_CAP_TPM_PROPERTIES     0x00000006
>
>   /* TPM 2 data structures */
>
> diff --git a/src/tcgbios.c b/src/tcgbios.c
> index 40b3028..b86bf64 100644
> --- a/src/tcgbios.c
> +++ b/src/tcgbios.c
> @@ -381,7 +381,7 @@ tpm_simple_cmd(u8 locty, u32 ordinal
>       return ret;
>   }
>
> -static int
> +int
>   tpm20_getcapability(u32 capability, u32 property, u32 count,
>                       struct tpm_rsp_header *rsp, u32 rsize)
>   {
> diff --git a/src/tcgbios.h b/src/tcgbios.h
> index 32fb941..9fc711a 100644
> --- a/src/tcgbios.h
> +++ b/src/tcgbios.h
> @@ -1,6 +1,7 @@
>   #ifndef TCGBIOS_H
>   #define TCGBIOS_H
>
> +#include "std/tcg.h" // struct tpm_rsp_header
>   #include "types.h"
>
>   struct bregs;
> @@ -15,5 +16,8 @@ void tpm_add_cdrom_catalog(const u8 *addr, u32 length);
>   void tpm_option_rom(const void *addr, u32 len);
>   int tpm_can_show_menu(void);
>   void tpm_menu(void);
> +int
> +tpm20_getcapability(u32 capability, u32 property, u32 count,
> +                    struct tpm_rsp_header *rsp, u32 rsize);
>
>   #endif /* TCGBIOS_H */



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On 02/26/2018 05:09 PM, Stefan Berger wrote:
> On 02/26/2018 03:37 PM, Stephen Douthit wrote:
>> tis_get_tpm_version() was returning the interface version, which is always
>> 1.2 since tis_probe() would have failed if the interface wasn't TIS.
>>
>> New version check is based on the tpm2_probe() function from the Linux
>> tpm_tis driver.
>>
>> Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
>> Tested-by: Stephen Douthit <stephend@silicom-usa.com>
>> ---
>>   src/hw/tpm_drivers.c | 21 +++++++++++++++------
>>   src/std/tcg.h        |  1 +
>>   src/tcgbios.c        |  2 +-
>>   src/tcgbios.h        |  4 ++++
>>   4 files changed, 21 insertions(+), 7 deletions(-)
>>
>> diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
>> index 789d70a..32c34df 100644
>> --- a/src/hw/tpm_drivers.c
>> +++ b/src/hw/tpm_drivers.c
>> @@ -11,6 +11,7 @@
>>   #include "config.h" // CONFIG_TPM_TIS_SHA1THRESHOLD
>>   #include "hw/tpm_drivers.h" // struct tpm_driver
>>   #include "std/tcg.h" // TCG_RESPONSE_TIMEOUT
>> +#include "tcgbios.h" // tpm20_getcapability
>>   #include "output.h" // warn_timeout
>>   #include "stacks.h" // yield
>>   #include "string.h" // memcpy
>> @@ -119,7 +120,7 @@ static u32 tis_probe(void)
>>       if ((didvid != 0) && (didvid != 0xffffffff))
>>           rc = 1;
>>
>> -    /* TPM 2 has an interface register */
>> +    /* Low 32 bits of CRB interface register overlap TIS interface register */
>>       u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
> 
> Since this is tis_probe, I don't think we need to mention the CRB here ...

I think that was a note to myself I forgot to strip out when I
dropped my debug prints.  I'll change the comment back.

>>
>>       if ((ifaceid & 0xf) != 0xf) {
>> @@ -142,13 +143,21 @@ static u32 tis_probe(void)
>>
>>   static TPMVersion tis_get_tpm_version(void)
>>   {
>> -    /* TPM 2 has an interface register */
>> -    u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>> +    u8 buffer[128];
>> +    int ret;
>> +    struct tpm2_res_getcapability *trg =
>> +      (struct tpm2_res_getcapability *)&buffer;
>> +
>> +    ret = tpm20_getcapability(TPM2_CAP_TPM_PROPERTIES, cpu_to_be32(0x100),
>> +                              cpu_to_be32(1), &trg->hdr, sizeof(buffer));
>> +    if (ret == TPM2_RC_INITIALIZE)
>> +        return TPM_VERSION_2;
>> +    else if (ret)
>> +        return TPM_VERSION_NONE;
> I haven't tried yet, but likely this will not work for TPM 1.2 since it will also return an error.

Doh.  That makes sense.  I'll need to find a 1.2 system to test on to
avoid stupid mistakes like that.

> Wouldn't the check for the tag below not be sufficient? We are doing something similar in QEMU when probing for the TPM. Here we send TPM 2 command TPM_CC_ReadClock and check the tag for TPM 2 type and then TPM 1.2 command TPM_ORD_GetTicks and check for TPM 1.2 tag.

It might be, it wasn't clear to me if the tag could be trusted if the
return code wasn't success.  The Linux tpm2_probe() code bails before
the tag comparison if tpm_transmit_cmd() returns an error.

Is there a block of QEMU code you would recommend as a reference for
probing TPMs?  I'm not very familiar with that code base, and a
pointer would be handy.

> Do you know what value does the InterfaceType show on your TIS? I only tested this with QEMU TIS and here we return 0x0 in those 4 bits, which means, following specs, 'FIFO interface as defined in PTP for TPM 2.0 is active'.

I don't see it in my notes, I can put some debug prints back in
tomorrow and will get back to you.

Thanks,
Steve

>>
>> -    if ((ifaceid & 0xf) == 0) {
>> -        /* TPM 2 */
>> +    if (cpu_to_be32(trg->hdr.tag) == TPM2_ST_NO_SESSIONS)
>>           return TPM_VERSION_2;
>> -    }
>> +
>>       return TPM_VERSION_1_2;
>>   }
>>
>> diff --git a/src/std/tcg.h b/src/std/tcg.h
>> index 09a92d8..4c07493 100644
>> --- a/src/std/tcg.h
>> +++ b/src/std/tcg.h
>> @@ -357,6 +357,7 @@ struct tpm_res_sha1complete {
>>
>>   /* TPM 2 Capabilities */
>>   #define TPM2_CAP_PCRS               0x00000005
>> +#define TPM2_CAP_TPM_PROPERTIES     0x00000006
>>
>>   /* TPM 2 data structures */
>>
>> diff --git a/src/tcgbios.c b/src/tcgbios.c
>> index 40b3028..b86bf64 100644
>> --- a/src/tcgbios.c
>> +++ b/src/tcgbios.c
>> @@ -381,7 +381,7 @@ tpm_simple_cmd(u8 locty, u32 ordinal
>>       return ret;
>>   }
>>
>> -static int
>> +int
>>   tpm20_getcapability(u32 capability, u32 property, u32 count,
>>                       struct tpm_rsp_header *rsp, u32 rsize)
>>   {
>> diff --git a/src/tcgbios.h b/src/tcgbios.h
>> index 32fb941..9fc711a 100644
>> --- a/src/tcgbios.h
>> +++ b/src/tcgbios.h
>> @@ -1,6 +1,7 @@
>>   #ifndef TCGBIOS_H
>>   #define TCGBIOS_H
>>
>> +#include "std/tcg.h" // struct tpm_rsp_header
>>   #include "types.h"
>>
>>   struct bregs;
>> @@ -15,5 +16,8 @@ void tpm_add_cdrom_catalog(const u8 *addr, u32 length);
>>   void tpm_option_rom(const void *addr, u32 len);
>>   int tpm_can_show_menu(void);
>>   void tpm_menu(void);
>> +int
>> +tpm20_getcapability(u32 capability, u32 property, u32 count,
>> +                    struct tpm_rsp_header *rsp, u32 rsize);
>>
>>   #endif /* TCGBIOS_H */
> 
> 


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On 02/26/2018 05:44 PM, Stephen Douthit wrote:
> On 02/26/2018 05:09 PM, Stefan Berger wrote:
>> On 02/26/2018 03:37 PM, Stephen Douthit wrote:
>>> tis_get_tpm_version() was returning the interface version, which is 
>>> always
>>> 1.2 since tis_probe() would have failed if the interface wasn't TIS.
>>>
>>> New version check is based on the tpm2_probe() function from the Linux
>>> tpm_tis driver.
>>>
>>> Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
>>> Tested-by: Stephen Douthit <stephend@silicom-usa.com>
>>> ---
>>>   src/hw/tpm_drivers.c | 21 +++++++++++++++------
>>>   src/std/tcg.h        |  1 +
>>>   src/tcgbios.c        |  2 +-
>>>   src/tcgbios.h        |  4 ++++
>>>   4 files changed, 21 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
>>> index 789d70a..32c34df 100644
>>> --- a/src/hw/tpm_drivers.c
>>> +++ b/src/hw/tpm_drivers.c
>>> @@ -11,6 +11,7 @@
>>>   #include "config.h" // CONFIG_TPM_TIS_SHA1THRESHOLD
>>>   #include "hw/tpm_drivers.h" // struct tpm_driver
>>>   #include "std/tcg.h" // TCG_RESPONSE_TIMEOUT
>>> +#include "tcgbios.h" // tpm20_getcapability
>>>   #include "output.h" // warn_timeout
>>>   #include "stacks.h" // yield
>>>   #include "string.h" // memcpy
>>> @@ -119,7 +120,7 @@ static u32 tis_probe(void)
>>>       if ((didvid != 0) && (didvid != 0xffffffff))
>>>           rc = 1;
>>>
>>> -    /* TPM 2 has an interface register */
>>> +    /* Low 32 bits of CRB interface register overlap TIS interface 
>>> register */
>>>       u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>
>> Since this is tis_probe, I don't think we need to mention the CRB 
>> here ...
>
> I think that was a note to myself I forgot to strip out when I
> dropped my debug prints.  I'll change the comment back.
>
>>>
>>>       if ((ifaceid & 0xf) != 0xf) {
>>> @@ -142,13 +143,21 @@ static u32 tis_probe(void)
>>>
>>>   static TPMVersion tis_get_tpm_version(void)
>>>   {
>>> -    /* TPM 2 has an interface register */
>>> -    u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>> +    u8 buffer[128];
>>> +    int ret;
>>> +    struct tpm2_res_getcapability *trg =
>>> +      (struct tpm2_res_getcapability *)&buffer;
>>> +
>>> +    ret = tpm20_getcapability(TPM2_CAP_TPM_PROPERTIES, 
>>> cpu_to_be32(0x100),
>>> +                              cpu_to_be32(1), &trg->hdr, 
>>> sizeof(buffer));
>>> +    if (ret == TPM2_RC_INITIALIZE)
>>> +        return TPM_VERSION_2;
>>> +    else if (ret)
>>> +        return TPM_VERSION_NONE;
>> I haven't tried yet, but likely this will not work for TPM 1.2 since 
>> it will also return an error.
>
> Doh.  That makes sense.  I'll need to find a 1.2 system to test on to
> avoid stupid mistakes like that.
>
>> Wouldn't the check for the tag below not be sufficient? We are doing 
>> something similar in QEMU when probing for the TPM. Here we send TPM 
>> 2 command TPM_CC_ReadClock and check the tag for TPM 2 type and then 
>> TPM 1.2 command TPM_ORD_GetTicks and check for TPM 1.2 tag.
>
> It might be, it wasn't clear to me if the tag could be trusted if the
> return code wasn't success.  The Linux tpm2_probe() code bails before
> the tag comparison if tpm_transmit_cmd() returns an error.
>
> Is there a block of QEMU code you would recommend as a reference for
> probing TPMs?  I'm not very familiar with that code base, and a
> pointer would be handy.

https://github.com/stefanberger/qemu-tpm/blob/v2.4.1%2Btpm/hw/tpm/tpm_util.c#L94

What I don't like about the sending of commands is that we're breaking 
the layer here. We basically cannot send commands using this higher 
level API. The lowest we could go would be to call tpmhw_transmit, but 
that function cannot be used as it is but has to be split up to take 
tpm_driver as a parameter. You would pass to it 
&tpm_drivers[TIS_DRIVER_INDEX].

As far as I know, TPM 1.2 didn't have that register, so they either 
return static 0 or 0xffffffff in that register.

Though if reading the flags from the interface register really turns out 
to be insufficient, I think you should try to send a command like 
TPM2_CC_ReadClock. If you get back a TPM2_ST_NO_SESSION, it's a TPM 2. 
If you get a TPM_TAG_RSP_COMMAND it's a TPM 12.


>
>> Do you know what value does the InterfaceType show on your TIS? I 
>> only tested this with QEMU TIS and here we return 0x0 in those 4 
>> bits, which means, following specs, 'FIFO interface as defined in PTP 
>> for TPM 2.0 is active'.
>
> I don't see it in my notes, I can put some debug prints back in
> tomorrow and will get back to you.
>
> Thanks,
> Steve
>
>>>
>>> -    if ((ifaceid & 0xf) == 0) {
>>> -        /* TPM 2 */
>>> +    if (cpu_to_be32(trg->hdr.tag) == TPM2_ST_NO_SESSIONS)
>>>           return TPM_VERSION_2;
>>> -    }
>>> +
>>>       return TPM_VERSION_1_2;
>>>   }
>>>
>>> diff --git a/src/std/tcg.h b/src/std/tcg.h
>>> index 09a92d8..4c07493 100644
>>> --- a/src/std/tcg.h
>>> +++ b/src/std/tcg.h
>>> @@ -357,6 +357,7 @@ struct tpm_res_sha1complete {
>>>
>>>   /* TPM 2 Capabilities */
>>>   #define TPM2_CAP_PCRS               0x00000005
>>> +#define TPM2_CAP_TPM_PROPERTIES     0x00000006
>>>
>>>   /* TPM 2 data structures */
>>>
>>> diff --git a/src/tcgbios.c b/src/tcgbios.c
>>> index 40b3028..b86bf64 100644
>>> --- a/src/tcgbios.c
>>> +++ b/src/tcgbios.c
>>> @@ -381,7 +381,7 @@ tpm_simple_cmd(u8 locty, u32 ordinal
>>>       return ret;
>>>   }
>>>
>>> -static int
>>> +int
>>>   tpm20_getcapability(u32 capability, u32 property, u32 count,
>>>                       struct tpm_rsp_header *rsp, u32 rsize)
>>>   {
>>> diff --git a/src/tcgbios.h b/src/tcgbios.h
>>> index 32fb941..9fc711a 100644
>>> --- a/src/tcgbios.h
>>> +++ b/src/tcgbios.h
>>> @@ -1,6 +1,7 @@
>>>   #ifndef TCGBIOS_H
>>>   #define TCGBIOS_H
>>>
>>> +#include "std/tcg.h" // struct tpm_rsp_header
>>>   #include "types.h"
>>>
>>>   struct bregs;
>>> @@ -15,5 +16,8 @@ void tpm_add_cdrom_catalog(const u8 *addr, u32 
>>> length);
>>>   void tpm_option_rom(const void *addr, u32 len);
>>>   int tpm_can_show_menu(void);
>>>   void tpm_menu(void);
>>> +int
>>> +tpm20_getcapability(u32 capability, u32 property, u32 count,
>>> +                    struct tpm_rsp_header *rsp, u32 rsize);
>>>
>>>   #endif /* TCGBIOS_H */
>>
>>
>


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On 02/26/2018 06:02 PM, Stefan Berger wrote:
> On 02/26/2018 05:44 PM, Stephen Douthit wrote:
>> On 02/26/2018 05:09 PM, Stefan Berger wrote:
>>> On 02/26/2018 03:37 PM, Stephen Douthit wrote:
>>>> tis_get_tpm_version() was returning the interface version, which is always
>>>> 1.2 since tis_probe() would have failed if the interface wasn't TIS.
>>>>
>>>> New version check is based on the tpm2_probe() function from the Linux
>>>> tpm_tis driver.
>>>>
>>>> Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
>>>> Tested-by: Stephen Douthit <stephend@silicom-usa.com>
>>>> ---
>>>>   src/hw/tpm_drivers.c | 21 +++++++++++++++------
>>>>   src/std/tcg.h        |  1 +
>>>>   src/tcgbios.c        |  2 +-
>>>>   src/tcgbios.h        |  4 ++++
>>>>   4 files changed, 21 insertions(+), 7 deletions(-)
>>>>
>>>> diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
>>>> index 789d70a..32c34df 100644
>>>> --- a/src/hw/tpm_drivers.c
>>>> +++ b/src/hw/tpm_drivers.c
>>>> @@ -11,6 +11,7 @@
>>>>   #include "config.h" // CONFIG_TPM_TIS_SHA1THRESHOLD
>>>>   #include "hw/tpm_drivers.h" // struct tpm_driver
>>>>   #include "std/tcg.h" // TCG_RESPONSE_TIMEOUT
>>>> +#include "tcgbios.h" // tpm20_getcapability
>>>>   #include "output.h" // warn_timeout
>>>>   #include "stacks.h" // yield
>>>>   #include "string.h" // memcpy
>>>> @@ -119,7 +120,7 @@ static u32 tis_probe(void)
>>>>       if ((didvid != 0) && (didvid != 0xffffffff))
>>>>           rc = 1;
>>>>
>>>> -    /* TPM 2 has an interface register */
>>>> +    /* Low 32 bits of CRB interface register overlap TIS interface register */
>>>>       u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>
>>> Since this is tis_probe, I don't think we need to mention the CRB here ...
>>
>> I think that was a note to myself I forgot to strip out when I
>> dropped my debug prints.  I'll change the comment back.
>>
>>>>
>>>>       if ((ifaceid & 0xf) != 0xf) {
>>>> @@ -142,13 +143,21 @@ static u32 tis_probe(void)
>>>>
>>>>   static TPMVersion tis_get_tpm_version(void)
>>>>   {
>>>> -    /* TPM 2 has an interface register */
>>>> -    u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>> +    u8 buffer[128];
>>>> +    int ret;
>>>> +    struct tpm2_res_getcapability *trg =
>>>> +      (struct tpm2_res_getcapability *)&buffer;
>>>> +
>>>> +    ret = tpm20_getcapability(TPM2_CAP_TPM_PROPERTIES, cpu_to_be32(0x100),
>>>> +                              cpu_to_be32(1), &trg->hdr, sizeof(buffer));
>>>> +    if (ret == TPM2_RC_INITIALIZE)
>>>> +        return TPM_VERSION_2;
>>>> +    else if (ret)
>>>> +        return TPM_VERSION_NONE;
>>> I haven't tried yet, but likely this will not work for TPM 1.2 since it will also return an error.
>>
>> Doh.  That makes sense.  I'll need to find a 1.2 system to test on to
>> avoid stupid mistakes like that.
>>
>>> Wouldn't the check for the tag below not be sufficient? We are doing something similar in QEMU when probing for the TPM. Here we send TPM 2 command TPM_CC_ReadClock and check the tag for TPM 2 type and then TPM 1.2 command TPM_ORD_GetTicks and check for TPM 1.2 tag.
>>
>> It might be, it wasn't clear to me if the tag could be trusted if the
>> return code wasn't success.  The Linux tpm2_probe() code bails before
>> the tag comparison if tpm_transmit_cmd() returns an error.
>>
>> Is there a block of QEMU code you would recommend as a reference for
>> probing TPMs?  I'm not very familiar with that code base, and a
>> pointer would be handy.
> 
> https://github.com/stefanberger/qemu-tpm/blob/v2.4.1%2Btpm/hw/tpm/tpm_util.c#L94
> 
> What I don't like about the sending of commands is that we're breaking the layer here. We basically cannot send commands using this higher level API. The lowest we could go would be to call tpmhw_transmit, but that function cannot be used as it is but has to be split up to take tpm_driver as a parameter. You would pass to it &tpm_drivers[TIS_DRIVER_INDEX].
> 
> As far as I know, TPM 1.2 didn't have that register, so they either return static 0 or 0xffffffff in that register.
> 
> Though if reading the flags from the interface register really turns out to be insufficient, I think you should try to send a command like TPM2_CC_ReadClock. If you get back a TPM2_ST_NO_SESSION, it's a TPM 2. If you get a TPM_TAG_RSP_COMMAND it's a TPM 12.

Thanks for all the info.  This gives me some experiments to run, and
I'll try to find a solution that avoids sending commands if possible.

>>
>>> Do you know what value does the InterfaceType show on your TIS? I only tested this with QEMU TIS and here we return 0x0 in those 4 bits, which means, following specs, 'FIFO interface as defined in PTP for TPM 2.0 is active'.
>>
>> I don't see it in my notes, I can put some debug prints back in
>> tomorrow and will get back to you.
>>
>> Thanks,
>> Steve
>>
>>>>
>>>> -    if ((ifaceid & 0xf) == 0) {
>>>> -        /* TPM 2 */
>>>> +    if (cpu_to_be32(trg->hdr.tag) == TPM2_ST_NO_SESSIONS)
>>>>           return TPM_VERSION_2;
>>>> -    }
>>>> +
>>>>       return TPM_VERSION_1_2;
>>>>   }
>>>>
>>>> diff --git a/src/std/tcg.h b/src/std/tcg.h
>>>> index 09a92d8..4c07493 100644
>>>> --- a/src/std/tcg.h
>>>> +++ b/src/std/tcg.h
>>>> @@ -357,6 +357,7 @@ struct tpm_res_sha1complete {
>>>>
>>>>   /* TPM 2 Capabilities */
>>>>   #define TPM2_CAP_PCRS               0x00000005
>>>> +#define TPM2_CAP_TPM_PROPERTIES     0x00000006
>>>>
>>>>   /* TPM 2 data structures */
>>>>
>>>> diff --git a/src/tcgbios.c b/src/tcgbios.c
>>>> index 40b3028..b86bf64 100644
>>>> --- a/src/tcgbios.c
>>>> +++ b/src/tcgbios.c
>>>> @@ -381,7 +381,7 @@ tpm_simple_cmd(u8 locty, u32 ordinal
>>>>       return ret;
>>>>   }
>>>>
>>>> -static int
>>>> +int
>>>>   tpm20_getcapability(u32 capability, u32 property, u32 count,
>>>>                       struct tpm_rsp_header *rsp, u32 rsize)
>>>>   {
>>>> diff --git a/src/tcgbios.h b/src/tcgbios.h
>>>> index 32fb941..9fc711a 100644
>>>> --- a/src/tcgbios.h
>>>> +++ b/src/tcgbios.h
>>>> @@ -1,6 +1,7 @@
>>>>   #ifndef TCGBIOS_H
>>>>   #define TCGBIOS_H
>>>>
>>>> +#include "std/tcg.h" // struct tpm_rsp_header
>>>>   #include "types.h"
>>>>
>>>>   struct bregs;
>>>> @@ -15,5 +16,8 @@ void tpm_add_cdrom_catalog(const u8 *addr, u32 length);
>>>>   void tpm_option_rom(const void *addr, u32 len);
>>>>   int tpm_can_show_menu(void);
>>>>   void tpm_menu(void);
>>>> +int
>>>> +tpm20_getcapability(u32 capability, u32 property, u32 count,
>>>> +                    struct tpm_rsp_header *rsp, u32 rsize);
>>>>
>>>>   #endif /* TCGBIOS_H */
>>>
>>>
>>
> 


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On 02/26/2018 06:24 PM, Stephen Douthit wrote:
> On 02/26/2018 06:02 PM, Stefan Berger wrote:
>> On 02/26/2018 05:44 PM, Stephen Douthit wrote:
>>> On 02/26/2018 05:09 PM, Stefan Berger wrote:
>>>> On 02/26/2018 03:37 PM, Stephen Douthit wrote:
>>>>> tis_get_tpm_version() was returning the interface version, which 
>>>>> is always
>>>>> 1.2 since tis_probe() would have failed if the interface wasn't TIS.
>>>>>
>>>>> New version check is based on the tpm2_probe() function from the 
>>>>> Linux
>>>>> tpm_tis driver.
>>>>>
>>>>> Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
>>>>> Tested-by: Stephen Douthit <stephend@silicom-usa.com>
>>>>> ---
>>>>>   src/hw/tpm_drivers.c | 21 +++++++++++++++------
>>>>>   src/std/tcg.h        |  1 +
>>>>>   src/tcgbios.c        |  2 +-
>>>>>   src/tcgbios.h        |  4 ++++
>>>>>   4 files changed, 21 insertions(+), 7 deletions(-)
>>>>>
>>>>> diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
>>>>> index 789d70a..32c34df 100644
>>>>> --- a/src/hw/tpm_drivers.c
>>>>> +++ b/src/hw/tpm_drivers.c
>>>>> @@ -11,6 +11,7 @@
>>>>>   #include "config.h" // CONFIG_TPM_TIS_SHA1THRESHOLD
>>>>>   #include "hw/tpm_drivers.h" // struct tpm_driver
>>>>>   #include "std/tcg.h" // TCG_RESPONSE_TIMEOUT
>>>>> +#include "tcgbios.h" // tpm20_getcapability
>>>>>   #include "output.h" // warn_timeout
>>>>>   #include "stacks.h" // yield
>>>>>   #include "string.h" // memcpy
>>>>> @@ -119,7 +120,7 @@ static u32 tis_probe(void)
>>>>>       if ((didvid != 0) && (didvid != 0xffffffff))
>>>>>           rc = 1;
>>>>>
>>>>> -    /* TPM 2 has an interface register */
>>>>> +    /* Low 32 bits of CRB interface register overlap TIS 
>>>>> interface register */
>>>>>       u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>>
>>>> Since this is tis_probe, I don't think we need to mention the CRB 
>>>> here ...
>>>
>>> I think that was a note to myself I forgot to strip out when I
>>> dropped my debug prints.  I'll change the comment back.
>>>
>>>>>
>>>>>       if ((ifaceid & 0xf) != 0xf) {
>>>>> @@ -142,13 +143,21 @@ static u32 tis_probe(void)
>>>>>
>>>>>   static TPMVersion tis_get_tpm_version(void)
>>>>>   {
>>>>> -    /* TPM 2 has an interface register */
>>>>> -    u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>>> +    u8 buffer[128];
>>>>> +    int ret;
>>>>> +    struct tpm2_res_getcapability *trg =
>>>>> +      (struct tpm2_res_getcapability *)&buffer;
>>>>> +
>>>>> +    ret = tpm20_getcapability(TPM2_CAP_TPM_PROPERTIES, 
>>>>> cpu_to_be32(0x100),
>>>>> +                              cpu_to_be32(1), &trg->hdr, 
>>>>> sizeof(buffer));
>>>>> +    if (ret == TPM2_RC_INITIALIZE)
>>>>> +        return TPM_VERSION_2;
>>>>> +    else if (ret)
>>>>> +        return TPM_VERSION_NONE;
>>>> I haven't tried yet, but likely this will not work for TPM 1.2 
>>>> since it will also return an error.
>>>
>>> Doh.  That makes sense.  I'll need to find a 1.2 system to test on to
>>> avoid stupid mistakes like that.
>>>
>>>> Wouldn't the check for the tag below not be sufficient? We are 
>>>> doing something similar in QEMU when probing for the TPM. Here we 
>>>> send TPM 2 command TPM_CC_ReadClock and check the tag for TPM 2 
>>>> type and then TPM 1.2 command TPM_ORD_GetTicks and check for TPM 
>>>> 1.2 tag.
>>>
>>> It might be, it wasn't clear to me if the tag could be trusted if the
>>> return code wasn't success.  The Linux tpm2_probe() code bails before
>>> the tag comparison if tpm_transmit_cmd() returns an error.
>>>
>>> Is there a block of QEMU code you would recommend as a reference for
>>> probing TPMs?  I'm not very familiar with that code base, and a
>>> pointer would be handy.
>>
>> https://github.com/stefanberger/qemu-tpm/blob/v2.4.1%2Btpm/hw/tpm/tpm_util.c#L94 
>>
>>
>> What I don't like about the sending of commands is that we're 
>> breaking the layer here. We basically cannot send commands using this 
>> higher level API. The lowest we could go would be to call 
>> tpmhw_transmit, but that function cannot be used as it is but has to 
>> be split up to take tpm_driver as a parameter. You would pass to it 
>> &tpm_drivers[TIS_DRIVER_INDEX].
>>
>> As far as I know, TPM 1.2 didn't have that register, so they either 
>> return static 0 or 0xffffffff in that register.
>>
>> Though if reading the flags from the interface register really turns 
>> out to be insufficient, I think you should try to send a command like 
>> TPM2_CC_ReadClock. If you get back a TPM2_ST_NO_SESSION, it's a TPM 
>> 2. If you get a TPM_TAG_RSP_COMMAND it's a TPM 12.
>
> Thanks for all the info.  This gives me some experiments to run, and
> I'll try to find a solution that avoids sending commands if possible.

The following document on pdf page 100 defines bits 28-30 of the 
interface capability register. If the value there is 0x3 (mask 0x7), we 
should be sure to have a TPM 2. Hopefully that's sufficient also for 
your device for determining that it's a TPM 2.

https://trustedcomputinggroup.org/wp-content/uploads/TCG_PC_Client_Platform_TPM_Profile_PTP_Specification_Family_2.0_Revision_1.3v22.pdf



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On 02/26/2018 07:45 PM, Stefan Berger wrote:
> On 02/26/2018 06:24 PM, Stephen Douthit wrote:
>> On 02/26/2018 06:02 PM, Stefan Berger wrote:
>>> On 02/26/2018 05:44 PM, Stephen Douthit wrote:
>>>> On 02/26/2018 05:09 PM, Stefan Berger wrote:
>>>>> On 02/26/2018 03:37 PM, Stephen Douthit wrote:
>>>>>> tis_get_tpm_version() was returning the interface version, which is always
>>>>>> 1.2 since tis_probe() would have failed if the interface wasn't TIS.
>>>>>>
>>>>>> New version check is based on the tpm2_probe() function from the Linux
>>>>>> tpm_tis driver.
>>>>>>
>>>>>> Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
>>>>>> Tested-by: Stephen Douthit <stephend@silicom-usa.com>
>>>>>> ---
>>>>>>   src/hw/tpm_drivers.c | 21 +++++++++++++++------
>>>>>>   src/std/tcg.h        |  1 +
>>>>>>   src/tcgbios.c        |  2 +-
>>>>>>   src/tcgbios.h        |  4 ++++
>>>>>>   4 files changed, 21 insertions(+), 7 deletions(-)
>>>>>>
>>>>>> diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
>>>>>> index 789d70a..32c34df 100644
>>>>>> --- a/src/hw/tpm_drivers.c
>>>>>> +++ b/src/hw/tpm_drivers.c
>>>>>> @@ -11,6 +11,7 @@
>>>>>>   #include "config.h" // CONFIG_TPM_TIS_SHA1THRESHOLD
>>>>>>   #include "hw/tpm_drivers.h" // struct tpm_driver
>>>>>>   #include "std/tcg.h" // TCG_RESPONSE_TIMEOUT
>>>>>> +#include "tcgbios.h" // tpm20_getcapability
>>>>>>   #include "output.h" // warn_timeout
>>>>>>   #include "stacks.h" // yield
>>>>>>   #include "string.h" // memcpy
>>>>>> @@ -119,7 +120,7 @@ static u32 tis_probe(void)
>>>>>>       if ((didvid != 0) && (didvid != 0xffffffff))
>>>>>>           rc = 1;
>>>>>>
>>>>>> -    /* TPM 2 has an interface register */
>>>>>> +    /* Low 32 bits of CRB interface register overlap TIS interface register */
>>>>>>       u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>>>
>>>>> Since this is tis_probe, I don't think we need to mention the CRB here ...
>>>>
>>>> I think that was a note to myself I forgot to strip out when I
>>>> dropped my debug prints.  I'll change the comment back.
>>>>
>>>>>>
>>>>>>       if ((ifaceid & 0xf) != 0xf) {
>>>>>> @@ -142,13 +143,21 @@ static u32 tis_probe(void)
>>>>>>
>>>>>>   static TPMVersion tis_get_tpm_version(void)
>>>>>>   {
>>>>>> -    /* TPM 2 has an interface register */
>>>>>> -    u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>>>> +    u8 buffer[128];
>>>>>> +    int ret;
>>>>>> +    struct tpm2_res_getcapability *trg =
>>>>>> +      (struct tpm2_res_getcapability *)&buffer;
>>>>>> +
>>>>>> +    ret = tpm20_getcapability(TPM2_CAP_TPM_PROPERTIES, cpu_to_be32(0x100),
>>>>>> +                              cpu_to_be32(1), &trg->hdr, sizeof(buffer));
>>>>>> +    if (ret == TPM2_RC_INITIALIZE)
>>>>>> +        return TPM_VERSION_2;
>>>>>> +    else if (ret)
>>>>>> +        return TPM_VERSION_NONE;
>>>>> I haven't tried yet, but likely this will not work for TPM 1.2 since it will also return an error.
>>>>
>>>> Doh.  That makes sense.  I'll need to find a 1.2 system to test on to
>>>> avoid stupid mistakes like that.
>>>>
>>>>> Wouldn't the check for the tag below not be sufficient? We are doing something similar in QEMU when probing for the TPM. Here we send TPM 2 command TPM_CC_ReadClock and check the tag for TPM 2 type and then TPM 1.2 command TPM_ORD_GetTicks and check for TPM 1.2 tag.
>>>>
>>>> It might be, it wasn't clear to me if the tag could be trusted if the
>>>> return code wasn't success.  The Linux tpm2_probe() code bails before
>>>> the tag comparison if tpm_transmit_cmd() returns an error.
>>>>
>>>> Is there a block of QEMU code you would recommend as a reference for
>>>> probing TPMs?  I'm not very familiar with that code base, and a
>>>> pointer would be handy.
>>>
>>> https://github.com/stefanberger/qemu-tpm/blob/v2.4.1%2Btpm/hw/tpm/tpm_util.c#L94
>>>
>>> What I don't like about the sending of commands is that we're breaking the layer here. We basically cannot send commands using this higher level API. The lowest we could go would be to call tpmhw_transmit, but that function cannot be used as it is but has to be split up to take tpm_driver as a parameter. You would pass to it &tpm_drivers[TIS_DRIVER_INDEX].
>>>
>>> As far as I know, TPM 1.2 didn't have that register, so they either return static 0 or 0xffffffff in that register.
>>>
>>> Though if reading the flags from the interface register really turns out to be insufficient, I think you should try to send a command like TPM2_CC_ReadClock. If you get back a TPM2_ST_NO_SESSION, it's a TPM 2. If you get a TPM_TAG_RSP_COMMAND it's a TPM 12.
>>
>> Thanks for all the info.  This gives me some experiments to run, and
>> I'll try to find a solution that avoids sending commands if possible.
> 
> The following document on pdf page 100 defines bits 28-30 of the interface capability register. If the value there is 0x3 (mask 0x7), we should be sure to have a TPM 2. Hopefully that's sufficient also for your device for determining that it's a TPM 2.
> 
> https://trustedcomputinggroup.org/wp-content/uploads/TCG_PC_Client_Platform_TPM_Profile_PTP_Specification_Family_2.0_Revision_1.3v22.pdf
> 
> 

My interface ID reads as 0xffffffff, and the interface capability
register reads as intf_cap 0x30000697.  So your suggestion of
checking for 3 in that bitfield of the interface capability register
works here.

If I change the version check function to the following and drop all
the other changes from patch 3/3 would that be acceptable?

static TPMVersion tis_get_tpm_version(void)
{
     u32 reg = readl(TIS_REG(0, TIS_REG_IFACE_ID));

     /* FIFO interface as defined in PTP for TPM 2.0 is active */
     if ((reg & 0xf) == 0) {
         return TPM_VERSION_2;
     }
     /*
      * FIFO interface as defined in TIS1.3 is active
      * Interface capabilities are defined in TIS_REG_INTF_CAPABILITY
      */
     else if ((reg & 0xf) == 0xf) {
         reg = readl(TIS_REG(0, TIS_REG_INTF_CAPABILITY));
         /* Interface 1.3 for TPM 2.0 */
         if (((reg >> 28) & 0x7) == 3)
             return TPM_VERSION_2;
     }

     return TPM_VERSION_1_2;
}

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On 02/27/2018 12:14 PM, Stephen Douthit wrote:
> On 02/26/2018 07:45 PM, Stefan Berger wrote:
>> On 02/26/2018 06:24 PM, Stephen Douthit wrote:
>>> On 02/26/2018 06:02 PM, Stefan Berger wrote:
>>>> On 02/26/2018 05:44 PM, Stephen Douthit wrote:
>>>>> On 02/26/2018 05:09 PM, Stefan Berger wrote:
>>>>>> On 02/26/2018 03:37 PM, Stephen Douthit wrote:
>>>>>>> tis_get_tpm_version() was returning the interface version, which 
>>>>>>> is always
>>>>>>> 1.2 since tis_probe() would have failed if the interface wasn't 
>>>>>>> TIS.
>>>>>>>
>>>>>>> New version check is based on the tpm2_probe() function from the 
>>>>>>> Linux
>>>>>>> tpm_tis driver.
>>>>>>>
>>>>>>> Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
>>>>>>> Tested-by: Stephen Douthit <stephend@silicom-usa.com>
>>>>>>> ---
>>>>>>>   src/hw/tpm_drivers.c | 21 +++++++++++++++------
>>>>>>>   src/std/tcg.h        |  1 +
>>>>>>>   src/tcgbios.c        |  2 +-
>>>>>>>   src/tcgbios.h        |  4 ++++
>>>>>>>   4 files changed, 21 insertions(+), 7 deletions(-)
>>>>>>>
>>>>>>> diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
>>>>>>> index 789d70a..32c34df 100644
>>>>>>> --- a/src/hw/tpm_drivers.c
>>>>>>> +++ b/src/hw/tpm_drivers.c
>>>>>>> @@ -11,6 +11,7 @@
>>>>>>>   #include "config.h" // CONFIG_TPM_TIS_SHA1THRESHOLD
>>>>>>>   #include "hw/tpm_drivers.h" // struct tpm_driver
>>>>>>>   #include "std/tcg.h" // TCG_RESPONSE_TIMEOUT
>>>>>>> +#include "tcgbios.h" // tpm20_getcapability
>>>>>>>   #include "output.h" // warn_timeout
>>>>>>>   #include "stacks.h" // yield
>>>>>>>   #include "string.h" // memcpy
>>>>>>> @@ -119,7 +120,7 @@ static u32 tis_probe(void)
>>>>>>>       if ((didvid != 0) && (didvid != 0xffffffff))
>>>>>>>           rc = 1;
>>>>>>>
>>>>>>> -    /* TPM 2 has an interface register */
>>>>>>> +    /* Low 32 bits of CRB interface register overlap TIS 
>>>>>>> interface register */
>>>>>>>       u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>>>>
>>>>>> Since this is tis_probe, I don't think we need to mention the CRB 
>>>>>> here ...
>>>>>
>>>>> I think that was a note to myself I forgot to strip out when I
>>>>> dropped my debug prints.  I'll change the comment back.
>>>>>
>>>>>>>
>>>>>>>       if ((ifaceid & 0xf) != 0xf) {
>>>>>>> @@ -142,13 +143,21 @@ static u32 tis_probe(void)
>>>>>>>
>>>>>>>   static TPMVersion tis_get_tpm_version(void)
>>>>>>>   {
>>>>>>> -    /* TPM 2 has an interface register */
>>>>>>> -    u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>>>>> +    u8 buffer[128];
>>>>>>> +    int ret;
>>>>>>> +    struct tpm2_res_getcapability *trg =
>>>>>>> +      (struct tpm2_res_getcapability *)&buffer;
>>>>>>> +
>>>>>>> +    ret = tpm20_getcapability(TPM2_CAP_TPM_PROPERTIES, 
>>>>>>> cpu_to_be32(0x100),
>>>>>>> +                              cpu_to_be32(1), &trg->hdr, 
>>>>>>> sizeof(buffer));
>>>>>>> +    if (ret == TPM2_RC_INITIALIZE)
>>>>>>> +        return TPM_VERSION_2;
>>>>>>> +    else if (ret)
>>>>>>> +        return TPM_VERSION_NONE;
>>>>>> I haven't tried yet, but likely this will not work for TPM 1.2 
>>>>>> since it will also return an error.
>>>>>
>>>>> Doh.  That makes sense.  I'll need to find a 1.2 system to test on to
>>>>> avoid stupid mistakes like that.
>>>>>
>>>>>> Wouldn't the check for the tag below not be sufficient? We are 
>>>>>> doing something similar in QEMU when probing for the TPM. Here we 
>>>>>> send TPM 2 command TPM_CC_ReadClock and check the tag for TPM 2 
>>>>>> type and then TPM 1.2 command TPM_ORD_GetTicks and check for TPM 
>>>>>> 1.2 tag.
>>>>>
>>>>> It might be, it wasn't clear to me if the tag could be trusted if the
>>>>> return code wasn't success.  The Linux tpm2_probe() code bails before
>>>>> the tag comparison if tpm_transmit_cmd() returns an error.
>>>>>
>>>>> Is there a block of QEMU code you would recommend as a reference for
>>>>> probing TPMs?  I'm not very familiar with that code base, and a
>>>>> pointer would be handy.
>>>>
>>>> https://github.com/stefanberger/qemu-tpm/blob/v2.4.1%2Btpm/hw/tpm/tpm_util.c#L94 
>>>>
>>>>
>>>> What I don't like about the sending of commands is that we're 
>>>> breaking the layer here. We basically cannot send commands using 
>>>> this higher level API. The lowest we could go would be to call 
>>>> tpmhw_transmit, but that function cannot be used as it is but has 
>>>> to be split up to take tpm_driver as a parameter. You would pass to 
>>>> it &tpm_drivers[TIS_DRIVER_INDEX].
>>>>
>>>> As far as I know, TPM 1.2 didn't have that register, so they either 
>>>> return static 0 or 0xffffffff in that register.
>>>>
>>>> Though if reading the flags from the interface register really 
>>>> turns out to be insufficient, I think you should try to send a 
>>>> command like TPM2_CC_ReadClock. If you get back a 
>>>> TPM2_ST_NO_SESSION, it's a TPM 2. If you get a TPM_TAG_RSP_COMMAND 
>>>> it's a TPM 12.
>>>
>>> Thanks for all the info.  This gives me some experiments to run, and
>>> I'll try to find a solution that avoids sending commands if possible.
>>
>> The following document on pdf page 100 defines bits 28-30 of the 
>> interface capability register. If the value there is 0x3 (mask 0x7), 
>> we should be sure to have a TPM 2. Hopefully that's sufficient also 
>> for your device for determining that it's a TPM 2.
>>
>> https://trustedcomputinggroup.org/wp-content/uploads/TCG_PC_Client_Platform_TPM_Profile_PTP_Specification_Family_2.0_Revision_1.3v22.pdf 
>>
>>
>>
>
> My interface ID reads as 0xffffffff, and the interface capability
> register reads as intf_cap 0x30000697.  So your suggestion of
> checking for 3 in that bitfield of the interface capability register
> works here.
>
> If I change the version check function to the following and drop all
> the other changes from patch 3/3 would that be acceptable?
>
> static TPMVersion tis_get_tpm_version(void)
> {
>     u32 reg = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>
>     /* FIFO interface as defined in PTP for TPM 2.0 is active */
>     if ((reg & 0xf) == 0) {
>         return TPM_VERSION_2;
>     }
>     /*
>      * FIFO interface as defined in TIS1.3 is active
>      * Interface capabilities are defined in TIS_REG_INTF_CAPABILITY
>      */
>     else if ((reg & 0xf) == 0xf) {
>         reg = readl(TIS_REG(0, TIS_REG_INTF_CAPABILITY));
>         /* Interface 1.3 for TPM 2.0 */
>         if (((reg >> 28) & 0x7) == 3)
>             return TPM_VERSION_2;


I think this is actually the better test and you should put this one up 
front.

    Stefan

>     }
>
>     return TPM_VERSION_1_2;
> }
>


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On 02/27/2018 12:17 PM, Stefan Berger wrote:
> On 02/27/2018 12:14 PM, Stephen Douthit wrote:
>> On 02/26/2018 07:45 PM, Stefan Berger wrote:
>>> On 02/26/2018 06:24 PM, Stephen Douthit wrote:
>>>> On 02/26/2018 06:02 PM, Stefan Berger wrote:
>>>>> On 02/26/2018 05:44 PM, Stephen Douthit wrote:
>>>>>> On 02/26/2018 05:09 PM, Stefan Berger wrote:
>>>>>>> On 02/26/2018 03:37 PM, Stephen Douthit wrote:
>>>>>>>> tis_get_tpm_version() was returning the interface version, which is always
>>>>>>>> 1.2 since tis_probe() would have failed if the interface wasn't TIS.
>>>>>>>>
>>>>>>>> New version check is based on the tpm2_probe() function from the Linux
>>>>>>>> tpm_tis driver.
>>>>>>>>
>>>>>>>> Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
>>>>>>>> Tested-by: Stephen Douthit <stephend@silicom-usa.com>
>>>>>>>> ---
>>>>>>>>   src/hw/tpm_drivers.c | 21 +++++++++++++++------
>>>>>>>>   src/std/tcg.h        |  1 +
>>>>>>>>   src/tcgbios.c        |  2 +-
>>>>>>>>   src/tcgbios.h        |  4 ++++
>>>>>>>>   4 files changed, 21 insertions(+), 7 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
>>>>>>>> index 789d70a..32c34df 100644
>>>>>>>> --- a/src/hw/tpm_drivers.c
>>>>>>>> +++ b/src/hw/tpm_drivers.c
>>>>>>>> @@ -11,6 +11,7 @@
>>>>>>>>   #include "config.h" // CONFIG_TPM_TIS_SHA1THRESHOLD
>>>>>>>>   #include "hw/tpm_drivers.h" // struct tpm_driver
>>>>>>>>   #include "std/tcg.h" // TCG_RESPONSE_TIMEOUT
>>>>>>>> +#include "tcgbios.h" // tpm20_getcapability
>>>>>>>>   #include "output.h" // warn_timeout
>>>>>>>>   #include "stacks.h" // yield
>>>>>>>>   #include "string.h" // memcpy
>>>>>>>> @@ -119,7 +120,7 @@ static u32 tis_probe(void)
>>>>>>>>       if ((didvid != 0) && (didvid != 0xffffffff))
>>>>>>>>           rc = 1;
>>>>>>>>
>>>>>>>> -    /* TPM 2 has an interface register */
>>>>>>>> +    /* Low 32 bits of CRB interface register overlap TIS interface register */
>>>>>>>>       u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>>>>>
>>>>>>> Since this is tis_probe, I don't think we need to mention the CRB here ...
>>>>>>
>>>>>> I think that was a note to myself I forgot to strip out when I
>>>>>> dropped my debug prints.  I'll change the comment back.
>>>>>>
>>>>>>>>
>>>>>>>>       if ((ifaceid & 0xf) != 0xf) {
>>>>>>>> @@ -142,13 +143,21 @@ static u32 tis_probe(void)
>>>>>>>>
>>>>>>>>   static TPMVersion tis_get_tpm_version(void)
>>>>>>>>   {
>>>>>>>> -    /* TPM 2 has an interface register */
>>>>>>>> -    u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>>>>>> +    u8 buffer[128];
>>>>>>>> +    int ret;
>>>>>>>> +    struct tpm2_res_getcapability *trg =
>>>>>>>> +      (struct tpm2_res_getcapability *)&buffer;
>>>>>>>> +
>>>>>>>> +    ret = tpm20_getcapability(TPM2_CAP_TPM_PROPERTIES, cpu_to_be32(0x100),
>>>>>>>> +                              cpu_to_be32(1), &trg->hdr, sizeof(buffer));
>>>>>>>> +    if (ret == TPM2_RC_INITIALIZE)
>>>>>>>> +        return TPM_VERSION_2;
>>>>>>>> +    else if (ret)
>>>>>>>> +        return TPM_VERSION_NONE;
>>>>>>> I haven't tried yet, but likely this will not work for TPM 1.2 since it will also return an error.
>>>>>>
>>>>>> Doh.  That makes sense.  I'll need to find a 1.2 system to test on to
>>>>>> avoid stupid mistakes like that.
>>>>>>
>>>>>>> Wouldn't the check for the tag below not be sufficient? We are doing something similar in QEMU when probing for the TPM. Here we send TPM 2 command TPM_CC_ReadClock and check the tag for TPM 2 type and then TPM 1.2 command TPM_ORD_GetTicks and check for TPM 1.2 tag.
>>>>>>
>>>>>> It might be, it wasn't clear to me if the tag could be trusted if the
>>>>>> return code wasn't success.  The Linux tpm2_probe() code bails before
>>>>>> the tag comparison if tpm_transmit_cmd() returns an error.
>>>>>>
>>>>>> Is there a block of QEMU code you would recommend as a reference for
>>>>>> probing TPMs?  I'm not very familiar with that code base, and a
>>>>>> pointer would be handy.
>>>>>
>>>>> https://github.com/stefanberger/qemu-tpm/blob/v2.4.1%2Btpm/hw/tpm/tpm_util.c#L94
>>>>>
>>>>> What I don't like about the sending of commands is that we're breaking the layer here. We basically cannot send commands using this higher level API. The lowest we could go would be to call tpmhw_transmit, but that function cannot be used as it is but has to be split up to take tpm_driver as a parameter. You would pass to it &tpm_drivers[TIS_DRIVER_INDEX].
>>>>>
>>>>> As far as I know, TPM 1.2 didn't have that register, so they either return static 0 or 0xffffffff in that register.
>>>>>
>>>>> Though if reading the flags from the interface register really turns out to be insufficient, I think you should try to send a command like TPM2_CC_ReadClock. If you get back a TPM2_ST_NO_SESSION, it's a TPM 2. If you get a TPM_TAG_RSP_COMMAND it's a TPM 12.
>>>>
>>>> Thanks for all the info.  This gives me some experiments to run, and
>>>> I'll try to find a solution that avoids sending commands if possible.
>>>
>>> The following document on pdf page 100 defines bits 28-30 of the interface capability register. If the value there is 0x3 (mask 0x7), we should be sure to have a TPM 2. Hopefully that's sufficient also for your device for determining that it's a TPM 2.
>>>
>>> https://trustedcomputinggroup.org/wp-content/uploads/TCG_PC_Client_Platform_TPM_Profile_PTP_Specification_Family_2.0_Revision_1.3v22.pdf
>>>
>>>
>>
>> My interface ID reads as 0xffffffff, and the interface capability
>> register reads as intf_cap 0x30000697.  So your suggestion of
>> checking for 3 in that bitfield of the interface capability register
>> works here.
>>
>> If I change the version check function to the following and drop all
>> the other changes from patch 3/3 would that be acceptable?
>>
>> static TPMVersion tis_get_tpm_version(void)
>> {
>>     u32 reg = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>
>>     /* FIFO interface as defined in PTP for TPM 2.0 is active */
>>     if ((reg & 0xf) == 0) {
>>         return TPM_VERSION_2;
>>     }
>>     /*
>>      * FIFO interface as defined in TIS1.3 is active
>>      * Interface capabilities are defined in TIS_REG_INTF_CAPABILITY
>>      */
>>     else if ((reg & 0xf) == 0xf) {
>>         reg = readl(TIS_REG(0, TIS_REG_INTF_CAPABILITY));
>>         /* Interface 1.3 for TPM 2.0 */
>>         if (((reg >> 28) & 0x7) == 3)
>>             return TPM_VERSION_2;
> 
> 
> I think this is actually the better test and you should put this one up front.

By "up front" do you want me to swap the order of if/else if tests,
or make this the first patch in the series?

>     Stefan
> 
>>     }
>>
>>     return TPM_VERSION_1_2;
>> }
>>
> 


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On 02/27/2018 12:35 PM, Stephen Douthit wrote:
> On 02/27/2018 12:17 PM, Stefan Berger wrote:
>> On 02/27/2018 12:14 PM, Stephen Douthit wrote:
>>> On 02/26/2018 07:45 PM, Stefan Berger wrote:
>>>> On 02/26/2018 06:24 PM, Stephen Douthit wrote:
>>>>> On 02/26/2018 06:02 PM, Stefan Berger wrote:
>>>>>> On 02/26/2018 05:44 PM, Stephen Douthit wrote:
>>>>>>> On 02/26/2018 05:09 PM, Stefan Berger wrote:
>>>>>>>> On 02/26/2018 03:37 PM, Stephen Douthit wrote:
>>>>>>>>> tis_get_tpm_version() was returning the interface version, 
>>>>>>>>> which is always
>>>>>>>>> 1.2 since tis_probe() would have failed if the interface 
>>>>>>>>> wasn't TIS.
>>>>>>>>>
>>>>>>>>> New version check is based on the tpm2_probe() function from 
>>>>>>>>> the Linux
>>>>>>>>> tpm_tis driver.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
>>>>>>>>> Tested-by: Stephen Douthit <stephend@silicom-usa.com>
>>>>>>>>> ---
>>>>>>>>>   src/hw/tpm_drivers.c | 21 +++++++++++++++------
>>>>>>>>>   src/std/tcg.h        |  1 +
>>>>>>>>>   src/tcgbios.c        |  2 +-
>>>>>>>>>   src/tcgbios.h        |  4 ++++
>>>>>>>>>   4 files changed, 21 insertions(+), 7 deletions(-)
>>>>>>>>>
>>>>>>>>> diff --git a/src/hw/tpm_drivers.c b/src/hw/tpm_drivers.c
>>>>>>>>> index 789d70a..32c34df 100644
>>>>>>>>> --- a/src/hw/tpm_drivers.c
>>>>>>>>> +++ b/src/hw/tpm_drivers.c
>>>>>>>>> @@ -11,6 +11,7 @@
>>>>>>>>>   #include "config.h" // CONFIG_TPM_TIS_SHA1THRESHOLD
>>>>>>>>>   #include "hw/tpm_drivers.h" // struct tpm_driver
>>>>>>>>>   #include "std/tcg.h" // TCG_RESPONSE_TIMEOUT
>>>>>>>>> +#include "tcgbios.h" // tpm20_getcapability
>>>>>>>>>   #include "output.h" // warn_timeout
>>>>>>>>>   #include "stacks.h" // yield
>>>>>>>>>   #include "string.h" // memcpy
>>>>>>>>> @@ -119,7 +120,7 @@ static u32 tis_probe(void)
>>>>>>>>>       if ((didvid != 0) && (didvid != 0xffffffff))
>>>>>>>>>           rc = 1;
>>>>>>>>>
>>>>>>>>> -    /* TPM 2 has an interface register */
>>>>>>>>> +    /* Low 32 bits of CRB interface register overlap TIS 
>>>>>>>>> interface register */
>>>>>>>>>       u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>>>>>>
>>>>>>>> Since this is tis_probe, I don't think we need to mention the 
>>>>>>>> CRB here ...
>>>>>>>
>>>>>>> I think that was a note to myself I forgot to strip out when I
>>>>>>> dropped my debug prints.  I'll change the comment back.
>>>>>>>
>>>>>>>>>
>>>>>>>>>       if ((ifaceid & 0xf) != 0xf) {
>>>>>>>>> @@ -142,13 +143,21 @@ static u32 tis_probe(void)
>>>>>>>>>
>>>>>>>>>   static TPMVersion tis_get_tpm_version(void)
>>>>>>>>>   {
>>>>>>>>> -    /* TPM 2 has an interface register */
>>>>>>>>> -    u32 ifaceid = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>>>>>>> +    u8 buffer[128];
>>>>>>>>> +    int ret;
>>>>>>>>> +    struct tpm2_res_getcapability *trg =
>>>>>>>>> +      (struct tpm2_res_getcapability *)&buffer;
>>>>>>>>> +
>>>>>>>>> +    ret = tpm20_getcapability(TPM2_CAP_TPM_PROPERTIES, 
>>>>>>>>> cpu_to_be32(0x100),
>>>>>>>>> +                              cpu_to_be32(1), &trg->hdr, 
>>>>>>>>> sizeof(buffer));
>>>>>>>>> +    if (ret == TPM2_RC_INITIALIZE)
>>>>>>>>> +        return TPM_VERSION_2;
>>>>>>>>> +    else if (ret)
>>>>>>>>> +        return TPM_VERSION_NONE;
>>>>>>>> I haven't tried yet, but likely this will not work for TPM 1.2 
>>>>>>>> since it will also return an error.
>>>>>>>
>>>>>>> Doh.  That makes sense.  I'll need to find a 1.2 system to test 
>>>>>>> on to
>>>>>>> avoid stupid mistakes like that.
>>>>>>>
>>>>>>>> Wouldn't the check for the tag below not be sufficient? We are 
>>>>>>>> doing something similar in QEMU when probing for the TPM. Here 
>>>>>>>> we send TPM 2 command TPM_CC_ReadClock and check the tag for 
>>>>>>>> TPM 2 type and then TPM 1.2 command TPM_ORD_GetTicks and check 
>>>>>>>> for TPM 1.2 tag.
>>>>>>>
>>>>>>> It might be, it wasn't clear to me if the tag could be trusted 
>>>>>>> if the
>>>>>>> return code wasn't success.  The Linux tpm2_probe() code bails 
>>>>>>> before
>>>>>>> the tag comparison if tpm_transmit_cmd() returns an error.
>>>>>>>
>>>>>>> Is there a block of QEMU code you would recommend as a reference 
>>>>>>> for
>>>>>>> probing TPMs?  I'm not very familiar with that code base, and a
>>>>>>> pointer would be handy.
>>>>>>
>>>>>> https://github.com/stefanberger/qemu-tpm/blob/v2.4.1%2Btpm/hw/tpm/tpm_util.c#L94 
>>>>>>
>>>>>>
>>>>>> What I don't like about the sending of commands is that we're 
>>>>>> breaking the layer here. We basically cannot send commands using 
>>>>>> this higher level API. The lowest we could go would be to call 
>>>>>> tpmhw_transmit, but that function cannot be used as it is but has 
>>>>>> to be split up to take tpm_driver as a parameter. You would pass 
>>>>>> to it &tpm_drivers[TIS_DRIVER_INDEX].
>>>>>>
>>>>>> As far as I know, TPM 1.2 didn't have that register, so they 
>>>>>> either return static 0 or 0xffffffff in that register.
>>>>>>
>>>>>> Though if reading the flags from the interface register really 
>>>>>> turns out to be insufficient, I think you should try to send a 
>>>>>> command like TPM2_CC_ReadClock. If you get back a 
>>>>>> TPM2_ST_NO_SESSION, it's a TPM 2. If you get a 
>>>>>> TPM_TAG_RSP_COMMAND it's a TPM 12.
>>>>>
>>>>> Thanks for all the info.  This gives me some experiments to run, and
>>>>> I'll try to find a solution that avoids sending commands if possible.
>>>>
>>>> The following document on pdf page 100 defines bits 28-30 of the 
>>>> interface capability register. If the value there is 0x3 (mask 
>>>> 0x7), we should be sure to have a TPM 2. Hopefully that's 
>>>> sufficient also for your device for determining that it's a TPM 2.
>>>>
>>>> https://trustedcomputinggroup.org/wp-content/uploads/TCG_PC_Client_Platform_TPM_Profile_PTP_Specification_Family_2.0_Revision_1.3v22.pdf 
>>>>
>>>>
>>>>
>>>
>>> My interface ID reads as 0xffffffff, and the interface capability
>>> register reads as intf_cap 0x30000697.  So your suggestion of
>>> checking for 3 in that bitfield of the interface capability register
>>> works here.
>>>
>>> If I change the version check function to the following and drop all
>>> the other changes from patch 3/3 would that be acceptable?
>>>
>>> static TPMVersion tis_get_tpm_version(void)
>>> {
>>>     u32 reg = readl(TIS_REG(0, TIS_REG_IFACE_ID));
>>>
>>>     /* FIFO interface as defined in PTP for TPM 2.0 is active */
>>>     if ((reg & 0xf) == 0) {
>>>         return TPM_VERSION_2;
>>>     }
>>>     /*
>>>      * FIFO interface as defined in TIS1.3 is active
>>>      * Interface capabilities are defined in TIS_REG_INTF_CAPABILITY
>>>      */
>>>     else if ((reg & 0xf) == 0xf) {
>>>         reg = readl(TIS_REG(0, TIS_REG_INTF_CAPABILITY));
>>>         /* Interface 1.3 for TPM 2.0 */
>>>         if (((reg >> 28) & 0x7) == 3)
>>>             return TPM_VERSION_2;
>>
>>
>> I think this is actually the better test and you should put this one 
>> up front.
>
> By "up front" do you want me to swap the order of if/else if tests,
> or make this the first patch in the series?

Make this the first test in tis_get_tpm_version().


>
>>     Stefan
>>
>>>     }
>>>
>>>     return TPM_VERSION_1_2;
>>> }
>>>
>>
>


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