[Xen-users] vTPM operations info

[Andrea Genuise <andrea.genuise@xxxxxxxxxxxxxxxxxx>]

Hi,

I'm studying the behaviour and the performances of the XEN vTPM
architecture,
so I have configured an environment using CentOS 7 both for host and guest.

When I start a guest with the vtpm attached, I see this output inside
the vtpm console:

[...]
tpm_integrity.c:58: Info: TPM_PCRRead()
tpm_cmd_handler.c:4161: Info: TPM command succeeded
tpm_data.c:209: Debug: size of permanent data: 6963
vtpmblk.c:69: Debug: Begin Write data=0x20008096e0 1en=6992 slot=1
ssize=1048576
vtpmblk.c:88: Info: Wrote 6992 bytes to NVM persistent storage
vtpm_cmd.c:201: Info: Sending encryption key to backend
tpm_cmd_handler.c:4220: Debug: tpm_handle_command(0)
tpm_cmd_handler.c:3517: Debug: [TPM_TAG_RQU_COMMAND]
tpm_cmd_hand1er.c:3883: Debug: [TPM_ORD_PCRRead]
tpm_integrity.c:58: Info: TPM_PCRRead()
tpm_cmd_handler.c:4161: Info: TPM command succeeded
tpm_data.c:209: Debug: size of permanent data: 6963
vtpmblk.c:69: Debug: Begin Write data=0x20008096e0 1en=6992 slot=0
ssize=1048576
vtpmblk.c:88: Info: Wrote 6992 bytes to NVM persistent storage
vtpm_cmd.c:201: Info: Sending encryption key to backend
tpm_cmd_handler.c:4220: Debug: tpm_handle_command(0)
tpm_cmd_handler.c:3517: Debug: [TPM_TAG_RQU_COMMAND]
tpm_cmd_handler.c:3878: Debug: [TPM_ORD_Extend]
tpm_integrity.c:39: Info: TPM_Extend()
tpm_cmd_hand1er.c:4161: Info: TPM command succeeded
tpm_data.c:209: Debug: size of permanent data: 6963
vtpmblk.c:69: Debug: Begin Write data=0x20008096e0 1en=6992 slot=1
ssize=1048576
vtpmblk.c:88: Info: Wrote 6992 bytes to NVM persistent storage
vtpm_cmd.c:201: Info: Sending encryption key to backend
tpm_cmd_handler.c:4220: Debug: tpm_handle_command(0)
tpm_cmd_handler.c:3517: Debug: [TPM_TAG_RQU_COMMAND]
tpm_cmd_handler.c:3818: Debug: [TPM_ORD_GetRandom]
tpm_crypto.c:218: Info: TPM_GetRandom()
tpm_cmd_handler.c:4161: Info: TPM command succeeded
tpm_data.c:209: Debug: size of permanent data: 6963
vtpmblk.c:69: Debug: Begin Write data=0x2000809670 1en=6992 slot=0
ssize=1048576
vtpmblk.c:88: Info: Wrote 6992 bytes to NVM persistent storage
vtpm_cmd.c:201: Info: Sending encryption key to backend
tpm_cmd_handler.c:4220: Debug: tpm_handle_command(0)
tpm_cmd_handler.c:3517: Debug: [TPM_TAG_RQU_COMMAND]
tpm_cmd_handler.c:3818: Debug: [TPM_ORD_GetRandom]
[...]

I know that the single TPM_Extend() operation is performed by IMA,
which extends the boot_aggregate into PCR 10.

But actually there are a lot of PCRRead() and GetRandom() calls (omitted
here).
Any idea about who could have requested them from within the VM?
Perhaps the xen-tpmfront driver did it at init time?

I'd like to know who is the caller of that commands.

Thank you.

Regards,
Andrea

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