[Qemu-discuss] Trustedgrub2 reports No TPM found

[anshul makkar]

Hi,

I had a working vTPM solution with TPM 1.2 using swtpm, libtpm qemu2.8, 
cuse.

I wanted to try TPM 2.0 so I switched to:

swtpm: tpm2-preview branch. Compiled using ./configure --with-tpm2 
--enable-debug --enable-cuse

libtpm: tpm2-preview.rev142 branch. Compiled using ./configure 
--with-tpm2 --enable-debug

Installed TPM2.0-TSS software stack.

Using seabios with TPM patches and TrustedGrub2. 
https://github.com/ts468/seabios-tpm

Now when I start guest with TrustedGrub2, I get an error message from 
grub that TPM device not found. Even Windows guest fails to detect TPM.

Command that I used to start the guest

swtpm_cuse --tpm2 -M 260 -m 1 -n vtpm0 . I can see /dev/vtpm0 after this 
command.

Launch the guest: sudo qemu-system-x86_64  -enable-kvm  -m 2048 -boot b 
-bios seabios.bin -boot menu=on -tpmdev cuse-tpm,id=tpm0,path=/dev/vtpm0 
-device tpm-tis,tpmdev=tpm0 -drive format=raw,file=ubuntu.img

I debugged TrustedGrub2.0 code and found that it issues BIOS call INT 
1Ah, (AH)=BBh,(AL)=00h ( TCG_StatusCheck ) which fails.

TPM 1.2 used to work fine, so just wondering if I have missed any 
components.


Please can you share your thoughts.

Thanks

Anshul Makkar