Re: [Qemu-discuss] QEMU-TPM with SeaBIOS

[Jakob Bohm]

On 8/15/2012 9:40 AM, khan wahid wrote:
> Hi,
> I want to build a trusted integrity measurement OS, so that a remote party can 
> check the system's integrity. But I don't have a hardware TPM, so I run the TPM 
> emulator (http://tpm-emulator.berlios.de/) and patched my Qemu and SeaBIOS with 
> the TPM related Patches (provided by Mr. Stefan Berger) to test the integrity 
> measurement in virtual machine based Linux. To launch a Linux through Qemu, at 
> first I compiled Linux from the source with Kernel-IMA functionality. Now I 
> have the following files-
> The compiled kernel-IMA image at 
> /home/rrsuj/linux-2.6.32.59/arch/x86/boot/bzImage
> And the new initrd at /boot/initrd.img-2.6.32.59
> The patched bios.bin at /home/rrsuj/seabios-0.6.2/out/bios.bin
>
> I first check that the TPM emulator is running, so that Qemu and SeaBIOS find a 
> TPM (although virtual). Then I execute the following command -
>
> #qemu-system-i386  -kernel  /home/rrsuj/linux-2.6.32.59/arch/x86/boot/bzImage  
> -initrd /boot/initrd.img-2.6.32.59  -bios 
> /home/rrsuj/Downloads/seabios/seabios-0.6.2/out/bios.bin
> It tries to boot Linux, but gives error-
> "VFS: cannot open root device "<NULL>" or unknown-block (8,1)"
> "Please append a correct "root=" boot option;"

In other words, the default root device indicated by a few reserved bytes
near the start of your bzImage or dynamically set by code in your
initrd.img was blockdev major 8, minor 1 a.k.a. /dev/sda1, but neither your
bzImage nor any modules loaded by your initrd.img knew how to map
"blockdev 8,1" to "sda1".  So I guess you haven't loaded the relevant SCSI
driver.

> So I did-
> #qemu-system-i386 -kernel /home/rrsuj/Downloads/linux-2.6.32.59/arch/x86/boot/bzImage  
> -initrd /boot/initrd.img-2.6.32.59  -append "root=/dev/sda1"  -bios 
> /home/rrsuj/Downloads/seabios/seabios-0.6.2/out/bios.bin
> but the error changes slightly-
> "VFS: cannot open root device "sda1" or unknown-block (0,0)"
> "Please append a correct "root=" boot option;"

So this time, neither your bzImage, nor any of the loaded modules knew
how to map "sda1" to "(8,1)", probably for the same reason as in your
first attempt.

> The output of "sudo fdisk -l" is-
> Device Boot      Start         End      Blocks   Id  System
> /dev/sda1   *           1        2686    21569536   83  Linux
> /dev/sda2            2686        2808      979969    5  Extended
> /dev/sda5            2686        2808      979968   82  Linux swap / Solaris

How did you run this command if you could not boot your vm?

I guess you ran this using a different kernel or initrd which did load 
the proper drivers.

> So please tell me, what should I do? I had a plan to install TrustedGrub inside 
> the virtual machine (the guest Linux), so that I can measure the total system 
> from SeaBIOS to TrustedGrub to Linux-IMA. But it is not booting as I mentioned.
> Thank you for your help.
> Best regards


--
Jakob Bohm, CIO, partner, WiseMo A/S. http://www.wisemo.com
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