Re: [Qemu-devel] Is is possible to virtualise or share the TPM?

[Jordi Cucurull Juan]

Dear Stefan,

What does it mean that the patches with the VTPM functionality exist but 
they are behind the regular ones? Does it mean that they are not 
currently updated? That they have less priority?

Best regards,
Jordi.



On 08/29/2012 02:57 PM, Stefan Berger wrote:
> On 08/23/2012 04:05 PM, Corey Bryant wrote:
> > On 08/21/2012 06:31 AM, Jordi Cucurull Juan wrote:
> > > Dear all,
> > >
> > > After applying the TPM patches to QEMU, I was wondering if it is
> > > possible to simultaneously use the TPM in more than one virtual 
> > > machine,
> > > i.e. virtualisation of the TPM.
> > >
> > > According to the paper "Stefan Berger, Ramón Cáceres, Kenneth A.
> > > Goldman, Ronald Perez, Reiner Sailer, Leendert van Doorn. vTPM:
> > > Virtualizing the Trusted Platform Module" this seems to be possible in
> > > Xen. Is not possible in QEMU?
> > >
> > > Thanks!
> > > Jordi.
> >
> > I don't think the pass-through driver supports use by multiple VMs. 
> > Stefan Berger should be able to answer better so I'm adding him to 
> > the thread.
>
> The pass-through driver cannot provide access for multiple VMs to the 
> single hardware TPM on the host. The usage model and the statefulness 
> of the TPM (SRK password, owner password, keys) basically 
> prevent/complicate this. The implementation for Xen was indep. of the 
> Qemu code base today and there we used a software implementation of 
> the TPM that provided a private TPm instance to each VM. I have 
> patches for this for Qemu but due to an IRC chat in Sept. 2011 they 
> are 'behind' the pass-through driver patches.
>
>    Stefan


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Jordi Cucurull Juan
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