Re: [Qemu-devel] [PATCH 0/4] virt: provide secure-only RAM and first flash

[Paolo Bonzini]

On 08/03/2016 13:16, Ard Biesheuvel wrote:
> > > > As far as this QEMU port is concerned, having some flash in secure and
> > > > some in non-secure is going to be useful regardless, and 64 MB is
> > > > plenty for both the code and the data. So if users of the Trustzone
> > > > port (which is disjoint from the KVM port in any case) can tolerate
> > > > having the code and the variables in the same pflash file, I could
> > > > simply move the code into the second flash, and we could reserve the
> > > > first flash for secure (so it sits at physical address 0x0
> > >
> > > Uhm, actually, the code is not even in the flash to begin with. So
> > > having the second bank be non-secure only makes perfect sense imo
> >
> > Interesting, where is the code?
>
> The UEFI code is loaded into DRAM by the secure firmware, and
> relocated and executed from there.

And if (as in the closed source implementations) UEFI had access to
TrustZone, would the privileged parts of the code be moved to secure DRAM?

Still, the UEFI code must still be protected from tampering, so it
should also reside in secure flash.

Paolo