Hello,
I'm no expert on PPC KVM and don't have much experience with it myself so
what I say may or may not be correct, it's just my understanding.
Nevertheless I share it in the hope that it may help and maybe those who
know will correct me.
On Thu, Dec 12, 2019 at 1:17 AM Paolo Bonzini <pbonz...@redhat.com> wrote:
On 12/12/19 02:59, Wayne Li wrote:
We wrote a project that is created on top of the QEMU source code; it
calls functions from the QEMU code. I run the executable created by
compiling that project/QEMU code. Anyway, looking at the following
documentation:
https://www.kernel.org/doc/Documentation/powerpc/cpu_families.txt
It looks like the PowerPC 7457 is Book3S and the PowerPC e6500 is
BookE. Is that why you think I require a Book3S KVM? Exactly why do
you feel this way? Also would that mean my team would need to go and
buy a board with a Book3S processor?
CCing the PPC maintainer. There are aspects of BookE and Book3S that
are different and not really interchangeable in the privileged interface.
It's best to look at the kvm sources in Linux under linux/arch/powerpc/kvm
or also ask on the appropriate Linux list for KVM specific questions.
AFAIK KVM between BookE and BookS CPUs doesn't work, at least running
BookE guest on a BookS host doesn't work which is what we've tried. You
seem to want the opposite direction: running BookS code on BookE host but
I think PPC KVM works best on BookS host running BookS code and apart from
that there's some support for running BookE code on BookE host for e500
but that's not much supported any more and that's it, other combinations
are likely untested and don't work. So it's best to have host CPU match
target (running e500 code on e6500 host or run 7457 code on same or newer
host CPU, but the more different the host from the guest the most problems
are to be expected). There are also HV and PR KVM where HV needs new
enough CPU that supports it (e6500 probably does) but guest CPU cannot be
different than host with HV KVM. With PR KVM there's some more freedom
about host and guest as only user space runs on host CPU with privileged
instructions are software emulated but mixing BookE and BookS is not
supported even with PR KVM if I'm not mistaken. So you may have better
luck with some BookS host but I can't tell for sure.
Regrads,
BALATON Zoltan