On Fri, Sep 11, 2020 at 01:31:23AM -0300, Fabiano Rosas wrote: > The nested KVM code does not yet support HPT guests. Calling the > KVM_CAP_PPC_ALLOC_HTAB ioctl currently leads to KVM setting the guest > as HPT and erroneously executing code in L1 that should only run in > hypervisor mode, leading to an exception in the L1 vcpu thread when it > enters the nested guest. > > This can be reproduced with -machine max-cpu-compat=power8 in the L2 > guest command line. > > The KVM code has since been modified to fail the ioctl when running in > a nested environment so QEMU needs to be able to handle that. This > patch provides an error message informing the user about the lack of > support for HPT in nested guests. > > Signed-off-by: Fabiano Rosas <faro...@linux.ibm.com>
Applied to ppc-for-5.2.
> ---
> hw/ppc/spapr.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 9bce1892b5..ea2c755310 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1483,6 +1483,12 @@ void spapr_reallocate_hpt(SpaprMachineState *spapr,
> int shift,
> spapr_free_hpt(spapr);
>
> rc = kvmppc_reset_htab(shift);
> +
> + if (rc == -EOPNOTSUPP) {
> + error_setg(errp, "HPT not supported in nested guests");
> + return;
> + }
> +
> if (rc < 0) {
> /* kernel-side HPT needed, but couldn't allocate one */
> error_setg_errno(errp, errno,
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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