On Fri, Nov 26, 2021 at 06:51:38PM +0100, Cédric le Goater wrote: > On 11/26/21 02:11, David Gibson wrote: > > On Thu, Nov 25, 2021 at 07:42:02PM -0300, Daniel Henrique Barboza wrote: > > > If one tries to use -machine powernv9,accel=kvm in a Power9 host, a > > > cryptic error will be shown: > > > > > > qemu-system-ppc64: Register sync failed... If you're using kvm-hv.ko, > > > only "-cpu host" is possible > > > qemu-system-ppc64: kvm_init_vcpu: kvm_arch_init_vcpu failed (0): Invalid > > > argument > > > > > > Appending '-cpu host' will throw another error: > > > > > > qemu-system-ppc64: invalid chip model 'host' for powernv9 machine > > > > > > The root cause is that in IBM PowerPC we have different specs for the > > > bare-metal > > > and the guests. The bare-metal follows OPAL, the guests follow PAPR. The > > > kernel > > > KVM modules presented in the ppc kernels implements PAPR. This means that > > > we > > > can't use KVM accel when using the powernv machine, which is the > > > emulation of > > > the bare-metal host. > > > > > > All that said, let's give a more informative error in this case. > > > > > > Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com> > > > --- > > > hw/ppc/pnv.c | 5 +++++ > > > 1 file changed, 5 insertions(+) > > > > > > diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c > > > index 71e45515f1..e5b87e8730 100644 > > > --- a/hw/ppc/pnv.c > > > +++ b/hw/ppc/pnv.c > > > @@ -742,6 +742,11 @@ static void pnv_init(MachineState *machine) > > > DriveInfo *pnor = drive_get(IF_MTD, 0, 0); > > > DeviceState *dev; > > > + if (kvm_enabled()) { > > > + error_report("The powernv machine does not work with KVM > > > acceleration"); > > > + exit(EXIT_FAILURE); > > > + } > > > > > > Hmm.. my only concern here is that powernv could, at least > > theoretically, work with KVM PR. I don't think it does right now, > > though. > > At the same time, it is nice to not let the user think that it could work > in its current state. Don't you think so ?
Right, I'm thinking of the implication if you have an old qemu but a new KVM which let it work. Chances of KVM actually implementing this probably aren't good though, so requiring the qemu update if we ever do is probably the better deal. -- 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
signature.asc
Description: PGP signature