On Thu, 14 Sep 2017 13:27:49 +0200 Greg Kurz <[email protected]> wrote: > On Thu, 14 Sep 2017 13:17:48 +0200 > Thomas Huth <[email protected]> wrote: > > > On 14.09.2017 12:48, Greg Kurz wrote: > > > If the host has both KVM PR and KVM HV loaded and we pass: > > > > > > -machine pseries,accel=kvm,kvm-type=PR > > > > > > the kvmppc_is_pr() returns false instead of true. Since the helper > > > is mostly used as fallback, it doesn't have any real impact with > > > recent kernels. A notable exception is the workaround to allow > > > migration between compatible hosts with different PVRs (eg, POWER8 > > > and POWER8E), since KVM still doesn't provide a way to check if a > > > specific PVR is supported (see commit c363a37a450f for details). > > > > > > According to the official KVM API documentation [1], KVM_PPC_GET_PVINFO > > > is "vm ioctl", but we check it as a global ioctl. The following function > > > in KVM is hence called with kvm == NULL and considers we're in HV mode. > > > > > > int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > > > { > > > int r; > > > /* Assume we're using HV mode when the HV module is loaded */ > > > int hv_enabled = kvmppc_hv_ops ? 1 : 0; > > > > > > if (kvm) { > > > /* > > > * Hooray - we know which VM type we're running on. Depend on > > > * that rather than the guess above. > > > */ > > > hv_enabled = is_kvmppc_hv_enabled(kvm); > > > } > > > > > > Let's use kvm_vm_check_extension() to fix the issue. > > > > By the way, what about the other CAPs that rely on hv_enabled? grepping > > through the QEMU sources, I can see: > > > > cap_ppc_smt = kvm_check_extension(s, KVM_CAP_PPC_SMT); > >
So this one was already fixed in David's ppc-for-2.11 branch thanks to
commit fa98fbfcdfcb9... which introduced a new KVM_CAP_PPC_SMT_POSSIBLE
cap, which is also a VM ioctl and needs to be fixed :)
cap_ppc_smt_possible = kvm_check_extension(s, KVM_CAP_PPC_SMT_POSSIBLE);
> > cap_htab_fd = kvm_check_extension(s, KVM_CAP_PPC_HTAB_FD);
> >
Needs fixing.
> > int ret = kvm_check_extension(s, KVM_CAP_NR_VCPUS);
> >
Needs fixing.
> > return kvm_check_extension(kvm_state, KVM_CAP_SYNC_MMU);
> >
Needs fixing.
> > !kvm_check_extension(cs->kvm_state, KVM_CAP_SW_TLB)) {
> >
This seems to be e500 specific, and thus isn't affected.
> > ... do we need to fix them, too?
> >
>
> I'm currently going through the KVM code to see which ones need to be
> fixed. I'll send more patches shortly :)
>
> Cheers,
>
> --
> Greg
>
> > Thomas
>
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