On Sat, 19 May 2018 15:56:38 +1000 Paul Mackerras <paulus@xxxxxxxxxx> wrote: > This relaxes the restriction on using PR KVM on POWER9. The existing > code does work inside a guest partition running in HPT mode, because > hypercalls such as H_ENTER use the old HPTE format, not the new > format used by POWER9, and so no change to PR KVM's HPT manipulation > code is required. PR KVM will still refuse to run if the kernel is > using radix translation or if it is running bare-metal. > > Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx> > --- With your other patch applied (https://patchwork.ozlabs.org/patch/916766/). Tested-by: Greg Kurz <groug@xxxxxxxx> > arch/powerpc/kvm/book3s_pr.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c > index 67061d3..3d0251e 100644 > --- a/arch/powerpc/kvm/book3s_pr.c > +++ b/arch/powerpc/kvm/book3s_pr.c > @@ -1735,9 +1735,16 @@ static void kvmppc_core_destroy_vm_pr(struct kvm *kvm) > static int kvmppc_core_check_processor_compat_pr(void) > { > /* > - * Disable KVM for Power9 untill the required bits merged. > + * PR KVM can work on POWER9 inside a guest partition > + * running in HPT mode. It can't work if we are using > + * radix translation (because radix provides no way for > + * a process to have unique translations in quadrant 3) > + * or in a bare-metal HPT-mode host (because POWER9 > + * uses a modified HPTE format which the PR KVM code > + * has not been adapted to use). > */ > - if (cpu_has_feature(CPU_FTR_ARCH_300)) > + if (cpu_has_feature(CPU_FTR_ARCH_300) && > + (radix_enabled() || cpu_has_feature(CPU_FTR_HVMODE))) > return -EIO; > return 0; > }
