On Mon, Oct 08, 2018 at 04:31:16PM +1100, Paul Mackerras wrote:
> With this, the KVM-HV module can be loaded in a guest running under
> KVM-HV, and if the hypervisor supports nested virtualization, this
> guest can now act as a nested hypervisor and run nested guests.
>
> This also adds some checks to inform userspace that HPT guests are not
> supported by nested hypervisors (by returning false for the
> KVM_CAP_PPC_MMU_HASH_V3 capability), and to prevent userspace from
> configuring a guest to use HPT mode.
>
> Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx>
Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> ---
> arch/powerpc/kvm/book3s_hv.c | 16 ++++++++++++----
> arch/powerpc/kvm/powerpc.c | 3 ++-
> 2 files changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 127bb5f..152bf75 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -4807,11 +4807,15 @@ static int kvmppc_core_emulate_mfspr_hv(struct kvm_vcpu *vcpu, int sprn,
>
> static int kvmppc_core_check_processor_compat_hv(void)
> {
> - if (!cpu_has_feature(CPU_FTR_HVMODE) ||
> - !cpu_has_feature(CPU_FTR_ARCH_206))
> - return -EIO;
> + if (cpu_has_feature(CPU_FTR_HVMODE) &&
> + cpu_has_feature(CPU_FTR_ARCH_206))
> + return 0;
>
> - return 0;
> + /* POWER9 in radix mode is capable of being a nested hypervisor. */
> + if (cpu_has_feature(CPU_FTR_ARCH_300) && radix_enabled())
> + return 0;
> +
> + return -EIO;
> }
>
> #ifdef CONFIG_KVM_XICS
> @@ -5129,6 +5133,10 @@ static int kvmhv_configure_mmu(struct kvm *kvm, struct kvm_ppc_mmuv3_cfg *cfg)
> if (radix && !radix_enabled())
> return -EINVAL;
>
> + /* If we're a nested hypervisor, we currently only support radix */
> + if (kvmhv_on_pseries() && !radix)
> + return -EINVAL;
> +
> mutex_lock(&kvm->lock);
> if (radix != kvm_is_radix(kvm)) {
> if (kvm->arch.mmu_ready) {
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index eba5756..1f4b128 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -594,7 +594,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> r = !!(hv_enabled && radix_enabled());
> break;
> case KVM_CAP_PPC_MMU_HASH_V3:
> - r = !!(hv_enabled && cpu_has_feature(CPU_FTR_ARCH_300));
> + r = !!(hv_enabled && cpu_has_feature(CPU_FTR_ARCH_300) &&
> + cpu_has_feature(CPU_FTR_HVMODE));
> break;
> #endif
> case KVM_CAP_SYNC_MMU:
--
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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