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>
---
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:
--
2.7.4
