KVM: PPC: Book3S HV: Framework and hcall stubs for nested virtualization

This starts the process of adding the code to support nested HV-style
virtualization.  It defines a new H_SET_PARTITION_TABLE hypercall which
a nested hypervisor can use to set the base address and size of a
partition table in its memory (analogous to the PTCR register).
On the host (level 0 hypervisor) side, the H_SET_PARTITION_TABLE
hypercall from the guest is handled by code that saves the virtual
PTCR value for the guest.

This also adds code for creating and destroying nested guests and for
reading the partition table entry for a nested guest from L1 memory.
Each nested guest has its own shadow LPID value, different in general
from the LPID value used by the nested hypervisor to refer to it.  The
shadow LPID value is allocated at nested guest creation time.

Nested hypervisor functionality is only available for a radix guest,
which therefore means a radix host on a POWER9 (or later) processor.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 28 insertions, 3 deletions

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 8c20a90a6851..d8fc49effab0 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -934,6 +934,19 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
 		if (ret == H_TOO_HARD)
 			return RESUME_HOST;
 		break;
+
+	case H_SET_PARTITION_TABLE:
+		ret = H_FUNCTION;
+		if (vcpu->kvm->arch.nested_enable)
+			ret = kvmhv_set_partition_table(vcpu);
+		break;
+	case H_ENTER_NESTED:
+		ret = H_FUNCTION;
+		break;
+	case H_TLB_INVALIDATE:
+		ret = H_FUNCTION;
+		break;
+
 	default:
 		return RESUME_HOST;
 	}
@@ -4157,8 +4170,7 @@ void kvmppc_setup_partition_table(struct kvm *kvm)
 			__pa(kvm->arch.pgtable) | RADIX_PGD_INDEX_SIZE;
 		dw1 = PATB_GR | kvm->arch.process_table;
 	}
-
-	mmu_partition_table_set_entry(kvm->arch.lpid, dw0, dw1);
+	kvmhv_set_ptbl_entry(kvm->arch.lpid, dw0, dw1);
 }
 
 /*
@@ -4254,6 +4266,10 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)
 /* Must be called with kvm->lock held and mmu_ready = 0 and no vcpus running */
 int kvmppc_switch_mmu_to_hpt(struct kvm *kvm)
 {
+	if (kvm->arch.nested_enable) {
+		kvm->arch.nested_enable = false;
+		kvmhv_release_all_nested(kvm);
+	}
 	kvmppc_free_radix(kvm);
 	kvmppc_update_lpcr(kvm, LPCR_VPM1,
 			   LPCR_VPM1 | LPCR_UPRT | LPCR_GTSE | LPCR_HR);
@@ -4374,6 +4390,8 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm)
 
 	kvmppc_alloc_host_rm_ops();
 
+	kvmhv_vm_nested_init(kvm);
+
 	/*
 	 * Since we don't flush the TLB when tearing down a VM,
 	 * and this lpid might have previously been used,
@@ -4517,8 +4535,10 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
 
 	/* Perform global invalidation and return lpid to the pool */
 	if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+		if (kvm->arch.nested_enable)
+			kvmhv_release_all_nested(kvm);
 		kvm->arch.process_table = 0;
-		kvmppc_setup_partition_table(kvm);
+		kvmhv_set_ptbl_entry(kvm->arch.lpid, 0, 0);
 	}
 	kvmppc_free_lpid(kvm->arch.lpid);
 
@@ -4989,6 +5009,10 @@ static int kvmppc_book3s_init_hv(void)
 	if (r < 0)
 		return -ENODEV;
 
+	r = kvmhv_nested_init();
+	if (r)
+		return r;
+
 	r = kvm_init_subcore_bitmap();
 	if (r)
 		return r;
@@ -5047,6 +5071,7 @@ static void kvmppc_book3s_exit_hv(void)
 	if (kvmppc_radix_possible())
 		kvmppc_radix_exit();
 	kvmppc_hv_ops = NULL;
+	kvmhv_nested_exit();
 }
 
 module_init(kvmppc_book3s_init_hv);