Commit aa069a99 authored by Paul Mackerras's avatar Paul Mackerras

KVM: PPC: Book3S HV: Add a VM capability to enable nested virtualization

With this, userspace can enable a KVM-HV guest to run nested guests
under it.

The administrator can control whether any nested guests can be run;
setting the "nested" module parameter to false prevents any guests
becoming nested hypervisors (that is, any attempt to enable the nested
capability on a guest will fail).  Guests which are already nested
hypervisors will continue to be so.
Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
parent 9d67121a
......@@ -4532,6 +4532,20 @@ With this capability, a guest may read the MSR_PLATFORM_INFO MSR. Otherwise,
a #GP would be raised when the guest tries to access. Currently, this
capability does not enable write permissions of this MSR for the guest.
7.16 KVM_CAP_PPC_NESTED_HV
Architectures: ppc
Parameters: none
Returns: 0 on success, -EINVAL when the implementation doesn't support
nested-HV virtualization.
HV-KVM on POWER9 and later systems allows for "nested-HV"
virtualization, which provides a way for a guest VM to run guests that
can run using the CPU's supervisor mode (privileged non-hypervisor
state). Enabling this capability on a VM depends on the CPU having
the necessary functionality and on the facility being enabled with a
kvm-hv module parameter.
8. Other capabilities.
----------------------
......
......@@ -325,6 +325,7 @@ struct kvmppc_ops {
int (*set_smt_mode)(struct kvm *kvm, unsigned long mode,
unsigned long flags);
void (*giveup_ext)(struct kvm_vcpu *vcpu, ulong msr);
int (*enable_nested)(struct kvm *kvm);
};
extern struct kvmppc_ops *kvmppc_hv_ops;
......
......@@ -122,6 +122,16 @@ module_param_cb(h_ipi_redirect, &module_param_ops, &h_ipi_redirect, 0644);
MODULE_PARM_DESC(h_ipi_redirect, "Redirect H_IPI wakeup to a free host core");
#endif
/* If set, guests are allowed to create and control nested guests */
static bool nested = true;
module_param(nested, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(nested, "Enable nested virtualization (only on POWER9)");
static inline bool nesting_enabled(struct kvm *kvm)
{
return kvm->arch.nested_enable && kvm_is_radix(kvm);
}
/* If set, the threads on each CPU core have to be in the same MMU mode */
static bool no_mixing_hpt_and_radix;
......@@ -963,12 +973,12 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
case H_SET_PARTITION_TABLE:
ret = H_FUNCTION;
if (vcpu->kvm->arch.nested_enable)
if (nesting_enabled(vcpu->kvm))
ret = kvmhv_set_partition_table(vcpu);
break;
case H_ENTER_NESTED:
ret = H_FUNCTION;
if (!vcpu->kvm->arch.nested_enable)
if (!nesting_enabled(vcpu->kvm))
break;
ret = kvmhv_enter_nested_guest(vcpu);
if (ret == H_INTERRUPT) {
......@@ -978,8 +988,7 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
break;
case H_TLB_INVALIDATE:
ret = H_FUNCTION;
if (!vcpu->kvm->arch.nested_enable)
break;
if (nesting_enabled(vcpu->kvm))
ret = kvmhv_do_nested_tlbie(vcpu);
break;
......@@ -4508,10 +4517,8 @@ 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;
if (nesting_enabled(kvm))
kvmhv_release_all_nested(kvm);
}
kvmppc_free_radix(kvm);
kvmppc_update_lpcr(kvm, LPCR_VPM1,
LPCR_VPM1 | LPCR_UPRT | LPCR_GTSE | LPCR_HR);
......@@ -4788,7 +4795,7 @@ 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)
if (nesting_enabled(kvm))
kvmhv_release_all_nested(kvm);
kvm->arch.process_table = 0;
kvmhv_set_ptbl_entry(kvm->arch.lpid, 0, 0);
......@@ -5181,6 +5188,19 @@ static int kvmhv_configure_mmu(struct kvm *kvm, struct kvm_ppc_mmuv3_cfg *cfg)
return err;
}
static int kvmhv_enable_nested(struct kvm *kvm)
{
if (!nested)
return -EPERM;
if (!cpu_has_feature(CPU_FTR_ARCH_300))
return -ENODEV;
/* kvm == NULL means the caller is testing if the capability exists */
if (kvm)
kvm->arch.nested_enable = true;
return 0;
}
static struct kvmppc_ops kvm_ops_hv = {
.get_sregs = kvm_arch_vcpu_ioctl_get_sregs_hv,
.set_sregs = kvm_arch_vcpu_ioctl_set_sregs_hv,
......@@ -5220,6 +5240,7 @@ static struct kvmppc_ops kvm_ops_hv = {
.configure_mmu = kvmhv_configure_mmu,
.get_rmmu_info = kvmhv_get_rmmu_info,
.set_smt_mode = kvmhv_set_smt_mode,
.enable_nested = kvmhv_enable_nested,
};
static int kvm_init_subcore_bitmap(void)
......
......@@ -597,6 +597,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
r = !!(hv_enabled && cpu_has_feature(CPU_FTR_ARCH_300) &&
cpu_has_feature(CPU_FTR_HVMODE));
break;
case KVM_CAP_PPC_NESTED_HV:
r = !!(hv_enabled && kvmppc_hv_ops->enable_nested &&
!kvmppc_hv_ops->enable_nested(NULL));
break;
#endif
case KVM_CAP_SYNC_MMU:
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
......@@ -2115,6 +2119,14 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
r = kvm->arch.kvm_ops->set_smt_mode(kvm, mode, flags);
break;
}
case KVM_CAP_PPC_NESTED_HV:
r = -EINVAL;
if (!is_kvmppc_hv_enabled(kvm) ||
!kvm->arch.kvm_ops->enable_nested)
break;
r = kvm->arch.kvm_ops->enable_nested(kvm);
break;
#endif
default:
r = -EINVAL;
......
......@@ -953,6 +953,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_NESTED_STATE 157
#define KVM_CAP_ARM_INJECT_SERROR_ESR 158
#define KVM_CAP_MSR_PLATFORM_INFO 159
#define KVM_CAP_PPC_NESTED_HV 160
#ifdef KVM_CAP_IRQ_ROUTING
......
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