Commit aa069a99 authored by Paul Mackerras's avatar Paul Mackerras
Browse files

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

Documentation/virtual/kvm/api.txt

+14 −0
Original line number Diff line number Diff line
@@ -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.

----------------------

arch/powerpc/include/asm/kvm_ppc.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

arch/powerpc/kvm/book3s_hv.c

+30 −9
Original line number Diff line number Diff line
@@ -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)

arch/powerpc/kvm/powerpc.c

+12 −0
Original line number Diff line number Diff line
@@ -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;

include/uapi/linux/kvm.h

+1 −0
Original line number Diff line number Diff line
@@ -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