On Thu, Oct 04, 2018 at 09:56:09PM +1000, Paul Mackerras wrote:
> 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.
>
> Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx>
Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> ---
> Documentation/virtual/kvm/api.txt | 14 ++++++++++++++
> arch/powerpc/include/asm/kvm_ppc.h | 1 +
> arch/powerpc/kvm/book3s_hv.c | 19 +++++++++++++++++++
> arch/powerpc/kvm/powerpc.c | 12 ++++++++++++
> include/uapi/linux/kvm.h | 1 +
> 5 files changed, 47 insertions(+)
>
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index 017d851..a2d4832 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -4522,6 +4522,20 @@ hpage module parameter is not set to 1, -EINVAL is returned.
> While it is generally possible to create a huge page backed VM without
> this capability, the VM will not be able to run.
>
> +7.15 KVM_CAP_PPC_NESTED_HV
> +
> +Architectures: ppc
> +Parameters: enable flag (0 to disable, non-zero to enable)
> +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.
> ----------------------
>
> diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
> index 245e564..80f0091 100644
> --- a/arch/powerpc/include/asm/kvm_ppc.h
> +++ b/arch/powerpc/include/asm/kvm_ppc.h
> @@ -327,6 +327,7 @@ 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, bool enable);
> };
>
> extern struct kvmppc_ops *kvmppc_hv_ops;
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 7f89b22..d3cc013 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -118,6 +118,11 @@ 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)");
> +
> /* If set, the threads on each CPU core have to be in the same MMU mode */
> static bool no_mixing_hpt_and_radix;
>
> @@ -5165,6 +5170,19 @@ static int kvmhv_configure_mmu(struct kvm *kvm, struct kvm_ppc_mmuv3_cfg *cfg)
> return err;
> }
>
> +static int kvmhv_enable_nested(struct kvm *kvm, bool enable)
> +{
> + 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 = enable;
> + 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,
> @@ -5204,6 +5222,7 @@ 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)
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index eba5756..449ae1d 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -596,6 +596,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> case KVM_CAP_PPC_MMU_HASH_V3:
> r = !!(hv_enabled && cpu_has_feature(CPU_FTR_ARCH_300));
> break;
> + case KVM_CAP_PPC_NESTED_HV:
> + r = !!(hv_enabled && kvmppc_hv_ops->enable_nested &&
> + !kvmppc_hv_ops->enable_nested(NULL, false));
> + break;
> #endif
> case KVM_CAP_SYNC_MMU:
> #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
> @@ -2114,6 +2118,14 @@ 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, !!cap->args[0]);
> + break;
> #endif
> default:
> r = -EINVAL;
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 07548de..a6d5a46 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -952,6 +952,7 @@ struct kvm_ppc_resize_hpt {
> #define KVM_CAP_S390_HPAGE_1M 156
> #define KVM_CAP_NESTED_STATE 157
> #define KVM_CAP_ARM_INJECT_SERROR_ESR 158
> +#define KVM_CAP_PPC_NESTED_HV 160
>
> #ifdef KVM_CAP_IRQ_ROUTING
>
--
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
Attachment:
signature.asc
Description: PGP signature
