| Message ID | 1538654169-15602-33-git-send-email-paulus@ozlabs.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | KVM: PPC: Book3S HV: Nested HV virtualization | expand |
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@ozlabs.org> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > --- > 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 >
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
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@ozlabs.org> --- 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(+)