From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Gibson Subject: Re: [PATCH v3 33/33] KVM: PPC: Book3S HV: Add a VM capability to enable nested virtualization Date: Wed, 3 Oct 2018 16:21:44 +1000 Message-ID: <20181003062144.GY1886@umbus.fritz.box> References: <1538479892-14835-1-git-send-email-paulus@ozlabs.org> <1538479892-14835-34-git-send-email-paulus@ozlabs.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="tpZe61tYkA9f+p/0" Cc: linuxppc-dev@ozlabs.org, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org To: Paul Mackerras Return-path: Content-Disposition: inline In-Reply-To: <1538479892-14835-34-git-send-email-paulus@ozlabs.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+glppe-linuxppc-embedded-2=m.gmane.org@lists.ozlabs.org Sender: "Linuxppc-dev" List-Id: kvm.vger.kernel.org --tpZe61tYkA9f+p/0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Oct 02, 2018 at 09:31:32PM +1000, Paul Mackerras wrote: > With this, userspace can enable a KVM-HV guest to run nested guests > under it. >=20 > Signed-off-by: Paul Mackerras > --- > Documentation/virtual/kvm/api.txt | 14 ++++++++++++++ > arch/powerpc/include/asm/kvm_ppc.h | 1 + > arch/powerpc/kvm/book3s_hv.c | 17 +++++++++++++++++ > arch/powerpc/kvm/powerpc.c | 12 ++++++++++++ > include/uapi/linux/kvm.h | 1 + > 5 files changed, 45 insertions(+) >=20 > diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kv= m/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. > =20 > +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. > ---------------------- > =20 > diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/as= m/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); > }; > =20 > extern struct kvmppc_ops *kvmppc_hv_ops; > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index 196bff1..a5b3862 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 c= ore"); > #endif > =20 > +/* If set, guests are allowed to create and control nested guests */ > +static bool enable_nested =3D true; > +module_param(enable_nested, bool, S_IRUGO | S_IWUSR); > +MODULE_PARM_DESC(enable_nested, "Enable nested virtualization (only on P= OWER9)"); I'd suggest calling the module parameter just "nested" to match x86. > /* If set, the threads on each CPU core have to be in the same MMU mode = */ > static bool no_mixing_hpt_and_radix; > =20 > @@ -5188,6 +5193,17 @@ static int kvmhv_configure_mmu(struct kvm *kvm, st= ruct kvm_ppc_mmuv3_cfg *cfg) > return err; > } > =20 > +static int kvmhv_enable_nested(struct kvm *kvm, bool enable) > +{ > + if (!(enable_nested && cpu_has_feature(CPU_FTR_ARCH_300))) > + return -EINVAL; Maybe EPERM, rather than EINVAL. There's nothing invalid about the ioctl() parameters - we just can't do what they want. > + > + /* kvm =3D=3D NULL means the caller is testing if the capability exists= */ > + if (kvm) > + kvm->arch.nested_enable =3D enable; > + return 0; > +} > + > static struct kvmppc_ops kvm_ops_hv =3D { > .get_sregs =3D kvm_arch_vcpu_ioctl_get_sregs_hv, > .set_sregs =3D kvm_arch_vcpu_ioctl_set_sregs_hv, > @@ -5227,6 +5243,7 @@ static struct kvmppc_ops kvm_ops_hv =3D { > .configure_mmu =3D kvmhv_configure_mmu, > .get_rmmu_info =3D kvmhv_get_rmmu_info, > .set_smt_mode =3D kvmhv_set_smt_mode, > + .enable_nested =3D kvmhv_enable_nested, > }; > =20 > 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, lo= ng ext) > case KVM_CAP_PPC_MMU_HASH_V3: > r =3D !!(hv_enabled && cpu_has_feature(CPU_FTR_ARCH_300)); > break; > + case KVM_CAP_PPC_NESTED_HV: > + r =3D !!(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 =3D kvm->arch.kvm_ops->set_smt_mode(kvm, mode, flags); > break; > } > + > + case KVM_CAP_PPC_NESTED_HV: > + r =3D -EINVAL; > + if (!is_kvmppc_hv_enabled(kvm) || > + !kvm->arch.kvm_ops->enable_nested) > + break; > + r =3D kvm->arch.kvm_ops->enable_nested(kvm, !!cap->args[0]); > + break; > #endif > default: > r =3D -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 > =20 > #ifdef KVM_CAP_IRQ_ROUTING > =20 --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. 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