KVM: PPC: Book3S HV: Add userspace interfaces for POWER9 MMU

This adds two capabilities and two ioctls to allow userspace to
find out about and configure the POWER9 MMU in a guest.  The two
capabilities tell userspace whether KVM can support a guest using
the radix MMU, or using the hashed page table (HPT) MMU with a
process table and segment tables.  (Note that the MMUs in the
POWER9 processor cores do not use the process and segment tables
when in HPT mode, but the nest MMU does).

The KVM_PPC_CONFIGURE_V3_MMU ioctl allows userspace to specify
whether a guest will use the radix MMU or the HPT MMU, and to
specify the size and location (in guest space) of the process
table.

The KVM_PPC_GET_RMMU_INFO ioctl gives userspace information about
the radix MMU.  It returns a list of supported radix tree geometries
(base page size and number of bits indexed at each level of the
radix tree) and the encoding used to specify the various page
sizes for the TLB invalidate entry instruction.

Initially, both capabilities return 0 and the ioctls return -EINVAL,
until the necessary infrastructure for them to operate correctly
is added.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

4 files changed, 67 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 2da67bf1f2ec..48c760f89590 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -291,6 +291,8 @@ struct kvmppc_ops {
 				       struct irq_bypass_producer *);
 	void (*irq_bypass_del_producer)(struct irq_bypass_consumer *,
 					struct irq_bypass_producer *);
+	int (*configure_mmu)(struct kvm *kvm, struct kvm_ppc_mmuv3_cfg *cfg);
+	int (*get_rmmu_info)(struct kvm *kvm, struct kvm_ppc_rmmu_info *info);
 };
 
 extern struct kvmppc_ops *kvmppc_hv_ops;
diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
index 3603b6f51b11..cc0908b6c2a0 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -413,6 +413,26 @@ struct kvm_get_htab_header {
 	__u16	n_invalid;
 };
 
+/* For KVM_PPC_CONFIGURE_V3_MMU */
+struct kvm_ppc_mmuv3_cfg {
+	__u64	flags;
+	__u64	process_table;	/* second doubleword of partition table entry */
+};
+
+/* Flag values for KVM_PPC_CONFIGURE_V3_MMU */
+#define KVM_PPC_MMUV3_RADIX	1	/* 1 = radix mode, 0 = HPT */
+#define KVM_PPC_MMUV3_GTSE	2	/* global translation shootdown enb. */
+
+/* For KVM_PPC_GET_RMMU_INFO */
+struct kvm_ppc_rmmu_info {
+	struct kvm_ppc_radix_geom {
+		__u8	page_shift;
+		__u8	level_bits[4];
+		__u8	pad[3];
+	}	geometries[8];
+	__u32	ap_encodings[8];
+};
+
 /* Per-vcpu XICS interrupt controller state */
 #define KVM_REG_PPC_ICP_STATE	(KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x8c)
 
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index ec34e39471a7..5f08ed070ae5 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3657,6 +3657,17 @@ static void init_default_hcalls(void)
 	}
 }
 
+/* dummy implementations for now */
+static int kvmhv_configure_mmu(struct kvm *kvm, struct kvm_ppc_mmuv3_cfg *cfg)
+{
+	return -EINVAL;
+}
+
+static int kvmhv_get_rmmu_info(struct kvm *kvm, struct kvm_ppc_rmmu_info *info)
+{
+	return -EINVAL;
+}
+
 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,
@@ -3694,6 +3705,8 @@ static struct kvmppc_ops kvm_ops_hv = {
 	.irq_bypass_add_producer = kvmppc_irq_bypass_add_producer_hv,
 	.irq_bypass_del_producer = kvmppc_irq_bypass_del_producer_hv,
 #endif
+	.configure_mmu = kvmhv_configure_mmu,
+	.get_rmmu_info = kvmhv_get_rmmu_info,
 };
 
 static int kvm_init_subcore_bitmap(void)
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index cd892dec7cb6..38c0d154c01e 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -565,6 +565,13 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_PPC_HWRNG:
 		r = kvmppc_hwrng_present();
 		break;
+	case KVM_CAP_PPC_MMU_RADIX:
+		r = !!(0 && hv_enabled && radix_enabled());
+		break;
+	case KVM_CAP_PPC_MMU_HASH_V3:
+		r = !!(0 && hv_enabled && !radix_enabled() &&
+		       cpu_has_feature(CPU_FTR_ARCH_300));
+		break;
 #endif
 	case KVM_CAP_SYNC_MMU:
 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
@@ -1468,6 +1475,31 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		r = kvm_vm_ioctl_rtas_define_token(kvm, argp);
 		break;
 	}
+	case KVM_PPC_CONFIGURE_V3_MMU: {
+		struct kvm *kvm = filp->private_data;
+		struct kvm_ppc_mmuv3_cfg cfg;
+
+		r = -EINVAL;
+		if (!kvm->arch.kvm_ops->configure_mmu)
+			goto out;
+		r = -EFAULT;
+		if (copy_from_user(&cfg, argp, sizeof(cfg)))
+			goto out;
+		r = kvm->arch.kvm_ops->configure_mmu(kvm, &cfg);
+		break;
+	}
+	case KVM_PPC_GET_RMMU_INFO: {
+		struct kvm *kvm = filp->private_data;
+		struct kvm_ppc_rmmu_info info;
+
+		r = -EINVAL;
+		if (!kvm->arch.kvm_ops->get_rmmu_info)
+			goto out;
+		r = kvm->arch.kvm_ops->get_rmmu_info(kvm, &info);
+		if (r >= 0 && copy_to_user(argp, &info, sizeof(info)))
+			r = -EFAULT;
+		break;
+	}
 	default: {
 		struct kvm *kvm = filp->private_data;
 		r = kvm->arch.kvm_ops->arch_vm_ioctl(filp, ioctl, arg);