Commit c9270132 authored by Paul Mackerras's avatar Paul Mackerras Committed by Michael Ellerman
Browse files

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: default avatarPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent bc355125

Documentation/virtual/kvm/api.txt

+83 −0
Original line number Diff line number Diff line
@@ -3201,6 +3201,71 @@ struct kvm_reinject_control { 
pit_reinject = 0 (!reinject mode) is recommended, unless running an old

operating system that uses the PIT for timing (e.g. Linux 2.4.x).



4.99 KVM_PPC_CONFIGURE_V3_MMU



Capability: KVM_CAP_PPC_RADIX_MMU or KVM_CAP_PPC_HASH_MMU_V3

Architectures: ppc

Type: vm ioctl

Parameters: struct kvm_ppc_mmuv3_cfg (in)

Returns: 0 on success,

         -EFAULT if struct kvm_ppc_mmuv3_cfg cannot be read,

         -EINVAL if the configuration is invalid



This ioctl controls whether the guest will use radix or HPT (hashed

page table) translation, and sets the pointer to the process table for

the guest.



struct kvm_ppc_mmuv3_cfg {

	__u64	flags;

	__u64	process_table;

};



There are two bits that can be set in flags; KVM_PPC_MMUV3_RADIX and

KVM_PPC_MMUV3_GTSE.  KVM_PPC_MMUV3_RADIX, if set, configures the guest

to use radix tree translation, and if clear, to use HPT translation.

KVM_PPC_MMUV3_GTSE, if set and if KVM permits it, configures the guest

to be able to use the global TLB and SLB invalidation instructions;

if clear, the guest may not use these instructions.



The process_table field specifies the address and size of the guest

process table, which is in the guest's space.  This field is formatted

as the second doubleword of the partition table entry, as defined in

the Power ISA V3.00, Book III section 5.7.6.1.



4.100 KVM_PPC_GET_RMMU_INFO



Capability: KVM_CAP_PPC_RADIX_MMU

Architectures: ppc

Type: vm ioctl

Parameters: struct kvm_ppc_rmmu_info (out)

Returns: 0 on success,

	 -EFAULT if struct kvm_ppc_rmmu_info cannot be written,

	 -EINVAL if no useful information can be returned



This ioctl returns a structure containing two things: (a) a list

containing supported radix tree geometries, and (b) a list that maps

page sizes to put in the "AP" (actual page size) field for the tlbie

(TLB invalidate entry) instruction.



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];

};



The geometries[] field gives up to 8 supported geometries for the

radix page table, in terms of the log base 2 of the smallest page

size, and the number of bits indexed at each level of the tree, from

the PTE level up to the PGD level in that order.  Any unused entries

will have 0 in the page_shift field.



The ap_encodings gives the supported page sizes and their AP field

encodings, encoded with the AP value in the top 3 bits and the log

base 2 of the page size in the bottom 6 bits.



5. The kvm_run structure

------------------------
@@ -3942,3 +4007,21 @@ In order to use SynIC, it has to be activated by setting this 
capability via KVM_ENABLE_CAP ioctl on the vcpu fd. Note that this

will disable the use of APIC hardware virtualization even if supported

by the CPU, as it's incompatible with SynIC auto-EOI behavior.



8.3 KVM_CAP_PPC_RADIX_MMU



Architectures: ppc



This capability, if KVM_CHECK_EXTENSION indicates that it is

available, means that that the kernel can support guests using the

radix MMU defined in Power ISA V3.00 (as implemented in the POWER9

processor).



8.4 KVM_CAP_PPC_HASH_MMU_V3



Architectures: ppc



This capability, if KVM_CHECK_EXTENSION indicates that it is

available, means that that the kernel can support guests using the

hashed page table MMU defined in Power ISA V3.00 (as implemented in

the POWER9 processor), including in-memory segment tables.

arch/powerpc/include/asm/kvm_ppc.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

arch/powerpc/include/uapi/asm/kvm.h

+20 −0
Original line number Diff line number Diff line
@@ -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)

arch/powerpc/kvm/book3s_hv.c

+13 −0
Original line number Diff line number Diff line
@@ -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)

arch/powerpc/kvm/powerpc.c

+32 −0
Original line number Diff line number Diff line
@@ -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);

CRA Git | Maintained and supported by SUSTech CRA and CCSE