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Commit 8b78645c authored by Paul Mackerras's avatar Paul Mackerras Committed by Alexander Graf
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KVM: PPC: Book3S: Facilities to save/restore XICS presentation ctrler state 



This adds the ability for userspace to save and restore the state
of the XICS interrupt presentation controllers (ICPs) via the
KVM_GET/SET_ONE_REG interface.  Since there is one ICP per vcpu, we
simply define a new 64-bit register in the ONE_REG space for the ICP
state.  The state includes the CPU priority setting, the pending IPI
priority, and the priority and source number of any pending external
interrupt.

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
parent d19bd862

Documentation/virtual/kvm/api.txt

+1 −0
Original line number Diff line number Diff line
@@ -1808,6 +1808,7 @@ registers, find a list below: 
  PPC   | KVM_REG_PPC_TLB2PS	| 32

  PPC   | KVM_REG_PPC_TLB3PS	| 32

  PPC   | KVM_REG_PPC_EPTCFG	| 32

  PPC   | KVM_REG_PPC_ICP_STATE | 64



ARM registers are mapped using the lower 32 bits.  The upper 16 of that

is the register group type, or coprocessor number:

arch/powerpc/include/asm/kvm_ppc.h

+2 −0
Original line number Diff line number Diff line
@@ -313,6 +313,8 @@ extern void kvmppc_xics_free_icp(struct kvm_vcpu *vcpu); 
extern int kvmppc_xics_create_icp(struct kvm_vcpu *vcpu, unsigned long server);

extern int kvm_vm_ioctl_xics_irq(struct kvm *kvm, struct kvm_irq_level *args);

extern int kvmppc_xics_hcall(struct kvm_vcpu *vcpu, u32 cmd);

extern u64 kvmppc_xics_get_icp(struct kvm_vcpu *vcpu);

extern int kvmppc_xics_set_icp(struct kvm_vcpu *vcpu, u64 icpval);

#else

static inline int kvmppc_xics_enabled(struct kvm_vcpu *vcpu)

	{ return 0; }

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

+12 −0
Original line number Diff line number Diff line
@@ -390,6 +390,18 @@ struct kvm_get_htab_header { 
	__u16	n_invalid;

};



/* Per-vcpu XICS interrupt controller state */

#define KVM_REG_PPC_ICP_STATE	(KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x8c)



#define  KVM_REG_PPC_ICP_CPPR_SHIFT	56	/* current proc priority */

#define  KVM_REG_PPC_ICP_CPPR_MASK	0xff

#define  KVM_REG_PPC_ICP_XISR_SHIFT	32	/* interrupt status field */

#define  KVM_REG_PPC_ICP_XISR_MASK	0xffffff

#define  KVM_REG_PPC_ICP_MFRR_SHIFT	24	/* pending IPI priority */

#define  KVM_REG_PPC_ICP_MFRR_MASK	0xff

#define  KVM_REG_PPC_ICP_PPRI_SHIFT	16	/* pending irq priority */

#define  KVM_REG_PPC_ICP_PPRI_MASK	0xff



/* Device control API: PPC-specific devices */

#define KVM_DEV_MPIC_GRP_MISC		1

#define   KVM_DEV_MPIC_BASE_ADDR	0	/* 64-bit */

arch/powerpc/kvm/book3s.c

+19 −0
Original line number Diff line number Diff line
@@ -535,6 +535,15 @@ int kvm_vcpu_ioctl_get_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg) 
					 &opcode, sizeof(u32));

			break;

		}

#ifdef CONFIG_KVM_XICS

		case KVM_REG_PPC_ICP_STATE:

			if (!vcpu->arch.icp) {

				r = -ENXIO;

				break;

			}

			val = get_reg_val(reg->id, kvmppc_xics_get_icp(vcpu));

			break;

#endif /* CONFIG_KVM_XICS */

		default:

			r = -EINVAL;

			break;
@@ -597,6 +606,16 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg) 
			vcpu->arch.vscr.u[3] = set_reg_val(reg->id, val);

			break;

#endif /* CONFIG_ALTIVEC */

#ifdef CONFIG_KVM_XICS

		case KVM_REG_PPC_ICP_STATE:

			if (!vcpu->arch.icp) {

				r = -ENXIO;

				break;

			}

			r = kvmppc_xics_set_icp(vcpu,

						set_reg_val(reg->id, val));

			break;

#endif /* CONFIG_KVM_XICS */

		default:

			r = -EINVAL;

			break;

arch/powerpc/kvm/book3s_xics.c

+90 −0
Original line number Diff line number Diff line
@@ -954,6 +954,96 @@ int kvmppc_xics_create_icp(struct kvm_vcpu *vcpu, unsigned long server_num) 
	return 0;

}



u64 kvmppc_xics_get_icp(struct kvm_vcpu *vcpu)

{

	struct kvmppc_icp *icp = vcpu->arch.icp;

	union kvmppc_icp_state state;



	if (!icp)

		return 0;

	state = icp->state;

	return ((u64)state.cppr << KVM_REG_PPC_ICP_CPPR_SHIFT) |

		((u64)state.xisr << KVM_REG_PPC_ICP_XISR_SHIFT) |

		((u64)state.mfrr << KVM_REG_PPC_ICP_MFRR_SHIFT) |

		((u64)state.pending_pri << KVM_REG_PPC_ICP_PPRI_SHIFT);

}



int kvmppc_xics_set_icp(struct kvm_vcpu *vcpu, u64 icpval)

{

	struct kvmppc_icp *icp = vcpu->arch.icp;

	struct kvmppc_xics *xics = vcpu->kvm->arch.xics;

	union kvmppc_icp_state old_state, new_state;

	struct kvmppc_ics *ics;

	u8 cppr, mfrr, pending_pri;

	u32 xisr;

	u16 src;

	bool resend;



	if (!icp || !xics)

		return -ENOENT;



	cppr = icpval >> KVM_REG_PPC_ICP_CPPR_SHIFT;

	xisr = (icpval >> KVM_REG_PPC_ICP_XISR_SHIFT) &

		KVM_REG_PPC_ICP_XISR_MASK;

	mfrr = icpval >> KVM_REG_PPC_ICP_MFRR_SHIFT;

	pending_pri = icpval >> KVM_REG_PPC_ICP_PPRI_SHIFT;



	/* Require the new state to be internally consistent */

	if (xisr == 0) {

		if (pending_pri != 0xff)

			return -EINVAL;

	} else if (xisr == XICS_IPI) {

		if (pending_pri != mfrr || pending_pri >= cppr)

			return -EINVAL;

	} else {

		if (pending_pri >= mfrr || pending_pri >= cppr)

			return -EINVAL;

		ics = kvmppc_xics_find_ics(xics, xisr, &src);

		if (!ics)

			return -EINVAL;

	}



	new_state.raw = 0;

	new_state.cppr = cppr;

	new_state.xisr = xisr;

	new_state.mfrr = mfrr;

	new_state.pending_pri = pending_pri;



	/*

	 * Deassert the CPU interrupt request.

	 * icp_try_update will reassert it if necessary.

	 */

	kvmppc_book3s_dequeue_irqprio(icp->vcpu,

				      BOOK3S_INTERRUPT_EXTERNAL_LEVEL);



	/*

	 * Note that if we displace an interrupt from old_state.xisr,

	 * we don't mark it as rejected.  We expect userspace to set

	 * the state of the interrupt sources to be consistent with

	 * the ICP states (either before or afterwards, which doesn't

	 * matter).  We do handle resends due to CPPR becoming less

	 * favoured because that is necessary to end up with a

	 * consistent state in the situation where userspace restores

	 * the ICS states before the ICP states.

	 */

	do {

		old_state = ACCESS_ONCE(icp->state);



		if (new_state.mfrr <= old_state.mfrr) {

			resend = false;

			new_state.need_resend = old_state.need_resend;

		} else {

			resend = old_state.need_resend;

			new_state.need_resend = 0;

		}

	} while (!icp_try_update(icp, old_state, new_state, false));



	if (resend)

		icp_check_resend(xics, icp);



	return 0;

}



/* -- ioctls -- */



int kvm_vm_ioctl_xics_irq(struct kvm *kvm, struct kvm_irq_level *args)