Initial import

1 files changed, 1411 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
new file mode 100644
index 000000000..c6ca7db64
--- /dev/null
+++ b/arch/powerpc/kvm/book3s_xics.c
@@ -0,0 +1,1411 @@
+/*
+ * Copyright 2012 Michael Ellerman, IBM Corporation.
+ * Copyright 2012 Benjamin Herrenschmidt, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kvm_host.h>
+#include <linux/err.h>
+#include <linux/gfp.h>
+#include <linux/anon_inodes.h>
+#include <linux/spinlock.h>
+
+#include <asm/uaccess.h>
+#include <asm/kvm_book3s.h>
+#include <asm/kvm_ppc.h>
+#include <asm/hvcall.h>
+#include <asm/xics.h>
+#include <asm/debug.h>
+#include <asm/time.h>
+
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+#include "book3s_xics.h"
+
+#if 1
+#define XICS_DBG(fmt...) do { } while (0)
+#else
+#define XICS_DBG(fmt...) trace_printk(fmt)
+#endif
+
+#define ENABLE_REALMODE	true
+#define DEBUG_REALMODE	false
+
+/*
+ * LOCKING
+ * =======
+ *
+ * Each ICS has a spin lock protecting the information about the IRQ
+ * sources and avoiding simultaneous deliveries if the same interrupt.
+ *
+ * ICP operations are done via a single compare & swap transaction
+ * (most ICP state fits in the union kvmppc_icp_state)
+ */
+
+/*
+ * TODO
+ * ====
+ *
+ * - To speed up resends, keep a bitmap of "resend" set bits in the
+ *   ICS
+ *
+ * - Speed up server# -> ICP lookup (array ? hash table ?)
+ *
+ * - Make ICS lockless as well, or at least a per-interrupt lock or hashed
+ *   locks array to improve scalability
+ */
+
+/* -- ICS routines -- */
+
+static void icp_deliver_irq(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
+			    u32 new_irq);
+
+/*
+ * Return value ideally indicates how the interrupt was handled, but no
+ * callers look at it (given that we don't implement KVM_IRQ_LINE_STATUS),
+ * so just return 0.
+ */
+static int ics_deliver_irq(struct kvmppc_xics *xics, u32 irq, u32 level)
+{
+	struct ics_irq_state *state;
+	struct kvmppc_ics *ics;
+	u16 src;
+
+	XICS_DBG("ics deliver %#x (level: %d)\n", irq, level);
+
+	ics = kvmppc_xics_find_ics(xics, irq, &src);
+	if (!ics) {
+		XICS_DBG("ics_deliver_irq: IRQ 0x%06x not found !\n", irq);
+		return -EINVAL;
+	}
+	state = &ics->irq_state[src];
+	if (!state->exists)
+		return -EINVAL;
+
+	/*
+	 * We set state->asserted locklessly. This should be fine as
+	 * we are the only setter, thus concurrent access is undefined
+	 * to begin with.
+	 */
+	if (level == 1 || level == KVM_INTERRUPT_SET_LEVEL)
+		state->asserted = 1;
+	else if (level == 0 || level == KVM_INTERRUPT_UNSET) {
+		state->asserted = 0;
+		return 0;
+	}
+
+	/* Attempt delivery */
+	icp_deliver_irq(xics, NULL, irq);
+
+	return 0;
+}
+
+static void ics_check_resend(struct kvmppc_xics *xics, struct kvmppc_ics *ics,
+			     struct kvmppc_icp *icp)
+{
+	int i;
+
+	unsigned long flags;
+
+	local_irq_save(flags);
+	arch_spin_lock(&ics->lock);
+
+	for (i = 0; i < KVMPPC_XICS_IRQ_PER_ICS; i++) {
+		struct ics_irq_state *state = &ics->irq_state[i];
+
+		if (!state->resend)
+			continue;
+
+		XICS_DBG("resend %#x prio %#x\n", state->number,
+			      state->priority);
+
+		arch_spin_unlock(&ics->lock);
+		local_irq_restore(flags);
+		icp_deliver_irq(xics, icp, state->number);
+		local_irq_save(flags);
+		arch_spin_lock(&ics->lock);
+	}
+
+	arch_spin_unlock(&ics->lock);
+	local_irq_restore(flags);
+}
+
+static bool write_xive(struct kvmppc_xics *xics, struct kvmppc_ics *ics,
+		       struct ics_irq_state *state,
+		       u32 server, u32 priority, u32 saved_priority)
+{
+	bool deliver;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	arch_spin_lock(&ics->lock);
+
+	state->server = server;
+	state->priority = priority;
+	state->saved_priority = saved_priority;
+	deliver = false;
+	if ((state->masked_pending || state->resend) && priority != MASKED) {
+		state->masked_pending = 0;
+		deliver = true;
+	}
+
+	arch_spin_unlock(&ics->lock);
+	local_irq_restore(flags);
+
+	return deliver;
+}
+
+int kvmppc_xics_set_xive(struct kvm *kvm, u32 irq, u32 server, u32 priority)
+{
+	struct kvmppc_xics *xics = kvm->arch.xics;
+	struct kvmppc_icp *icp;
+	struct kvmppc_ics *ics;
+	struct ics_irq_state *state;
+	u16 src;
+
+	if (!xics)
+		return -ENODEV;
+
+	ics = kvmppc_xics_find_ics(xics, irq, &src);
+	if (!ics)
+		return -EINVAL;
+	state = &ics->irq_state[src];
+
+	icp = kvmppc_xics_find_server(kvm, server);
+	if (!icp)
+		return -EINVAL;
+
+	XICS_DBG("set_xive %#x server %#x prio %#x MP:%d RS:%d\n",
+		 irq, server, priority,
+		 state->masked_pending, state->resend);
+
+	if (write_xive(xics, ics, state, server, priority, priority))
+		icp_deliver_irq(xics, icp, irq);
+
+	return 0;
+}
+
+int kvmppc_xics_get_xive(struct kvm *kvm, u32 irq, u32 *server, u32 *priority)
+{
+	struct kvmppc_xics *xics = kvm->arch.xics;
+	struct kvmppc_ics *ics;
+	struct ics_irq_state *state;
+	u16 src;
+	unsigned long flags;
+
+	if (!xics)
+		return -ENODEV;
+
+	ics = kvmppc_xics_find_ics(xics, irq, &src);
+	if (!ics)
+		return -EINVAL;
+	state = &ics->irq_state[src];
+
+	local_irq_save(flags);
+	arch_spin_lock(&ics->lock);
+	*server = state->server;
+	*priority = state->priority;
+	arch_spin_unlock(&ics->lock);
+	local_irq_restore(flags);
+
+	return 0;
+}
+
+int kvmppc_xics_int_on(struct kvm *kvm, u32 irq)
+{
+	struct kvmppc_xics *xics = kvm->arch.xics;
+	struct kvmppc_icp *icp;
+	struct kvmppc_ics *ics;
+	struct ics_irq_state *state;
+	u16 src;
+
+	if (!xics)
+		return -ENODEV;
+
+	ics = kvmppc_xics_find_ics(xics, irq, &src);
+	if (!ics)
+		return -EINVAL;
+	state = &ics->irq_state[src];
+
+	icp = kvmppc_xics_find_server(kvm, state->server);
+	if (!icp)
+		return -EINVAL;
+
+	if (write_xive(xics, ics, state, state->server, state->saved_priority,
+		       state->saved_priority))
+		icp_deliver_irq(xics, icp, irq);
+
+	return 0;
+}
+
+int kvmppc_xics_int_off(struct kvm *kvm, u32 irq)
+{
+	struct kvmppc_xics *xics = kvm->arch.xics;
+	struct kvmppc_ics *ics;
+	struct ics_irq_state *state;
+	u16 src;
+
+	if (!xics)
+		return -ENODEV;
+
+	ics = kvmppc_xics_find_ics(xics, irq, &src);
+	if (!ics)
+		return -EINVAL;
+	state = &ics->irq_state[src];
+
+	write_xive(xics, ics, state, state->server, MASKED, state->priority);
+
+	return 0;
+}
+
+/* -- ICP routines, including hcalls -- */
+
+static inline bool icp_try_update(struct kvmppc_icp *icp,
+				  union kvmppc_icp_state old,
+				  union kvmppc_icp_state new,
+				  bool change_self)
+{
+	bool success;
+
+	/* Calculate new output value */
+	new.out_ee = (new.xisr && (new.pending_pri < new.cppr));
+
+	/* Attempt atomic update */
+	success = cmpxchg64(&icp->state.raw, old.raw, new.raw) == old.raw;
+	if (!success)
+		goto bail;
+
+	XICS_DBG("UPD [%04x] - C:%02x M:%02x PP: %02x PI:%06x R:%d O:%d\n",
+		 icp->server_num,
+		 old.cppr, old.mfrr, old.pending_pri, old.xisr,
+		 old.need_resend, old.out_ee);
+	XICS_DBG("UPD        - C:%02x M:%02x PP: %02x PI:%06x R:%d O:%d\n",
+		 new.cppr, new.mfrr, new.pending_pri, new.xisr,
+		 new.need_resend, new.out_ee);
+	/*
+	 * Check for output state update
+	 *
+	 * Note that this is racy since another processor could be updating
+	 * the state already. This is why we never clear the interrupt output
+	 * here, we only ever set it. The clear only happens prior to doing
+	 * an update and only by the processor itself. Currently we do it
+	 * in Accept (H_XIRR) and Up_Cppr (H_XPPR).
+	 *
+	 * We also do not try to figure out whether the EE state has changed,
+	 * we unconditionally set it if the new state calls for it. The reason
+	 * for that is that we opportunistically remove the pending interrupt
+	 * flag when raising CPPR, so we need to set it back here if an
+	 * interrupt is still pending.
+	 */
+	if (new.out_ee) {
+		kvmppc_book3s_queue_irqprio(icp->vcpu,
+					    BOOK3S_INTERRUPT_EXTERNAL_LEVEL);
+		if (!change_self)
+			kvmppc_fast_vcpu_kick(icp->vcpu);
+	}
+ bail:
+	return success;
+}
+
+static void icp_check_resend(struct kvmppc_xics *xics,
+			     struct kvmppc_icp *icp)
+{
+	u32 icsid;
+
+	/* Order this load with the test for need_resend in the caller */
+	smp_rmb();
+	for_each_set_bit(icsid, icp->resend_map, xics->max_icsid + 1) {
+		struct kvmppc_ics *ics = xics->ics[icsid];
+
+		if (!test_and_clear_bit(icsid, icp->resend_map))
+			continue;
+		if (!ics)
+			continue;
+		ics_check_resend(xics, ics, icp);
+	}
+}
+
+static bool icp_try_to_deliver(struct kvmppc_icp *icp, u32 irq, u8 priority,
+			       u32 *reject)
+{
+	union kvmppc_icp_state old_state, new_state;
+	bool success;
+
+	XICS_DBG("try deliver %#x(P:%#x) to server %#x\n", irq, priority,
+		 icp->server_num);
+
+	do {
+		old_state = new_state = READ_ONCE(icp->state);
+
+		*reject = 0;
+
+		/* See if we can deliver */
+		success = new_state.cppr > priority &&
+			new_state.mfrr > priority &&
+			new_state.pending_pri > priority;
+
+		/*
+		 * If we can, check for a rejection and perform the
+		 * delivery
+		 */
+		if (success) {
+			*reject = new_state.xisr;
+			new_state.xisr = irq;
+			new_state.pending_pri = priority;
+		} else {
+			/*
+			 * If we failed to deliver we set need_resend
+			 * so a subsequent CPPR state change causes us
+			 * to try a new delivery.
+			 */
+			new_state.need_resend = true;
+		}
+
+	} while (!icp_try_update(icp, old_state, new_state, false));
+
+	return success;
+}
+
+static void icp_deliver_irq(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
+			    u32 new_irq)
+{
+	struct ics_irq_state *state;
+	struct kvmppc_ics *ics;
+	u32 reject;
+	u16 src;
+	unsigned long flags;
+
+	/*
+	 * This is used both for initial delivery of an interrupt and
+	 * for subsequent rejection.
+	 *
+	 * Rejection can be racy vs. resends. We have evaluated the
+	 * rejection in an atomic ICP transaction which is now complete,
+	 * so potentially the ICP can already accept the interrupt again.
+	 *
+	 * So we need to retry the delivery. Essentially the reject path
+	 * boils down to a failed delivery. Always.
+	 *
+	 * Now the interrupt could also have moved to a different target,
+	 * thus we may need to re-do the ICP lookup as well
+	 */
+
+ again:
+	/* Get the ICS state and lock it */
+	ics = kvmppc_xics_find_ics(xics, new_irq, &src);
+	if (!ics) {
+		XICS_DBG("icp_deliver_irq: IRQ 0x%06x not found !\n", new_irq);
+		return;
+	}
+	state = &ics->irq_state[src];
+
+	/* Get a lock on the ICS */
+	local_irq_save(flags);
+	arch_spin_lock(&ics->lock);
+
+	/* Get our server */
+	if (!icp || state->server != icp->server_num) {
+		icp = kvmppc_xics_find_server(xics->kvm, state->server);
+		if (!icp) {
+			pr_warn("icp_deliver_irq: IRQ 0x%06x server 0x%x not found !\n",
+				new_irq, state->server);
+			goto out;
+		}
+	}
+
+	/* Clear the resend bit of that interrupt */
+	state->resend = 0;
+
+	/*
+	 * If masked, bail out
+	 *
+	 * Note: PAPR doesn't mention anything about masked pending
+	 * when doing a resend, only when doing a delivery.
+	 *
+	 * However that would have the effect of losing a masked
+	 * interrupt that was rejected and isn't consistent with
+	 * the whole masked_pending business which is about not
+	 * losing interrupts that occur while masked.
+	 *
+	 * I don't differenciate normal deliveries and resends, this
+	 * implementation will differ from PAPR and not lose such
+	 * interrupts.
+	 */
+	if (state->priority == MASKED) {
+		XICS_DBG("irq %#x masked pending\n", new_irq);
+		state->masked_pending = 1;
+		goto out;
+	}
+
+	/*
+	 * Try the delivery, this will set the need_resend flag
+	 * in the ICP as part of the atomic transaction if the
+	 * delivery is not possible.
+	 *
+	 * Note that if successful, the new delivery might have itself
+	 * rejected an interrupt that was "delivered" before we took the
+	 * ics spin lock.
+	 *
+	 * In this case we do the whole sequence all over again for the
+	 * new guy. We cannot assume that the rejected interrupt is less
+	 * favored than the new one, and thus doesn't need to be delivered,
+	 * because by the time we exit icp_try_to_deliver() the target
+	 * processor may well have alrady consumed & completed it, and thus
+	 * the rejected interrupt might actually be already acceptable.
+	 */
+	if (icp_try_to_deliver(icp, new_irq, state->priority, &reject)) {
+		/*
+		 * Delivery was successful, did we reject somebody else ?
+		 */
+		if (reject && reject != XICS_IPI) {
+			arch_spin_unlock(&ics->lock);
+			local_irq_restore(flags);
+			new_irq = reject;
+			goto again;
+		}
+	} else {
+		/*
+		 * We failed to deliver the interrupt we need to set the
+		 * resend map bit and mark the ICS state as needing a resend
+		 */
+		set_bit(ics->icsid, icp->resend_map);
+		state->resend = 1;
+
+		/*
+		 * If the need_resend flag got cleared in the ICP some time
+		 * between icp_try_to_deliver() atomic update and now, then
+		 * we know it might have missed the resend_map bit. So we
+		 * retry
+		 */
+		smp_mb();
+		if (!icp->state.need_resend) {
+			arch_spin_unlock(&ics->lock);
+			local_irq_restore(flags);
+			goto again;
+		}
+	}
+ out:
+	arch_spin_unlock(&ics->lock);
+	local_irq_restore(flags);
+}
+
+static void icp_down_cppr(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
+			  u8 new_cppr)
+{
+	union kvmppc_icp_state old_state, new_state;
+	bool resend;
+
+	/*
+	 * This handles several related states in one operation:
+	 *
+	 * ICP State: Down_CPPR
+	 *
+	 * Load CPPR with new value and if the XISR is 0
+	 * then check for resends:
+	 *
+	 * ICP State: Resend
+	 *
+	 * If MFRR is more favored than CPPR, check for IPIs
+	 * and notify ICS of a potential resend. This is done
+	 * asynchronously (when used in real mode, we will have
+	 * to exit here).
+	 *
+	 * We do not handle the complete Check_IPI as documented
+	 * here. In the PAPR, this state will be used for both
+	 * Set_MFRR and Down_CPPR. However, we know that we aren't
+	 * changing the MFRR state here so we don't need to handle
+	 * the case of an MFRR causing a reject of a pending irq,
+	 * this will have been handled when the MFRR was set in the
+	 * first place.
+	 *
+	 * Thus we don't have to handle rejects, only resends.
+	 *
+	 * When implementing real mode for HV KVM, resend will lead to
+	 * a H_TOO_HARD return and the whole transaction will be handled
+	 * in virtual mode.
+	 */
+	do {
+		old_state = new_state = READ_ONCE(icp->state);
+
+		/* Down_CPPR */
+		new_state.cppr = new_cppr;
+
+		/*
+		 * Cut down Resend / Check_IPI / IPI
+		 *
+		 * The logic is that we cannot have a pending interrupt
+		 * trumped by an IPI at this point (see above), so we
+		 * know that either the pending interrupt is already an
+		 * IPI (in which case we don't care to override it) or
+		 * it's either more favored than us or non existent
+		 */
+		if (new_state.mfrr < new_cppr &&
+		    new_state.mfrr <= new_state.pending_pri) {
+			WARN_ON(new_state.xisr != XICS_IPI &&
+				new_state.xisr != 0);
+			new_state.pending_pri = new_state.mfrr;
+			new_state.xisr = XICS_IPI;
+		}
+
+		/* Latch/clear resend bit */
+		resend = new_state.need_resend;
+		new_state.need_resend = 0;
+
+	} while (!icp_try_update(icp, old_state, new_state, true));
+
+	/*
+	 * Now handle resend checks. Those are asynchronous to the ICP
+	 * state update in HW (ie bus transactions) so we can handle them
+	 * separately here too
+	 */
+	if (resend)
+		icp_check_resend(xics, icp);
+}
+
+static noinline unsigned long kvmppc_h_xirr(struct kvm_vcpu *vcpu)
+{
+	union kvmppc_icp_state old_state, new_state;
+	struct kvmppc_icp *icp = vcpu->arch.icp;
+	u32 xirr;
+
+	/* First, remove EE from the processor */
+	kvmppc_book3s_dequeue_irqprio(icp->vcpu,
+				      BOOK3S_INTERRUPT_EXTERNAL_LEVEL);
+
+	/*
+	 * ICP State: Accept_Interrupt
+	 *
+	 * Return the pending interrupt (if any) along with the
+	 * current CPPR, then clear the XISR & set CPPR to the
+	 * pending priority
+	 */
+	do {
+		old_state = new_state = READ_ONCE(icp->state);
+
+		xirr = old_state.xisr | (((u32)old_state.cppr) << 24);
+		if (!old_state.xisr)
+			break;
+		new_state.cppr = new_state.pending_pri;
+		new_state.pending_pri = 0xff;
+		new_state.xisr = 0;
+
+	} while (!icp_try_update(icp, old_state, new_state, true));
+
+	XICS_DBG("h_xirr vcpu %d xirr %#x\n", vcpu->vcpu_id, xirr);
+
+	return xirr;
+}
+
+static noinline int kvmppc_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
+				 unsigned long mfrr)
+{
+	union kvmppc_icp_state old_state, new_state;
+	struct kvmppc_xics *xics = vcpu->kvm->arch.xics;
+	struct kvmppc_icp *icp;
+	u32 reject;
+	bool resend;
+	bool local;
+
+	XICS_DBG("h_ipi vcpu %d to server %lu mfrr %#lx\n",
+		 vcpu->vcpu_id, server, mfrr);
+
+	icp = vcpu->arch.icp;
+	local = icp->server_num == server;
+	if (!local) {
+		icp = kvmppc_xics_find_server(vcpu->kvm, server);
+		if (!icp)
+			return H_PARAMETER;
+	}
+
+	/*
+	 * ICP state: Set_MFRR
+	 *
+	 * If the CPPR is more favored than the new MFRR, then
+	 * nothing needs to be rejected as there can be no XISR to
+	 * reject.  If the MFRR is being made less favored then
+	 * there might be a previously-rejected interrupt needing
+	 * to be resent.
+	 *
+	 * ICP state: Check_IPI
+	 *
+	 * If the CPPR is less favored, then we might be replacing
+	 * an interrupt, and thus need to possibly reject it.
+	 *
+	 * ICP State: IPI
+	 *
+	 * Besides rejecting any pending interrupts, we also
+	 * update XISR and pending_pri to mark IPI as pending.
+	 *
+	 * PAPR does not describe this state, but if the MFRR is being
+	 * made less favored than its earlier value, there might be
+	 * a previously-rejected interrupt needing to be resent.
+	 * Ideally, we would want to resend only if
+	 *	prio(pending_interrupt) < mfrr &&
+	 *	prio(pending_interrupt) < cppr
+	 * where pending interrupt is the one that was rejected. But
+	 * we don't have that state, so we simply trigger a resend
+	 * whenever the MFRR is made less favored.
+	 */
+	do {
+		old_state = new_state = READ_ONCE(icp->state);
+
+		/* Set_MFRR */
+		new_state.mfrr = mfrr;
+
+		/* Check_IPI */
+		reject = 0;
+		resend = false;
+		if (mfrr < new_state.cppr) {
+			/* Reject a pending interrupt if not an IPI */
+			if (mfrr <= new_state.pending_pri) {
+				reject = new_state.xisr;
+				new_state.pending_pri = mfrr;
+				new_state.xisr = XICS_IPI;
+			}
+		}
+
+		if (mfrr > old_state.mfrr) {
+			resend = new_state.need_resend;
+			new_state.need_resend = 0;
+		}
+	} while (!icp_try_update(icp, old_state, new_state, local));
+
+	/* Handle reject */
+	if (reject && reject != XICS_IPI)
+		icp_deliver_irq(xics, icp, reject);
+
+	/* Handle resend */
+	if (resend)
+		icp_check_resend(xics, icp);
+
+	return H_SUCCESS;
+}
+
+static int kvmppc_h_ipoll(struct kvm_vcpu *vcpu, unsigned long server)
+{
+	union kvmppc_icp_state state;
+	struct kvmppc_icp *icp;
+
+	icp = vcpu->arch.icp;
+	if (icp->server_num != server) {
+		icp = kvmppc_xics_find_server(vcpu->kvm, server);
+		if (!icp)
+			return H_PARAMETER;
+	}
+	state = READ_ONCE(icp->state);
+	kvmppc_set_gpr(vcpu, 4, ((u32)state.cppr << 24) | state.xisr);
+	kvmppc_set_gpr(vcpu, 5, state.mfrr);
+	return H_SUCCESS;
+}
+
+static noinline void kvmppc_h_cppr(struct kvm_vcpu *vcpu, unsigned long cppr)
+{
+	union kvmppc_icp_state old_state, new_state;
+	struct kvmppc_xics *xics = vcpu->kvm->arch.xics;
+	struct kvmppc_icp *icp = vcpu->arch.icp;
+	u32 reject;
+
+	XICS_DBG("h_cppr vcpu %d cppr %#lx\n", vcpu->vcpu_id, cppr);
+
+	/*
+	 * ICP State: Set_CPPR
+	 *
+	 * We can safely compare the new value with the current
+	 * value outside of the transaction as the CPPR is only
+	 * ever changed by the processor on itself
+	 */
+	if (cppr > icp->state.cppr)
+		icp_down_cppr(xics, icp, cppr);
+	else if (cppr == icp->state.cppr)
+		return;
+
+	/*
+	 * ICP State: Up_CPPR
+	 *
+	 * The processor is raising its priority, this can result
+	 * in a rejection of a pending interrupt:
+	 *
+	 * ICP State: Reject_Current
+	 *
+	 * We can remove EE from the current processor, the update
+	 * transaction will set it again if needed
+	 */
+	kvmppc_book3s_dequeue_irqprio(icp->vcpu,
+				      BOOK3S_INTERRUPT_EXTERNAL_LEVEL);
+
+	do {
+		old_state = new_state = READ_ONCE(icp->state);
+
+		reject = 0;
+		new_state.cppr = cppr;
+
+		if (cppr <= new_state.pending_pri) {
+			reject = new_state.xisr;
+			new_state.xisr = 0;
+			new_state.pending_pri = 0xff;
+		}
+
+	} while (!icp_try_update(icp, old_state, new_state, true));
+
+	/*
+	 * Check for rejects. They are handled by doing a new delivery
+	 * attempt (see comments in icp_deliver_irq).
+	 */
+	if (reject && reject != XICS_IPI)
+		icp_deliver_irq(xics, icp, reject);
+}
+
+static noinline int kvmppc_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr)
+{
+	struct kvmppc_xics *xics = vcpu->kvm->arch.xics;
+	struct kvmppc_icp *icp = vcpu->arch.icp;
+	struct kvmppc_ics *ics;
+	struct ics_irq_state *state;
+	u32 irq = xirr & 0x00ffffff;
+	u16 src;
+
+	XICS_DBG("h_eoi vcpu %d eoi %#lx\n", vcpu->vcpu_id, xirr);
+
+	/*
+	 * ICP State: EOI
+	 *
+	 * Note: If EOI is incorrectly used by SW to lower the CPPR
+	 * value (ie more favored), we do not check for rejection of
+	 * a pending interrupt, this is a SW error and PAPR sepcifies
+	 * that we don't have to deal with it.
+	 *
+	 * The sending of an EOI to the ICS is handled after the
+	 * CPPR update
+	 *
+	 * ICP State: Down_CPPR which we handle
+	 * in a separate function as it's shared with H_CPPR.
+	 */
+	icp_down_cppr(xics, icp, xirr >> 24);
+
+	/* IPIs have no EOI */
+	if (irq == XICS_IPI)
+		return H_SUCCESS;
+	/*
+	 * EOI handling: If the interrupt is still asserted, we need to
+	 * resend it. We can take a lockless "peek" at the ICS state here.
+	 *
+	 * "Message" interrupts will never have "asserted" set
+	 */
+	ics = kvmppc_xics_find_ics(xics, irq, &src);
+	if (!ics) {
+		XICS_DBG("h_eoi: IRQ 0x%06x not found !\n", irq);
+		return H_PARAMETER;
+	}
+	state = &ics->irq_state[src];
+
+	/* Still asserted, resend it */
+	if (state->asserted)
+		icp_deliver_irq(xics, icp, irq);
+
+	kvm_notify_acked_irq(vcpu->kvm, 0, irq);
+
+	return H_SUCCESS;
+}
+
+static noinline int kvmppc_xics_rm_complete(struct kvm_vcpu *vcpu, u32 hcall)
+{
+	struct kvmppc_xics *xics = vcpu->kvm->arch.xics;
+	struct kvmppc_icp *icp = vcpu->arch.icp;
+
+	XICS_DBG("XICS_RM: H_%x completing, act: %x state: %lx tgt: %p\n",
+		 hcall, icp->rm_action, icp->rm_dbgstate.raw, icp->rm_dbgtgt);
+
+	if (icp->rm_action & XICS_RM_KICK_VCPU) {
+		icp->n_rm_kick_vcpu++;
+		kvmppc_fast_vcpu_kick(icp->rm_kick_target);
+	}
+	if (icp->rm_action & XICS_RM_CHECK_RESEND) {
+		icp->n_rm_check_resend++;
+		icp_check_resend(xics, icp->rm_resend_icp);
+	}
+	if (icp->rm_action & XICS_RM_REJECT) {
+		icp->n_rm_reject++;
+		icp_deliver_irq(xics, icp, icp->rm_reject);
+	}
+	if (icp->rm_action & XICS_RM_NOTIFY_EOI) {
+		icp->n_rm_notify_eoi++;
+		kvm_notify_acked_irq(vcpu->kvm, 0, icp->rm_eoied_irq);
+	}
+
+	icp->rm_action = 0;
+
+	return H_SUCCESS;
+}
+
+int kvmppc_xics_hcall(struct kvm_vcpu *vcpu, u32 req)
+{
+	struct kvmppc_xics *xics = vcpu->kvm->arch.xics;
+	unsigned long res;
+	int rc = H_SUCCESS;
+
+	/* Check if we have an ICP */
+	if (!xics || !vcpu->arch.icp)
+		return H_HARDWARE;
+
+	/* These requests don't have real-mode implementations at present */
+	switch (req) {
+	case H_XIRR_X:
+		res = kvmppc_h_xirr(vcpu);
+		kvmppc_set_gpr(vcpu, 4, res);
+		kvmppc_set_gpr(vcpu, 5, get_tb());
+		return rc;
+	case H_IPOLL:
+		rc = kvmppc_h_ipoll(vcpu, kvmppc_get_gpr(vcpu, 4));
+		return rc;
+	}
+
+	/* Check for real mode returning too hard */
+	if (xics->real_mode && is_kvmppc_hv_enabled(vcpu->kvm))
+		return kvmppc_xics_rm_complete(vcpu, req);
+
+	switch (req) {
+	case H_XIRR:
+		res = kvmppc_h_xirr(vcpu);
+		kvmppc_set_gpr(vcpu, 4, res);
+		break;
+	case H_CPPR:
+		kvmppc_h_cppr(vcpu, kvmppc_get_gpr(vcpu, 4));
+		break;
+	case H_EOI:
+		rc = kvmppc_h_eoi(vcpu, kvmppc_get_gpr(vcpu, 4));
+		break;
+	case H_IPI:
+		rc = kvmppc_h_ipi(vcpu, kvmppc_get_gpr(vcpu, 4),
+				  kvmppc_get_gpr(vcpu, 5));
+		break;
+	}
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(kvmppc_xics_hcall);
+
+
+/* -- Initialisation code etc. -- */
+
+static int xics_debug_show(struct seq_file *m, void *private)
+{
+	struct kvmppc_xics *xics = m->private;
+	struct kvm *kvm = xics->kvm;
+	struct kvm_vcpu *vcpu;
+	int icsid, i;
+	unsigned long flags;
+	unsigned long t_rm_kick_vcpu, t_rm_check_resend;
+	unsigned long t_rm_reject, t_rm_notify_eoi;
+	unsigned long t_reject, t_check_resend;
+
+	if (!kvm)
+		return 0;
+
+	t_rm_kick_vcpu = 0;
+	t_rm_notify_eoi = 0;
+	t_rm_check_resend = 0;
+	t_rm_reject = 0;
+	t_check_resend = 0;
+	t_reject = 0;
+
+	seq_printf(m, "=========\nICP state\n=========\n");
+
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		struct kvmppc_icp *icp = vcpu->arch.icp;
+		union kvmppc_icp_state state;
+
+		if (!icp)
+			continue;
+
+		state.raw = READ_ONCE(icp->state.raw);
+		seq_printf(m, "cpu server %#lx XIRR:%#x PPRI:%#x CPPR:%#x MFRR:%#x OUT:%d NR:%d\n",
+			   icp->server_num, state.xisr,
+			   state.pending_pri, state.cppr, state.mfrr,
+			   state.out_ee, state.need_resend);
+		t_rm_kick_vcpu += icp->n_rm_kick_vcpu;
+		t_rm_notify_eoi += icp->n_rm_notify_eoi;
+		t_rm_check_resend += icp->n_rm_check_resend;
+		t_rm_reject += icp->n_rm_reject;
+		t_check_resend += icp->n_check_resend;
+		t_reject += icp->n_reject;
+	}
+
+	seq_printf(m, "ICP Guest->Host totals: kick_vcpu=%lu check_resend=%lu reject=%lu notify_eoi=%lu\n",
+			t_rm_kick_vcpu, t_rm_check_resend,
+			t_rm_reject, t_rm_notify_eoi);
+	seq_printf(m, "ICP Real Mode totals: check_resend=%lu resend=%lu\n",
+			t_check_resend, t_reject);
+	for (icsid = 0; icsid <= KVMPPC_XICS_MAX_ICS_ID; icsid++) {
+		struct kvmppc_ics *ics = xics->ics[icsid];
+
+		if (!ics)
+			continue;
+
+		seq_printf(m, "=========\nICS state for ICS 0x%x\n=========\n",
+			   icsid);
+
+		local_irq_save(flags);
+		arch_spin_lock(&ics->lock);
+
+		for (i = 0; i < KVMPPC_XICS_IRQ_PER_ICS; i++) {
+			struct ics_irq_state *irq = &ics->irq_state[i];
+
+			seq_printf(m, "irq 0x%06x: server %#x prio %#x save prio %#x asserted %d resend %d masked pending %d\n",
+				   irq->number, irq->server, irq->priority,
+				   irq->saved_priority, irq->asserted,
+				   irq->resend, irq->masked_pending);
+
+		}
+		arch_spin_unlock(&ics->lock);
+		local_irq_restore(flags);
+	}
+	return 0;
+}
+
+static int xics_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, xics_debug_show, inode->i_private);
+}
+
+static const struct file_operations xics_debug_fops = {
+	.open = xics_debug_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static void xics_debugfs_init(struct kvmppc_xics *xics)
+{
+	char *name;
+
+	name = kasprintf(GFP_KERNEL, "kvm-xics-%p", xics);
+	if (!name) {
+		pr_err("%s: no memory for name\n", __func__);
+		return;
+	}
+
+	xics->dentry = debugfs_create_file(name, S_IRUGO, powerpc_debugfs_root,
+					   xics, &xics_debug_fops);
+
+	pr_debug("%s: created %s\n", __func__, name);
+	kfree(name);
+}
+
+static struct kvmppc_ics *kvmppc_xics_create_ics(struct kvm *kvm,
+					struct kvmppc_xics *xics, int irq)
+{
+	struct kvmppc_ics *ics;
+	int i, icsid;
+
+	icsid = irq >> KVMPPC_XICS_ICS_SHIFT;
+
+	mutex_lock(&kvm->lock);
+
+	/* ICS already exists - somebody else got here first */
+	if (xics->ics[icsid])
+		goto out;
+
+	/* Create the ICS */
+	ics = kzalloc(sizeof(struct kvmppc_ics), GFP_KERNEL);
+	if (!ics)
+		goto out;
+
+	ics->icsid = icsid;
+
+	for (i = 0; i < KVMPPC_XICS_IRQ_PER_ICS; i++) {
+		ics->irq_state[i].number = (icsid << KVMPPC_XICS_ICS_SHIFT) | i;
+		ics->irq_state[i].priority = MASKED;
+		ics->irq_state[i].saved_priority = MASKED;
+	}
+	smp_wmb();
+	xics->ics[icsid] = ics;
+
+	if (icsid > xics->max_icsid)
+		xics->max_icsid = icsid;
+
+ out:
+	mutex_unlock(&kvm->lock);
+	return xics->ics[icsid];
+}
+
+int kvmppc_xics_create_icp(struct kvm_vcpu *vcpu, unsigned long server_num)
+{
+	struct kvmppc_icp *icp;
+
+	if (!vcpu->kvm->arch.xics)
+		return -ENODEV;
+
+	if (kvmppc_xics_find_server(vcpu->kvm, server_num))
+		return -EEXIST;
+
+	icp = kzalloc(sizeof(struct kvmppc_icp), GFP_KERNEL);
+	if (!icp)
+		return -ENOMEM;
+
+	icp->vcpu = vcpu;
+	icp->server_num = server_num;
+	icp->state.mfrr = MASKED;
+	icp->state.pending_pri = MASKED;
+	vcpu->arch.icp = icp;
+
+	XICS_DBG("created server for vcpu %d\n", vcpu->vcpu_id);
+
+	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 = READ_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;
+}
+
+static int xics_get_source(struct kvmppc_xics *xics, long irq, u64 addr)
+{
+	int ret;
+	struct kvmppc_ics *ics;
+	struct ics_irq_state *irqp;
+	u64 __user *ubufp = (u64 __user *) addr;
+	u16 idx;
+	u64 val, prio;
+	unsigned long flags;
+
+	ics = kvmppc_xics_find_ics(xics, irq, &idx);
+	if (!ics)
+		return -ENOENT;
+
+	irqp = &ics->irq_state[idx];
+	local_irq_save(flags);
+	arch_spin_lock(&ics->lock);
+	ret = -ENOENT;
+	if (irqp->exists) {
+		val = irqp->server;
+		prio = irqp->priority;
+		if (prio == MASKED) {
+			val |= KVM_XICS_MASKED;
+			prio = irqp->saved_priority;
+		}
+		val |= prio << KVM_XICS_PRIORITY_SHIFT;
+		if (irqp->asserted)
+			val |= KVM_XICS_LEVEL_SENSITIVE | KVM_XICS_PENDING;
+		else if (irqp->masked_pending || irqp->resend)
+			val |= KVM_XICS_PENDING;
+		ret = 0;
+	}
+	arch_spin_unlock(&ics->lock);
+	local_irq_restore(flags);
+
+	if (!ret && put_user(val, ubufp))
+		ret = -EFAULT;
+
+	return ret;
+}
+
+static int xics_set_source(struct kvmppc_xics *xics, long irq, u64 addr)
+{
+	struct kvmppc_ics *ics;
+	struct ics_irq_state *irqp;
+	u64 __user *ubufp = (u64 __user *) addr;
+	u16 idx;
+	u64 val;
+	u8 prio;
+	u32 server;
+	unsigned long flags;
+
+	if (irq < KVMPPC_XICS_FIRST_IRQ || irq >= KVMPPC_XICS_NR_IRQS)
+		return -ENOENT;
+
+	ics = kvmppc_xics_find_ics(xics, irq, &idx);
+	if (!ics) {
+		ics = kvmppc_xics_create_ics(xics->kvm, xics, irq);
+		if (!ics)
+			return -ENOMEM;
+	}
+	irqp = &ics->irq_state[idx];
+	if (get_user(val, ubufp))
+		return -EFAULT;
+
+	server = val & KVM_XICS_DESTINATION_MASK;
+	prio = val >> KVM_XICS_PRIORITY_SHIFT;
+	if (prio != MASKED &&
+	    kvmppc_xics_find_server(xics->kvm, server) == NULL)
+		return -EINVAL;
+
+	local_irq_save(flags);
+	arch_spin_lock(&ics->lock);
+	irqp->server = server;
+	irqp->saved_priority = prio;
+	if (val & KVM_XICS_MASKED)
+		prio = MASKED;
+	irqp->priority = prio;
+	irqp->resend = 0;
+	irqp->masked_pending = 0;
+	irqp->asserted = 0;
+	if ((val & KVM_XICS_PENDING) && (val & KVM_XICS_LEVEL_SENSITIVE))
+		irqp->asserted = 1;
+	irqp->exists = 1;
+	arch_spin_unlock(&ics->lock);
+	local_irq_restore(flags);
+
+	if (val & KVM_XICS_PENDING)
+		icp_deliver_irq(xics, NULL, irqp->number);
+
+	return 0;
+}
+
+int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
+		bool line_status)
+{
+	struct kvmppc_xics *xics = kvm->arch.xics;
+
+	return ics_deliver_irq(xics, irq, level);
+}
+
+int kvm_set_msi(struct kvm_kernel_irq_routing_entry *irq_entry, struct kvm *kvm,
+		int irq_source_id, int level, bool line_status)
+{
+	if (!level)
+		return -1;
+	return kvm_set_irq(kvm, irq_source_id, irq_entry->gsi,
+			   level, line_status);
+}
+
+static int xics_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
+{
+	struct kvmppc_xics *xics = dev->private;
+
+	switch (attr->group) {
+	case KVM_DEV_XICS_GRP_SOURCES:
+		return xics_set_source(xics, attr->attr, attr->addr);
+	}
+	return -ENXIO;
+}
+
+static int xics_get_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
+{
+	struct kvmppc_xics *xics = dev->private;
+
+	switch (attr->group) {
+	case KVM_DEV_XICS_GRP_SOURCES:
+		return xics_get_source(xics, attr->attr, attr->addr);
+	}
+	return -ENXIO;
+}
+
+static int xics_has_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
+{
+	switch (attr->group) {
+	case KVM_DEV_XICS_GRP_SOURCES:
+		if (attr->attr >= KVMPPC_XICS_FIRST_IRQ &&
+		    attr->attr < KVMPPC_XICS_NR_IRQS)
+			return 0;
+		break;
+	}
+	return -ENXIO;
+}
+
+static void kvmppc_xics_free(struct kvm_device *dev)
+{
+	struct kvmppc_xics *xics = dev->private;
+	int i;
+	struct kvm *kvm = xics->kvm;
+
+	debugfs_remove(xics->dentry);
+
+	if (kvm)
+		kvm->arch.xics = NULL;
+
+	for (i = 0; i <= xics->max_icsid; i++)
+		kfree(xics->ics[i]);
+	kfree(xics);
+	kfree(dev);
+}
+
+static int kvmppc_xics_create(struct kvm_device *dev, u32 type)
+{
+	struct kvmppc_xics *xics;
+	struct kvm *kvm = dev->kvm;
+	int ret = 0;
+
+	xics = kzalloc(sizeof(*xics), GFP_KERNEL);
+	if (!xics)
+		return -ENOMEM;
+
+	dev->private = xics;
+	xics->dev = dev;
+	xics->kvm = kvm;
+
+	/* Already there ? */
+	mutex_lock(&kvm->lock);
+	if (kvm->arch.xics)
+		ret = -EEXIST;
+	else
+		kvm->arch.xics = xics;
+	mutex_unlock(&kvm->lock);
+
+	if (ret) {
+		kfree(xics);
+		return ret;
+	}
+
+	xics_debugfs_init(xics);
+
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+	if (cpu_has_feature(CPU_FTR_ARCH_206)) {
+		/* Enable real mode support */
+		xics->real_mode = ENABLE_REALMODE;
+		xics->real_mode_dbg = DEBUG_REALMODE;
+	}
+#endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
+
+	return 0;
+}
+
+struct kvm_device_ops kvm_xics_ops = {
+	.name = "kvm-xics",
+	.create = kvmppc_xics_create,
+	.destroy = kvmppc_xics_free,
+	.set_attr = xics_set_attr,
+	.get_attr = xics_get_attr,
+	.has_attr = xics_has_attr,
+};
+
+int kvmppc_xics_connect_vcpu(struct kvm_device *dev, struct kvm_vcpu *vcpu,
+			     u32 xcpu)
+{
+	struct kvmppc_xics *xics = dev->private;
+	int r = -EBUSY;
+
+	if (dev->ops != &kvm_xics_ops)
+		return -EPERM;
+	if (xics->kvm != vcpu->kvm)
+		return -EPERM;
+	if (vcpu->arch.irq_type)
+		return -EBUSY;
+
+	r = kvmppc_xics_create_icp(vcpu, xcpu);
+	if (!r)
+		vcpu->arch.irq_type = KVMPPC_IRQ_XICS;
+
+	return r;
+}
+
+void kvmppc_xics_free_icp(struct kvm_vcpu *vcpu)
+{
+	if (!vcpu->arch.icp)
+		return;
+	kfree(vcpu->arch.icp);
+	vcpu->arch.icp = NULL;
+	vcpu->arch.irq_type = KVMPPC_IRQ_DEFAULT;
+}
+
+static int xics_set_irq(struct kvm_kernel_irq_routing_entry *e,
+			struct kvm *kvm, int irq_source_id, int level,
+			bool line_status)
+{
+	return kvm_set_irq(kvm, irq_source_id, e->gsi, level, line_status);
+}
+
+int kvm_irq_map_gsi(struct kvm *kvm,
+		    struct kvm_kernel_irq_routing_entry *entries, int gsi)
+{
+	entries->gsi = gsi;
+	entries->type = KVM_IRQ_ROUTING_IRQCHIP;
+	entries->set = xics_set_irq;
+	entries->irqchip.irqchip = 0;
+	entries->irqchip.pin = gsi;
+	return 1;
+}
+
+int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
+{
+	return pin;
+}