1 files changed, 406 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_rm_xics.c b/arch/powerpc/kvm/book3s_hv_rm_xics.c
new file mode 100644
index 00000000000..b4b0082f761
--- /dev/null
+++ b/arch/powerpc/kvm/book3s_hv_rm_xics.c
@@ -0,0 +1,406 @@
+/*
+ * 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 <asm/kvm_book3s.h>
+#include <asm/kvm_ppc.h>
+#include <asm/hvcall.h>
+#include <asm/xics.h>
+#include <asm/debug.h>
+#include <asm/synch.h>
+#include <asm/ppc-opcode.h>
+
+#include "book3s_xics.h"
+
+#define DEBUG_PASSUP
+
+static inline void rm_writeb(unsigned long paddr, u8 val)
+{
+	__asm__ __volatile__("sync; stbcix %0,0,%1"
+		: : "r" (val), "r" (paddr) : "memory");
+}
+
+static void icp_rm_set_vcpu_irq(struct kvm_vcpu *vcpu,
+				struct kvm_vcpu *this_vcpu)
+{
+	struct kvmppc_icp *this_icp = this_vcpu->arch.icp;
+	unsigned long xics_phys;
+	int cpu;
+
+	/* Mark the target VCPU as having an interrupt pending */
+	vcpu->stat.queue_intr++;
+	set_bit(BOOK3S_IRQPRIO_EXTERNAL_LEVEL, &vcpu->arch.pending_exceptions);
+
+	/* Kick self ? Just set MER and return */
+	if (vcpu == this_vcpu) {
+		mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_MER);
+		return;
+	}
+
+	/* Check if the core is loaded, if not, too hard */
+	cpu = vcpu->cpu;
+	if (cpu < 0 || cpu >= nr_cpu_ids) {
+		this_icp->rm_action |= XICS_RM_KICK_VCPU;
+		this_icp->rm_kick_target = vcpu;
+		return;
+	}
+	/* In SMT cpu will always point to thread 0, we adjust it */
+	cpu += vcpu->arch.ptid;
+
+	/* Not too hard, then poke the target */
+	xics_phys = paca[cpu].kvm_hstate.xics_phys;
+	rm_writeb(xics_phys + XICS_MFRR, IPI_PRIORITY);
+}
+
+static void icp_rm_clr_vcpu_irq(struct kvm_vcpu *vcpu)
+{
+	/* Note: Only called on self ! */
+	clear_bit(BOOK3S_IRQPRIO_EXTERNAL_LEVEL,
+		  &vcpu->arch.pending_exceptions);
+	mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~LPCR_MER);
+}
+
+static inline bool icp_rm_try_update(struct kvmppc_icp *icp,
+				     union kvmppc_icp_state old,
+				     union kvmppc_icp_state new)
+{
+	struct kvm_vcpu *this_vcpu = local_paca->kvm_hstate.kvm_vcpu;
+	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;
+
+	/*
+	 * 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)
+		icp_rm_set_vcpu_irq(icp->vcpu, this_vcpu);
+
+	/* Expose the state change for debug purposes */
+	this_vcpu->arch.icp->rm_dbgstate = new;
+	this_vcpu->arch.icp->rm_dbgtgt = icp->vcpu;
+
+ bail:
+	return success;
+}
+
+static inline int check_too_hard(struct kvmppc_xics *xics,
+				 struct kvmppc_icp *icp)
+{
+	return (xics->real_mode_dbg || icp->rm_action) ? H_TOO_HARD : H_SUCCESS;
+}
+
+static void icp_rm_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 = ACCESS_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) {
+			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_rm_try_update(icp, old_state, new_state));
+
+	/*
+	 * Now handle resend checks. Those are asynchronous to the ICP
+	 * state update in HW (ie bus transactions) so we can handle them
+	 * separately here as well.
+	 */
+	if (resend)
+		icp->rm_action |= XICS_RM_CHECK_RESEND;
+}
+
+
+unsigned long kvmppc_rm_h_xirr(struct kvm_vcpu *vcpu)
+{
+	union kvmppc_icp_state old_state, new_state;
+	struct kvmppc_xics *xics = vcpu->kvm->arch.xics;
+	struct kvmppc_icp *icp = vcpu->arch.icp;
+	u32 xirr;
+
+	if (!xics || !xics->real_mode)
+		return H_TOO_HARD;
+
+	/* First clear the interrupt */
+	icp_rm_clr_vcpu_irq(icp->vcpu);
+
+	/*
+	 * 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 = ACCESS_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_rm_try_update(icp, old_state, new_state));
+
+	/* Return the result in GPR4 */
+	vcpu->arch.gpr[4] = xirr;
+
+	return check_too_hard(xics, icp);
+}
+
+int kvmppc_rm_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, *this_icp = vcpu->arch.icp;
+	u32 reject;
+	bool resend;
+	bool local;
+
+	if (!xics || !xics->real_mode)
+		return H_TOO_HARD;
+
+	local = this_icp->server_num == server;
+	if (local)
+		icp = this_icp;
+	else
+		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 done as there can be no XISR to
+	 * reject.
+	 *
+	 * If the CPPR is less favored, then we might be replacing
+	 * an interrupt, and thus need to possibly reject it as in
+	 *
+	 * ICP state: Check_IPI
+	 */
+	do {
+		old_state = new_state = ACCESS_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 && mfrr > new_state.cppr) {
+			resend = new_state.need_resend;
+			new_state.need_resend = 0;
+		}
+	} while (!icp_rm_try_update(icp, old_state, new_state));
+
+	/* Pass rejects to virtual mode */
+	if (reject && reject != XICS_IPI) {
+		this_icp->rm_action |= XICS_RM_REJECT;
+		this_icp->rm_reject = reject;
+	}
+
+	/* Pass resends to virtual mode */
+	if (resend)
+		this_icp->rm_action |= XICS_RM_CHECK_RESEND;
+
+	return check_too_hard(xics, this_icp);
+}
+
+int kvmppc_rm_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;
+
+	if (!xics || !xics->real_mode)
+		return H_TOO_HARD;
+
+	/*
+	 * 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_rm_down_cppr(xics, icp, cppr);
+		goto bail;
+	} else if (cppr == icp->state.cppr)
+		return H_SUCCESS;
+
+	/*
+	 * 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
+	 */
+	icp_rm_clr_vcpu_irq(icp->vcpu);
+
+	do {
+		old_state = new_state = ACCESS_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_rm_try_update(icp, old_state, new_state));
+
+	/* Pass rejects to virtual mode */
+	if (reject && reject != XICS_IPI) {
+		icp->rm_action |= XICS_RM_REJECT;
+		icp->rm_reject = reject;
+	}
+ bail:
+	return check_too_hard(xics, icp);
+}
+
+int kvmppc_rm_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;
+
+	if (!xics || !xics->real_mode)
+		return H_TOO_HARD;
+
+	/*
+	 * 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_rm_down_cppr(xics, icp, xirr >> 24);
+
+	/* IPIs have no EOI */
+	if (irq == XICS_IPI)
+		goto bail;
+	/*
+	 * 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)
+		goto bail;
+	state = &ics->irq_state[src];
+
+	/* Still asserted, resend it, we make it look like a reject */
+	if (state->asserted) {
+		icp->rm_action |= XICS_RM_REJECT;
+		icp->rm_reject = irq;
+	}
+ bail:
+	return check_too_hard(xics, icp);
+}