Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3292 insertions, 0 deletions

diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
new file mode 100644
index 000000000..d70c4f8e1
--- /dev/null
+++ b/arch/mips/kvm/emulate.c
@@ -0,0 +1,3292 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * KVM/MIPS: Instruction/Exception emulation
+ *
+ * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
+ * Authors: Sanjay Lal <sanjayl@kymasys.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/ktime.h>
+#include <linux/kvm_host.h>
+#include <linux/vmalloc.h>
+#include <linux/fs.h>
+#include <linux/memblock.h>
+#include <linux/random.h>
+#include <asm/page.h>
+#include <asm/cacheflush.h>
+#include <asm/cacheops.h>
+#include <asm/cpu-info.h>
+#include <asm/mmu_context.h>
+#include <asm/tlbflush.h>
+#include <asm/inst.h>
+
+#undef CONFIG_MIPS_MT
+#include <asm/r4kcache.h>
+#define CONFIG_MIPS_MT
+
+#include "interrupt.h"
+#include "commpage.h"
+
+#include "trace.h"
+
+/*
+ * Compute the return address and do emulate branch simulation, if required.
+ * This function should be called only in branch delay slot active.
+ */
+static int kvm_compute_return_epc(struct kvm_vcpu *vcpu, unsigned long instpc,
+				  unsigned long *out)
+{
+	unsigned int dspcontrol;
+	union mips_instruction insn;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	long epc = instpc;
+	long nextpc;
+	int err;
+
+	if (epc & 3) {
+		kvm_err("%s: unaligned epc\n", __func__);
+		return -EINVAL;
+	}
+
+	/* Read the instruction */
+	err = kvm_get_badinstrp((u32 *)epc, vcpu, &insn.word);
+	if (err)
+		return err;
+
+	switch (insn.i_format.opcode) {
+		/* jr and jalr are in r_format format. */
+	case spec_op:
+		switch (insn.r_format.func) {
+		case jalr_op:
+			arch->gprs[insn.r_format.rd] = epc + 8;
+			fallthrough;
+		case jr_op:
+			nextpc = arch->gprs[insn.r_format.rs];
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+
+		/*
+		 * This group contains:
+		 * bltz_op, bgez_op, bltzl_op, bgezl_op,
+		 * bltzal_op, bgezal_op, bltzall_op, bgezall_op.
+		 */
+	case bcond_op:
+		switch (insn.i_format.rt) {
+		case bltz_op:
+		case bltzl_op:
+			if ((long)arch->gprs[insn.i_format.rs] < 0)
+				epc = epc + 4 + (insn.i_format.simmediate << 2);
+			else
+				epc += 8;
+			nextpc = epc;
+			break;
+
+		case bgez_op:
+		case bgezl_op:
+			if ((long)arch->gprs[insn.i_format.rs] >= 0)
+				epc = epc + 4 + (insn.i_format.simmediate << 2);
+			else
+				epc += 8;
+			nextpc = epc;
+			break;
+
+		case bltzal_op:
+		case bltzall_op:
+			arch->gprs[31] = epc + 8;
+			if ((long)arch->gprs[insn.i_format.rs] < 0)
+				epc = epc + 4 + (insn.i_format.simmediate << 2);
+			else
+				epc += 8;
+			nextpc = epc;
+			break;
+
+		case bgezal_op:
+		case bgezall_op:
+			arch->gprs[31] = epc + 8;
+			if ((long)arch->gprs[insn.i_format.rs] >= 0)
+				epc = epc + 4 + (insn.i_format.simmediate << 2);
+			else
+				epc += 8;
+			nextpc = epc;
+			break;
+		case bposge32_op:
+			if (!cpu_has_dsp) {
+				kvm_err("%s: DSP branch but not DSP ASE\n",
+					__func__);
+				return -EINVAL;
+			}
+
+			dspcontrol = rddsp(0x01);
+
+			if (dspcontrol >= 32)
+				epc = epc + 4 + (insn.i_format.simmediate << 2);
+			else
+				epc += 8;
+			nextpc = epc;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+
+		/* These are unconditional and in j_format. */
+	case jal_op:
+		arch->gprs[31] = instpc + 8;
+		fallthrough;
+	case j_op:
+		epc += 4;
+		epc >>= 28;
+		epc <<= 28;
+		epc |= (insn.j_format.target << 2);
+		nextpc = epc;
+		break;
+
+		/* These are conditional and in i_format. */
+	case beq_op:
+	case beql_op:
+		if (arch->gprs[insn.i_format.rs] ==
+		    arch->gprs[insn.i_format.rt])
+			epc = epc + 4 + (insn.i_format.simmediate << 2);
+		else
+			epc += 8;
+		nextpc = epc;
+		break;
+
+	case bne_op:
+	case bnel_op:
+		if (arch->gprs[insn.i_format.rs] !=
+		    arch->gprs[insn.i_format.rt])
+			epc = epc + 4 + (insn.i_format.simmediate << 2);
+		else
+			epc += 8;
+		nextpc = epc;
+		break;
+
+	case blez_op:	/* POP06 */
+#ifndef CONFIG_CPU_MIPSR6
+	case blezl_op:	/* removed in R6 */
+#endif
+		if (insn.i_format.rt != 0)
+			goto compact_branch;
+		if ((long)arch->gprs[insn.i_format.rs] <= 0)
+			epc = epc + 4 + (insn.i_format.simmediate << 2);
+		else
+			epc += 8;
+		nextpc = epc;
+		break;
+
+	case bgtz_op:	/* POP07 */
+#ifndef CONFIG_CPU_MIPSR6
+	case bgtzl_op:	/* removed in R6 */
+#endif
+		if (insn.i_format.rt != 0)
+			goto compact_branch;
+		if ((long)arch->gprs[insn.i_format.rs] > 0)
+			epc = epc + 4 + (insn.i_format.simmediate << 2);
+		else
+			epc += 8;
+		nextpc = epc;
+		break;
+
+		/* And now the FPA/cp1 branch instructions. */
+	case cop1_op:
+		kvm_err("%s: unsupported cop1_op\n", __func__);
+		return -EINVAL;
+
+#ifdef CONFIG_CPU_MIPSR6
+	/* R6 added the following compact branches with forbidden slots */
+	case blezl_op:	/* POP26 */
+	case bgtzl_op:	/* POP27 */
+		/* only rt == 0 isn't compact branch */
+		if (insn.i_format.rt != 0)
+			goto compact_branch;
+		return -EINVAL;
+	case pop10_op:
+	case pop30_op:
+		/* only rs == rt == 0 is reserved, rest are compact branches */
+		if (insn.i_format.rs != 0 || insn.i_format.rt != 0)
+			goto compact_branch;
+		return -EINVAL;
+	case pop66_op:
+	case pop76_op:
+		/* only rs == 0 isn't compact branch */
+		if (insn.i_format.rs != 0)
+			goto compact_branch;
+		return -EINVAL;
+compact_branch:
+		/*
+		 * If we've hit an exception on the forbidden slot, then
+		 * the branch must not have been taken.
+		 */
+		epc += 8;
+		nextpc = epc;
+		break;
+#else
+compact_branch:
+		/* Fall through - Compact branches not supported before R6 */
+#endif
+	default:
+		return -EINVAL;
+	}
+
+	*out = nextpc;
+	return 0;
+}
+
+enum emulation_result update_pc(struct kvm_vcpu *vcpu, u32 cause)
+{
+	int err;
+
+	if (cause & CAUSEF_BD) {
+		err = kvm_compute_return_epc(vcpu, vcpu->arch.pc,
+					     &vcpu->arch.pc);
+		if (err)
+			return EMULATE_FAIL;
+	} else {
+		vcpu->arch.pc += 4;
+	}
+
+	kvm_debug("update_pc(): New PC: %#lx\n", vcpu->arch.pc);
+
+	return EMULATE_DONE;
+}
+
+/**
+ * kvm_get_badinstr() - Get bad instruction encoding.
+ * @opc:	Guest pointer to faulting instruction.
+ * @vcpu:	KVM VCPU information.
+ *
+ * Gets the instruction encoding of the faulting instruction, using the saved
+ * BadInstr register value if it exists, otherwise falling back to reading guest
+ * memory at @opc.
+ *
+ * Returns:	The instruction encoding of the faulting instruction.
+ */
+int kvm_get_badinstr(u32 *opc, struct kvm_vcpu *vcpu, u32 *out)
+{
+	if (cpu_has_badinstr) {
+		*out = vcpu->arch.host_cp0_badinstr;
+		return 0;
+	} else {
+		return kvm_get_inst(opc, vcpu, out);
+	}
+}
+
+/**
+ * kvm_get_badinstrp() - Get bad prior instruction encoding.
+ * @opc:	Guest pointer to prior faulting instruction.
+ * @vcpu:	KVM VCPU information.
+ *
+ * Gets the instruction encoding of the prior faulting instruction (the branch
+ * containing the delay slot which faulted), using the saved BadInstrP register
+ * value if it exists, otherwise falling back to reading guest memory at @opc.
+ *
+ * Returns:	The instruction encoding of the prior faulting instruction.
+ */
+int kvm_get_badinstrp(u32 *opc, struct kvm_vcpu *vcpu, u32 *out)
+{
+	if (cpu_has_badinstrp) {
+		*out = vcpu->arch.host_cp0_badinstrp;
+		return 0;
+	} else {
+		return kvm_get_inst(opc, vcpu, out);
+	}
+}
+
+/**
+ * kvm_mips_count_disabled() - Find whether the CP0_Count timer is disabled.
+ * @vcpu:	Virtual CPU.
+ *
+ * Returns:	1 if the CP0_Count timer is disabled by either the guest
+ *		CP0_Cause.DC bit or the count_ctl.DC bit.
+ *		0 otherwise (in which case CP0_Count timer is running).
+ */
+int kvm_mips_count_disabled(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+
+	return	(vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC) ||
+		(kvm_read_c0_guest_cause(cop0) & CAUSEF_DC);
+}
+
+/**
+ * kvm_mips_ktime_to_count() - Scale ktime_t to a 32-bit count.
+ *
+ * Caches the dynamic nanosecond bias in vcpu->arch.count_dyn_bias.
+ *
+ * Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running).
+ */
+static u32 kvm_mips_ktime_to_count(struct kvm_vcpu *vcpu, ktime_t now)
+{
+	s64 now_ns, periods;
+	u64 delta;
+
+	now_ns = ktime_to_ns(now);
+	delta = now_ns + vcpu->arch.count_dyn_bias;
+
+	if (delta >= vcpu->arch.count_period) {
+		/* If delta is out of safe range the bias needs adjusting */
+		periods = div64_s64(now_ns, vcpu->arch.count_period);
+		vcpu->arch.count_dyn_bias = -periods * vcpu->arch.count_period;
+		/* Recalculate delta with new bias */
+		delta = now_ns + vcpu->arch.count_dyn_bias;
+	}
+
+	/*
+	 * We've ensured that:
+	 *   delta < count_period
+	 *
+	 * Therefore the intermediate delta*count_hz will never overflow since
+	 * at the boundary condition:
+	 *   delta = count_period
+	 *   delta = NSEC_PER_SEC * 2^32 / count_hz
+	 *   delta * count_hz = NSEC_PER_SEC * 2^32
+	 */
+	return div_u64(delta * vcpu->arch.count_hz, NSEC_PER_SEC);
+}
+
+/**
+ * kvm_mips_count_time() - Get effective current time.
+ * @vcpu:	Virtual CPU.
+ *
+ * Get effective monotonic ktime. This is usually a straightforward ktime_get(),
+ * except when the master disable bit is set in count_ctl, in which case it is
+ * count_resume, i.e. the time that the count was disabled.
+ *
+ * Returns:	Effective monotonic ktime for CP0_Count.
+ */
+static inline ktime_t kvm_mips_count_time(struct kvm_vcpu *vcpu)
+{
+	if (unlikely(vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC))
+		return vcpu->arch.count_resume;
+
+	return ktime_get();
+}
+
+/**
+ * kvm_mips_read_count_running() - Read the current count value as if running.
+ * @vcpu:	Virtual CPU.
+ * @now:	Kernel time to read CP0_Count at.
+ *
+ * Returns the current guest CP0_Count register at time @now and handles if the
+ * timer interrupt is pending and hasn't been handled yet.
+ *
+ * Returns:	The current value of the guest CP0_Count register.
+ */
+static u32 kvm_mips_read_count_running(struct kvm_vcpu *vcpu, ktime_t now)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	ktime_t expires, threshold;
+	u32 count, compare;
+	int running;
+
+	/* Calculate the biased and scaled guest CP0_Count */
+	count = vcpu->arch.count_bias + kvm_mips_ktime_to_count(vcpu, now);
+	compare = kvm_read_c0_guest_compare(cop0);
+
+	/*
+	 * Find whether CP0_Count has reached the closest timer interrupt. If
+	 * not, we shouldn't inject it.
+	 */
+	if ((s32)(count - compare) < 0)
+		return count;
+
+	/*
+	 * The CP0_Count we're going to return has already reached the closest
+	 * timer interrupt. Quickly check if it really is a new interrupt by
+	 * looking at whether the interval until the hrtimer expiry time is
+	 * less than 1/4 of the timer period.
+	 */
+	expires = hrtimer_get_expires(&vcpu->arch.comparecount_timer);
+	threshold = ktime_add_ns(now, vcpu->arch.count_period / 4);
+	if (ktime_before(expires, threshold)) {
+		/*
+		 * Cancel it while we handle it so there's no chance of
+		 * interference with the timeout handler.
+		 */
+		running = hrtimer_cancel(&vcpu->arch.comparecount_timer);
+
+		/* Nothing should be waiting on the timeout */
+		kvm_mips_callbacks->queue_timer_int(vcpu);
+
+		/*
+		 * Restart the timer if it was running based on the expiry time
+		 * we read, so that we don't push it back 2 periods.
+		 */
+		if (running) {
+			expires = ktime_add_ns(expires,
+					       vcpu->arch.count_period);
+			hrtimer_start(&vcpu->arch.comparecount_timer, expires,
+				      HRTIMER_MODE_ABS);
+		}
+	}
+
+	return count;
+}
+
+/**
+ * kvm_mips_read_count() - Read the current count value.
+ * @vcpu:	Virtual CPU.
+ *
+ * Read the current guest CP0_Count value, taking into account whether the timer
+ * is stopped.
+ *
+ * Returns:	The current guest CP0_Count value.
+ */
+u32 kvm_mips_read_count(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+
+	/* If count disabled just read static copy of count */
+	if (kvm_mips_count_disabled(vcpu))
+		return kvm_read_c0_guest_count(cop0);
+
+	return kvm_mips_read_count_running(vcpu, ktime_get());
+}
+
+/**
+ * kvm_mips_freeze_hrtimer() - Safely stop the hrtimer.
+ * @vcpu:	Virtual CPU.
+ * @count:	Output pointer for CP0_Count value at point of freeze.
+ *
+ * Freeze the hrtimer safely and return both the ktime and the CP0_Count value
+ * at the point it was frozen. It is guaranteed that any pending interrupts at
+ * the point it was frozen are handled, and none after that point.
+ *
+ * This is useful where the time/CP0_Count is needed in the calculation of the
+ * new parameters.
+ *
+ * Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running).
+ *
+ * Returns:	The ktime at the point of freeze.
+ */
+ktime_t kvm_mips_freeze_hrtimer(struct kvm_vcpu *vcpu, u32 *count)
+{
+	ktime_t now;
+
+	/* stop hrtimer before finding time */
+	hrtimer_cancel(&vcpu->arch.comparecount_timer);
+	now = ktime_get();
+
+	/* find count at this point and handle pending hrtimer */
+	*count = kvm_mips_read_count_running(vcpu, now);
+
+	return now;
+}
+
+/**
+ * kvm_mips_resume_hrtimer() - Resume hrtimer, updating expiry.
+ * @vcpu:	Virtual CPU.
+ * @now:	ktime at point of resume.
+ * @count:	CP0_Count at point of resume.
+ *
+ * Resumes the timer and updates the timer expiry based on @now and @count.
+ * This can be used in conjunction with kvm_mips_freeze_timer() when timer
+ * parameters need to be changed.
+ *
+ * It is guaranteed that a timer interrupt immediately after resume will be
+ * handled, but not if CP_Compare is exactly at @count. That case is already
+ * handled by kvm_mips_freeze_timer().
+ *
+ * Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running).
+ */
+static void kvm_mips_resume_hrtimer(struct kvm_vcpu *vcpu,
+				    ktime_t now, u32 count)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	u32 compare;
+	u64 delta;
+	ktime_t expire;
+
+	/* Calculate timeout (wrap 0 to 2^32) */
+	compare = kvm_read_c0_guest_compare(cop0);
+	delta = (u64)(u32)(compare - count - 1) + 1;
+	delta = div_u64(delta * NSEC_PER_SEC, vcpu->arch.count_hz);
+	expire = ktime_add_ns(now, delta);
+
+	/* Update hrtimer to use new timeout */
+	hrtimer_cancel(&vcpu->arch.comparecount_timer);
+	hrtimer_start(&vcpu->arch.comparecount_timer, expire, HRTIMER_MODE_ABS);
+}
+
+/**
+ * kvm_mips_restore_hrtimer() - Restore hrtimer after a gap, updating expiry.
+ * @vcpu:	Virtual CPU.
+ * @before:	Time before Count was saved, lower bound of drift calculation.
+ * @count:	CP0_Count at point of restore.
+ * @min_drift:	Minimum amount of drift permitted before correction.
+ *		Must be <= 0.
+ *
+ * Restores the timer from a particular @count, accounting for drift. This can
+ * be used in conjunction with kvm_mips_freeze_timer() when a hardware timer is
+ * to be used for a period of time, but the exact ktime corresponding to the
+ * final Count that must be restored is not known.
+ *
+ * It is gauranteed that a timer interrupt immediately after restore will be
+ * handled, but not if CP0_Compare is exactly at @count. That case should
+ * already be handled when the hardware timer state is saved.
+ *
+ * Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is not
+ * stopped).
+ *
+ * Returns:	Amount of correction to count_bias due to drift.
+ */
+int kvm_mips_restore_hrtimer(struct kvm_vcpu *vcpu, ktime_t before,
+			     u32 count, int min_drift)
+{
+	ktime_t now, count_time;
+	u32 now_count, before_count;
+	u64 delta;
+	int drift, ret = 0;
+
+	/* Calculate expected count at before */
+	before_count = vcpu->arch.count_bias +
+			kvm_mips_ktime_to_count(vcpu, before);
+
+	/*
+	 * Detect significantly negative drift, where count is lower than
+	 * expected. Some negative drift is expected when hardware counter is
+	 * set after kvm_mips_freeze_timer(), and it is harmless to allow the
+	 * time to jump forwards a little, within reason. If the drift is too
+	 * significant, adjust the bias to avoid a big Guest.CP0_Count jump.
+	 */
+	drift = count - before_count;
+	if (drift < min_drift) {
+		count_time = before;
+		vcpu->arch.count_bias += drift;
+		ret = drift;
+		goto resume;
+	}
+
+	/* Calculate expected count right now */
+	now = ktime_get();
+	now_count = vcpu->arch.count_bias + kvm_mips_ktime_to_count(vcpu, now);
+
+	/*
+	 * Detect positive drift, where count is higher than expected, and
+	 * adjust the bias to avoid guest time going backwards.
+	 */
+	drift = count - now_count;
+	if (drift > 0) {
+		count_time = now;
+		vcpu->arch.count_bias += drift;
+		ret = drift;
+		goto resume;
+	}
+
+	/* Subtract nanosecond delta to find ktime when count was read */
+	delta = (u64)(u32)(now_count - count);
+	delta = div_u64(delta * NSEC_PER_SEC, vcpu->arch.count_hz);
+	count_time = ktime_sub_ns(now, delta);
+
+resume:
+	/* Resume using the calculated ktime */
+	kvm_mips_resume_hrtimer(vcpu, count_time, count);
+	return ret;
+}
+
+/**
+ * kvm_mips_write_count() - Modify the count and update timer.
+ * @vcpu:	Virtual CPU.
+ * @count:	Guest CP0_Count value to set.
+ *
+ * Sets the CP0_Count value and updates the timer accordingly.
+ */
+void kvm_mips_write_count(struct kvm_vcpu *vcpu, u32 count)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	ktime_t now;
+
+	/* Calculate bias */
+	now = kvm_mips_count_time(vcpu);
+	vcpu->arch.count_bias = count - kvm_mips_ktime_to_count(vcpu, now);
+
+	if (kvm_mips_count_disabled(vcpu))
+		/* The timer's disabled, adjust the static count */
+		kvm_write_c0_guest_count(cop0, count);
+	else
+		/* Update timeout */
+		kvm_mips_resume_hrtimer(vcpu, now, count);
+}
+
+/**
+ * kvm_mips_init_count() - Initialise timer.
+ * @vcpu:	Virtual CPU.
+ * @count_hz:	Frequency of timer.
+ *
+ * Initialise the timer to the specified frequency, zero it, and set it going if
+ * it's enabled.
+ */
+void kvm_mips_init_count(struct kvm_vcpu *vcpu, unsigned long count_hz)
+{
+	vcpu->arch.count_hz = count_hz;
+	vcpu->arch.count_period = div_u64((u64)NSEC_PER_SEC << 32, count_hz);
+	vcpu->arch.count_dyn_bias = 0;
+
+	/* Starting at 0 */
+	kvm_mips_write_count(vcpu, 0);
+}
+
+/**
+ * kvm_mips_set_count_hz() - Update the frequency of the timer.
+ * @vcpu:	Virtual CPU.
+ * @count_hz:	Frequency of CP0_Count timer in Hz.
+ *
+ * Change the frequency of the CP0_Count timer. This is done atomically so that
+ * CP0_Count is continuous and no timer interrupt is lost.
+ *
+ * Returns:	-EINVAL if @count_hz is out of range.
+ *		0 on success.
+ */
+int kvm_mips_set_count_hz(struct kvm_vcpu *vcpu, s64 count_hz)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	int dc;
+	ktime_t now;
+	u32 count;
+
+	/* ensure the frequency is in a sensible range... */
+	if (count_hz <= 0 || count_hz > NSEC_PER_SEC)
+		return -EINVAL;
+	/* ... and has actually changed */
+	if (vcpu->arch.count_hz == count_hz)
+		return 0;
+
+	/* Safely freeze timer so we can keep it continuous */
+	dc = kvm_mips_count_disabled(vcpu);
+	if (dc) {
+		now = kvm_mips_count_time(vcpu);
+		count = kvm_read_c0_guest_count(cop0);
+	} else {
+		now = kvm_mips_freeze_hrtimer(vcpu, &count);
+	}
+
+	/* Update the frequency */
+	vcpu->arch.count_hz = count_hz;
+	vcpu->arch.count_period = div_u64((u64)NSEC_PER_SEC << 32, count_hz);
+	vcpu->arch.count_dyn_bias = 0;
+
+	/* Calculate adjusted bias so dynamic count is unchanged */
+	vcpu->arch.count_bias = count - kvm_mips_ktime_to_count(vcpu, now);
+
+	/* Update and resume hrtimer */
+	if (!dc)
+		kvm_mips_resume_hrtimer(vcpu, now, count);
+	return 0;
+}
+
+/**
+ * kvm_mips_write_compare() - Modify compare and update timer.
+ * @vcpu:	Virtual CPU.
+ * @compare:	New CP0_Compare value.
+ * @ack:	Whether to acknowledge timer interrupt.
+ *
+ * Update CP0_Compare to a new value and update the timeout.
+ * If @ack, atomically acknowledge any pending timer interrupt, otherwise ensure
+ * any pending timer interrupt is preserved.
+ */
+void kvm_mips_write_compare(struct kvm_vcpu *vcpu, u32 compare, bool ack)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	int dc;
+	u32 old_compare = kvm_read_c0_guest_compare(cop0);
+	s32 delta = compare - old_compare;
+	u32 cause;
+	ktime_t now = ktime_set(0, 0); /* silence bogus GCC warning */
+	u32 count;
+
+	/* if unchanged, must just be an ack */
+	if (old_compare == compare) {
+		if (!ack)
+			return;
+		kvm_mips_callbacks->dequeue_timer_int(vcpu);
+		kvm_write_c0_guest_compare(cop0, compare);
+		return;
+	}
+
+	/*
+	 * If guest CP0_Compare moves forward, CP0_GTOffset should be adjusted
+	 * too to prevent guest CP0_Count hitting guest CP0_Compare.
+	 *
+	 * The new GTOffset corresponds to the new value of CP0_Compare, and is
+	 * set prior to it being written into the guest context. We disable
+	 * preemption until the new value is written to prevent restore of a
+	 * GTOffset corresponding to the old CP0_Compare value.
+	 */
+	if (IS_ENABLED(CONFIG_KVM_MIPS_VZ) && delta > 0) {
+		preempt_disable();
+		write_c0_gtoffset(compare - read_c0_count());
+		back_to_back_c0_hazard();
+	}
+
+	/* freeze_hrtimer() takes care of timer interrupts <= count */
+	dc = kvm_mips_count_disabled(vcpu);
+	if (!dc)
+		now = kvm_mips_freeze_hrtimer(vcpu, &count);
+
+	if (ack)
+		kvm_mips_callbacks->dequeue_timer_int(vcpu);
+	else if (IS_ENABLED(CONFIG_KVM_MIPS_VZ))
+		/*
+		 * With VZ, writing CP0_Compare acks (clears) CP0_Cause.TI, so
+		 * preserve guest CP0_Cause.TI if we don't want to ack it.
+		 */
+		cause = kvm_read_c0_guest_cause(cop0);
+
+	kvm_write_c0_guest_compare(cop0, compare);
+
+	if (IS_ENABLED(CONFIG_KVM_MIPS_VZ)) {
+		if (delta > 0)
+			preempt_enable();
+
+		back_to_back_c0_hazard();
+
+		if (!ack && cause & CAUSEF_TI)
+			kvm_write_c0_guest_cause(cop0, cause);
+	}
+
+	/* resume_hrtimer() takes care of timer interrupts > count */
+	if (!dc)
+		kvm_mips_resume_hrtimer(vcpu, now, count);
+
+	/*
+	 * If guest CP0_Compare is moving backward, we delay CP0_GTOffset change
+	 * until after the new CP0_Compare is written, otherwise new guest
+	 * CP0_Count could hit new guest CP0_Compare.
+	 */
+	if (IS_ENABLED(CONFIG_KVM_MIPS_VZ) && delta <= 0)
+		write_c0_gtoffset(compare - read_c0_count());
+}
+
+/**
+ * kvm_mips_count_disable() - Disable count.
+ * @vcpu:	Virtual CPU.
+ *
+ * Disable the CP0_Count timer. A timer interrupt on or before the final stop
+ * time will be handled but not after.
+ *
+ * Assumes CP0_Count was previously enabled but now Guest.CP0_Cause.DC or
+ * count_ctl.DC has been set (count disabled).
+ *
+ * Returns:	The time that the timer was stopped.
+ */
+static ktime_t kvm_mips_count_disable(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	u32 count;
+	ktime_t now;
+
+	/* Stop hrtimer */
+	hrtimer_cancel(&vcpu->arch.comparecount_timer);
+
+	/* Set the static count from the dynamic count, handling pending TI */
+	now = ktime_get();
+	count = kvm_mips_read_count_running(vcpu, now);
+	kvm_write_c0_guest_count(cop0, count);
+
+	return now;
+}
+
+/**
+ * kvm_mips_count_disable_cause() - Disable count using CP0_Cause.DC.
+ * @vcpu:	Virtual CPU.
+ *
+ * Disable the CP0_Count timer and set CP0_Cause.DC. A timer interrupt on or
+ * before the final stop time will be handled if the timer isn't disabled by
+ * count_ctl.DC, but not after.
+ *
+ * Assumes CP0_Cause.DC is clear (count enabled).
+ */
+void kvm_mips_count_disable_cause(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+
+	kvm_set_c0_guest_cause(cop0, CAUSEF_DC);
+	if (!(vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC))
+		kvm_mips_count_disable(vcpu);
+}
+
+/**
+ * kvm_mips_count_enable_cause() - Enable count using CP0_Cause.DC.
+ * @vcpu:	Virtual CPU.
+ *
+ * Enable the CP0_Count timer and clear CP0_Cause.DC. A timer interrupt after
+ * the start time will be handled if the timer isn't disabled by count_ctl.DC,
+ * potentially before even returning, so the caller should be careful with
+ * ordering of CP0_Cause modifications so as not to lose it.
+ *
+ * Assumes CP0_Cause.DC is set (count disabled).
+ */
+void kvm_mips_count_enable_cause(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	u32 count;
+
+	kvm_clear_c0_guest_cause(cop0, CAUSEF_DC);
+
+	/*
+	 * Set the dynamic count to match the static count.
+	 * This starts the hrtimer if count_ctl.DC allows it.
+	 * Otherwise it conveniently updates the biases.
+	 */
+	count = kvm_read_c0_guest_count(cop0);
+	kvm_mips_write_count(vcpu, count);
+}
+
+/**
+ * kvm_mips_set_count_ctl() - Update the count control KVM register.
+ * @vcpu:	Virtual CPU.
+ * @count_ctl:	Count control register new value.
+ *
+ * Set the count control KVM register. The timer is updated accordingly.
+ *
+ * Returns:	-EINVAL if reserved bits are set.
+ *		0 on success.
+ */
+int kvm_mips_set_count_ctl(struct kvm_vcpu *vcpu, s64 count_ctl)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	s64 changed = count_ctl ^ vcpu->arch.count_ctl;
+	s64 delta;
+	ktime_t expire, now;
+	u32 count, compare;
+
+	/* Only allow defined bits to be changed */
+	if (changed & ~(s64)(KVM_REG_MIPS_COUNT_CTL_DC))
+		return -EINVAL;
+
+	/* Apply new value */
+	vcpu->arch.count_ctl = count_ctl;
+
+	/* Master CP0_Count disable */
+	if (changed & KVM_REG_MIPS_COUNT_CTL_DC) {
+		/* Is CP0_Cause.DC already disabling CP0_Count? */
+		if (kvm_read_c0_guest_cause(cop0) & CAUSEF_DC) {
+			if (count_ctl & KVM_REG_MIPS_COUNT_CTL_DC)
+				/* Just record the current time */
+				vcpu->arch.count_resume = ktime_get();
+		} else if (count_ctl & KVM_REG_MIPS_COUNT_CTL_DC) {
+			/* disable timer and record current time */
+			vcpu->arch.count_resume = kvm_mips_count_disable(vcpu);
+		} else {
+			/*
+			 * Calculate timeout relative to static count at resume
+			 * time (wrap 0 to 2^32).
+			 */
+			count = kvm_read_c0_guest_count(cop0);
+			compare = kvm_read_c0_guest_compare(cop0);
+			delta = (u64)(u32)(compare - count - 1) + 1;
+			delta = div_u64(delta * NSEC_PER_SEC,
+					vcpu->arch.count_hz);
+			expire = ktime_add_ns(vcpu->arch.count_resume, delta);
+
+			/* Handle pending interrupt */
+			now = ktime_get();
+			if (ktime_compare(now, expire) >= 0)
+				/* Nothing should be waiting on the timeout */
+				kvm_mips_callbacks->queue_timer_int(vcpu);
+
+			/* Resume hrtimer without changing bias */
+			count = kvm_mips_read_count_running(vcpu, now);
+			kvm_mips_resume_hrtimer(vcpu, now, count);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * kvm_mips_set_count_resume() - Update the count resume KVM register.
+ * @vcpu:		Virtual CPU.
+ * @count_resume:	Count resume register new value.
+ *
+ * Set the count resume KVM register.
+ *
+ * Returns:	-EINVAL if out of valid range (0..now).
+ *		0 on success.
+ */
+int kvm_mips_set_count_resume(struct kvm_vcpu *vcpu, s64 count_resume)
+{
+	/*
+	 * It doesn't make sense for the resume time to be in the future, as it
+	 * would be possible for the next interrupt to be more than a full
+	 * period in the future.
+	 */
+	if (count_resume < 0 || count_resume > ktime_to_ns(ktime_get()))
+		return -EINVAL;
+
+	vcpu->arch.count_resume = ns_to_ktime(count_resume);
+	return 0;
+}
+
+/**
+ * kvm_mips_count_timeout() - Push timer forward on timeout.
+ * @vcpu:	Virtual CPU.
+ *
+ * Handle an hrtimer event by push the hrtimer forward a period.
+ *
+ * Returns:	The hrtimer_restart value to return to the hrtimer subsystem.
+ */
+enum hrtimer_restart kvm_mips_count_timeout(struct kvm_vcpu *vcpu)
+{
+	/* Add the Count period to the current expiry time */
+	hrtimer_add_expires_ns(&vcpu->arch.comparecount_timer,
+			       vcpu->arch.count_period);
+	return HRTIMER_RESTART;
+}
+
+enum emulation_result kvm_mips_emul_eret(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	enum emulation_result er = EMULATE_DONE;
+
+	if (kvm_read_c0_guest_status(cop0) & ST0_ERL) {
+		kvm_clear_c0_guest_status(cop0, ST0_ERL);
+		vcpu->arch.pc = kvm_read_c0_guest_errorepc(cop0);
+	} else if (kvm_read_c0_guest_status(cop0) & ST0_EXL) {
+		kvm_debug("[%#lx] ERET to %#lx\n", vcpu->arch.pc,
+			  kvm_read_c0_guest_epc(cop0));
+		kvm_clear_c0_guest_status(cop0, ST0_EXL);
+		vcpu->arch.pc = kvm_read_c0_guest_epc(cop0);
+
+	} else {
+		kvm_err("[%#lx] ERET when MIPS_SR_EXL|MIPS_SR_ERL == 0\n",
+			vcpu->arch.pc);
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
+enum emulation_result kvm_mips_emul_wait(struct kvm_vcpu *vcpu)
+{
+	kvm_debug("[%#lx] !!!WAIT!!! (%#lx)\n", vcpu->arch.pc,
+		  vcpu->arch.pending_exceptions);
+
+	++vcpu->stat.wait_exits;
+	trace_kvm_exit(vcpu, KVM_TRACE_EXIT_WAIT);
+	if (!vcpu->arch.pending_exceptions) {
+		kvm_vz_lose_htimer(vcpu);
+		vcpu->arch.wait = 1;
+		kvm_vcpu_block(vcpu);
+
+		/*
+		 * We we are runnable, then definitely go off to user space to
+		 * check if any I/O interrupts are pending.
+		 */
+		if (kvm_check_request(KVM_REQ_UNHALT, vcpu)) {
+			kvm_clear_request(KVM_REQ_UNHALT, vcpu);
+			vcpu->run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
+		}
+	}
+
+	return EMULATE_DONE;
+}
+
+static void kvm_mips_change_entryhi(struct kvm_vcpu *vcpu,
+				    unsigned long entryhi)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
+	int cpu, i;
+	u32 nasid = entryhi & KVM_ENTRYHI_ASID;
+
+	if (((kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID) != nasid)) {
+		trace_kvm_asid_change(vcpu, kvm_read_c0_guest_entryhi(cop0) &
+				      KVM_ENTRYHI_ASID, nasid);
+
+		/*
+		 * Flush entries from the GVA page tables.
+		 * Guest user page table will get flushed lazily on re-entry to
+		 * guest user if the guest ASID actually changes.
+		 */
+		kvm_mips_flush_gva_pt(kern_mm->pgd, KMF_KERN);
+
+		/*
+		 * Regenerate/invalidate kernel MMU context.
+		 * The user MMU context will be regenerated lazily on re-entry
+		 * to guest user if the guest ASID actually changes.
+		 */
+		preempt_disable();
+		cpu = smp_processor_id();
+		get_new_mmu_context(kern_mm);
+		for_each_possible_cpu(i)
+			if (i != cpu)
+				set_cpu_context(i, kern_mm, 0);
+		preempt_enable();
+	}
+	kvm_write_c0_guest_entryhi(cop0, entryhi);
+}
+
+enum emulation_result kvm_mips_emul_tlbr(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_mips_tlb *tlb;
+	unsigned long pc = vcpu->arch.pc;
+	int index;
+
+	index = kvm_read_c0_guest_index(cop0);
+	if (index < 0 || index >= KVM_MIPS_GUEST_TLB_SIZE) {
+		/* UNDEFINED */
+		kvm_debug("[%#lx] TLBR Index %#x out of range\n", pc, index);
+		index &= KVM_MIPS_GUEST_TLB_SIZE - 1;
+	}
+
+	tlb = &vcpu->arch.guest_tlb[index];
+	kvm_write_c0_guest_pagemask(cop0, tlb->tlb_mask);
+	kvm_write_c0_guest_entrylo0(cop0, tlb->tlb_lo[0]);
+	kvm_write_c0_guest_entrylo1(cop0, tlb->tlb_lo[1]);
+	kvm_mips_change_entryhi(vcpu, tlb->tlb_hi);
+
+	return EMULATE_DONE;
+}
+
+/**
+ * kvm_mips_invalidate_guest_tlb() - Indicates a change in guest MMU map.
+ * @vcpu:	VCPU with changed mappings.
+ * @tlb:	TLB entry being removed.
+ *
+ * This is called to indicate a single change in guest MMU mappings, so that we
+ * can arrange TLB flushes on this and other CPUs.
+ */
+static void kvm_mips_invalidate_guest_tlb(struct kvm_vcpu *vcpu,
+					  struct kvm_mips_tlb *tlb)
+{
+	struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
+	struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;
+	int cpu, i;
+	bool user;
+
+	/* No need to flush for entries which are already invalid */
+	if (!((tlb->tlb_lo[0] | tlb->tlb_lo[1]) & ENTRYLO_V))
+		return;
+	/* Don't touch host kernel page tables or TLB mappings */
+	if ((unsigned long)tlb->tlb_hi > 0x7fffffff)
+		return;
+	/* User address space doesn't need flushing for KSeg2/3 changes */
+	user = tlb->tlb_hi < KVM_GUEST_KSEG0;
+
+	preempt_disable();
+
+	/* Invalidate page table entries */
+	kvm_trap_emul_invalidate_gva(vcpu, tlb->tlb_hi & VPN2_MASK, user);
+
+	/*
+	 * Probe the shadow host TLB for the entry being overwritten, if one
+	 * matches, invalidate it
+	 */
+	kvm_mips_host_tlb_inv(vcpu, tlb->tlb_hi, user, true);
+
+	/* Invalidate the whole ASID on other CPUs */
+	cpu = smp_processor_id();
+	for_each_possible_cpu(i) {
+		if (i == cpu)
+			continue;
+		if (user)
+			set_cpu_context(i, user_mm, 0);
+		set_cpu_context(i, kern_mm, 0);
+	}
+
+	preempt_enable();
+}
+
+/* Write Guest TLB Entry @ Index */
+enum emulation_result kvm_mips_emul_tlbwi(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	int index = kvm_read_c0_guest_index(cop0);
+	struct kvm_mips_tlb *tlb = NULL;
+	unsigned long pc = vcpu->arch.pc;
+
+	if (index < 0 || index >= KVM_MIPS_GUEST_TLB_SIZE) {
+		kvm_debug("%s: illegal index: %d\n", __func__, index);
+		kvm_debug("[%#lx] COP0_TLBWI [%d] (entryhi: %#lx, entrylo0: %#lx entrylo1: %#lx, mask: %#lx)\n",
+			  pc, index, kvm_read_c0_guest_entryhi(cop0),
+			  kvm_read_c0_guest_entrylo0(cop0),
+			  kvm_read_c0_guest_entrylo1(cop0),
+			  kvm_read_c0_guest_pagemask(cop0));
+		index = (index & ~0x80000000) % KVM_MIPS_GUEST_TLB_SIZE;
+	}
+
+	tlb = &vcpu->arch.guest_tlb[index];
+
+	kvm_mips_invalidate_guest_tlb(vcpu, tlb);
+
+	tlb->tlb_mask = kvm_read_c0_guest_pagemask(cop0);
+	tlb->tlb_hi = kvm_read_c0_guest_entryhi(cop0);
+	tlb->tlb_lo[0] = kvm_read_c0_guest_entrylo0(cop0);
+	tlb->tlb_lo[1] = kvm_read_c0_guest_entrylo1(cop0);
+
+	kvm_debug("[%#lx] COP0_TLBWI [%d] (entryhi: %#lx, entrylo0: %#lx entrylo1: %#lx, mask: %#lx)\n",
+		  pc, index, kvm_read_c0_guest_entryhi(cop0),
+		  kvm_read_c0_guest_entrylo0(cop0),
+		  kvm_read_c0_guest_entrylo1(cop0),
+		  kvm_read_c0_guest_pagemask(cop0));
+
+	return EMULATE_DONE;
+}
+
+/* Write Guest TLB Entry @ Random Index */
+enum emulation_result kvm_mips_emul_tlbwr(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_mips_tlb *tlb = NULL;
+	unsigned long pc = vcpu->arch.pc;
+	int index;
+
+	index = prandom_u32_max(KVM_MIPS_GUEST_TLB_SIZE);
+	tlb = &vcpu->arch.guest_tlb[index];
+
+	kvm_mips_invalidate_guest_tlb(vcpu, tlb);
+
+	tlb->tlb_mask = kvm_read_c0_guest_pagemask(cop0);
+	tlb->tlb_hi = kvm_read_c0_guest_entryhi(cop0);
+	tlb->tlb_lo[0] = kvm_read_c0_guest_entrylo0(cop0);
+	tlb->tlb_lo[1] = kvm_read_c0_guest_entrylo1(cop0);
+
+	kvm_debug("[%#lx] COP0_TLBWR[%d] (entryhi: %#lx, entrylo0: %#lx entrylo1: %#lx)\n",
+		  pc, index, kvm_read_c0_guest_entryhi(cop0),
+		  kvm_read_c0_guest_entrylo0(cop0),
+		  kvm_read_c0_guest_entrylo1(cop0));
+
+	return EMULATE_DONE;
+}
+
+enum emulation_result kvm_mips_emul_tlbp(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	long entryhi = kvm_read_c0_guest_entryhi(cop0);
+	unsigned long pc = vcpu->arch.pc;
+	int index = -1;
+
+	index = kvm_mips_guest_tlb_lookup(vcpu, entryhi);
+
+	kvm_write_c0_guest_index(cop0, index);
+
+	kvm_debug("[%#lx] COP0_TLBP (entryhi: %#lx), index: %d\n", pc, entryhi,
+		  index);
+
+	return EMULATE_DONE;
+}
+
+/**
+ * kvm_mips_config1_wrmask() - Find mask of writable bits in guest Config1
+ * @vcpu:	Virtual CPU.
+ *
+ * Finds the mask of bits which are writable in the guest's Config1 CP0
+ * register, by userland (currently read-only to the guest).
+ */
+unsigned int kvm_mips_config1_wrmask(struct kvm_vcpu *vcpu)
+{
+	unsigned int mask = 0;
+
+	/* Permit FPU to be present if FPU is supported */
+	if (kvm_mips_guest_can_have_fpu(&vcpu->arch))
+		mask |= MIPS_CONF1_FP;
+
+	return mask;
+}
+
+/**
+ * kvm_mips_config3_wrmask() - Find mask of writable bits in guest Config3
+ * @vcpu:	Virtual CPU.
+ *
+ * Finds the mask of bits which are writable in the guest's Config3 CP0
+ * register, by userland (currently read-only to the guest).
+ */
+unsigned int kvm_mips_config3_wrmask(struct kvm_vcpu *vcpu)
+{
+	/* Config4 and ULRI are optional */
+	unsigned int mask = MIPS_CONF_M | MIPS_CONF3_ULRI;
+
+	/* Permit MSA to be present if MSA is supported */
+	if (kvm_mips_guest_can_have_msa(&vcpu->arch))
+		mask |= MIPS_CONF3_MSA;
+
+	return mask;
+}
+
+/**
+ * kvm_mips_config4_wrmask() - Find mask of writable bits in guest Config4
+ * @vcpu:	Virtual CPU.
+ *
+ * Finds the mask of bits which are writable in the guest's Config4 CP0
+ * register, by userland (currently read-only to the guest).
+ */
+unsigned int kvm_mips_config4_wrmask(struct kvm_vcpu *vcpu)
+{
+	/* Config5 is optional */
+	unsigned int mask = MIPS_CONF_M;
+
+	/* KScrExist */
+	mask |= 0xfc << MIPS_CONF4_KSCREXIST_SHIFT;
+
+	return mask;
+}
+
+/**
+ * kvm_mips_config5_wrmask() - Find mask of writable bits in guest Config5
+ * @vcpu:	Virtual CPU.
+ *
+ * Finds the mask of bits which are writable in the guest's Config5 CP0
+ * register, by the guest itself.
+ */
+unsigned int kvm_mips_config5_wrmask(struct kvm_vcpu *vcpu)
+{
+	unsigned int mask = 0;
+
+	/* Permit MSAEn changes if MSA supported and enabled */
+	if (kvm_mips_guest_has_msa(&vcpu->arch))
+		mask |= MIPS_CONF5_MSAEN;
+
+	/*
+	 * Permit guest FPU mode changes if FPU is enabled and the relevant
+	 * feature exists according to FIR register.
+	 */
+	if (kvm_mips_guest_has_fpu(&vcpu->arch)) {
+		if (cpu_has_fre)
+			mask |= MIPS_CONF5_FRE;
+		/* We don't support UFR or UFE */
+	}
+
+	return mask;
+}
+
+enum emulation_result kvm_mips_emulate_CP0(union mips_instruction inst,
+					   u32 *opc, u32 cause,
+					   struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	enum emulation_result er = EMULATE_DONE;
+	u32 rt, rd, sel;
+	unsigned long curr_pc;
+
+	/*
+	 * Update PC and hold onto current PC in case there is
+	 * an error and we want to rollback the PC
+	 */
+	curr_pc = vcpu->arch.pc;
+	er = update_pc(vcpu, cause);
+	if (er == EMULATE_FAIL)
+		return er;
+
+	if (inst.co_format.co) {
+		switch (inst.co_format.func) {
+		case tlbr_op:	/*  Read indexed TLB entry  */
+			er = kvm_mips_emul_tlbr(vcpu);
+			break;
+		case tlbwi_op:	/*  Write indexed  */
+			er = kvm_mips_emul_tlbwi(vcpu);
+			break;
+		case tlbwr_op:	/*  Write random  */
+			er = kvm_mips_emul_tlbwr(vcpu);
+			break;
+		case tlbp_op:	/* TLB Probe */
+			er = kvm_mips_emul_tlbp(vcpu);
+			break;
+		case rfe_op:
+			kvm_err("!!!COP0_RFE!!!\n");
+			break;
+		case eret_op:
+			er = kvm_mips_emul_eret(vcpu);
+			goto dont_update_pc;
+		case wait_op:
+			er = kvm_mips_emul_wait(vcpu);
+			break;
+		case hypcall_op:
+			er = kvm_mips_emul_hypcall(vcpu, inst);
+			break;
+		}
+	} else {
+		rt = inst.c0r_format.rt;
+		rd = inst.c0r_format.rd;
+		sel = inst.c0r_format.sel;
+
+		switch (inst.c0r_format.rs) {
+		case mfc_op:
+#ifdef CONFIG_KVM_MIPS_DEBUG_COP0_COUNTERS
+			cop0->stat[rd][sel]++;
+#endif
+			/* Get reg */
+			if ((rd == MIPS_CP0_COUNT) && (sel == 0)) {
+				vcpu->arch.gprs[rt] =
+				    (s32)kvm_mips_read_count(vcpu);
+			} else if ((rd == MIPS_CP0_ERRCTL) && (sel == 0)) {
+				vcpu->arch.gprs[rt] = 0x0;
+#ifdef CONFIG_KVM_MIPS_DYN_TRANS
+				kvm_mips_trans_mfc0(inst, opc, vcpu);
+#endif
+			} else {
+				vcpu->arch.gprs[rt] = (s32)cop0->reg[rd][sel];
+
+#ifdef CONFIG_KVM_MIPS_DYN_TRANS
+				kvm_mips_trans_mfc0(inst, opc, vcpu);
+#endif
+			}
+
+			trace_kvm_hwr(vcpu, KVM_TRACE_MFC0,
+				      KVM_TRACE_COP0(rd, sel),
+				      vcpu->arch.gprs[rt]);
+			break;
+
+		case dmfc_op:
+			vcpu->arch.gprs[rt] = cop0->reg[rd][sel];
+
+			trace_kvm_hwr(vcpu, KVM_TRACE_DMFC0,
+				      KVM_TRACE_COP0(rd, sel),
+				      vcpu->arch.gprs[rt]);
+			break;
+
+		case mtc_op:
+#ifdef CONFIG_KVM_MIPS_DEBUG_COP0_COUNTERS
+			cop0->stat[rd][sel]++;
+#endif
+			trace_kvm_hwr(vcpu, KVM_TRACE_MTC0,
+				      KVM_TRACE_COP0(rd, sel),
+				      vcpu->arch.gprs[rt]);
+
+			if ((rd == MIPS_CP0_TLB_INDEX)
+			    && (vcpu->arch.gprs[rt] >=
+				KVM_MIPS_GUEST_TLB_SIZE)) {
+				kvm_err("Invalid TLB Index: %ld",
+					vcpu->arch.gprs[rt]);
+				er = EMULATE_FAIL;
+				break;
+			}
+			if ((rd == MIPS_CP0_PRID) && (sel == 1)) {
+				/*
+				 * Preserve core number, and keep the exception
+				 * base in guest KSeg0.
+				 */
+				kvm_change_c0_guest_ebase(cop0, 0x1ffff000,
+							  vcpu->arch.gprs[rt]);
+			} else if (rd == MIPS_CP0_TLB_HI && sel == 0) {
+				kvm_mips_change_entryhi(vcpu,
+							vcpu->arch.gprs[rt]);
+			}
+			/* Are we writing to COUNT */
+			else if ((rd == MIPS_CP0_COUNT) && (sel == 0)) {
+				kvm_mips_write_count(vcpu, vcpu->arch.gprs[rt]);
+				goto done;
+			} else if ((rd == MIPS_CP0_COMPARE) && (sel == 0)) {
+				/* If we are writing to COMPARE */
+				/* Clear pending timer interrupt, if any */
+				kvm_mips_write_compare(vcpu,
+						       vcpu->arch.gprs[rt],
+						       true);
+			} else if ((rd == MIPS_CP0_STATUS) && (sel == 0)) {
+				unsigned int old_val, val, change;
+
+				old_val = kvm_read_c0_guest_status(cop0);
+				val = vcpu->arch.gprs[rt];
+				change = val ^ old_val;
+
+				/* Make sure that the NMI bit is never set */
+				val &= ~ST0_NMI;
+
+				/*
+				 * Don't allow CU1 or FR to be set unless FPU
+				 * capability enabled and exists in guest
+				 * configuration.
+				 */
+				if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+					val &= ~(ST0_CU1 | ST0_FR);
+
+				/*
+				 * Also don't allow FR to be set if host doesn't
+				 * support it.
+				 */
+				if (!(current_cpu_data.fpu_id & MIPS_FPIR_F64))
+					val &= ~ST0_FR;
+
+
+				/* Handle changes in FPU mode */
+				preempt_disable();
+
+				/*
+				 * FPU and Vector register state is made
+				 * UNPREDICTABLE by a change of FR, so don't
+				 * even bother saving it.
+				 */
+				if (change & ST0_FR)
+					kvm_drop_fpu(vcpu);
+
+				/*
+				 * If MSA state is already live, it is undefined
+				 * how it interacts with FR=0 FPU state, and we
+				 * don't want to hit reserved instruction
+				 * exceptions trying to save the MSA state later
+				 * when CU=1 && FR=1, so play it safe and save
+				 * it first.
+				 */
+				if (change & ST0_CU1 && !(val & ST0_FR) &&
+				    vcpu->arch.aux_inuse & KVM_MIPS_AUX_MSA)
+					kvm_lose_fpu(vcpu);
+
+				/*
+				 * Propagate CU1 (FPU enable) changes
+				 * immediately if the FPU context is already
+				 * loaded. When disabling we leave the context
+				 * loaded so it can be quickly enabled again in
+				 * the near future.
+				 */
+				if (change & ST0_CU1 &&
+				    vcpu->arch.aux_inuse & KVM_MIPS_AUX_FPU)
+					change_c0_status(ST0_CU1, val);
+
+				preempt_enable();
+
+				kvm_write_c0_guest_status(cop0, val);
+
+#ifdef CONFIG_KVM_MIPS_DYN_TRANS
+				/*
+				 * If FPU present, we need CU1/FR bits to take
+				 * effect fairly soon.
+				 */
+				if (!kvm_mips_guest_has_fpu(&vcpu->arch))
+					kvm_mips_trans_mtc0(inst, opc, vcpu);
+#endif
+			} else if ((rd == MIPS_CP0_CONFIG) && (sel == 5)) {
+				unsigned int old_val, val, change, wrmask;
+
+				old_val = kvm_read_c0_guest_config5(cop0);
+				val = vcpu->arch.gprs[rt];
+
+				/* Only a few bits are writable in Config5 */
+				wrmask = kvm_mips_config5_wrmask(vcpu);
+				change = (val ^ old_val) & wrmask;
+				val = old_val ^ change;
+
+
+				/* Handle changes in FPU/MSA modes */
+				preempt_disable();
+
+				/*
+				 * Propagate FRE changes immediately if the FPU
+				 * context is already loaded.
+				 */
+				if (change & MIPS_CONF5_FRE &&
+				    vcpu->arch.aux_inuse & KVM_MIPS_AUX_FPU)
+					change_c0_config5(MIPS_CONF5_FRE, val);
+
+				/*
+				 * Propagate MSAEn changes immediately if the
+				 * MSA context is already loaded. When disabling
+				 * we leave the context loaded so it can be
+				 * quickly enabled again in the near future.
+				 */
+				if (change & MIPS_CONF5_MSAEN &&
+				    vcpu->arch.aux_inuse & KVM_MIPS_AUX_MSA)
+					change_c0_config5(MIPS_CONF5_MSAEN,
+							  val);
+
+				preempt_enable();
+
+				kvm_write_c0_guest_config5(cop0, val);
+			} else if ((rd == MIPS_CP0_CAUSE) && (sel == 0)) {
+				u32 old_cause, new_cause;
+
+				old_cause = kvm_read_c0_guest_cause(cop0);
+				new_cause = vcpu->arch.gprs[rt];
+				/* Update R/W bits */
+				kvm_change_c0_guest_cause(cop0, 0x08800300,
+							  new_cause);
+				/* DC bit enabling/disabling timer? */
+				if ((old_cause ^ new_cause) & CAUSEF_DC) {
+					if (new_cause & CAUSEF_DC)
+						kvm_mips_count_disable_cause(vcpu);
+					else
+						kvm_mips_count_enable_cause(vcpu);
+				}
+			} else if ((rd == MIPS_CP0_HWRENA) && (sel == 0)) {
+				u32 mask = MIPS_HWRENA_CPUNUM |
+					   MIPS_HWRENA_SYNCISTEP |
+					   MIPS_HWRENA_CC |
+					   MIPS_HWRENA_CCRES;
+
+				if (kvm_read_c0_guest_config3(cop0) &
+				    MIPS_CONF3_ULRI)
+					mask |= MIPS_HWRENA_ULR;
+				cop0->reg[rd][sel] = vcpu->arch.gprs[rt] & mask;
+			} else {
+				cop0->reg[rd][sel] = vcpu->arch.gprs[rt];
+#ifdef CONFIG_KVM_MIPS_DYN_TRANS
+				kvm_mips_trans_mtc0(inst, opc, vcpu);
+#endif
+			}
+			break;
+
+		case dmtc_op:
+			kvm_err("!!!!!!![%#lx]dmtc_op: rt: %d, rd: %d, sel: %d!!!!!!\n",
+				vcpu->arch.pc, rt, rd, sel);
+			trace_kvm_hwr(vcpu, KVM_TRACE_DMTC0,
+				      KVM_TRACE_COP0(rd, sel),
+				      vcpu->arch.gprs[rt]);
+			er = EMULATE_FAIL;
+			break;
+
+		case mfmc0_op:
+#ifdef KVM_MIPS_DEBUG_COP0_COUNTERS
+			cop0->stat[MIPS_CP0_STATUS][0]++;
+#endif
+			if (rt != 0)
+				vcpu->arch.gprs[rt] =
+				    kvm_read_c0_guest_status(cop0);
+			/* EI */
+			if (inst.mfmc0_format.sc) {
+				kvm_debug("[%#lx] mfmc0_op: EI\n",
+					  vcpu->arch.pc);
+				kvm_set_c0_guest_status(cop0, ST0_IE);
+			} else {
+				kvm_debug("[%#lx] mfmc0_op: DI\n",
+					  vcpu->arch.pc);
+				kvm_clear_c0_guest_status(cop0, ST0_IE);
+			}
+
+			break;
+
+		case wrpgpr_op:
+			{
+				u32 css = cop0->reg[MIPS_CP0_STATUS][2] & 0xf;
+				u32 pss =
+				    (cop0->reg[MIPS_CP0_STATUS][2] >> 6) & 0xf;
+				/*
+				 * We don't support any shadow register sets, so
+				 * SRSCtl[PSS] == SRSCtl[CSS] = 0
+				 */
+				if (css || pss) {
+					er = EMULATE_FAIL;
+					break;
+				}
+				kvm_debug("WRPGPR[%d][%d] = %#lx\n", pss, rd,
+					  vcpu->arch.gprs[rt]);
+				vcpu->arch.gprs[rd] = vcpu->arch.gprs[rt];
+			}
+			break;
+		default:
+			kvm_err("[%#lx]MachEmulateCP0: unsupported COP0, copz: 0x%x\n",
+				vcpu->arch.pc, inst.c0r_format.rs);
+			er = EMULATE_FAIL;
+			break;
+		}
+	}
+
+done:
+	/* Rollback PC only if emulation was unsuccessful */
+	if (er == EMULATE_FAIL)
+		vcpu->arch.pc = curr_pc;
+
+dont_update_pc:
+	/*
+	 * This is for special instructions whose emulation
+	 * updates the PC, so do not overwrite the PC under
+	 * any circumstances
+	 */
+
+	return er;
+}
+
+enum emulation_result kvm_mips_emulate_store(union mips_instruction inst,
+					     u32 cause,
+					     struct kvm_vcpu *vcpu)
+{
+	int r;
+	enum emulation_result er;
+	u32 rt;
+	struct kvm_run *run = vcpu->run;
+	void *data = run->mmio.data;
+	unsigned int imme;
+	unsigned long curr_pc;
+
+	/*
+	 * Update PC and hold onto current PC in case there is
+	 * an error and we want to rollback the PC
+	 */
+	curr_pc = vcpu->arch.pc;
+	er = update_pc(vcpu, cause);
+	if (er == EMULATE_FAIL)
+		return er;
+
+	rt = inst.i_format.rt;
+
+	run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
+						vcpu->arch.host_cp0_badvaddr);
+	if (run->mmio.phys_addr == KVM_INVALID_ADDR)
+		goto out_fail;
+
+	switch (inst.i_format.opcode) {
+#if defined(CONFIG_64BIT) && defined(CONFIG_KVM_MIPS_VZ)
+	case sd_op:
+		run->mmio.len = 8;
+		*(u64 *)data = vcpu->arch.gprs[rt];
+
+		kvm_debug("[%#lx] OP_SD: eaddr: %#lx, gpr: %#lx, data: %#llx\n",
+			  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+			  vcpu->arch.gprs[rt], *(u64 *)data);
+		break;
+#endif
+
+	case sw_op:
+		run->mmio.len = 4;
+		*(u32 *)data = vcpu->arch.gprs[rt];
+
+		kvm_debug("[%#lx] OP_SW: eaddr: %#lx, gpr: %#lx, data: %#x\n",
+			  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+			  vcpu->arch.gprs[rt], *(u32 *)data);
+		break;
+
+	case sh_op:
+		run->mmio.len = 2;
+		*(u16 *)data = vcpu->arch.gprs[rt];
+
+		kvm_debug("[%#lx] OP_SH: eaddr: %#lx, gpr: %#lx, data: %#x\n",
+			  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+			  vcpu->arch.gprs[rt], *(u16 *)data);
+		break;
+
+	case sb_op:
+		run->mmio.len = 1;
+		*(u8 *)data = vcpu->arch.gprs[rt];
+
+		kvm_debug("[%#lx] OP_SB: eaddr: %#lx, gpr: %#lx, data: %#x\n",
+			  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+			  vcpu->arch.gprs[rt], *(u8 *)data);
+		break;
+
+	case swl_op:
+		run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
+					vcpu->arch.host_cp0_badvaddr) & (~0x3);
+		run->mmio.len = 4;
+		imme = vcpu->arch.host_cp0_badvaddr & 0x3;
+		switch (imme) {
+		case 0:
+			*(u32 *)data = ((*(u32 *)data) & 0xffffff00) |
+					(vcpu->arch.gprs[rt] >> 24);
+			break;
+		case 1:
+			*(u32 *)data = ((*(u32 *)data) & 0xffff0000) |
+					(vcpu->arch.gprs[rt] >> 16);
+			break;
+		case 2:
+			*(u32 *)data = ((*(u32 *)data) & 0xff000000) |
+					(vcpu->arch.gprs[rt] >> 8);
+			break;
+		case 3:
+			*(u32 *)data = vcpu->arch.gprs[rt];
+			break;
+		default:
+			break;
+		}
+
+		kvm_debug("[%#lx] OP_SWL: eaddr: %#lx, gpr: %#lx, data: %#x\n",
+			  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+			  vcpu->arch.gprs[rt], *(u32 *)data);
+		break;
+
+	case swr_op:
+		run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
+					vcpu->arch.host_cp0_badvaddr) & (~0x3);
+		run->mmio.len = 4;
+		imme = vcpu->arch.host_cp0_badvaddr & 0x3;
+		switch (imme) {
+		case 0:
+			*(u32 *)data = vcpu->arch.gprs[rt];
+			break;
+		case 1:
+			*(u32 *)data = ((*(u32 *)data) & 0xff) |
+					(vcpu->arch.gprs[rt] << 8);
+			break;
+		case 2:
+			*(u32 *)data = ((*(u32 *)data) & 0xffff) |
+					(vcpu->arch.gprs[rt] << 16);
+			break;
+		case 3:
+			*(u32 *)data = ((*(u32 *)data) & 0xffffff) |
+					(vcpu->arch.gprs[rt] << 24);
+			break;
+		default:
+			break;
+		}
+
+		kvm_debug("[%#lx] OP_SWR: eaddr: %#lx, gpr: %#lx, data: %#x\n",
+			  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+			  vcpu->arch.gprs[rt], *(u32 *)data);
+		break;
+
+#if defined(CONFIG_64BIT) && defined(CONFIG_KVM_MIPS_VZ)
+	case sdl_op:
+		run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
+					vcpu->arch.host_cp0_badvaddr) & (~0x7);
+
+		run->mmio.len = 8;
+		imme = vcpu->arch.host_cp0_badvaddr & 0x7;
+		switch (imme) {
+		case 0:
+			*(u64 *)data = ((*(u64 *)data) & 0xffffffffffffff00) |
+					((vcpu->arch.gprs[rt] >> 56) & 0xff);
+			break;
+		case 1:
+			*(u64 *)data = ((*(u64 *)data) & 0xffffffffffff0000) |
+					((vcpu->arch.gprs[rt] >> 48) & 0xffff);
+			break;
+		case 2:
+			*(u64 *)data = ((*(u64 *)data) & 0xffffffffff000000) |
+					((vcpu->arch.gprs[rt] >> 40) & 0xffffff);
+			break;
+		case 3:
+			*(u64 *)data = ((*(u64 *)data) & 0xffffffff00000000) |
+					((vcpu->arch.gprs[rt] >> 32) & 0xffffffff);
+			break;
+		case 4:
+			*(u64 *)data = ((*(u64 *)data) & 0xffffff0000000000) |
+					((vcpu->arch.gprs[rt] >> 24) & 0xffffffffff);
+			break;
+		case 5:
+			*(u64 *)data = ((*(u64 *)data) & 0xffff000000000000) |
+					((vcpu->arch.gprs[rt] >> 16) & 0xffffffffffff);
+			break;
+		case 6:
+			*(u64 *)data = ((*(u64 *)data) & 0xff00000000000000) |
+					((vcpu->arch.gprs[rt] >> 8) & 0xffffffffffffff);
+			break;
+		case 7:
+			*(u64 *)data = vcpu->arch.gprs[rt];
+			break;
+		default:
+			break;
+		}
+
+		kvm_debug("[%#lx] OP_SDL: eaddr: %#lx, gpr: %#lx, data: %llx\n",
+			  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+			  vcpu->arch.gprs[rt], *(u64 *)data);
+		break;
+
+	case sdr_op:
+		run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
+					vcpu->arch.host_cp0_badvaddr) & (~0x7);
+
+		run->mmio.len = 8;
+		imme = vcpu->arch.host_cp0_badvaddr & 0x7;
+		switch (imme) {
+		case 0:
+			*(u64 *)data = vcpu->arch.gprs[rt];
+			break;
+		case 1:
+			*(u64 *)data = ((*(u64 *)data) & 0xff) |
+					(vcpu->arch.gprs[rt] << 8);
+			break;
+		case 2:
+			*(u64 *)data = ((*(u64 *)data) & 0xffff) |
+					(vcpu->arch.gprs[rt] << 16);
+			break;
+		case 3:
+			*(u64 *)data = ((*(u64 *)data) & 0xffffff) |
+					(vcpu->arch.gprs[rt] << 24);
+			break;
+		case 4:
+			*(u64 *)data = ((*(u64 *)data) & 0xffffffff) |
+					(vcpu->arch.gprs[rt] << 32);
+			break;
+		case 5:
+			*(u64 *)data = ((*(u64 *)data) & 0xffffffffff) |
+					(vcpu->arch.gprs[rt] << 40);
+			break;
+		case 6:
+			*(u64 *)data = ((*(u64 *)data) & 0xffffffffffff) |
+					(vcpu->arch.gprs[rt] << 48);
+			break;
+		case 7:
+			*(u64 *)data = ((*(u64 *)data) & 0xffffffffffffff) |
+					(vcpu->arch.gprs[rt] << 56);
+			break;
+		default:
+			break;
+		}
+
+		kvm_debug("[%#lx] OP_SDR: eaddr: %#lx, gpr: %#lx, data: %llx\n",
+			  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+			  vcpu->arch.gprs[rt], *(u64 *)data);
+		break;
+#endif
+
+#ifdef CONFIG_CPU_LOONGSON64
+	case sdc2_op:
+		rt = inst.loongson3_lsdc2_format.rt;
+		switch (inst.loongson3_lsdc2_format.opcode1) {
+		/*
+		 * Loongson-3 overridden sdc2 instructions.
+		 * opcode1              instruction
+		 *   0x0          gssbx: store 1 bytes from GPR
+		 *   0x1          gsshx: store 2 bytes from GPR
+		 *   0x2          gsswx: store 4 bytes from GPR
+		 *   0x3          gssdx: store 8 bytes from GPR
+		 */
+		case 0x0:
+			run->mmio.len = 1;
+			*(u8 *)data = vcpu->arch.gprs[rt];
+
+			kvm_debug("[%#lx] OP_GSSBX: eaddr: %#lx, gpr: %#lx, data: %#x\n",
+				  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+				  vcpu->arch.gprs[rt], *(u8 *)data);
+			break;
+		case 0x1:
+			run->mmio.len = 2;
+			*(u16 *)data = vcpu->arch.gprs[rt];
+
+			kvm_debug("[%#lx] OP_GSSSHX: eaddr: %#lx, gpr: %#lx, data: %#x\n",
+				  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+				  vcpu->arch.gprs[rt], *(u16 *)data);
+			break;
+		case 0x2:
+			run->mmio.len = 4;
+			*(u32 *)data = vcpu->arch.gprs[rt];
+
+			kvm_debug("[%#lx] OP_GSSWX: eaddr: %#lx, gpr: %#lx, data: %#x\n",
+				  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+				  vcpu->arch.gprs[rt], *(u32 *)data);
+			break;
+		case 0x3:
+			run->mmio.len = 8;
+			*(u64 *)data = vcpu->arch.gprs[rt];
+
+			kvm_debug("[%#lx] OP_GSSDX: eaddr: %#lx, gpr: %#lx, data: %#llx\n",
+				  vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
+				  vcpu->arch.gprs[rt], *(u64 *)data);
+			break;
+		default:
+			kvm_err("Godson Extended GS-Store not yet supported (inst=0x%08x)\n",
+				inst.word);
+			break;
+		}
+		break;
+#endif
+	default:
+		kvm_err("Store not yet supported (inst=0x%08x)\n",
+			inst.word);
+		goto out_fail;
+	}
+
+	vcpu->mmio_needed = 1;
+	run->mmio.is_write = 1;
+	vcpu->mmio_is_write = 1;
+
+	r = kvm_io_bus_write(vcpu, KVM_MMIO_BUS,
+			run->mmio.phys_addr, run->mmio.len, data);
+
+	if (!r) {
+		vcpu->mmio_needed = 0;
+		return EMULATE_DONE;
+	}
+
+	return EMULATE_DO_MMIO;
+
+out_fail:
+	/* Rollback PC if emulation was unsuccessful */
+	vcpu->arch.pc = curr_pc;
+	return EMULATE_FAIL;
+}
+
+enum emulation_result kvm_mips_emulate_load(union mips_instruction inst,
+					    u32 cause, struct kvm_vcpu *vcpu)
+{
+	struct kvm_run *run = vcpu->run;
+	int r;
+	enum emulation_result er;
+	unsigned long curr_pc;
+	u32 op, rt;
+	unsigned int imme;
+
+	rt = inst.i_format.rt;
+	op = inst.i_format.opcode;
+
+	/*
+	 * Find the resume PC now while we have safe and easy access to the
+	 * prior branch instruction, and save it for
+	 * kvm_mips_complete_mmio_load() to restore later.
+	 */
+	curr_pc = vcpu->arch.pc;
+	er = update_pc(vcpu, cause);
+	if (er == EMULATE_FAIL)
+		return er;
+	vcpu->arch.io_pc = vcpu->arch.pc;
+	vcpu->arch.pc = curr_pc;
+
+	vcpu->arch.io_gpr = rt;
+
+	run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
+						vcpu->arch.host_cp0_badvaddr);
+	if (run->mmio.phys_addr == KVM_INVALID_ADDR)
+		return EMULATE_FAIL;
+
+	vcpu->mmio_needed = 2;	/* signed */
+	switch (op) {
+#if defined(CONFIG_64BIT) && defined(CONFIG_KVM_MIPS_VZ)
+	case ld_op:
+		run->mmio.len = 8;
+		break;
+
+	case lwu_op:
+		vcpu->mmio_needed = 1;	/* unsigned */
+		fallthrough;
+#endif
+	case lw_op:
+		run->mmio.len = 4;
+		break;
+
+	case lhu_op:
+		vcpu->mmio_needed = 1;	/* unsigned */
+		fallthrough;
+	case lh_op:
+		run->mmio.len = 2;
+		break;
+
+	case lbu_op:
+		vcpu->mmio_needed = 1;	/* unsigned */
+		fallthrough;
+	case lb_op:
+		run->mmio.len = 1;
+		break;
+
+	case lwl_op:
+		run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
+					vcpu->arch.host_cp0_badvaddr) & (~0x3);
+
+		run->mmio.len = 4;
+		imme = vcpu->arch.host_cp0_badvaddr & 0x3;
+		switch (imme) {
+		case 0:
+			vcpu->mmio_needed = 3;	/* 1 byte */
+			break;
+		case 1:
+			vcpu->mmio_needed = 4;	/* 2 bytes */
+			break;
+		case 2:
+			vcpu->mmio_needed = 5;	/* 3 bytes */
+			break;
+		case 3:
+			vcpu->mmio_needed = 6;	/* 4 bytes */
+			break;
+		default:
+			break;
+		}
+		break;
+
+	case lwr_op:
+		run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
+					vcpu->arch.host_cp0_badvaddr) & (~0x3);
+
+		run->mmio.len = 4;
+		imme = vcpu->arch.host_cp0_badvaddr & 0x3;
+		switch (imme) {
+		case 0:
+			vcpu->mmio_needed = 7;	/* 4 bytes */
+			break;
+		case 1:
+			vcpu->mmio_needed = 8;	/* 3 bytes */
+			break;
+		case 2:
+			vcpu->mmio_needed = 9;	/* 2 bytes */
+			break;
+		case 3:
+			vcpu->mmio_needed = 10;	/* 1 byte */
+			break;
+		default:
+			break;
+		}
+		break;
+
+#if defined(CONFIG_64BIT) && defined(CONFIG_KVM_MIPS_VZ)
+	case ldl_op:
+		run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
+					vcpu->arch.host_cp0_badvaddr) & (~0x7);
+
+		run->mmio.len = 8;
+		imme = vcpu->arch.host_cp0_badvaddr & 0x7;
+		switch (imme) {
+		case 0:
+			vcpu->mmio_needed = 11;	/* 1 byte */
+			break;
+		case 1:
+			vcpu->mmio_needed = 12;	/* 2 bytes */
+			break;
+		case 2:
+			vcpu->mmio_needed = 13;	/* 3 bytes */
+			break;
+		case 3:
+			vcpu->mmio_needed = 14;	/* 4 bytes */
+			break;
+		case 4:
+			vcpu->mmio_needed = 15;	/* 5 bytes */
+			break;
+		case 5:
+			vcpu->mmio_needed = 16;	/* 6 bytes */
+			break;
+		case 6:
+			vcpu->mmio_needed = 17;	/* 7 bytes */
+			break;
+		case 7:
+			vcpu->mmio_needed = 18;	/* 8 bytes */
+			break;
+		default:
+			break;
+		}
+		break;
+
+	case ldr_op:
+		run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
+					vcpu->arch.host_cp0_badvaddr) & (~0x7);
+
+		run->mmio.len = 8;
+		imme = vcpu->arch.host_cp0_badvaddr & 0x7;
+		switch (imme) {
+		case 0:
+			vcpu->mmio_needed = 19;	/* 8 bytes */
+			break;
+		case 1:
+			vcpu->mmio_needed = 20;	/* 7 bytes */
+			break;
+		case 2:
+			vcpu->mmio_needed = 21;	/* 6 bytes */
+			break;
+		case 3:
+			vcpu->mmio_needed = 22;	/* 5 bytes */
+			break;
+		case 4:
+			vcpu->mmio_needed = 23;	/* 4 bytes */
+			break;
+		case 5:
+			vcpu->mmio_needed = 24;	/* 3 bytes */
+			break;
+		case 6:
+			vcpu->mmio_needed = 25;	/* 2 bytes */
+			break;
+		case 7:
+			vcpu->mmio_needed = 26;	/* 1 byte */
+			break;
+		default:
+			break;
+		}
+		break;
+#endif
+
+#ifdef CONFIG_CPU_LOONGSON64
+	case ldc2_op:
+		rt = inst.loongson3_lsdc2_format.rt;
+		switch (inst.loongson3_lsdc2_format.opcode1) {
+		/*
+		 * Loongson-3 overridden ldc2 instructions.
+		 * opcode1              instruction
+		 *   0x0          gslbx: store 1 bytes from GPR
+		 *   0x1          gslhx: store 2 bytes from GPR
+		 *   0x2          gslwx: store 4 bytes from GPR
+		 *   0x3          gsldx: store 8 bytes from GPR
+		 */
+		case 0x0:
+			run->mmio.len = 1;
+			vcpu->mmio_needed = 27;	/* signed */
+			break;
+		case 0x1:
+			run->mmio.len = 2;
+			vcpu->mmio_needed = 28;	/* signed */
+			break;
+		case 0x2:
+			run->mmio.len = 4;
+			vcpu->mmio_needed = 29;	/* signed */
+			break;
+		case 0x3:
+			run->mmio.len = 8;
+			vcpu->mmio_needed = 30;	/* signed */
+			break;
+		default:
+			kvm_err("Godson Extended GS-Load for float not yet supported (inst=0x%08x)\n",
+				inst.word);
+			break;
+		}
+		break;
+#endif
+
+	default:
+		kvm_err("Load not yet supported (inst=0x%08x)\n",
+			inst.word);
+		vcpu->mmio_needed = 0;
+		return EMULATE_FAIL;
+	}
+
+	run->mmio.is_write = 0;
+	vcpu->mmio_is_write = 0;
+
+	r = kvm_io_bus_read(vcpu, KVM_MMIO_BUS,
+			run->mmio.phys_addr, run->mmio.len, run->mmio.data);
+
+	if (!r) {
+		kvm_mips_complete_mmio_load(vcpu);
+		vcpu->mmio_needed = 0;
+		return EMULATE_DONE;
+	}
+
+	return EMULATE_DO_MMIO;
+}
+
+#ifndef CONFIG_KVM_MIPS_VZ
+static enum emulation_result kvm_mips_guest_cache_op(int (*fn)(unsigned long),
+						     unsigned long curr_pc,
+						     unsigned long addr,
+						     struct kvm_vcpu *vcpu,
+						     u32 cause)
+{
+	int err;
+
+	for (;;) {
+		/* Carefully attempt the cache operation */
+		kvm_trap_emul_gva_lockless_begin(vcpu);
+		err = fn(addr);
+		kvm_trap_emul_gva_lockless_end(vcpu);
+
+		if (likely(!err))
+			return EMULATE_DONE;
+
+		/*
+		 * Try to handle the fault and retry, maybe we just raced with a
+		 * GVA invalidation.
+		 */
+		switch (kvm_trap_emul_gva_fault(vcpu, addr, false)) {
+		case KVM_MIPS_GVA:
+		case KVM_MIPS_GPA:
+			/* bad virtual or physical address */
+			return EMULATE_FAIL;
+		case KVM_MIPS_TLB:
+			/* no matching guest TLB */
+			vcpu->arch.host_cp0_badvaddr = addr;
+			vcpu->arch.pc = curr_pc;
+			kvm_mips_emulate_tlbmiss_ld(cause, NULL, vcpu);
+			return EMULATE_EXCEPT;
+		case KVM_MIPS_TLBINV:
+			/* invalid matching guest TLB */
+			vcpu->arch.host_cp0_badvaddr = addr;
+			vcpu->arch.pc = curr_pc;
+			kvm_mips_emulate_tlbinv_ld(cause, NULL, vcpu);
+			return EMULATE_EXCEPT;
+		default:
+			break;
+		}
+	}
+}
+
+enum emulation_result kvm_mips_emulate_cache(union mips_instruction inst,
+					     u32 *opc, u32 cause,
+					     struct kvm_vcpu *vcpu)
+{
+	enum emulation_result er = EMULATE_DONE;
+	u32 cache, op_inst, op, base;
+	s16 offset;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	unsigned long va;
+	unsigned long curr_pc;
+
+	/*
+	 * Update PC and hold onto current PC in case there is
+	 * an error and we want to rollback the PC
+	 */
+	curr_pc = vcpu->arch.pc;
+	er = update_pc(vcpu, cause);
+	if (er == EMULATE_FAIL)
+		return er;
+
+	base = inst.i_format.rs;
+	op_inst = inst.i_format.rt;
+	if (cpu_has_mips_r6)
+		offset = inst.spec3_format.simmediate;
+	else
+		offset = inst.i_format.simmediate;
+	cache = op_inst & CacheOp_Cache;
+	op = op_inst & CacheOp_Op;
+
+	va = arch->gprs[base] + offset;
+
+	kvm_debug("CACHE (cache: %#x, op: %#x, base[%d]: %#lx, offset: %#x\n",
+		  cache, op, base, arch->gprs[base], offset);
+
+	/*
+	 * Treat INDEX_INV as a nop, basically issued by Linux on startup to
+	 * invalidate the caches entirely by stepping through all the
+	 * ways/indexes
+	 */
+	if (op == Index_Writeback_Inv) {
+		kvm_debug("@ %#lx/%#lx CACHE (cache: %#x, op: %#x, base[%d]: %#lx, offset: %#x\n",
+			  vcpu->arch.pc, vcpu->arch.gprs[31], cache, op, base,
+			  arch->gprs[base], offset);
+
+		if (cache == Cache_D) {
+#ifdef CONFIG_CPU_R4K_CACHE_TLB
+			r4k_blast_dcache();
+#else
+			switch (boot_cpu_type()) {
+			case CPU_CAVIUM_OCTEON3:
+				/* locally flush icache */
+				local_flush_icache_range(0, 0);
+				break;
+			default:
+				__flush_cache_all();
+				break;
+			}
+#endif
+		} else if (cache == Cache_I) {
+#ifdef CONFIG_CPU_R4K_CACHE_TLB
+			r4k_blast_icache();
+#else
+			switch (boot_cpu_type()) {
+			case CPU_CAVIUM_OCTEON3:
+				/* locally flush icache */
+				local_flush_icache_range(0, 0);
+				break;
+			default:
+				flush_icache_all();
+				break;
+			}
+#endif
+		} else {
+			kvm_err("%s: unsupported CACHE INDEX operation\n",
+				__func__);
+			return EMULATE_FAIL;
+		}
+
+#ifdef CONFIG_KVM_MIPS_DYN_TRANS
+		kvm_mips_trans_cache_index(inst, opc, vcpu);
+#endif
+		goto done;
+	}
+
+	/* XXXKYMA: Only a subset of cache ops are supported, used by Linux */
+	if (op_inst == Hit_Writeback_Inv_D || op_inst == Hit_Invalidate_D) {
+		/*
+		 * Perform the dcache part of icache synchronisation on the
+		 * guest's behalf.
+		 */
+		er = kvm_mips_guest_cache_op(protected_writeback_dcache_line,
+					     curr_pc, va, vcpu, cause);
+		if (er != EMULATE_DONE)
+			goto done;
+#ifdef CONFIG_KVM_MIPS_DYN_TRANS
+		/*
+		 * Replace the CACHE instruction, with a SYNCI, not the same,
+		 * but avoids a trap
+		 */
+		kvm_mips_trans_cache_va(inst, opc, vcpu);
+#endif
+	} else if (op_inst == Hit_Invalidate_I) {
+		/* Perform the icache synchronisation on the guest's behalf */
+		er = kvm_mips_guest_cache_op(protected_writeback_dcache_line,
+					     curr_pc, va, vcpu, cause);
+		if (er != EMULATE_DONE)
+			goto done;
+		er = kvm_mips_guest_cache_op(protected_flush_icache_line,
+					     curr_pc, va, vcpu, cause);
+		if (er != EMULATE_DONE)
+			goto done;
+
+#ifdef CONFIG_KVM_MIPS_DYN_TRANS
+		/* Replace the CACHE instruction, with a SYNCI */
+		kvm_mips_trans_cache_va(inst, opc, vcpu);
+#endif
+	} else {
+		kvm_err("NO-OP CACHE (cache: %#x, op: %#x, base[%d]: %#lx, offset: %#x\n",
+			cache, op, base, arch->gprs[base], offset);
+		er = EMULATE_FAIL;
+	}
+
+done:
+	/* Rollback PC only if emulation was unsuccessful */
+	if (er == EMULATE_FAIL)
+		vcpu->arch.pc = curr_pc;
+	/* Guest exception needs guest to resume */
+	if (er == EMULATE_EXCEPT)
+		er = EMULATE_DONE;
+
+	return er;
+}
+
+enum emulation_result kvm_mips_emulate_inst(u32 cause, u32 *opc,
+					    struct kvm_vcpu *vcpu)
+{
+	union mips_instruction inst;
+	enum emulation_result er = EMULATE_DONE;
+	int err;
+
+	/* Fetch the instruction. */
+	if (cause & CAUSEF_BD)
+		opc += 1;
+	err = kvm_get_badinstr(opc, vcpu, &inst.word);
+	if (err)
+		return EMULATE_FAIL;
+
+	switch (inst.r_format.opcode) {
+	case cop0_op:
+		er = kvm_mips_emulate_CP0(inst, opc, cause, vcpu);
+		break;
+
+#ifndef CONFIG_CPU_MIPSR6
+	case cache_op:
+		++vcpu->stat.cache_exits;
+		trace_kvm_exit(vcpu, KVM_TRACE_EXIT_CACHE);
+		er = kvm_mips_emulate_cache(inst, opc, cause, vcpu);
+		break;
+#else
+	case spec3_op:
+		switch (inst.spec3_format.func) {
+		case cache6_op:
+			++vcpu->stat.cache_exits;
+			trace_kvm_exit(vcpu, KVM_TRACE_EXIT_CACHE);
+			er = kvm_mips_emulate_cache(inst, opc, cause,
+						    vcpu);
+			break;
+		default:
+			goto unknown;
+		}
+		break;
+unknown:
+#endif
+
+	default:
+		kvm_err("Instruction emulation not supported (%p/%#x)\n", opc,
+			inst.word);
+		kvm_arch_vcpu_dump_regs(vcpu);
+		er = EMULATE_FAIL;
+		break;
+	}
+
+	return er;
+}
+#endif /* CONFIG_KVM_MIPS_VZ */
+
+/**
+ * kvm_mips_guest_exception_base() - Find guest exception vector base address.
+ *
+ * Returns:	The base address of the current guest exception vector, taking
+ *		both Guest.CP0_Status.BEV and Guest.CP0_EBase into account.
+ */
+long kvm_mips_guest_exception_base(struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+
+	if (kvm_read_c0_guest_status(cop0) & ST0_BEV)
+		return KVM_GUEST_CKSEG1ADDR(0x1fc00200);
+	else
+		return kvm_read_c0_guest_ebase(cop0) & MIPS_EBASE_BASE;
+}
+
+enum emulation_result kvm_mips_emulate_syscall(u32 cause,
+					       u32 *opc,
+					       struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("Delivering SYSCALL @ pc %#lx\n", arch->pc);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (EXCCODE_SYS << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+
+	} else {
+		kvm_err("Trying to deliver SYSCALL when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
+enum emulation_result kvm_mips_emulate_tlbmiss_ld(u32 cause,
+						  u32 *opc,
+						  struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	unsigned long entryhi = (vcpu->arch.  host_cp0_badvaddr & VPN2_MASK) |
+			(kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID);
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("[EXL == 0] delivering TLB MISS @ pc %#lx\n",
+			  arch->pc);
+
+		/* set pc to the exception entry point */
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x0;
+
+	} else {
+		kvm_debug("[EXL == 1] delivering TLB MISS @ pc %#lx\n",
+			  arch->pc);
+
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+	}
+
+	kvm_change_c0_guest_cause(cop0, (0xff),
+				  (EXCCODE_TLBL << CAUSEB_EXCCODE));
+
+	/* setup badvaddr, context and entryhi registers for the guest */
+	kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
+	/* XXXKYMA: is the context register used by linux??? */
+	kvm_write_c0_guest_entryhi(cop0, entryhi);
+
+	return EMULATE_DONE;
+}
+
+enum emulation_result kvm_mips_emulate_tlbinv_ld(u32 cause,
+						 u32 *opc,
+						 struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	unsigned long entryhi =
+		(vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
+		(kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID);
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("[EXL == 0] delivering TLB INV @ pc %#lx\n",
+			  arch->pc);
+	} else {
+		kvm_debug("[EXL == 1] delivering TLB MISS @ pc %#lx\n",
+			  arch->pc);
+	}
+
+	/* set pc to the exception entry point */
+	arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+
+	kvm_change_c0_guest_cause(cop0, (0xff),
+				  (EXCCODE_TLBL << CAUSEB_EXCCODE));
+
+	/* setup badvaddr, context and entryhi registers for the guest */
+	kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
+	/* XXXKYMA: is the context register used by linux??? */
+	kvm_write_c0_guest_entryhi(cop0, entryhi);
+
+	return EMULATE_DONE;
+}
+
+enum emulation_result kvm_mips_emulate_tlbmiss_st(u32 cause,
+						  u32 *opc,
+						  struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	unsigned long entryhi = (vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
+			(kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID);
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("[EXL == 0] Delivering TLB MISS @ pc %#lx\n",
+			  arch->pc);
+
+		/* Set PC to the exception entry point */
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x0;
+	} else {
+		kvm_debug("[EXL == 1] Delivering TLB MISS @ pc %#lx\n",
+			  arch->pc);
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+	}
+
+	kvm_change_c0_guest_cause(cop0, (0xff),
+				  (EXCCODE_TLBS << CAUSEB_EXCCODE));
+
+	/* setup badvaddr, context and entryhi registers for the guest */
+	kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
+	/* XXXKYMA: is the context register used by linux??? */
+	kvm_write_c0_guest_entryhi(cop0, entryhi);
+
+	return EMULATE_DONE;
+}
+
+enum emulation_result kvm_mips_emulate_tlbinv_st(u32 cause,
+						 u32 *opc,
+						 struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	unsigned long entryhi = (vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
+		(kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID);
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("[EXL == 0] Delivering TLB MISS @ pc %#lx\n",
+			  arch->pc);
+	} else {
+		kvm_debug("[EXL == 1] Delivering TLB MISS @ pc %#lx\n",
+			  arch->pc);
+	}
+
+	/* Set PC to the exception entry point */
+	arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+
+	kvm_change_c0_guest_cause(cop0, (0xff),
+				  (EXCCODE_TLBS << CAUSEB_EXCCODE));
+
+	/* setup badvaddr, context and entryhi registers for the guest */
+	kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
+	/* XXXKYMA: is the context register used by linux??? */
+	kvm_write_c0_guest_entryhi(cop0, entryhi);
+
+	return EMULATE_DONE;
+}
+
+enum emulation_result kvm_mips_emulate_tlbmod(u32 cause,
+					      u32 *opc,
+					      struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	unsigned long entryhi = (vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
+			(kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID);
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("[EXL == 0] Delivering TLB MOD @ pc %#lx\n",
+			  arch->pc);
+	} else {
+		kvm_debug("[EXL == 1] Delivering TLB MOD @ pc %#lx\n",
+			  arch->pc);
+	}
+
+	arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+
+	kvm_change_c0_guest_cause(cop0, (0xff),
+				  (EXCCODE_MOD << CAUSEB_EXCCODE));
+
+	/* setup badvaddr, context and entryhi registers for the guest */
+	kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
+	/* XXXKYMA: is the context register used by linux??? */
+	kvm_write_c0_guest_entryhi(cop0, entryhi);
+
+	return EMULATE_DONE;
+}
+
+enum emulation_result kvm_mips_emulate_fpu_exc(u32 cause,
+					       u32 *opc,
+					       struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+	}
+
+	arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+
+	kvm_change_c0_guest_cause(cop0, (0xff),
+				  (EXCCODE_CPU << CAUSEB_EXCCODE));
+	kvm_change_c0_guest_cause(cop0, (CAUSEF_CE), (0x1 << CAUSEB_CE));
+
+	return EMULATE_DONE;
+}
+
+enum emulation_result kvm_mips_emulate_ri_exc(u32 cause,
+					      u32 *opc,
+					      struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("Delivering RI @ pc %#lx\n", arch->pc);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (EXCCODE_RI << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+
+	} else {
+		kvm_err("Trying to deliver RI when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
+enum emulation_result kvm_mips_emulate_bp_exc(u32 cause,
+					      u32 *opc,
+					      struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("Delivering BP @ pc %#lx\n", arch->pc);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (EXCCODE_BP << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+
+	} else {
+		kvm_err("Trying to deliver BP when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
+enum emulation_result kvm_mips_emulate_trap_exc(u32 cause,
+						u32 *opc,
+						struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("Delivering TRAP @ pc %#lx\n", arch->pc);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (EXCCODE_TR << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+
+	} else {
+		kvm_err("Trying to deliver TRAP when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
+enum emulation_result kvm_mips_emulate_msafpe_exc(u32 cause,
+						  u32 *opc,
+						  struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("Delivering MSAFPE @ pc %#lx\n", arch->pc);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (EXCCODE_MSAFPE << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+
+	} else {
+		kvm_err("Trying to deliver MSAFPE when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
+enum emulation_result kvm_mips_emulate_fpe_exc(u32 cause,
+					       u32 *opc,
+					       struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("Delivering FPE @ pc %#lx\n", arch->pc);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (EXCCODE_FPE << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+
+	} else {
+		kvm_err("Trying to deliver FPE when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
+enum emulation_result kvm_mips_emulate_msadis_exc(u32 cause,
+						  u32 *opc,
+						  struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_debug("Delivering MSADIS @ pc %#lx\n", arch->pc);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (EXCCODE_MSADIS << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+
+	} else {
+		kvm_err("Trying to deliver MSADIS when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
+enum emulation_result kvm_mips_handle_ri(u32 cause, u32 *opc,
+					 struct kvm_vcpu *vcpu)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+	unsigned long curr_pc;
+	union mips_instruction inst;
+	int err;
+
+	/*
+	 * Update PC and hold onto current PC in case there is
+	 * an error and we want to rollback the PC
+	 */
+	curr_pc = vcpu->arch.pc;
+	er = update_pc(vcpu, cause);
+	if (er == EMULATE_FAIL)
+		return er;
+
+	/* Fetch the instruction. */
+	if (cause & CAUSEF_BD)
+		opc += 1;
+	err = kvm_get_badinstr(opc, vcpu, &inst.word);
+	if (err) {
+		kvm_err("%s: Cannot get inst @ %p (%d)\n", __func__, opc, err);
+		return EMULATE_FAIL;
+	}
+
+	if (inst.r_format.opcode == spec3_op &&
+	    inst.r_format.func == rdhwr_op &&
+	    inst.r_format.rs == 0 &&
+	    (inst.r_format.re >> 3) == 0) {
+		int usermode = !KVM_GUEST_KERNEL_MODE(vcpu);
+		int rd = inst.r_format.rd;
+		int rt = inst.r_format.rt;
+		int sel = inst.r_format.re & 0x7;
+
+		/* If usermode, check RDHWR rd is allowed by guest HWREna */
+		if (usermode && !(kvm_read_c0_guest_hwrena(cop0) & BIT(rd))) {
+			kvm_debug("RDHWR %#x disallowed by HWREna @ %p\n",
+				  rd, opc);
+			goto emulate_ri;
+		}
+		switch (rd) {
+		case MIPS_HWR_CPUNUM:		/* CPU number */
+			arch->gprs[rt] = vcpu->vcpu_id;
+			break;
+		case MIPS_HWR_SYNCISTEP:	/* SYNCI length */
+			arch->gprs[rt] = min(current_cpu_data.dcache.linesz,
+					     current_cpu_data.icache.linesz);
+			break;
+		case MIPS_HWR_CC:		/* Read count register */
+			arch->gprs[rt] = (s32)kvm_mips_read_count(vcpu);
+			break;
+		case MIPS_HWR_CCRES:		/* Count register resolution */
+			switch (current_cpu_data.cputype) {
+			case CPU_20KC:
+			case CPU_25KF:
+				arch->gprs[rt] = 1;
+				break;
+			default:
+				arch->gprs[rt] = 2;
+			}
+			break;
+		case MIPS_HWR_ULR:		/* Read UserLocal register */
+			arch->gprs[rt] = kvm_read_c0_guest_userlocal(cop0);
+			break;
+
+		default:
+			kvm_debug("RDHWR %#x not supported @ %p\n", rd, opc);
+			goto emulate_ri;
+		}
+
+		trace_kvm_hwr(vcpu, KVM_TRACE_RDHWR, KVM_TRACE_HWR(rd, sel),
+			      vcpu->arch.gprs[rt]);
+	} else {
+		kvm_debug("Emulate RI not supported @ %p: %#x\n",
+			  opc, inst.word);
+		goto emulate_ri;
+	}
+
+	return EMULATE_DONE;
+
+emulate_ri:
+	/*
+	 * Rollback PC (if in branch delay slot then the PC already points to
+	 * branch target), and pass the RI exception to the guest OS.
+	 */
+	vcpu->arch.pc = curr_pc;
+	return kvm_mips_emulate_ri_exc(cause, opc, vcpu);
+}
+
+enum emulation_result kvm_mips_complete_mmio_load(struct kvm_vcpu *vcpu)
+{
+	struct kvm_run *run = vcpu->run;
+	unsigned long *gpr = &vcpu->arch.gprs[vcpu->arch.io_gpr];
+	enum emulation_result er = EMULATE_DONE;
+
+	if (run->mmio.len > sizeof(*gpr)) {
+		kvm_err("Bad MMIO length: %d", run->mmio.len);
+		er = EMULATE_FAIL;
+		goto done;
+	}
+
+	/* Restore saved resume PC */
+	vcpu->arch.pc = vcpu->arch.io_pc;
+
+	switch (run->mmio.len) {
+	case 8:
+		switch (vcpu->mmio_needed) {
+		case 11:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffffffffffff) |
+				(((*(s64 *)run->mmio.data) & 0xff) << 56);
+			break;
+		case 12:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffffffffff) |
+				(((*(s64 *)run->mmio.data) & 0xffff) << 48);
+			break;
+		case 13:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffffffff) |
+				(((*(s64 *)run->mmio.data) & 0xffffff) << 40);
+			break;
+		case 14:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffffff) |
+				(((*(s64 *)run->mmio.data) & 0xffffffff) << 32);
+			break;
+		case 15:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffff) |
+				(((*(s64 *)run->mmio.data) & 0xffffffffff) << 24);
+			break;
+		case 16:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffff) |
+				(((*(s64 *)run->mmio.data) & 0xffffffffffff) << 16);
+			break;
+		case 17:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xff) |
+				(((*(s64 *)run->mmio.data) & 0xffffffffffffff) << 8);
+			break;
+		case 18:
+		case 19:
+			*gpr = *(s64 *)run->mmio.data;
+			break;
+		case 20:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xff00000000000000) |
+				((((*(s64 *)run->mmio.data)) >> 8) & 0xffffffffffffff);
+			break;
+		case 21:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffff000000000000) |
+				((((*(s64 *)run->mmio.data)) >> 16) & 0xffffffffffff);
+			break;
+		case 22:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffff0000000000) |
+				((((*(s64 *)run->mmio.data)) >> 24) & 0xffffffffff);
+			break;
+		case 23:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffffff00000000) |
+				((((*(s64 *)run->mmio.data)) >> 32) & 0xffffffff);
+			break;
+		case 24:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffffffff000000) |
+				((((*(s64 *)run->mmio.data)) >> 40) & 0xffffff);
+			break;
+		case 25:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffffffffff0000) |
+				((((*(s64 *)run->mmio.data)) >> 48) & 0xffff);
+			break;
+		case 26:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffffffffffff00) |
+				((((*(s64 *)run->mmio.data)) >> 56) & 0xff);
+			break;
+		default:
+			*gpr = *(s64 *)run->mmio.data;
+		}
+		break;
+
+	case 4:
+		switch (vcpu->mmio_needed) {
+		case 1:
+			*gpr = *(u32 *)run->mmio.data;
+			break;
+		case 2:
+			*gpr = *(s32 *)run->mmio.data;
+			break;
+		case 3:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffff) |
+				(((*(s32 *)run->mmio.data) & 0xff) << 24);
+			break;
+		case 4:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffff) |
+				(((*(s32 *)run->mmio.data) & 0xffff) << 16);
+			break;
+		case 5:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xff) |
+				(((*(s32 *)run->mmio.data) & 0xffffff) << 8);
+			break;
+		case 6:
+		case 7:
+			*gpr = *(s32 *)run->mmio.data;
+			break;
+		case 8:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xff000000) |
+				((((*(s32 *)run->mmio.data)) >> 8) & 0xffffff);
+			break;
+		case 9:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffff0000) |
+				((((*(s32 *)run->mmio.data)) >> 16) & 0xffff);
+			break;
+		case 10:
+			*gpr = (vcpu->arch.gprs[vcpu->arch.io_gpr] & 0xffffff00) |
+				((((*(s32 *)run->mmio.data)) >> 24) & 0xff);
+			break;
+		default:
+			*gpr = *(s32 *)run->mmio.data;
+		}
+		break;
+
+	case 2:
+		if (vcpu->mmio_needed == 1)
+			*gpr = *(u16 *)run->mmio.data;
+		else
+			*gpr = *(s16 *)run->mmio.data;
+
+		break;
+	case 1:
+		if (vcpu->mmio_needed == 1)
+			*gpr = *(u8 *)run->mmio.data;
+		else
+			*gpr = *(s8 *)run->mmio.data;
+		break;
+	}
+
+done:
+	return er;
+}
+
+static enum emulation_result kvm_mips_emulate_exc(u32 cause,
+						  u32 *opc,
+						  struct kvm_vcpu *vcpu)
+{
+	u32 exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	struct kvm_vcpu_arch *arch = &vcpu->arch;
+	enum emulation_result er = EMULATE_DONE;
+
+	if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
+		/* save old pc */
+		kvm_write_c0_guest_epc(cop0, arch->pc);
+		kvm_set_c0_guest_status(cop0, ST0_EXL);
+
+		if (cause & CAUSEF_BD)
+			kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
+		else
+			kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
+
+		kvm_change_c0_guest_cause(cop0, (0xff),
+					  (exccode << CAUSEB_EXCCODE));
+
+		/* Set PC to the exception entry point */
+		arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
+		kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
+
+		kvm_debug("Delivering EXC %d @ pc %#lx, badVaddr: %#lx\n",
+			  exccode, kvm_read_c0_guest_epc(cop0),
+			  kvm_read_c0_guest_badvaddr(cop0));
+	} else {
+		kvm_err("Trying to deliver EXC when EXL is already set\n");
+		er = EMULATE_FAIL;
+	}
+
+	return er;
+}
+
+enum emulation_result kvm_mips_check_privilege(u32 cause,
+					       u32 *opc,
+					       struct kvm_vcpu *vcpu)
+{
+	enum emulation_result er = EMULATE_DONE;
+	u32 exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
+	unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
+
+	int usermode = !KVM_GUEST_KERNEL_MODE(vcpu);
+
+	if (usermode) {
+		switch (exccode) {
+		case EXCCODE_INT:
+		case EXCCODE_SYS:
+		case EXCCODE_BP:
+		case EXCCODE_RI:
+		case EXCCODE_TR:
+		case EXCCODE_MSAFPE:
+		case EXCCODE_FPE:
+		case EXCCODE_MSADIS:
+			break;
+
+		case EXCCODE_CPU:
+			if (((cause & CAUSEF_CE) >> CAUSEB_CE) == 0)
+				er = EMULATE_PRIV_FAIL;
+			break;
+
+		case EXCCODE_MOD:
+			break;
+
+		case EXCCODE_TLBL:
+			/*
+			 * We we are accessing Guest kernel space, then send an
+			 * address error exception to the guest
+			 */
+			if (badvaddr >= (unsigned long) KVM_GUEST_KSEG0) {
+				kvm_debug("%s: LD MISS @ %#lx\n", __func__,
+					  badvaddr);
+				cause &= ~0xff;
+				cause |= (EXCCODE_ADEL << CAUSEB_EXCCODE);
+				er = EMULATE_PRIV_FAIL;
+			}
+			break;
+
+		case EXCCODE_TLBS:
+			/*
+			 * We we are accessing Guest kernel space, then send an
+			 * address error exception to the guest
+			 */
+			if (badvaddr >= (unsigned long) KVM_GUEST_KSEG0) {
+				kvm_debug("%s: ST MISS @ %#lx\n", __func__,
+					  badvaddr);
+				cause &= ~0xff;
+				cause |= (EXCCODE_ADES << CAUSEB_EXCCODE);
+				er = EMULATE_PRIV_FAIL;
+			}
+			break;
+
+		case EXCCODE_ADES:
+			kvm_debug("%s: address error ST @ %#lx\n", __func__,
+				  badvaddr);
+			if ((badvaddr & PAGE_MASK) == KVM_GUEST_COMMPAGE_ADDR) {
+				cause &= ~0xff;
+				cause |= (EXCCODE_TLBS << CAUSEB_EXCCODE);
+			}
+			er = EMULATE_PRIV_FAIL;
+			break;
+		case EXCCODE_ADEL:
+			kvm_debug("%s: address error LD @ %#lx\n", __func__,
+				  badvaddr);
+			if ((badvaddr & PAGE_MASK) == KVM_GUEST_COMMPAGE_ADDR) {
+				cause &= ~0xff;
+				cause |= (EXCCODE_TLBL << CAUSEB_EXCCODE);
+			}
+			er = EMULATE_PRIV_FAIL;
+			break;
+		default:
+			er = EMULATE_PRIV_FAIL;
+			break;
+		}
+	}
+
+	if (er == EMULATE_PRIV_FAIL)
+		kvm_mips_emulate_exc(cause, opc, vcpu);
+
+	return er;
+}
+
+/*
+ * User Address (UA) fault, this could happen if
+ * (1) TLB entry not present/valid in both Guest and shadow host TLBs, in this
+ *     case we pass on the fault to the guest kernel and let it handle it.
+ * (2) TLB entry is present in the Guest TLB but not in the shadow, in this
+ *     case we inject the TLB from the Guest TLB into the shadow host TLB
+ */
+enum emulation_result kvm_mips_handle_tlbmiss(u32 cause,
+					      u32 *opc,
+					      struct kvm_vcpu *vcpu,
+					      bool write_fault)
+{
+	enum emulation_result er = EMULATE_DONE;
+	u32 exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
+	unsigned long va = vcpu->arch.host_cp0_badvaddr;
+	int index;
+
+	kvm_debug("kvm_mips_handle_tlbmiss: badvaddr: %#lx\n",
+		  vcpu->arch.host_cp0_badvaddr);
+
+	/*
+	 * KVM would not have got the exception if this entry was valid in the
+	 * shadow host TLB. Check the Guest TLB, if the entry is not there then
+	 * send the guest an exception. The guest exc handler should then inject
+	 * an entry into the guest TLB.
+	 */
+	index = kvm_mips_guest_tlb_lookup(vcpu,
+		      (va & VPN2_MASK) |
+		      (kvm_read_c0_guest_entryhi(vcpu->arch.cop0) &
+		       KVM_ENTRYHI_ASID));
+	if (index < 0) {
+		if (exccode == EXCCODE_TLBL) {
+			er = kvm_mips_emulate_tlbmiss_ld(cause, opc, vcpu);
+		} else if (exccode == EXCCODE_TLBS) {
+			er = kvm_mips_emulate_tlbmiss_st(cause, opc, vcpu);
+		} else {
+			kvm_err("%s: invalid exc code: %d\n", __func__,
+				exccode);
+			er = EMULATE_FAIL;
+		}
+	} else {
+		struct kvm_mips_tlb *tlb = &vcpu->arch.guest_tlb[index];
+
+		/*
+		 * Check if the entry is valid, if not then setup a TLB invalid
+		 * exception to the guest
+		 */
+		if (!TLB_IS_VALID(*tlb, va)) {
+			if (exccode == EXCCODE_TLBL) {
+				er = kvm_mips_emulate_tlbinv_ld(cause, opc,
+								vcpu);
+			} else if (exccode == EXCCODE_TLBS) {
+				er = kvm_mips_emulate_tlbinv_st(cause, opc,
+								vcpu);
+			} else {
+				kvm_err("%s: invalid exc code: %d\n", __func__,
+					exccode);
+				er = EMULATE_FAIL;
+			}
+		} else {
+			kvm_debug("Injecting hi: %#lx, lo0: %#lx, lo1: %#lx into shadow host TLB\n",
+				  tlb->tlb_hi, tlb->tlb_lo[0], tlb->tlb_lo[1]);
+			/*
+			 * OK we have a Guest TLB entry, now inject it into the
+			 * shadow host TLB
+			 */
+			if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb, va,
+								 write_fault)) {
+				kvm_err("%s: handling mapped seg tlb fault for %lx, index: %u, vcpu: %p, ASID: %#lx\n",
+					__func__, va, index, vcpu,
+					read_c0_entryhi());
+				er = EMULATE_FAIL;
+			}
+		}
+	}
+
+	return er;
+}