Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

1 files changed, 532 insertions, 25 deletions

diff --git a/arch/mips/kvm/kvm_mips_emul.c b/arch/mips/kvm/kvm_mips_emul.c
index e3fec99941a7..8d4840090082 100644
--- a/arch/mips/kvm/kvm_mips_emul.c
+++ b/arch/mips/kvm/kvm_mips_emul.c
@@ -11,6 +11,7 @@
 
 #include <linux/errno.h>
 #include <linux/err.h>
+#include <linux/ktime.h>
 #include <linux/kvm_host.h>
 #include <linux/module.h>
 #include <linux/vmalloc.h>
@@ -228,25 +229,520 @@ enum emulation_result update_pc(struct kvm_vcpu *vcpu, uint32_t cause)
 	return er;
 }
 
-/* Everytime the compare register is written to, we need to decide when to fire
- * the timer that represents timer ticks to the GUEST.
+/**
+ * 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).
  */
-enum emulation_result kvm_mips_emulate_count(struct kvm_vcpu *vcpu)
+static inline int kvm_mips_count_disabled(struct kvm_vcpu *vcpu)
 {
 	struct mips_coproc *cop0 = vcpu->arch.cop0;
-	enum emulation_result er = EMULATE_DONE;
+	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 uint32_t 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 uint32_t kvm_mips_read_count_running(struct kvm_vcpu *vcpu, ktime_t now)
+{
+	ktime_t expires;
+	int running;
+
+	/* Is the hrtimer pending? */
+	expires = hrtimer_get_expires(&vcpu->arch.comparecount_timer);
+	if (ktime_compare(now, expires) >= 0) {
+		/*
+		 * 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 the biased and scaled guest CP0_Count */
+	return vcpu->arch.count_bias + kvm_mips_ktime_to_count(vcpu, now);
+}
+
+/**
+ * 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.
+ */
+uint32_t 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.
+ */
+static ktime_t kvm_mips_freeze_hrtimer(struct kvm_vcpu *vcpu,
+				       uint32_t *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;
+}
+
 
-	/* If COUNT is enabled */
-	if (!(kvm_read_c0_guest_cause(cop0) & CAUSEF_DC)) {
-		hrtimer_try_to_cancel(&vcpu->arch.comparecount_timer);
-		hrtimer_start(&vcpu->arch.comparecount_timer,
-			      ktime_set(0, MS_TO_NS(10)), HRTIMER_MODE_REL);
+/**
+ * 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, uint32_t count)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	uint32_t compare;
+	u64 delta;
+	ktime_t expire;
+
+	/* Calculate timeout (wrap 0 to 2^32) */
+	compare = kvm_read_c0_guest_compare(cop0);
+	delta = (u64)(uint32_t)(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_update_hrtimer() - Update next expiry time of hrtimer.
+ * @vcpu:	Virtual CPU.
+ *
+ * Recalculates and updates the expiry time of the hrtimer. This can be used
+ * after timer parameters have been altered which do not depend on the time that
+ * the change occurs (in those cases kvm_mips_freeze_hrtimer() and
+ * kvm_mips_resume_hrtimer() are used directly).
+ *
+ * It is guaranteed that no timer interrupts will be lost in the process.
+ *
+ * Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running).
+ */
+static void kvm_mips_update_hrtimer(struct kvm_vcpu *vcpu)
+{
+	ktime_t now;
+	uint32_t count;
+
+	/*
+	 * freeze_hrtimer takes care of a timer interrupts <= count, and
+	 * resume_hrtimer the hrtimer takes care of a timer interrupts > count.
+	 */
+	now = kvm_mips_freeze_hrtimer(vcpu, &count);
+	kvm_mips_resume_hrtimer(vcpu, now, count);
+}
+
+/**
+ * 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, uint32_t 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.
+ *
+ * Initialise the timer to a sensible frequency, namely 100MHz, zero it, and set
+ * it going if it's enabled.
+ */
+void kvm_mips_init_count(struct kvm_vcpu *vcpu)
+{
+	/* 100 MHz */
+	vcpu->arch.count_hz = 100*1000*1000;
+	vcpu->arch.count_period = div_u64((u64)NSEC_PER_SEC << 32,
+					  vcpu->arch.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 {
-		hrtimer_try_to_cancel(&vcpu->arch.comparecount_timer);
+		now = kvm_mips_freeze_hrtimer(vcpu, &count);
 	}
 
-	return er;
+	/* 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.
+ *
+ * Update CP0_Compare to a new value and update the timeout.
+ */
+void kvm_mips_write_compare(struct kvm_vcpu *vcpu, uint32_t compare)
+{
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+
+	/* if unchanged, must just be an ack */
+	if (kvm_read_c0_guest_compare(cop0) == compare)
+		return;
+
+	/* Update compare */
+	kvm_write_c0_guest_compare(cop0, compare);
+
+	/* Update timeout if count enabled */
+	if (!kvm_mips_count_disabled(vcpu))
+		kvm_mips_update_hrtimer(vcpu);
+}
+
+/**
+ * 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;
+	uint32_t 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;
+	uint32_t 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;
+	uint32_t 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)(uint32_t)(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)
@@ -471,8 +967,7 @@ kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc, uint32_t cause,
 #endif
 			/* Get reg */
 			if ((rd == MIPS_CP0_COUNT) && (sel == 0)) {
-				/* XXXKYMA: Run the Guest count register @ 1/4 the rate of the host */
-				vcpu->arch.gprs[rt] = (read_c0_count() >> 2);
+				vcpu->arch.gprs[rt] = kvm_mips_read_count(vcpu);
 			} else if ((rd == MIPS_CP0_ERRCTL) && (sel == 0)) {
 				vcpu->arch.gprs[rt] = 0x0;
 #ifdef CONFIG_KVM_MIPS_DYN_TRANS
@@ -539,10 +1034,7 @@ kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc, uint32_t cause,
 			}
 			/* Are we writing to COUNT */
 			else if ((rd == MIPS_CP0_COUNT) && (sel == 0)) {
-				/* Linux doesn't seem to write into COUNT, we throw an error
-				 * if we notice a write to COUNT
-				 */
-				/*er = EMULATE_FAIL; */
+				kvm_mips_write_count(vcpu, vcpu->arch.gprs[rt]);
 				goto done;
 			} else if ((rd == MIPS_CP0_COMPARE) && (sel == 0)) {
 				kvm_debug("[%#x] MTCz, COMPARE %#lx <- %#lx\n",
@@ -552,8 +1044,8 @@ kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc, uint32_t cause,
 				/* If we are writing to COMPARE */
 				/* Clear pending timer interrupt, if any */
 				kvm_mips_callbacks->dequeue_timer_int(vcpu);
-				kvm_write_c0_guest_compare(cop0,
-							   vcpu->arch.gprs[rt]);
+				kvm_mips_write_compare(vcpu,
+						       vcpu->arch.gprs[rt]);
 			} else if ((rd == MIPS_CP0_STATUS) && (sel == 0)) {
 				kvm_write_c0_guest_status(cop0,
 							  vcpu->arch.gprs[rt]);
@@ -564,6 +1056,20 @@ kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc, uint32_t cause,
 #ifdef CONFIG_KVM_MIPS_DYN_TRANS
 				kvm_mips_trans_mtc0(inst, opc, vcpu);
 #endif
+			} else if ((rd == MIPS_CP0_CAUSE) && (sel == 0)) {
+				uint32_t 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 {
 				cop0->reg[rd][sel] = vcpu->arch.gprs[rt];
 #ifdef CONFIG_KVM_MIPS_DYN_TRANS
@@ -887,7 +1393,7 @@ int kvm_mips_sync_icache(unsigned long va, struct kvm_vcpu *vcpu)
 
 	printk("%s: va: %#lx, unmapped: %#x\n", __func__, va, CKSEG0ADDR(pa));
 
-	mips32_SyncICache(CKSEG0ADDR(pa), 32);
+	local_flush_icache_range(CKSEG0ADDR(pa), 32);
 	return 0;
 }
 
@@ -1325,8 +1831,12 @@ kvm_mips_handle_tlbmod(unsigned long cause, uint32_t *opc,
 		       struct kvm_run *run, struct kvm_vcpu *vcpu)
 {
 	enum emulation_result er = EMULATE_DONE;
-
 #ifdef DEBUG
+	struct mips_coproc *cop0 = vcpu->arch.cop0;
+	unsigned long entryhi = (vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
+				(kvm_read_c0_guest_entryhi(cop0) & ASID_MASK);
+	int index;
+
 	/*
 	 * If address not in the guest TLB, then we are in trouble
 	 */
@@ -1553,8 +2063,7 @@ kvm_mips_handle_ri(unsigned long cause, uint32_t *opc,
 					     current_cpu_data.icache.linesz);
 			break;
 		case 2:	/* Read count register */
-			printk("RDHWR: Cont register\n");
-			arch->gprs[rt] = kvm_read_c0_guest_count(cop0);
+			arch->gprs[rt] = kvm_mips_read_count(vcpu);
 			break;
 		case 3:	/* Count register resolution */
 			switch (current_cpu_data.cputype) {
@@ -1810,11 +2319,9 @@ kvm_mips_handle_tlbmiss(unsigned long cause, uint32_t *opc,
 				er = EMULATE_FAIL;
 			}
 		} else {
-#ifdef DEBUG
 			kvm_debug
 			    ("Injecting hi: %#lx, lo0: %#lx, lo1: %#lx into shadow host TLB\n",
 			     tlb->tlb_hi, tlb->tlb_lo0, tlb->tlb_lo1);
-#endif
 			/* OK we have a Guest TLB entry, now inject it into the shadow host TLB */
 			kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb, NULL,
 							     NULL);