[PATCH v6 0/4] KVM/ARM Architected Timers support

[PATCH v6 0/4] KVM/ARM Architected Timers support

[Christoffer Dall]

The following series implements support for the architected generic
timers for KVM/ARM.

This patch series can also be pulled from:
    git://github.com/virtualopensystems/linux-kvm-arm.git
            branch: kvm-arm-v16-vgic-timers

Changes since v5:
 - Renamed sync_{to,from} to {flush,sync}_hwstate
 - Removed ISB's in world-switch code
 - Avoid add/sub on vcpu pointer in world-switch

Changes since v1-v4:
 - Get virtual IRQ number from DT
 - Simplify access to cntvoff and cntv_cval
 - Remove extraneous bit clearing
 - Abstract timer arming/disarming to improve code readability
 - Context switch CNTKCTL across world-switches
 - Add CPU hotplug notifier

---

Marc Zyngier (4):
      ARM: arch_timers: switch to physical timers if HYP mode is available
      ARM: KVM: arch_timers: Add guest timer core support
      ARM: KVM: arch_timers: Add timer world switch
      ARM: KVM: arch_timers: Wire the init code and config option


 arch/arm/include/asm/kvm_arch_timer.h |   85 ++++++++++
 arch/arm/include/asm/kvm_asm.h        |    3 
 arch/arm/include/asm/kvm_host.h       |    5 +
 arch/arm/kernel/arch_timer.c          |    7 +
 arch/arm/kernel/asm-offsets.c         |    6 +
 arch/arm/kvm/Kconfig                  |    8 +
 arch/arm/kvm/Makefile                 |    1 
 arch/arm/kvm/arch_timer.c             |  271 +++++++++++++++++++++++++++++++++
 arch/arm/kvm/arm.c                    |   14 ++
 arch/arm/kvm/coproc.c                 |    4 
 arch/arm/kvm/interrupts.S             |    2 
 arch/arm/kvm/interrupts_head.S        |   90 +++++++++++
 arch/arm/kvm/vgic.c                   |    1 
 13 files changed, 495 insertions(+), 2 deletions(-)
 create mode 100644 arch/arm/include/asm/kvm_arch_timer.h
 create mode 100644 arch/arm/kvm/arch_timer.c

-- 

[PATCH v6 1/4] ARM: arch_timers: switch to physical timers if HYP mode is available

[Christoffer Dall]

From: Marc Zyngier <marc.zyngier@arm.com>

If we're booted in HYP mode, it is possible that we'll run some
kind of virtualized environment. In this case, it is a better to
switch to the physical timers, and leave the virtual timers to
guests.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kernel/arch_timer.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
index c8ef207..8adcd04 100644
--- a/arch/arm/kernel/arch_timer.c
+++ b/arch/arm/kernel/arch_timer.c
@@ -26,6 +26,7 @@
 #include <asm/arch_timer.h>
 #include <asm/system_info.h>
 #include <asm/sched_clock.h>
+#include <asm/virt.h>
 
 static unsigned long arch_timer_rate;
 
@@ -489,10 +490,14 @@ int __init arch_timer_of_register(void)
 		arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
 
 	/*
+	 * If HYP mode is available, we know that the physical timer
+	 * has been configured to be accessible from PL1. Use it, so
+	 * that a guest can use the virtual timer instead.
+	 *
 	 * If no interrupt provided for virtual timer, we'll have to
 	 * stick to the physical timer. It'd better be accessible...
 	 */
-	if (!arch_timer_ppi[VIRT_PPI]) {
+	if (is_hyp_mode_available() || !arch_timer_ppi[VIRT_PPI]) {
 		arch_timer_use_virtual = false;
 
 		if (!arch_timer_ppi[PHYS_SECURE_PPI] ||

[PATCH v6 2/4] ARM: KVM: arch_timers: Add guest timer core support

[Christoffer Dall]

From: Marc Zyngier <marc.zyngier@arm.com>

Add some the architected timer related infrastructure, and support timer
interrupt injection, which can happen as a resultof three possible
events:

- The virtual timer interrupt has fired while we were still
  executing the guest
- The timer interrupt hasn't fired, but it expired while we
  were doing the world switch
- A hrtimer we programmed earlier has fired

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
---
 arch/arm/include/asm/kvm_arch_timer.h |   85 ++++++++++
 arch/arm/include/asm/kvm_host.h       |    5 +
 arch/arm/kvm/arch_timer.c             |  271 +++++++++++++++++++++++++++++++++
 arch/arm/kvm/interrupts.S             |    2 
 arch/arm/kvm/interrupts_head.S        |   31 ++++
 5 files changed, 394 insertions(+)
 create mode 100644 arch/arm/include/asm/kvm_arch_timer.h
 create mode 100644 arch/arm/kvm/arch_timer.c

diff --git a/arch/arm/include/asm/kvm_arch_timer.h b/arch/arm/include/asm/kvm_arch_timer.h
new file mode 100644
index 0000000..68cb9e1
--- /dev/null
+++ b/arch/arm/include/asm/kvm_arch_timer.h
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef __ASM_ARM_KVM_ARCH_TIMER_H
+#define __ASM_ARM_KVM_ARCH_TIMER_H
+
+#include <linux/clocksource.h>
+#include <linux/hrtimer.h>
+#include <linux/workqueue.h>
+
+struct arch_timer_kvm {
+#ifdef CONFIG_KVM_ARM_TIMER
+	/* Is the timer enabled */
+	bool			enabled;
+
+	/* Virtual offset */
+	cycle_t			cntvoff;
+#endif
+};
+
+struct arch_timer_cpu {
+#ifdef CONFIG_KVM_ARM_TIMER
+	/* Registers: control register, timer value */
+	u32				cntv_ctl;	/* Saved/restored */
+	cycle_t				cntv_cval;	/* Saved/restored */
+
+	/*
+	 * Anything that is not used directly from assembly code goes
+	 * here.
+	 */
+
+	/* Background timer used when the guest is not running */
+	struct hrtimer			timer;
+
+	/* Work queued with the above timer expires */
+	struct work_struct		expired;
+
+	/* Background timer active */
+	bool				armed;
+
+	/* Timer IRQ */
+	const struct kvm_irq_level	*irq;
+#endif
+};
+
+#ifdef CONFIG_KVM_ARM_TIMER
+int kvm_timer_hyp_init(void);
+int kvm_timer_init(struct kvm *kvm);
+void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu);
+void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu);
+void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu);
+void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu);
+#else
+static inline int kvm_timer_hyp_init(void)
+{
+	return 0;
+};
+
+static inline int kvm_timer_init(struct kvm *kvm)
+{
+	return 0;
+}
+
+static inline void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) {}
+static inline void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu) {}
+static inline void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu) {}
+static inline void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu) {}
+#endif
+
+#endif
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index feac7f4..e58fd93 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -23,6 +23,7 @@
 #include <asm/kvm_asm.h>
 #include <asm/kvm_mmio.h>
 #include <asm/fpstate.h>
+#include <asm/kvm_arch_timer.h>
 
 #define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
 #define KVM_MEMORY_SLOTS 32
@@ -49,6 +50,9 @@ struct kvm_arch {
 	/* VTTBR value associated with below pgd and vmid */
 	u64    vttbr;
 
+	/* Timer */
+	struct arch_timer_kvm	timer;
+
 	/*
 	 * Anything that is not used directly from assembly code goes
 	 * here.
@@ -99,6 +103,7 @@ struct kvm_vcpu_arch {
 
 	/* VGIC state */
 	struct vgic_cpu vgic_cpu;
+	struct arch_timer_cpu timer_cpu;
 
 	/*
 	 * Anything that is not used directly from assembly code goes
diff --git a/arch/arm/kvm/arch_timer.c b/arch/arm/kvm/arch_timer.c
new file mode 100644
index 0000000..6ac938d
--- /dev/null
+++ b/arch/arm/kvm/arch_timer.c
@@ -0,0 +1,271 @@
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/cpu.h>
+#include <linux/of_irq.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/interrupt.h>
+
+#include <asm/arch_timer.h>
+
+#include <asm/kvm_vgic.h>
+#include <asm/kvm_arch_timer.h>
+
+static struct timecounter *timecounter;
+static struct workqueue_struct *wqueue;
+static struct kvm_irq_level timer_irq = {
+	.level	= 1,
+};
+
+static cycle_t kvm_phys_timer_read(void)
+{
+	return timecounter->cc->read(timecounter->cc);
+}
+
+static bool timer_is_armed(struct arch_timer_cpu *timer)
+{
+	return timer->armed;
+}
+
+/* timer_arm: as in "arm the timer", not as in ARM the company */
+static void timer_arm(struct arch_timer_cpu *timer, u64 ns)
+{
+	timer->armed = true;
+	hrtimer_start(&timer->timer, ktime_add_ns(ktime_get(), ns),
+		      HRTIMER_MODE_ABS);
+}
+
+static void timer_disarm(struct arch_timer_cpu *timer)
+{
+	if (timer_is_armed(timer)) {
+		hrtimer_cancel(&timer->timer);
+		cancel_work_sync(&timer->expired);
+		timer->armed = false;
+	}
+}
+
+static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+	timer->cntv_ctl |= 1 << 1; /* Mask the interrupt in the guest */
+	kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
+			    vcpu->arch.timer_cpu.irq->irq,
+			    vcpu->arch.timer_cpu.irq->level);
+}
+
+static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
+{
+	struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)dev_id;
+
+	/*
+	 * We disable the timer in the world switch and let it be
+	 * handled by kvm_timer_sync_hwstate(). Getting a timer
+	 * interrupt at this point is a sure sign of some major
+	 * breakage.
+	 */
+	pr_warn("Unexpected interrupt %d on vcpu %p\n", irq, vcpu);
+	return IRQ_HANDLED;
+}
+
+static void kvm_timer_inject_irq_work(struct work_struct *work)
+{
+	struct kvm_vcpu *vcpu;
+
+	vcpu = container_of(work, struct kvm_vcpu, arch.timer_cpu.expired);
+	vcpu->arch.timer_cpu.armed = false;
+	kvm_timer_inject_irq(vcpu);
+}
+
+static enum hrtimer_restart kvm_timer_expire(struct hrtimer *hrt)
+{
+	struct arch_timer_cpu *timer;
+	timer = container_of(hrt, struct arch_timer_cpu, timer);
+	queue_work(wqueue, &timer->expired);
+	return HRTIMER_NORESTART;
+}
+
+/**
+ * kvm_timer_flush_hwstate - prepare to move the virt timer to the cpu
+ * @vcpu: The vcpu pointer
+ *
+ * Disarm any pending soft timers, since the world-switch code will write the
+ * virtual timer state back to the physical CPU.
+ */
+void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+	/*
+	 * We're about to run this vcpu again, so there is no need to
+	 * keep the background timer running, as we're about to
+	 * populate the CPU timer again.
+	 */
+	timer_disarm(timer);
+}
+
+/**
+ * kvm_timer_sync_hwstate - sync timer state from cpu
+ * @vcpu: The vcpu pointer
+ *
+ * Check if the virtual timer was armed and either schedule a corresponding
+ * soft timer or inject directly if already expired.
+ */
+void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+	cycle_t cval, now;
+	u64 ns;
+
+	/* Check if the timer is enabled and unmasked first */
+	if ((timer->cntv_ctl & 3) != 1)
+		return;
+
+	cval = timer->cntv_cval;
+	now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
+
+	BUG_ON(timer_is_armed(timer));
+
+	if (cval <= now) {
+		/*
+		 * Timer has already expired while we were not
+		 * looking. Inject the interrupt and carry on.
+		 */
+		kvm_timer_inject_irq(vcpu);
+		return;
+	}
+
+	ns = cyclecounter_cyc2ns(timecounter->cc, cval - now);
+	timer_arm(timer, ns);
+}
+
+void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+	INIT_WORK(&timer->expired, kvm_timer_inject_irq_work);
+	hrtimer_init(&timer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	timer->timer.function = kvm_timer_expire;
+	timer->irq = &timer_irq;
+}
+
+static void kvm_timer_init_interrupt(void *info)
+{
+	enable_percpu_irq(timer_irq.irq, 0);
+}
+
+
+static int kvm_timer_cpu_notify(struct notifier_block *self,
+				unsigned long action, void *cpu)
+{
+	switch (action) {
+	case CPU_STARTING:
+	case CPU_STARTING_FROZEN:
+		kvm_timer_init_interrupt(NULL);
+		break;
+	case CPU_DYING:
+	case CPU_DYING_FROZEN:
+		disable_percpu_irq(timer_irq.irq);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block kvm_timer_cpu_nb = {
+	.notifier_call = kvm_timer_cpu_notify,
+};
+
+static const struct of_device_id arch_timer_of_match[] = {
+	{ .compatible	= "arm,armv7-timer",	},
+	{},
+};
+
+int kvm_timer_hyp_init(void)
+{
+	struct device_node *np;
+	unsigned int ppi;
+	int err;
+
+	timecounter = arch_timer_get_timecounter();
+	if (!timecounter)
+		return -ENODEV;
+
+	np = of_find_matching_node(NULL, arch_timer_of_match);
+	if (!np) {
+		kvm_err("kvm_arch_timer: can't find DT node\n");
+		return -ENODEV;
+	}
+
+	ppi = irq_of_parse_and_map(np, 2);
+	if (!ppi) {
+		kvm_err("kvm_arch_timer: no virtual timer interrupt\n");
+		err = -EINVAL;
+		goto out;
+	}
+
+	err = request_percpu_irq(ppi, kvm_arch_timer_handler,
+				 "kvm guest timer", kvm_get_running_vcpus());
+	if (err) {
+		kvm_err("kvm_arch_timer: can't request interrupt %d (%d)\n",
+			ppi, err);
+		goto out;
+	}
+
+	timer_irq.irq = ppi;
+
+	err = register_cpu_notifier(&kvm_timer_cpu_nb);
+	if (err) {
+		kvm_err("Cannot register timer CPU notifier\n");
+		goto out_free;
+	}
+
+	wqueue = create_singlethread_workqueue("kvm_arch_timer");
+	if (!wqueue) {
+		err = -ENOMEM;
+		goto out_free;
+	}
+
+	kvm_info("%s IRQ%d\n", np->name, ppi);
+	on_each_cpu(kvm_timer_init_interrupt, NULL, 1);
+
+	goto out;
+out_free:
+	free_percpu_irq(ppi, kvm_get_running_vcpus());
+out:
+	of_node_put(np);
+	return err;
+}
+
+void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
+
+	timer_disarm(timer);
+}
+
+int kvm_timer_init(struct kvm *kvm)
+{
+	if (timecounter && wqueue) {
+		kvm->arch.timer.cntvoff = kvm_phys_timer_read();
+		kvm->arch.timer.enabled = 1;
+	}
+
+	return 0;
+}
diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
index b19ee80..8b264fd 100644
--- a/arch/arm/kvm/interrupts.S
+++ b/arch/arm/kvm/interrupts.S
@@ -95,6 +95,7 @@ ENTRY(__kvm_vcpu_run)
 	save_host_regs
 
 	restore_vgic_state
+	restore_timer_state
 
 	@ Store hardware CP15 state and load guest state
 	read_cp15_state store_to_vcpu = 0
@@ -189,6 +190,7 @@ after_vfp_restore:
 	read_cp15_state store_to_vcpu = 1
 	write_cp15_state read_from_vcpu = 0
 
+	save_timer_state
 	save_vgic_state
 
 	restore_host_regs
diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S
index 9e815a5..dea987e 100644
--- a/arch/arm/kvm/interrupts_head.S
+++ b/arch/arm/kvm/interrupts_head.S
@@ -453,6 +453,37 @@ vcpu	.req	r0		@ vcpu pointer always in r0
 #endif
 .endm
 
+#define CNTHCTL_PL1PCTEN	(1 << 0)
+#define CNTHCTL_PL1PCEN		(1 << 1)
+
+/*
+ * Save the timer state onto the VCPU and allow physical timer/counter access
+ * for the host.
+ *
+ * Assumes vcpu pointer in vcpu reg
+ */
+.macro save_timer_state
+	@ Allow physical timer/counter access for the host
+	mrc	p15, 4, r2, c14, c1, 0	@ CNTHCTL
+	orr	r2, r2, #(CNTHCTL_PL1PCEN | CNTHCTL_PL1PCTEN)
+	mcr	p15, 4, r2, c14, c1, 0	@ CNTHCTL
+.endm
+
+/*
+ * Load the timer state from the VCPU and deny physical timer/counter access
+ * for the host.
+ *
+ * Assumes vcpu pointer in vcpu reg
+ */
+.macro restore_timer_state
+	@ Disallow physical timer access for the guest
+	@ Physical counter access is allowed
+	mrc	p15, 4, r2, c14, c1, 0	@ CNTHCTL
+	orr	r2, r2, #CNTHCTL_PL1PCTEN
+	bic	r2, r2, #CNTHCTL_PL1PCEN
+	mcr	p15, 4, r2, c14, c1, 0	@ CNTHCTL
+.endm
+
 .equ vmentry,	0
 .equ vmexit,	1
 

[PATCH v6 3/4] ARM: KVM: arch_timers: Add timer world switch

[Christoffer Dall]

From: Marc Zyngier <marc.zyngier@arm.com>

Do the necessary save/restore dance for the timers in the world
switch code. In the process, allow the guest to read the physical
counter, which is useful for its own clock_event_device.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
---
 arch/arm/include/asm/kvm_asm.h |    3 +-
 arch/arm/kernel/asm-offsets.c  |    6 ++++
 arch/arm/kvm/arm.c             |    3 ++
 arch/arm/kvm/coproc.c          |    4 +++
 arch/arm/kvm/interrupts_head.S |   59 ++++++++++++++++++++++++++++++++++++++++
 5 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 58d787b..8a60ed8 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -45,7 +45,8 @@
 #define c13_TID_URW	23	/* Thread ID, User R/W */
 #define c13_TID_URO	24	/* Thread ID, User R/O */
 #define c13_TID_PRIV	25	/* Thread ID, Privileged */
-#define NR_CP15_REGS	26	/* Number of regs (incl. invalid) */
+#define c14_CNTKCTL	26	/* Timer Control Register (PL1) */
+#define NR_CP15_REGS	27	/* Number of regs (incl. invalid) */
 
 #define ARM_EXCEPTION_RESET	  0
 #define ARM_EXCEPTION_UNDEFINED   1
diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index 17cea2e..5ce738b 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -179,6 +179,12 @@ int main(void)
   DEFINE(VGIC_CPU_APR,		offsetof(struct vgic_cpu, vgic_apr));
   DEFINE(VGIC_CPU_LR,		offsetof(struct vgic_cpu, vgic_lr));
   DEFINE(VGIC_CPU_NR_LR,	offsetof(struct vgic_cpu, nr_lr));
+#ifdef CONFIG_KVM_ARM_TIMER
+  DEFINE(VCPU_TIMER_CNTV_CTL,	offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_ctl));
+  DEFINE(VCPU_TIMER_CNTV_CVAL,	offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_cval));
+  DEFINE(KVM_TIMER_CNTVOFF,	offsetof(struct kvm, arch.timer.cntvoff));
+  DEFINE(KVM_TIMER_ENABLED,	offsetof(struct kvm, arch.timer.enabled));
+#endif
   DEFINE(KVM_VGIC_VCTRL,	offsetof(struct kvm, arch.vgic.vctrl_base));
 #endif
   DEFINE(KVM_VTTBR,		offsetof(struct kvm, arch.vttbr));
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 68cb2b550..1a98b5c 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -707,6 +707,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		update_vttbr(vcpu->kvm);
 
 		kvm_vgic_flush_hwstate(vcpu);
+		kvm_timer_flush_hwstate(vcpu);
 
 		local_irq_disable();
 
@@ -720,6 +721,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 
 		if (ret <= 0 || need_new_vmid_gen(vcpu->kvm)) {
 			local_irq_enable();
+			kvm_timer_sync_hwstate(vcpu);
 			kvm_vgic_sync_hwstate(vcpu);
 			continue;
 		}
@@ -759,6 +761,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		 * Back from guest
 		 *************************************************************/
 
+		kvm_timer_sync_hwstate(vcpu);
 		kvm_vgic_sync_hwstate(vcpu);
 
 		ret = handle_exit(vcpu, run, ret);
diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c
index d782638..4ea9a98 100644
--- a/arch/arm/kvm/coproc.c
+++ b/arch/arm/kvm/coproc.c
@@ -222,6 +222,10 @@ static const struct coproc_reg cp15_regs[] = {
 			NULL, reset_unknown, c13_TID_URO },
 	{ CRn(13), CRm( 0), Op1( 0), Op2( 4), is32,
 			NULL, reset_unknown, c13_TID_PRIV },
+
+	/* CNTKCTL: swapped by interrupt.S. */
+	{ CRn(14), CRm( 1), Op1( 0), Op2( 0), is32,
+			NULL, reset_val, c14_CNTKCTL, 0x00000000 },
 };
 
 /* Target specific emulation tables */
diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S
index dea987e..d2442f9 100644
--- a/arch/arm/kvm/interrupts_head.S
+++ b/arch/arm/kvm/interrupts_head.S
@@ -300,6 +300,14 @@ vcpu	.req	r0		@ vcpu pointer always in r0
 	str	r11, [vcpu, #CP15_OFFSET(c6_IFAR)]
 	str	r12, [vcpu, #CP15_OFFSET(c12_VBAR)]
 	.endif
+
+	mrc	p15, 0, r2, c14, c1, 0	@ CNTKCTL
+
+	.if \store_to_vcpu == 0
+	push	{r2}
+	.else
+	str	r2, [vcpu, #CP15_OFFSET(c14_CNTKCTL)]
+	.endif
 .endm
 
 /*
@@ -311,6 +319,14 @@ vcpu	.req	r0		@ vcpu pointer always in r0
  */
 .macro write_cp15_state read_from_vcpu
 	.if \read_from_vcpu == 0
+	pop	{r2}
+	.else
+	ldr	r2, [vcpu, #CP15_OFFSET(c14_CNTKCTL)]
+	.endif
+
+	mcr	p15, 0, r2, c14, c1, 0	@ CNTKCTL
+
+	.if \read_from_vcpu == 0
 	pop	{r2-r12}
 	.else
 	ldr	r2, [vcpu, #CP15_OFFSET(c13_CID)]
@@ -461,8 +477,28 @@ vcpu	.req	r0		@ vcpu pointer always in r0
  * for the host.
  *
  * Assumes vcpu pointer in vcpu reg
+ * Clobbers r2-r5
  */
 .macro save_timer_state
+#ifdef CONFIG_KVM_ARM_TIMER
+	ldr	r4, [vcpu, #VCPU_KVM]
+	ldr	r2, [r4, #KVM_TIMER_ENABLED]
+	cmp	r2, #0
+	beq	1f
+
+	mrc	p15, 0, r2, c14, c3, 1	@ CNTV_CTL
+	str	r2, [vcpu, #VCPU_TIMER_CNTV_CTL]
+	bic	r2, #1			@ Clear ENABLE
+	mcr	p15, 0, r2, c14, c3, 1	@ CNTV_CTL
+	isb
+
+	mrrc	p15, 3, r2, r3, c14	@ CNTV_CVAL
+	ldr	r4, =VCPU_TIMER_CNTV_CVAL
+	add	r5, vcpu, r4
+	strd	r2, r3, [r5]
+
+1:
+#endif
 	@ Allow physical timer/counter access for the host
 	mrc	p15, 4, r2, c14, c1, 0	@ CNTHCTL
 	orr	r2, r2, #(CNTHCTL_PL1PCEN | CNTHCTL_PL1PCTEN)
@@ -474,6 +510,7 @@ vcpu	.req	r0		@ vcpu pointer always in r0
  * for the host.
  *
  * Assumes vcpu pointer in vcpu reg
+ * Clobbers r2-r5
  */
 .macro restore_timer_state
 	@ Disallow physical timer access for the guest
@@ -482,6 +519,28 @@ vcpu	.req	r0		@ vcpu pointer always in r0
 	orr	r2, r2, #CNTHCTL_PL1PCTEN
 	bic	r2, r2, #CNTHCTL_PL1PCEN
 	mcr	p15, 4, r2, c14, c1, 0	@ CNTHCTL
+
+#ifdef CONFIG_KVM_ARM_TIMER
+	ldr	r4, [vcpu, #VCPU_KVM]
+	ldr	r2, [r4, #KVM_TIMER_ENABLED]
+	cmp	r2, #0
+	beq	1f
+
+	ldr	r2, [r4, #KVM_TIMER_CNTVOFF]
+	ldr	r3, [r4, #(KVM_TIMER_CNTVOFF + 4)]
+	mcrr	p15, 4, r2, r3, c14	@ CNTVOFF
+
+	ldr	r4, =VCPU_TIMER_CNTV_CVAL
+	add	r5, vcpu, r4
+	ldrd	r2, r3, [r5]
+	mcrr	p15, 3, r2, r3, c14	@ CNTV_CVAL
+	isb
+
+	ldr	r2, [vcpu, #VCPU_TIMER_CNTV_CTL]
+	and	r2, r2, #3
+	mcr	p15, 0, r2, c14, c3, 1	@ CNTV_CTL
+1:
+#endif
 .endm
 
 .equ vmentry,	0

[PATCH v6 4/4] ARM: KVM: arch_timers: Wire the init code and config option

[Christoffer Dall]

From: Marc Zyngier <marc.zyngier@arm.com>

It is now possible to select CONFIG_KVM_ARM_TIMER to enable the
KVM architected timer support.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
---
 arch/arm/kvm/Kconfig  |    8 ++++++++
 arch/arm/kvm/Makefile |    1 +
 arch/arm/kvm/arm.c    |   11 +++++++++++
 arch/arm/kvm/vgic.c   |    1 +
 4 files changed, 21 insertions(+)

diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
index d8126f2..49dd64e 100644
--- a/arch/arm/kvm/Kconfig
+++ b/arch/arm/kvm/Kconfig
@@ -59,6 +59,14 @@ config KVM_ARM_VGIC
 	---help---
 	  Adds support for a hardware assisted, in-kernel GIC emulation.
 
+config KVM_ARM_TIMER
+	bool "KVM support for Architected Timers"
+	depends on KVM_ARM_VGIC && ARM_ARCH_TIMER
+	select HAVE_KVM_IRQCHIP
+	default y
+	---help---
+	  Adds support for the Architected Timers in virtual machines
+
 source drivers/virtio/Kconfig
 
 endif # VIRTUALIZATION
diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
index dece8ed..fc96ce6 100644
--- a/arch/arm/kvm/Makefile
+++ b/arch/arm/kvm/Makefile
@@ -20,3 +20,4 @@ obj-y += kvm-arm.o init.o interrupts.o
 obj-y += arm.o guest.o mmu.o emulate.o reset.o
 obj-y += coproc.o coproc_a15.o mmio.o psci.o
 obj-$(CONFIG_KVM_ARM_VGIC) += vgic.o
+obj-$(CONFIG_KVM_ARM_TIMER) += arch_timer.o
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 1a98b5c..2ab3552 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -289,6 +289,7 @@ int kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
 void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
 {
 	kvm_mmu_free_memory_caches(vcpu);
+	kvm_timer_vcpu_terminate(vcpu);
 	kmem_cache_free(kvm_vcpu_cache, vcpu);
 }
 
@@ -330,6 +331,9 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 	if (ret)
 		return ret;
 
+	/* Set up the timer */
+	kvm_timer_vcpu_init(vcpu);
+
 	return 0;
 }
 
@@ -1096,6 +1100,13 @@ static int init_hyp_mode(void)
 		vgic_present = true;
 #endif
 
+	/*
+	 * Init HYP architected timer support
+	 */
+	err = kvm_timer_hyp_init();
+	if (err)
+		goto out_free_mappings;
+
 	kvm_info("Hyp mode initialized successfully\n");
 	return 0;
 out_free_vfp:
diff --git a/arch/arm/kvm/vgic.c b/arch/arm/kvm/vgic.c
index 519cde1..c451bf0 100644
--- a/arch/arm/kvm/vgic.c
+++ b/arch/arm/kvm/vgic.c
@@ -1417,6 +1417,7 @@ int kvm_vgic_init(struct kvm *kvm)
 	for (i = VGIC_NR_PRIVATE_IRQS; i < VGIC_NR_IRQS; i += 4)
 		vgic_set_target_reg(kvm, 0, i);
 
+	kvm_timer_init(kvm);
 	kvm->arch.vgic.ready = true;
 out:
 	mutex_unlock(&kvm->lock);