[PATCH v2 20/30] arm64: KVM: Plug the arch timer

[Marc Zyngier]

Add support for the in-kernel timer emulation. The include file
is a complete duplicate of the 32bit one - something to fix
at one point.

Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
 arch/arm/kvm/arch_timer.c               |  1 +
 arch/arm64/include/asm/kvm_arch_timer.h | 58 +++++++++++++++++++++++++++++++++
 arch/arm64/kvm/hyp.S                    | 56 +++++++++++++++++++++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 arch/arm64/include/asm/kvm_arch_timer.h

diff --git a/arch/arm/kvm/arch_timer.c b/arch/arm/kvm/arch_timer.c
index 6ac938d..ca04a99 100644
--- a/arch/arm/kvm/arch_timer.c
+++ b/arch/arm/kvm/arch_timer.c
@@ -194,6 +194,7 @@ static struct notifier_block kvm_timer_cpu_nb = {
 
 static const struct of_device_id arch_timer_of_match[] = {
 	{ .compatible	= "arm,armv7-timer",	},
+	{ .compatible	= "arm,armv8-timer",	},
 	{},
 };
 
diff --git a/arch/arm64/include/asm/kvm_arch_timer.h b/arch/arm64/include/asm/kvm_arch_timer.h
new file mode 100644
index 0000000..eb02273
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_arch_timer.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier at 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ARM64_KVM_ARCH_TIMER_H
+#define __ARM64_KVM_ARCH_TIMER_H
+
+#include <linux/clocksource.h>
+#include <linux/hrtimer.h>
+#include <linux/workqueue.h>
+
+struct arch_timer_kvm {
+	/* Is the timer enabled */
+	bool			enabled;
+
+	/* Virtual offset, restored only */
+	cycle_t			cntvoff;
+};
+
+struct arch_timer_cpu {
+	/* 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;
+
+	/* Registers: control register, timer value */
+	u32				cntv_ctl;	/* Saved/restored */
+	cycle_t				cntv_cval;	/* Saved/restored */
+};
+
+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);
+
+#endif
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index b2ace90..4b271b3 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -390,6 +390,60 @@ __kvm_hyp_code_start:
 2:
 .endm
 
+.macro save_timer_state
+	// x0: vcpu pointer
+	ldr	x2, [x0, #VCPU_KVM]
+	kern_hyp_va x2
+	ldr	w3, [x2, #KVM_TIMER_ENABLED]
+	cbz	w3, 1f
+
+	mrs	x3, cntv_ctl_el0
+	and	x3, x3, #3
+	str	w3, [x0, #VCPU_TIMER_CNTV_CTL]
+	bic	x3, x3, #1		// Clear Enable
+	msr	cntv_ctl_el0, x3
+
+	isb
+
+	mrs	x3, cntv_cval_el0
+	str	x3, [x0, #VCPU_TIMER_CNTV_CVAL]
+
+1:
+	// Allow physical timer/counter access for the host
+	mrs	x2, cnthctl_el2
+	orr	x2, x2, #3
+	msr	cnthctl_el2, x2
+
+	// Clear cntvoff for the host
+	msr	cntvoff_el2, xzr
+.endm
+
+.macro restore_timer_state
+	// x0: vcpu pointer
+	// Disallow physical timer access for the guest
+	// Physical counter access is allowed
+	mrs	x2, cnthctl_el2
+	orr	x2, x2, #1
+	bic	x2, x2, #2
+	msr	cnthctl_el2, x2
+
+	ldr	x2, [x0, #VCPU_KVM]
+	kern_hyp_va x2
+	ldr	w3, [x2, #KVM_TIMER_ENABLED]
+	cbz	w3, 1f
+
+	ldr	x3, [x2, #KVM_TIMER_CNTVOFF]
+	msr	cntvoff_el2, x3
+	ldr	x2, [x0, #VCPU_TIMER_CNTV_CVAL]
+	msr	cntv_cval_el0, x2
+	isb
+
+	ldr	w2, [x0, #VCPU_TIMER_CNTV_CTL]
+	and	x2, x2, #3
+	msr	cntv_ctl_el0, x2
+1:
+.endm
+
 __save_sysregs:
 	save_sysregs
 	ret
@@ -433,6 +487,7 @@ ENTRY(__kvm_vcpu_run)
 	activate_vm
 
 	restore_vgic_state
+	restore_timer_state
 
 	// Guest context
 	add	x2, x0, #VCPU_CONTEXT
@@ -456,6 +511,7 @@ __kvm_vcpu_return:
 	bl __save_fpsimd
 	bl __save_sysregs
 
+	save_timer_state
 	save_vgic_state
 
 	deactivate_traps
-- 
1.8.1.4