[PATCH v5 10/12] virt: geniezone: Add virtual timer support

[Yi-De Wu <yi-de.wu@mediatek.com>]

From: "Willix Yeh" <chi-shen.yeh@mediatek.com>

Implement vtimer migration handler.
- Using hrtimer for guest vtimer migration
- Identify migrate flag to do register hrtimer

Signed-off-by: Willix Yeh <chi-shen.yeh@mediatek.com>
Signed-off-by: Liju Chen <liju-clr.chen@mediatek.com>
Signed-off-by: Yi-De Wu <yi-de.wu@mediatek.com>
---
 arch/arm64/geniezone/Makefile           |  2 +-
 arch/arm64/geniezone/driver.c           | 26 ++++++++
 arch/arm64/geniezone/gzvm_arch_common.h | 18 ++++++
 arch/arm64/geniezone/vcpu.c             | 83 ++++++++++++++++++++++---
 arch/arm64/geniezone/vgic.c             | 16 +++++
 drivers/virt/geniezone/gzvm_main.c      |  5 ++
 drivers/virt/geniezone/gzvm_vcpu.c      |  4 +-
 include/linux/gzvm_drv.h                |  8 ++-
 8 files changed, 149 insertions(+), 13 deletions(-)
 create mode 100644 arch/arm64/geniezone/driver.c

diff --git a/arch/arm64/geniezone/Makefile b/arch/arm64/geniezone/Makefile
index 0e4f1087f9de..59e04cc0a000 100644
--- a/arch/arm64/geniezone/Makefile
+++ b/arch/arm64/geniezone/Makefile
@@ -4,6 +4,6 @@
 #
 include $(srctree)/drivers/virt/geniezone/Makefile
 
-gzvm-y += vm.o vcpu.o vgic.o
+gzvm-y += vm.o vcpu.o vgic.o driver.o
 
 obj-$(CONFIG_MTK_GZVM) += gzvm.o
diff --git a/arch/arm64/geniezone/driver.c b/arch/arm64/geniezone/driver.c
new file mode 100644
index 000000000000..fb6ec0fed4d8
--- /dev/null
+++ b/arch/arm64/geniezone/driver.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ */
+
+#include <linux/clocksource.h>
+#include <linux/gzvm_drv.h>
+#include "gzvm_arch_common.h"
+
+struct timecycle clock_scale_factor;
+
+int gzvm_arch_drv_init(void)
+{
+	/* clock_scale_factor init mult shift */
+	clocks_calc_mult_shift(&clock_scale_factor.mult,
+			       &clock_scale_factor.shift,
+			       arch_timer_get_cntfrq(),
+			       NSEC_PER_SEC,
+			       10);
+
+	return 0;
+}
+
+void gzvm_arch_drv_exit(void)
+{
+}
diff --git a/arch/arm64/geniezone/gzvm_arch_common.h b/arch/arm64/geniezone/gzvm_arch_common.h
index 82d2c44e819b..e51310be2376 100644
--- a/arch/arm64/geniezone/gzvm_arch_common.h
+++ b/arch/arm64/geniezone/gzvm_arch_common.h
@@ -51,6 +51,13 @@ enum {
 
 #define GIC_V3_NR_LRS			16
 
+struct timecycle {
+	u32 mult;
+	u32 shift;
+};
+
+extern struct timecycle clock_scale_factor;
+
 /**
  * gzvm_hypcall_wrapper() - the wrapper for hvc calls
  * @a0-a7: arguments passed in registers 0 to 7
@@ -84,14 +91,22 @@ static inline u16 get_vcpuid_from_tuple(unsigned int tuple)
  * @__pad: add an explicit '__u32 __pad;' in the middle to make it clear
  *         what the actual layout is.
  * @lr: The array of LRs(list registers).
+ * @vtimer_delay: The remaining time until the next tick of guest VM.
+ * @vtimer_migrate: The switch flag used for guest VM to do vtimer migration or not.
+ * @vtimer_irq_num: vtimer irq number.
  *
  * - Keep the same layout of hypervisor data struct.
  * - Sync list registers back for acking virtual device interrupt status.
+ * - Sync timer registers back for migrating timer to host's hwtimer to keep
+ *   timer working in background.
  */
 struct gzvm_vcpu_hwstate {
 	__le32 nr_lrs;
 	__le32 __pad;
 	__le64 lr[GIC_V3_NR_LRS];
+	__le64 vtimer_delay;
+	__le32 vtimer_migrate;
+	__le32 vtimer_irq_num;
 };
 
 static inline unsigned int
@@ -107,4 +122,7 @@ disassemble_vm_vcpu_tuple(unsigned int tuple, u16 *vmid, u16 *vcpuid)
 	*vcpuid = get_vcpuid_from_tuple(tuple);
 }
 
+int gzvm_vgic_inject_ppi(struct gzvm *gzvm, unsigned int vcpu_idx,
+			 u32 irq, bool level);
+
 #endif /* __GZVM_ARCH_COMMON_H__ */
diff --git a/arch/arm64/geniezone/vcpu.c b/arch/arm64/geniezone/vcpu.c
index 95681fd66656..b26bbadf10a0 100644
--- a/arch/arm64/geniezone/vcpu.c
+++ b/arch/arm64/geniezone/vcpu.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/arm-smccc.h>
+#include <linux/clocksource.h>
 #include <linux/err.h>
 #include <linux/uaccess.h>
 
@@ -40,25 +41,91 @@ int gzvm_arch_vcpu_update_one_reg(struct gzvm_vcpu *vcpu, __u64 reg_id,
 	return ret;
 }
 
+static void clear_migrate_state(struct gzvm_vcpu *vcpu)
+{
+	vcpu->hwstate->vtimer_migrate = 0;
+	vcpu->hwstate->vtimer_delay = 0;
+}
+
+static u64 gzvm_mtimer_delay_time(u64 delay)
+{
+	u64 ns;
+
+	ns = clocksource_cyc2ns(delay, clock_scale_factor.mult,
+				clock_scale_factor.shift);
+
+	return ns;
+}
+
+static void gzvm_mtimer_release(struct gzvm_vcpu *vcpu)
+{
+	hrtimer_cancel(&vcpu->gzvm_mtimer);
+
+	clear_migrate_state(vcpu);
+}
+
+static void gzvm_mtimer_catch(struct hrtimer *hrt, u64 delay)
+{
+	u64 ns;
+
+	ns = gzvm_mtimer_delay_time(delay);
+	hrtimer_start(hrt, ktime_add_ns(ktime_get(), ns), HRTIMER_MODE_ABS_HARD);
+}
+
+static void mtimer_irq_forward(struct gzvm_vcpu *vcpu)
+{
+	gzvm_vgic_inject_ppi(vcpu->gzvm, vcpu->vcpuid,
+			     vcpu->hwstate->vtimer_irq_num, 1);
+}
+
+static enum hrtimer_restart gzvm_mtimer_expire(struct hrtimer *hrt)
+{
+	struct gzvm_vcpu *vcpu;
+
+	vcpu = container_of(hrt, struct gzvm_vcpu, gzvm_mtimer);
+
+	mtimer_irq_forward(vcpu);
+
+	return HRTIMER_NORESTART;
+}
+
+static void vtimer_init(struct gzvm_vcpu *vcpu)
+{
+	/* gzvm_mtimer init based on hrtimer */
+	hrtimer_init(&vcpu->gzvm_mtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
+	vcpu->gzvm_mtimer.function = gzvm_mtimer_expire;
+}
+
 int gzvm_arch_vcpu_run(struct gzvm_vcpu *vcpu, __u64 *exit_reason)
 {
 	struct arm_smccc_res res;
 	unsigned long a1;
 	int ret;
 
+	/* hrtimer cancel and clear migrate state */
+	if (vcpu->hwstate->vtimer_migrate)
+		gzvm_mtimer_release(vcpu);
+
 	a1 = assemble_vm_vcpu_tuple(vcpu->gzvm->vm_id, vcpu->vcpuid);
 	ret = gzvm_hypcall_wrapper(MT_HVC_GZVM_RUN, a1, 0, 0, 0, 0, 0,
 				   0, &res);
+
+	/* hrtimer register if migration needed */
+	if (vcpu->hwstate->vtimer_migrate)
+		gzvm_mtimer_catch(&vcpu->gzvm_mtimer, vcpu->hwstate->vtimer_delay);
+
 	*exit_reason = res.a1;
 	return ret;
 }
 
-int gzvm_arch_destroy_vcpu(u16 vm_id, int vcpuid)
+int gzvm_arch_destroy_vcpu(struct gzvm_vcpu *vcpu)
 {
 	struct arm_smccc_res res;
 	unsigned long a1;
 
-	a1 = assemble_vm_vcpu_tuple(vm_id, vcpuid);
+	hrtimer_cancel(&vcpu->gzvm_mtimer);
+
+	a1 = assemble_vm_vcpu_tuple(vcpu->gzvm->vm_id, vcpu->vcpuid);
 	gzvm_hypcall_wrapper(MT_HVC_GZVM_DESTROY_VCPU, a1, 0, 0, 0, 0, 0, 0,
 			     &res);
 
@@ -67,20 +134,20 @@ int gzvm_arch_destroy_vcpu(u16 vm_id, int vcpuid)
 
 /**
  * gzvm_arch_create_vcpu() - Call smc to gz hypervisor to create vcpu
- * @vm_id: vm id
- * @vcpuid: vcpu id
- * @run: Virtual address of vcpu->run
+ * @vcpu: Pointer to struct gzvm_vcpu
  *
  * Return: The wrapper helps caller to convert geniezone errno to Linux errno.
  */
-int gzvm_arch_create_vcpu(u16 vm_id, int vcpuid, void *run)
+int gzvm_arch_create_vcpu(struct gzvm_vcpu *vcpu)
 {
 	struct arm_smccc_res res;
 	unsigned long a1, a2;
 	int ret;
 
-	a1 = assemble_vm_vcpu_tuple(vm_id, vcpuid);
-	a2 = (__u64)virt_to_phys(run);
+	vtimer_init(vcpu);
+
+	a1 = assemble_vm_vcpu_tuple(vcpu->gzvm->vm_id, vcpu->vcpuid);
+	a2 = (__u64)virt_to_phys(vcpu->run);
 	ret = gzvm_hypcall_wrapper(MT_HVC_GZVM_CREATE_VCPU, a1, a2, 0, 0, 0, 0,
 				   0, &res);
 
diff --git a/arch/arm64/geniezone/vgic.c b/arch/arm64/geniezone/vgic.c
index 3746e0c9e247..e24728997b57 100644
--- a/arch/arm64/geniezone/vgic.c
+++ b/arch/arm64/geniezone/vgic.c
@@ -91,6 +91,22 @@ static int gzvm_vgic_inject_spi(struct gzvm *gzvm, unsigned int vcpu_idx,
 				    level);
 }
 
+/**
+ * gzvm_vgic_inject_ppi() - Inject virtual ppi interrupt
+ * @gzvm: Pointer to struct gzvm
+ * @vcpu_idx: vcpu index
+ * @irq: This is spi interrupt number (starts from 0 instead of 32)
+ * @level: 1 if true else 0
+ *
+ * Return:
+ * * 0 if succeed else other negative values indicating each errors
+ */
+int gzvm_vgic_inject_ppi(struct gzvm *gzvm, unsigned int vcpu_idx,
+			 u32 irq, bool level)
+{
+	return gzvm_vgic_inject_irq(gzvm, 0, GZVM_IRQ_TYPE_PPI, irq, level);
+}
+
 int gzvm_arch_create_device(u16 vm_id, struct gzvm_create_device *gzvm_dev)
 {
 	struct arm_smccc_res res;
diff --git a/drivers/virt/geniezone/gzvm_main.c b/drivers/virt/geniezone/gzvm_main.c
index d4d5d75d3660..a4c235f3ff01 100644
--- a/drivers/virt/geniezone/gzvm_main.c
+++ b/drivers/virt/geniezone/gzvm_main.c
@@ -106,6 +106,10 @@ static int gzvm_drv_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
+	ret = gzvm_arch_drv_init();
+	if (ret)
+		return ret;
+
 	ret = misc_register(&gzvm_dev);
 	if (ret)
 		return ret;
@@ -121,6 +125,7 @@ static int gzvm_drv_remove(struct platform_device *pdev)
 	gzvm_drv_irqfd_exit();
 	gzvm_destroy_all_vms();
 	misc_deregister(&gzvm_dev);
+	gzvm_arch_drv_exit();
 	return 0;
 }
 
diff --git a/drivers/virt/geniezone/gzvm_vcpu.c b/drivers/virt/geniezone/gzvm_vcpu.c
index 72bd122a8be7..8dac8ba4c0cf 100644
--- a/drivers/virt/geniezone/gzvm_vcpu.c
+++ b/drivers/virt/geniezone/gzvm_vcpu.c
@@ -188,7 +188,7 @@ static void gzvm_destroy_vcpu(struct gzvm_vcpu *vcpu)
 	if (!vcpu)
 		return;
 
-	gzvm_arch_destroy_vcpu(vcpu->gzvm->vm_id, vcpu->vcpuid);
+	gzvm_arch_destroy_vcpu(vcpu);
 	/* clean guest's data */
 	memset(vcpu->run, 0, GZVM_VCPU_RUN_MAP_SIZE);
 	free_pages_exact(vcpu->run, GZVM_VCPU_RUN_MAP_SIZE);
@@ -257,7 +257,7 @@ int gzvm_vm_ioctl_create_vcpu(struct gzvm *gzvm, u32 cpuid)
 	vcpu->gzvm = gzvm;
 	mutex_init(&vcpu->lock);
 
-	ret = gzvm_arch_create_vcpu(gzvm->vm_id, vcpu->vcpuid, vcpu->run);
+	ret = gzvm_arch_create_vcpu(vcpu);
 	if (ret < 0)
 		goto free_vcpu_run;
 
diff --git a/include/linux/gzvm_drv.h b/include/linux/gzvm_drv.h
index 7bc00218dce6..e5b21ac9215b 100644
--- a/include/linux/gzvm_drv.h
+++ b/include/linux/gzvm_drv.h
@@ -6,6 +6,7 @@
 #ifndef __GZVM_DRV_H__
 #define __GZVM_DRV_H__
 
+#include <asm/arch_timer.h>
 #include <linux/eventfd.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
@@ -71,6 +72,7 @@ struct gzvm_vcpu {
 	struct mutex lock;
 	struct gzvm_vcpu_run *run;
 	struct gzvm_vcpu_hwstate *hwstate;
+	struct hrtimer gzvm_mtimer;
 };
 
 struct gzvm {
@@ -125,10 +127,12 @@ u64 gzvm_hva_to_pa_arch(u64 hva);
 int gzvm_vm_ioctl_create_vcpu(struct gzvm *gzvm, u32 cpuid);
 int gzvm_arch_vcpu_update_one_reg(struct gzvm_vcpu *vcpu, __u64 reg_id,
 				  bool is_write, __u64 *data);
-int gzvm_arch_create_vcpu(u16 vm_id, int vcpuid, void *run);
+int gzvm_arch_create_vcpu(struct gzvm_vcpu *vcpu);
 int gzvm_arch_vcpu_run(struct gzvm_vcpu *vcpu, __u64 *exit_reason);
-int gzvm_arch_destroy_vcpu(u16 vm_id, int vcpuid);
+int gzvm_arch_destroy_vcpu(struct gzvm_vcpu *vcpu);
 int gzvm_arch_inform_exit(u16 vm_id);
+int gzvm_arch_drv_init(void);
+void gzvm_arch_drv_exit(void);
 
 int gzvm_arch_create_device(u16 vm_id, struct gzvm_create_device *gzvm_dev);
 int gzvm_arch_inject_irq(struct gzvm *gzvm, unsigned int vcpu_idx,
-- 
2.18.0