[PATCH v5 4/6] psci: Add hvc call service for ptp_kvm.

[Jianyong Wu]

This patch is the base of ptp_kvm for arm64.
ptp_kvm modules will call hvc to get this service.
The service offers real time and counter cycle of host for guest.

Signed-off-by: Jianyong Wu <jianyong.wu@xxxxxxx>
---
 drivers/clocksource/arm_arch_timer.c |  5 +++++
 include/clocksource/arm_arch_timer.h |  5 +++++
 include/linux/arm-smccc.h            | 12 ++++++++++++
 virt/kvm/arm/psci.c                  | 21 +++++++++++++++++++++
 4 files changed, 43 insertions(+)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 07e57a49d1e8..3597f1f27b10 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -1634,3 +1634,8 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table)
 }
 TIMER_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init);
 #endif
+
+bool is_arm_arch_counter(void *cs)
+{
+	return (struct clocksource *)cs == &clocksource_counter;
+}
diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h
index 1d68d5613dae..5895d10a6148 100644
--- a/include/clocksource/arm_arch_timer.h
+++ b/include/clocksource/arm_arch_timer.h
@@ -86,6 +86,7 @@ extern u32 arch_timer_get_rate(void);
 extern u64 (*arch_timer_read_counter)(void);
 extern struct arch_timer_kvm_info *arch_timer_get_kvm_info(void);
 extern bool arch_timer_evtstrm_available(void);
+extern bool is_arm_arch_counter(void *);
 
 #else
 
@@ -104,6 +105,10 @@ static inline bool arch_timer_evtstrm_available(void)
 	return false;
 }
 
+bool is_arm_arch_counter(void *unuse)
+{
+	return false;
+}
 #endif
 
 #endif
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index a6e4d3e3d10a..bc0cdad10f35 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -94,6 +94,7 @@
 
 /* KVM "vendor specific" services */
 #define ARM_SMCCC_KVM_FUNC_FEATURES		0
+#define ARM_SMCCC_KVM_PTP			1
 #define ARM_SMCCC_KVM_FUNC_FEATURES_2		127
 #define ARM_SMCCC_KVM_NUM_FUNCS			128
 
@@ -103,6 +104,17 @@
 			   ARM_SMCCC_OWNER_VENDOR_HYP,			\
 			   ARM_SMCCC_KVM_FUNC_FEATURES)
 
+/*
+ * This ID used for virtual ptp kvm clock and it will pass second value
+ * and nanosecond value of host real time and system counter by vcpu
+ * register to guest.
+ */
+#define ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID				\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_32,				\
+			   ARM_SMCCC_OWNER_VENDOR_HYP,			\
+			   ARM_SMCCC_KVM_PTP)
+
 #ifndef __ASSEMBLY__
 
 #include <linux/linkage.h>
diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
index 0debf49bf259..f0ef388ebbfa 100644
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -392,6 +392,8 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 	u32 func_id = smccc_get_function(vcpu);
 	u32 val[4] = {};
 	u32 option;
+	u64 cycles;
+	struct system_time_snapshot systime_snapshot;
 
 	val[0] = SMCCC_RET_NOT_SUPPORTED;
 
@@ -431,6 +433,25 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 	case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
 		val[0] = BIT(ARM_SMCCC_KVM_FUNC_FEATURES);
 		break;
+	/*
+	 * This will used for virtual ptp kvm clock. three
+	 * values will be passed back.
+	 * reg0 stores high 32-bit host ktime;
+	 * reg1 stores low 32-bit host ktime;
+	 * reg2 stores high 32-bit difference of host cycles and cntvoff;
+	 * reg3 stores low 32-bit difference of host cycles and cntvoff.
+	 */
+	case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
+		ktime_get_snapshot(&systime_snapshot);
+		if (!is_arm_arch_counter(systime_snapshot.sc.cs))
+			return kvm_psci_call(vcpu);
+		val[0] = systime_snapshot.real >> 32;
+		val[1] = systime_snapshot.real << 32 >> 32;
+		cycles = systime_snapshot.sc.cycles -
+			 vcpu_vtimer(vcpu)->cntvoff;
+		val[2] = cycles >> 32;
+		val[3] = cycles << 32 >> 32;
+		break;
 	default:
 		return kvm_psci_call(vcpu);
 	}
-- 
2.17.1