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 <[email protected]>
---
 include/linux/arm-smccc.h | 12 ++++++++++++
 virt/kvm/arm/psci.c       | 22 ++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 6f82c87308ed..aafb6bac167d 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..682d892d6717 100644
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -9,6 +9,7 @@
 #include <linux/kvm_host.h>
 #include <linux/uaccess.h>
 #include <linux/wait.h>
+#include <linux/clocksource_ids.h>
 
 #include <asm/cputype.h>
 #include <asm/kvm_emulate.h>
@@ -389,6 +390,8 @@ static int kvm_psci_call(struct kvm_vcpu *vcpu)
 
 int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 {
+       struct system_time_snapshot systime_snapshot;
+       u64 cycles;
        u32 func_id = smccc_get_function(vcpu);
        u32 val[4] = {};
        u32 option;
@@ -431,6 +434,25 @@ 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 (systime_snapshot.cs_id != CSID_ARM_ARCH_COUNTER)
+                       return kvm_psci_call(vcpu);
+               val[0] = systime_snapshot.real >> 32;
+               val[1] = systime_snapshot.real << 32 >> 32;
+               cycles = systime_snapshot.cycles -
+                        vcpu_vtimer(vcpu)->cntvoff;
+               val[2] = cycles >> 32;
+               val[3] = cycles << 32 >> 32;
+               break;
        default:
                return kvm_psci_call(vcpu);
        }
-- 
2.17.1

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