[RFC PATCH v7 7/7] kvm: arm64: Add capability check extension for ptp_kvm

[Jianyong Wu]

Let userspace check if there is kvm ptp service in host.
before VMs migrate to a another host, VMM may check if this
cap is available to determine the migration behaviour.

Signed-off-by: Jianyong Wu <jianyong.wu@xxxxxxx>
Suggested-by: Marc Zyngier <maz@xxxxxxxxxx>
---
 drivers/clocksource/arm_arch_timer.c | 4 ++--
 drivers/ptp/ptp_kvm_arm64.c          | 1 -
 include/uapi/linux/kvm.h             | 1 +
 virt/kvm/arm/arm.c                   | 1 +
 4 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index b931ae94764f..e407e774ff36 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -1639,7 +1639,7 @@ TIMER_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init);
 
 #if IS_ENABLED(CONFIG_PTP_1588_CLOCK_KVM)
 #include <linux/arm-smccc.h>
-int kvm_arch_ptp_get_clock_fn(unsigned long *cycle, struct timespec64 *ts,
+int kvm_arch_ptp_get_crosststamp(unsigned long *cycle, struct timespec64 *ts,
 			      struct clocksource **cs)
 {
 	struct arm_smccc_res hvc_res;
@@ -1656,5 +1656,5 @@ int kvm_arch_ptp_get_clock_fn(unsigned long *cycle, struct timespec64 *ts,
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(kvm_arch_ptp_get_clock_fn);
+EXPORT_SYMBOL_GPL(kvm_arch_ptp_get_crosststamp);
 #endif
diff --git a/drivers/ptp/ptp_kvm_arm64.c b/drivers/ptp/ptp_kvm_arm64.c
index 7c697f20904f..f3f957117865 100644
--- a/drivers/ptp/ptp_kvm_arm64.c
+++ b/drivers/ptp/ptp_kvm_arm64.c
@@ -30,7 +30,6 @@ int kvm_arch_ptp_init(void)
 int kvm_arch_ptp_get_clock_generic(struct timespec64 *ts,
 				   struct arm_smccc_res *hvc_res)
 {
-	u64 ns;
 	ktime_t ktime_overall;
 
 	arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID,
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 2fe12b40d503..a0bff6002bd9 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -993,6 +993,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_ARM_SVE 170
 #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171
 #define KVM_CAP_ARM_PTRAUTH_GENERIC 172
+#define KVM_CAP_ARM_KVM_PTP 173
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index bd5c55916d0d..80999985160b 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -201,6 +201,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_MP_STATE:
 	case KVM_CAP_IMMEDIATE_EXIT:
 	case KVM_CAP_VCPU_EVENTS:
+	case KVM_CAP_ARM_KVM_PTP:
 		r = 1;
 		break;
 	case KVM_CAP_ARM_SET_DEVICE_ADDR:
-- 
2.17.1