It relies on transferring the wall clock and counter value from the
host to the guest using a KVM-specific hypercall.
-* ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID: 0x86000001
+``ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID``
+----------------------------------------
-This hypercall uses the SMC32/HVC32 calling convention:
+Retrieve current time information for the specific counter. There are no
+endianness restrictions.
-ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID
- ============== ======== =====================================
- Function ID: (uint32) 0x86000001
- Arguments: (uint32) KVM_PTP_VIRT_COUNTER(0)
- KVM_PTP_PHYS_COUNTER(1)
- Return Values: (int32) NOT_SUPPORTED(-1) on error, or
- (uint32) Upper 32 bits of wall clock time (r0)
- (uint32) Lower 32 bits of wall clock time (r1)
- (uint32) Upper 32 bits of counter (r2)
- (uint32) Lower 32 bits of counter (r3)
- Endianness: No Restrictions.
- ============== ======== =====================================
++---------------------+-------------------------------------------------------+
+| Presence: | Optional |
++---------------------+-------------------------------------------------------+
+| Calling convention: | HVC32 |
++---------------------+----------+--------------------------------------------+
+| Function ID: | (uint32) | 0x86000001 |
++---------------------+----------+----+---------------------------------------+
+| Arguments: | (uint32) | R1 | ``KVM_PTP_VIRT_COUNTER (0)`` |
+| | | +---------------------------------------+
+| | | | ``KVM_PTP_PHYS_COUNTER (1)`` |
++---------------------+----------+----+---------------------------------------+
+| Return Values: | (int32) | R0 | ``NOT_SUPPORTED (-1)`` on error, else |
+| | | | upper 32 bits of wall clock time |
+| +----------+----+---------------------------------------+
+| | (uint32) | R1 | Lower 32 bits of wall clock time |
+| +----------+----+---------------------------------------+
+| | (uint32) | R2 | Upper 32 bits of counter |
+| +----------+----+---------------------------------------+
+| | (uint32) | R3 | Lower 32 bits of counter |
++---------------------+----------+----+---------------------------------------+