[RFC PATCH v5 0/6] Enable ptp_kvm for arm64

[Jianyong Wu]

kvm ptp targets to provide high precision time sync between guest
and host in virtualization environment. This patch enable kvm ptp
for arm64.
This patch set base on [1][2][3]

change log:
from v4 to v5:
        (1) remove hvc delay compensasion as it should leave to userspace.
        (2) check current clocksource in hvc call service.
        (3) expose current clocksource by adding it to
system_time_snapshot.
        (4) add helper to check if clocksource is arm_arch_counter.
        (5) rename kvm_ptp.c to ptp_kvm_common.c
from v3 to v4:
        (1) fix clocksource of ptp_kvm to arch_sys_counter.
        (2) move kvm_arch_ptp_get_clock_fn into arm_arch_timer.c
        (3) subtract cntvoff before return cycles from host.
        (4) use ktime_get_snapshot instead of getnstimeofday and
get_current_counterval to return time and counter value.
        (5) split ktime and counter into two 32-bit block respectively
to avoid Y2038-safe issue.
        (6) set time compensation to device time as half of the delay of hvc call.
        (7) add ARM_ARCH_TIMER as dependency of ptp_kvm for
arm64.
from v2 to v3:
        (1) fix some issues in commit log.
        (2) add some receivers in send list.
from v1 to v2:
        (1) move arch-specific code from arch/ to driver/ptp/
        (2) offer mechanism to inform userspace if ptp_kvm service is
available.
        (3) separate ptp_kvm code for arm64 into hypervisor part and
guest part.
	(4) add API to expose monotonic clock and counter value.
        (5) refine code: remove no necessary part and reconsitution.

[1]https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/
commit/?h=kvm/hvc&id=125ea89e4a21e2fc5235410f966a996a1a7148bf
[2]https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/
commit/?h=kvm/hvc&id=464f5a1741e5959c3e4d2be1966ae0093b4dce06
[3]https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/
commit/?h=kvm/hvc&id=6597490e005d0eeca8ed8c1c1d7b4318ee014681

Jianyong Wu (6):
  psci: Export psci_ops.conduit symbol as modules will use it.
  ptp: Reorganize ptp_kvm modules to make it arch-independent.
  timekeeping: Add clocksource to system_time_snapshot
  psci: Add hvc call service for ptp_kvm.
  ptp: arm64: Enable ptp_kvm for arm64
  kvm: arm64: Add capability check extension for ptp_kvm

 drivers/clocksource/arm_arch_timer.c        | 27 +++++++
 drivers/firmware/psci/psci.c                |  6 ++
 drivers/ptp/Kconfig                         |  2 +-
 drivers/ptp/Makefile                        |  1 +
 drivers/ptp/ptp_kvm_arm64.c                 | 54 +++++++++++++
 drivers/ptp/{ptp_kvm.c => ptp_kvm_common.c} | 77 +++++-------------
 drivers/ptp/ptp_kvm_x86.c                   | 87 +++++++++++++++++++++
 include/asm-generic/ptp_kvm.h               | 12 +++
 include/clocksource/arm_arch_timer.h        |  5 ++
 include/linux/arm-smccc.h                   | 14 +++-
 include/linux/psci.h                        |  1 +
 include/linux/timekeeping.h                 | 35 +++++----
 include/uapi/linux/kvm.h                    |  1 +
 kernel/time/timekeeping.c                   |  7 +-
 virt/kvm/arm/arm.c                          |  1 +
 virt/kvm/arm/psci.c                         | 21 +++++
 16 files changed, 270 insertions(+), 81 deletions(-)
 create mode 100644 drivers/ptp/ptp_kvm_arm64.c
 rename drivers/ptp/{ptp_kvm.c => ptp_kvm_common.c} (63%)
 create mode 100644 drivers/ptp/ptp_kvm_x86.c
 create mode 100644 include/asm-generic/ptp_kvm.h

-- 
2.17.1