[RFC PATCH v11 0/9] Enable ptp_kvm for arm64

[Jianyong Wu]

kvm ptp targets to provide high precision time sync between guest
and host in virtualization environment. Here, we enable kvm ptp
for arm64.

change log:

from v11 to v10:
        (1) rebase code on 5.7_rc2.
        (2) remove support for arm32, as kvm support for arm32 will be
removed [1]
        (3) add error report in ptp_kvm initialization.

from v10 to v9:
        (1) change code base to v5.5.
	(2) enable ptp_kvm both for arm32 and arm64.
        (3) let user choose which of virtual counter or physical counter
should return when using crosstimestamp mode of ptp_kvm for arm/arm64.
        (4) extend input argument for getcrosstimestamp API.

from v8 to v9:
        (1) move ptp_kvm.h to driver/ptp/
        (2) replace license declaration of ptp_kvm.h the same with other
header files in the same directory.

from v7 to v8:
        (1) separate adding clocksource id for arm_arch_counter as a
single patch.
        (2) update commit message for patch 4/8.
        (3) refine patch 7/8 and patch 8/8 to make them more independent.

from v6 to v7:
        (1) include the omitted clocksource_id.h in last version.
        (2) reorder the header file in patch.
        (3) refine some words in commit message to make it more impersonal.

from v5 to v6:
        (1) apply Mark's patch[4] to get SMCCC conduit.
        (2) add mechanism to recognize current clocksource by add
clocksouce_id value into struct clocksource instead of method in patch-v5.
        (3) rename kvm_arch_ptp_get_clock_fn into
kvm_arch_ptp_get_crosststamp.

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://patchwork.kernel.org/cover/11373351/

Jianyong Wu (8):
  psci: export psci conduit get helper.
  ptp: Reorganize ptp_kvm modules to make it arch-independent.
  clocksource: Add clocksource id for arm arch counter
  psci: Add hypercall service for ptp_kvm.
  ptp: arm64: Enable ptp_kvm for arm/arm64
  ptp: extend input argument for getcrosstimestamp API
  arm64: add mechanism to let user choose which counter to return
  arm64: Add kvm capability check extension for ptp_kvm

Thomas Gleixner (1):
  time: Add mechanism to recognize clocksource in time_get_snapshot

 drivers/clocksource/arm_arch_timer.c        | 33 ++++++++
 drivers/firmware/psci/psci.c                |  1 +
 drivers/net/ethernet/intel/e1000e/ptp.c     |  3 +-
 drivers/ptp/Kconfig                         |  2 +-
 drivers/ptp/Makefile                        |  1 +
 drivers/ptp/ptp_chardev.c                   |  8 +-
 drivers/ptp/ptp_kvm.h                       | 11 +++
 drivers/ptp/ptp_kvm_arm64.c                 | 53 ++++++++++++
 drivers/ptp/{ptp_kvm.c => ptp_kvm_common.c} | 85 ++++++--------------
 drivers/ptp/ptp_kvm_x86.c                   | 89 +++++++++++++++++++++
 include/linux/arm-smccc.h                   | 21 +++++
 include/linux/clocksource.h                 |  6 ++
 include/linux/clocksource_ids.h             | 12 +++
 include/linux/ptp_clock_kernel.h            |  3 +-
 include/linux/timekeeping.h                 | 12 +--
 include/uapi/linux/kvm.h                    |  1 +
 include/uapi/linux/ptp_clock.h              |  4 +-
 kernel/time/clocksource.c                   |  3 +
 kernel/time/timekeeping.c                   |  1 +
 virt/kvm/arm/arm.c                          |  1 +
 virt/kvm/arm/hypercalls.c                   | 44 +++++++++-
 21 files changed, 322 insertions(+), 72 deletions(-)
 create mode 100644 drivers/ptp/ptp_kvm.h
 create mode 100644 drivers/ptp/ptp_kvm_arm64.c
 rename drivers/ptp/{ptp_kvm.c => ptp_kvm_common.c} (60%)
 create mode 100644 drivers/ptp/ptp_kvm_x86.c
 create mode 100644 include/linux/clocksource_ids.h

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2.17.1