[PATCH v6 00/10] arm64: Stolen time support

Steven Price
2019-10-11T12:59:42Z

This series add support for paravirtualized time for arm64 guests and
KVM hosts following the specification in Arm's document DEN 0057A:

https://developer.arm.com/docs/den0057/a

It implements support for stolen time, allowing the guest to
identify time when it is forcibly not executing.

Note that Live Physical Time (LPT) which was previously part of the
above specification has now been removed.

Also available as a git tree:
git://linux-arm.org/linux-sp.git stolen_time/v6

Changes from v5:
https://lore.kernel.org/kvm/20191002145037.51630-1-steven.price@arm.com/
* Convert document to RST format
* Rename PV_FEATURES to PV_TIME_FEATURES to match spec
* Correct SMC number of PV_TIME_ST

Changes from v4:
https://lore.kernel.org/kvm/20190830084255.55113-1-steven.price@arm.com/
* Rebased to v5.4-rc1
* Renamed KVM_ARM_VCPU_PVTIME_SET_IPA to remove _SET as it is used for
both set/get operations
* Added kvm/arm_hypercalls.h to header-test-$(CONFIG_ARM{,64}) as it is
only buildable on arm/arm64
* Documented no-steal-acc kernel parameter

Changes from v3:
https://lore.kernel.org/lkml/20190821153656.33429-1-steven.price@arm.com/
* There's no longer a PV_TIME device, instead there are attributes on
the VCPU. This allows the stolen time structures to be places
arbitrarily by user space (subject to 64 byte alignment).
* Split documentation between information on the hypercalls and the
attributes on the VCPU
* Fixed the type of SMCCC functions to return long not int

Changes from v2:
https://lore.kernel.org/lkml/20190819140436.12207-1-steven.price@arm.com/
* Switched from using gfn_to_hva_cache to a new macro kvm_put_guest()
that can provide the single-copy atomicity required (on arm64). This
macro is added in patch 4.
* Tidied up the locking for kvm_update_stolen_time().
pagefault_disable() was unnecessary and the caller didn't need to
take kvm->srcu as the function does it itself.
* Removed struct kvm_arch_pvtime from the arm implementation, replaced
instead with inline static functions which are empty for arm.
* Fixed a few checkpatch --strict warnings.

Changes from v1:
https://lore.kernel.org/lkml/20190802145017.42543-1-steven.price@arm.com/
* Host kernel no longer allocates the stolen time structure, instead it
is allocated by user space. This means the save/restore functionality
can be removed.
* Refactored the code so arm has stub implementations and to avoid
initcall
* Rebased to pick up Documentation/{virt->virtual} change
* Bunch of typo fixes

Christoffer Dall (1):
KVM: arm/arm64: Factor out hypercall handling from PSCI code

Steven Price (9):
KVM: arm64: Document PV-time interface
KVM: arm64: Implement PV_TIME_FEATURES call
KVM: Implement kvm_put_guest()
KVM: arm64: Support stolen time reporting via shared structure
KVM: Allow kvm_device_ops to be const
KVM: arm64: Provide VCPU attributes for stolen time
arm/arm64: Provide a wrapper for SMCCC 1.1 calls
arm/arm64: Make use of the SMCCC 1.1 wrapper
arm64: Retrieve stolen time as paravirtualized guest

.../admin-guide/kernel-parameters.txt | 6 +-
Documentation/virt/kvm/arm/pvtime.rst | 77 +++++++++
Documentation/virt/kvm/devices/vcpu.txt | 14 ++
arch/arm/include/asm/kvm_host.h | 26 +++
arch/arm/kvm/Makefile | 2 +-
arch/arm/kvm/handle_exit.c | 2 +-
arch/arm/mm/proc-v7-bugs.c | 13 +-
arch/arm64/include/asm/kvm_host.h | 30 +++-
arch/arm64/include/asm/paravirt.h | 9 +-
arch/arm64/include/asm/pvclock-abi.h | 17 ++
arch/arm64/include/uapi/asm/kvm.h | 2 +
arch/arm64/kernel/cpu_errata.c | 80 ++++------
arch/arm64/kernel/paravirt.c | 148 ++++++++++++++++++
arch/arm64/kernel/time.c | 3 +
arch/arm64/kvm/Kconfig | 1 +
arch/arm64/kvm/Makefile | 2 +
arch/arm64/kvm/guest.c | 9 ++
arch/arm64/kvm/handle_exit.c | 4 +-
include/Kbuild | 2 +
include/kvm/arm_hypercalls.h | 43 +++++
include/kvm/arm_psci.h | 2 +-
include/linux/arm-smccc.h | 58 +++++++
include/linux/cpuhotplug.h | 1 +
include/linux/kvm_host.h | 26 ++-
include/linux/kvm_types.h | 2 +
include/uapi/linux/kvm.h | 2 +
virt/kvm/arm/arm.c | 11 ++
virt/kvm/arm/hypercalls.c | 68 ++++++++
virt/kvm/arm/psci.c | 84 +---------
virt/kvm/arm/pvtime.c | 124 +++++++++++++++
virt/kvm/kvm_main.c | 6 +-
31 files changed, 717 insertions(+), 157 deletions(-)
create mode 100644 Documentation/virt/kvm/arm/pvtime.rst
create mode 100644 arch/arm64/include/asm/pvclock-abi.h
create mode 100644 include/kvm/arm_hypercalls.h
create mode 100644 virt/kvm/arm/hypercalls.c
create mode 100644 virt/kvm/arm/pvtime.c

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2.20.1