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[v4,0/6] hw/arm/virt: Introduce kvm-steal-time

Message ID 20201001061718.101915-1-drjones@redhat.com
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Series hw/arm/virt: Introduce kvm-steal-time | expand

Message

Andrew Jones Oct. 1, 2020, 6:17 a.m. UTC 
v4:
  - Rebased to latest master
  - Added an official linux header synch patch, replacing the
    hack patch used in v3
  - Added a patch to restore the arm-cpu-features test for AArch64
    that got lost in the meson shuffle
  - Added Eric's R-b's

v3:
  - Rebased: 5.2 machine type and kvm32 drop now included
  - Switched to using new KVM cap that has been merged upstream
  - Picked up some r-b's and some of Eric's comments from v2

v2: https://www.mail-archive.com/qemu-devel@nongnu.org/msg727588.html

KVM supports the ability to publish the amount of time that VCPUs
were runnable, but not running due to other host threads running
instead, to the guest. The guest scheduler may use that information
when making decisions and the guest may expose it to its userspace
(Linux publishes this information in /proc/stat). This feature is
called "steal time" as it represents the amount of time stolen from
a guest by scheduling out its VCPUs. To enable this feature KVM
userspace must provide a memory region that will be used to publish
the information to the guest. The memory region is typical migratable
region. The GPA of the region is given to KVM through a VCPU device
ioctl interface. This feature is only available for 64-bit guests
per the Arm PVTIME specification (DEN0057A).

This series provides the QEMU support of this feature. It will
be enabled by default for 5.2 machine types and later, but may
be disabled with a new CPU property "kvm-steal-time".

Thanks,
drew


Andrew Jones (6):
  linux headers: sync to 5.9-rc7
  target/arm/kvm: Make uncalled stubs explicitly unreachable
  hw/arm/virt: Move post cpu realize check into its own function
  hw/arm/virt: Move kvm pmu setup to virt_cpu_post_init
  tests/qtest: Restore aarch64 arm-cpu-features test
  hw/arm/virt: Implement kvm-steal-time

 docs/system/arm/cpu-features.rst |  11 ++++
 hw/arm/virt.c                    | 110 ++++++++++++++++++++++---------
 include/hw/arm/virt.h            |   5 ++
 linux-headers/linux/kvm.h        |   6 +-
 target/arm/cpu.c                 |   8 +++
 target/arm/cpu.h                 |   4 ++
 target/arm/kvm.c                 |  16 +++++
 target/arm/kvm64.c               |  64 ++++++++++++++++--
 target/arm/kvm_arm.h             |  94 ++++++++++++++++++++------
 target/arm/monitor.c             |   2 +-
 tests/qtest/arm-cpu-features.c   |  25 +++++--
 tests/qtest/meson.build          |   3 +-
 12 files changed, 286 insertions(+), 62 deletions(-)

Comments

Peter Maydell Oct. 8, 2020, 1:01 p.m. UTC | #1 
On Thu, 1 Oct 2020 at 07:17, Andrew Jones <drjones@redhat.com> wrote:
>

> v4:

>   - Rebased to latest master

>   - Added an official linux header synch patch, replacing the

>     hack patch used in v3

>   - Added a patch to restore the arm-cpu-features test for AArch64

>     that got lost in the meson shuffle

>   - Added Eric's R-b's

>

> v3:

>   - Rebased: 5.2 machine type and kvm32 drop now included

>   - Switched to using new KVM cap that has been merged upstream

>   - Picked up some r-b's and some of Eric's comments from v2

>

> v2: https://www.mail-archive.com/qemu-devel@nongnu.org/msg727588.html




Applied to target-arm.next, thanks.

-- PMM