Re: [PATCH v3 0/5] hw/arm/virt: Introduce kvm-steal-time

[Andrew Jones]

On Tue, Sep 29, 2020 at 04:47:33PM +0200, Andrew Jones wrote:
> 
> Hi Peter, Eric, and other interested parties,
> 
> Here's a gentle ping for reviewers.

Thanks for the review Eric! I'll send a Linux header update patch and a
rebase of this series with R-b's.

drew

> 
> Thanks,
> drew
> 
> On Wed, Sep 16, 2020 at 11:26:15AM +0200, Andrew Jones wrote:
> > Previous posting:
> > https://www.mail-archive.com/qemu-devel@nongnu.org/msg727588.html
> > 
> > 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
> > 
> > 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 (5):
> >   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
> >   DO NOT MERGE: HACK: Add steal time KVM cap to kvm.h
> >   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        |   1 +
> >  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 +++++--
> >  11 files changed, 281 insertions(+), 59 deletions(-)
> > 
> > -- 
> > 2.26.2
> > 
> 
>