RE: [RFC PATCH 00/12] hw/arm/virt: Introduce cpu and cache topology support

[Zengtao (B)]

Cc valentin

> -----Original Message-----
> From: Qemu-devel
> [mailto:qemu-devel-bounces+prime.zeng=hisilicon.com@nongnu.org]
> On Behalf Of Ying Fang
> Sent: Thursday, September 17, 2020 11:20 AM
> To: qemu-devel@nongnu.org
> Cc: peter.maydell@linaro.org; drjones@redhat.com; Zhanghailiang;
> Chenzhendong (alex); shannon.zhaosl@gmail.com;
> qemu-arm@nongnu.org; alistair.francis@wdc.com; fangying;
> imammedo@redhat.com
> Subject: [RFC PATCH 00/12] hw/arm/virt: Introduce cpu and cache
> topology support
> 
> An accurate cpu topology may help improve the cpu scheduler's
> decision
> making when dealing with multi-core system. So cpu topology
> description
> is helpful to provide guest with the right view. Cpu cache information
> may
> also have slight impact on the sched domain, and even userspace
> software
> may check the cpu cache information to do some optimizations. Thus
> this patch
> series is posted to provide cpu and cache topology support for arm.
> 
> To make the cpu topology consistent with MPIDR, an vcpu ioctl

For aarch64, the cpu topology don't depends on the MPDIR.
See https://patchwork.kernel.org/patch/11744387/ 

> KVM_ARM_SET_MP_AFFINITY is introduced so that userspace can set
> MPIDR
> according to the topology specified [1]. To describe the cpu topology
> both fdt and ACPI are supported. To describe the cpu cache
> information,
> a default cache hierarchy is given and can be made configurable later.
> The cpu topology is built according to processor hierarchy node
> structure.
> The cpu cache information is built according to cache type structure.
> 
> This patch series is partially based on the patches posted by Andrew
> Jone
> years ago [2], I jumped in on it since some OS vendor cooperative
> partners
> are eager for it. Thanks for Andrew's contribution. Please feel free to
> reply
> to me if there is anything improper.
> 
> [1] https://patchwork.kernel.org/cover/11781317
> [2]
> https://patchwork.ozlabs.org/project/qemu-devel/cover/2018070412
> 4923.32483-1-drjones@redhat.com
> 
> Andrew Jones (2):
>   device_tree: add qemu_fdt_add_path
>   hw/arm/virt: DT: add cpu-map
> 
> Ying Fang (10):
>   linux headers: Update linux header with
> KVM_ARM_SET_MP_AFFINITY
>   target/arm/kvm64: make MPIDR consistent with CPU Topology
>   target/arm/kvm32: make MPIDR consistent with CPU Topology
>   hw/arm/virt-acpi-build: distinguish possible and present cpus
>   hw/acpi/aml-build: add processor hierarchy node structure
>   hw/arm/virt-acpi-build: add PPTT table
>   target/arm/cpu: Add CPU cache description for arm
>   hw/arm/virt: add fdt cache information
>   hw/acpi/aml-build: build ACPI CPU cache topology information
>   hw/arm/virt-acpi-build: Enable CPU cache topology
> 
>  device_tree.c                |  24 +++++++
>  hw/acpi/aml-build.c          |  68 +++++++++++++++++++
>  hw/arm/virt-acpi-build.c     |  99
> +++++++++++++++++++++++++--
>  hw/arm/virt.c                | 128
> ++++++++++++++++++++++++++++++++++-
>  include/hw/acpi/acpi-defs.h  |  14 ++++
>  include/hw/acpi/aml-build.h  |  11 +++
>  include/hw/arm/virt.h        |   1 +
>  include/sysemu/device_tree.h |   1 +
>  linux-headers/linux/kvm.h    |   3 +
>  target/arm/cpu.c             |  42 ++++++++++++
>  target/arm/cpu.h             |  27 ++++++++
>  target/arm/kvm32.c           |  46 ++++++++++---
>  target/arm/kvm64.c           |  46 ++++++++++---
>  13 files changed, 488 insertions(+), 22 deletions(-)
> 
> --
> 2.23.0
>