mbox series

[v5,00/14] Nested PAPR API (KVM on PowerVM)

Message ID 20240308111940.1617660-1-harshpb@linux.ibm.com
Headers show
Series Nested PAPR API (KVM on PowerVM) | expand

Message

Harsh Prateek Bora March 8, 2024, 11:19 a.m. UTC 
There is an existing Nested-HV API to enable nested guests on powernv
machines. However, that is not supported on pseries/PowerVM LPARs.
This patch series implements required hcall interfaces to enable nested
guests with KVM on PowerVM.
Unlike Nested-HV, with this API, entire L2 state is retained by L0
during guest entry/exit and uses pre-defined Guest State Buffer (GSB)
format to communicate guest state between L1 and L2 via L0.

L0 here refers to the phyp/PowerVM, or launching a Qemu TCG L0 with the
newly introduced option cap-nested-papr=true.
L1 refers to the LPAR host on PowerVM or Linux booted on Qemu TCG with
above mentioned option cap-nested-papr=true.
L2 refers to nested guest running on top of L1 using KVM.
No SW changes needed for Qemu running in L1 Linux as well as L2 Kernel.

Linux Kernel side support is already merged upstream:
---
commit 19d31c5f115754c369c0995df47479c384757f82
Author: Jordan Niethe <jniethe5@gmail.com>
Date:   Thu Sep 14 13:05:59 2023 +1000

    KVM: PPC: Add support for nestedv2 guests
---
For more details, documentation can be referred in either of patch
series.

There are scripts available to assist in setting up an environment for
testing nested guests at https://github.com/iamjpn/kvm-powervm-test

A tree with this series is available at:
https://github.com/planetharsh/qemu/tree/upstream-0305-v5

Thanks to Michael Neuling, Shivaprasad Bhat, Amit Machhiwal, Kautuk
Consul, Vaibhav Jain and Jordan Niethe.

Changelog:
v5: addressed review comments from Nick on v4
v4: https://lore.kernel.org/qemu-devel/20240220083609.748325-1-harshpb@linux.ibm.com/
v3: https://lore.kernel.org/qemu-devel/20240118052438.1475437-1-harshpb@linux.ibm.com/
v2: https://lore.kernel.org/qemu-devel/20231012104951.194876-1-harshpb@linux.ibm.com/
v1: https://lore.kernel.org/qemu-devel/20230906043333.448244-1-harshpb@linux.ibm.com/

Harsh Prateek Bora (14):
  spapr: nested: register nested-hv api hcalls only for cap-nested-hv
  spapr: nested: move nested part of spapr_get_pate into spapr_nested.c
  spapr: nested: Introduce SpaprMachineStateNested to store related
    info.
  spapr: nested: keep nested-hv related code restricted to its API.
  spapr: nested: Document Nested PAPR API
  spapr: nested: Introduce H_GUEST_[GET|SET]_CAPABILITIES hcalls.
  spapr: nested: Introduce H_GUEST_[CREATE|DELETE] hcalls.
  spapr: nested: Introduce H_GUEST_CREATE_VCPU hcall.
  spapr: nested: Extend nested_ppc_state for nested PAPR API
  spapr: nested: Initialize the GSB elements lookup table.
  spapr: nested: Introduce H_GUEST_[GET|SET]_STATE hcalls.
  spapr: nested: Use correct source for parttbl info for nested PAPR
    API.
  spapr: nested: Introduce H_GUEST_RUN_VCPU hcall.
  spapr: nested: Introduce cap-nested-papr for Nested PAPR API

 docs/devel/nested-papr.txt    |  119 +++
 include/hw/ppc/spapr.h        |   27 +-
 include/hw/ppc/spapr_nested.h |  428 ++++++++-
 target/ppc/cpu.h              |    4 +
 hw/ppc/ppc.c                  |   10 +
 hw/ppc/spapr.c                |   35 +-
 hw/ppc/spapr_caps.c           |   62 ++
 hw/ppc/spapr_hcall.c          |   24 +-
 hw/ppc/spapr_nested.c         | 1550 ++++++++++++++++++++++++++++++++-
 9 files changed, 2204 insertions(+), 55 deletions(-)
 create mode 100644 docs/devel/nested-papr.txt

Comments

Nicholas Piggin March 12, 2024, 5:52 a.m. UTC | #1 
On Fri Mar 8, 2024 at 9:19 PM AEST, Harsh Prateek Bora wrote:
> There is an existing Nested-HV API to enable nested guests on powernv
> machines. However, that is not supported on pseries/PowerVM LPARs.
> This patch series implements required hcall interfaces to enable nested
> guests with KVM on PowerVM.
> Unlike Nested-HV, with this API, entire L2 state is retained by L0
> during guest entry/exit and uses pre-defined Guest State Buffer (GSB)
> format to communicate guest state between L1 and L2 via L0.
>
> L0 here refers to the phyp/PowerVM, or launching a Qemu TCG L0 with the
> newly introduced option cap-nested-papr=true.
> L1 refers to the LPAR host on PowerVM or Linux booted on Qemu TCG with
> above mentioned option cap-nested-papr=true.
> L2 refers to nested guest running on top of L1 using KVM.
> No SW changes needed for Qemu running in L1 Linux as well as L2 Kernel.
>
> Linux Kernel side support is already merged upstream:

This is all looking pretty good to me now. Considering it's quite
self-contained and adding a new feature, I think it's good to
merge.

I would like to have an avocado test for it, but the avocado
framework has a bug that's causing issues with the ppc hv test,
and we might have to move to a new host kernel with the KVM
support merged. I can take a look at that, I think we can add
new tests after soft-freeze.

Thanks,
Nick

> ---
> commit 19d31c5f115754c369c0995df47479c384757f82
> Author: Jordan Niethe <jniethe5@gmail.com>
> Date:   Thu Sep 14 13:05:59 2023 +1000
>
>     KVM: PPC: Add support for nestedv2 guests
> ---
> For more details, documentation can be referred in either of patch
> series.
>
> There are scripts available to assist in setting up an environment for
> testing nested guests at https://github.com/iamjpn/kvm-powervm-test
>
> A tree with this series is available at:
> https://github.com/planetharsh/qemu/tree/upstream-0305-v5
>
> Thanks to Michael Neuling, Shivaprasad Bhat, Amit Machhiwal, Kautuk
> Consul, Vaibhav Jain and Jordan Niethe.
>
> Changelog:
> v5: addressed review comments from Nick on v4
> v4: https://lore.kernel.org/qemu-devel/20240220083609.748325-1-harshpb@linux.ibm.com/
> v3: https://lore.kernel.org/qemu-devel/20240118052438.1475437-1-harshpb@linux.ibm.com/
> v2: https://lore.kernel.org/qemu-devel/20231012104951.194876-1-harshpb@linux.ibm.com/
> v1: https://lore.kernel.org/qemu-devel/20230906043333.448244-1-harshpb@linux.ibm.com/
>
> Harsh Prateek Bora (14):
>   spapr: nested: register nested-hv api hcalls only for cap-nested-hv
>   spapr: nested: move nested part of spapr_get_pate into spapr_nested.c
>   spapr: nested: Introduce SpaprMachineStateNested to store related
>     info.
>   spapr: nested: keep nested-hv related code restricted to its API.
>   spapr: nested: Document Nested PAPR API
>   spapr: nested: Introduce H_GUEST_[GET|SET]_CAPABILITIES hcalls.
>   spapr: nested: Introduce H_GUEST_[CREATE|DELETE] hcalls.
>   spapr: nested: Introduce H_GUEST_CREATE_VCPU hcall.
>   spapr: nested: Extend nested_ppc_state for nested PAPR API
>   spapr: nested: Initialize the GSB elements lookup table.
>   spapr: nested: Introduce H_GUEST_[GET|SET]_STATE hcalls.
>   spapr: nested: Use correct source for parttbl info for nested PAPR
>     API.
>   spapr: nested: Introduce H_GUEST_RUN_VCPU hcall.
>   spapr: nested: Introduce cap-nested-papr for Nested PAPR API
>
>  docs/devel/nested-papr.txt    |  119 +++
>  include/hw/ppc/spapr.h        |   27 +-
>  include/hw/ppc/spapr_nested.h |  428 ++++++++-
>  target/ppc/cpu.h              |    4 +
>  hw/ppc/ppc.c                  |   10 +
>  hw/ppc/spapr.c                |   35 +-
>  hw/ppc/spapr_caps.c           |   62 ++
>  hw/ppc/spapr_hcall.c          |   24 +-
>  hw/ppc/spapr_nested.c         | 1550 ++++++++++++++++++++++++++++++++-
>  9 files changed, 2204 insertions(+), 55 deletions(-)
>  create mode 100644 docs/devel/nested-papr.txt