Re: [PATCH v4 00/12] KVM: arm/arm64: Allow multiple GICv3 redistributor regions

[Auger Eric]

Hi,

On 04/27/2018 04:06 PM, Eric Auger wrote:
> At the moment the KVM VGICv3 only supports a single redistributor
> region (whose base address is set through the GICv3 kvm device
> KVM_DEV_ARM_VGIC_GRP_ADDR/KVM_VGIC_V3_ADDR_TYPE_REDIST). There,
> all the redistributors are laid out contiguously. The size of this
> single redistributor region is not set explicitly but instead
> induced at a late stage by the number of online vcpus.
> 
> The GIC specification does not mandate all redistributors to be
> contiguous. Moreover DT and ACPI were specified so that multiple
> redistributors regions can be defined.
> 
> The current interface brings a limitation on QEMU where ARM
> virt machine available GPA holes only allowed to assign a
> redistributor region fitting a max of 123 vcpus. Overcoming this
> limitation would force either to create a new machine or relocate
> the single rdist region or allow the allocation of multiple rdist
> regions.
> 
> This series enables this last alternative. A new GICv3 KVM device
> KVM_DEV_ARM_VGIC_GRP_ADDR/KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION allows
> to register individual redistributor regions whose size is defined
> explicitly. Those rdist regions then are filled by vcpu rdist frames
> according to the need. The vgic init and related base address checks
> are impacted.

For some unknown reason I got a timeout on the git send-email command,
hence this isolated cover letter. The series was fully resent. Sorry for
the inconvenience.

Thanks

Eric
> 
> Best Regards
> 
> Eric
> 
> Git: complete series available at
> https://github.com/eauger/linux/tree/v4.17-rc2-rdist-regions-v4
> Previous version:
> https://github.com/eauger/linux/tree/v4.16-rdist-regions-v3
> 
> History:
> 
> v3 -> v4:
> - Collected Christoffer's R-b
> - reworked vgic_v3_rdist_overlap and introduced vgic_dist_overlap
> - vgic_v3_insert_redist_region cleanup
> - inverse order for patches 6 and 7
> 
> v2 -> v3:
> - Add details to the user API documentation
> - early exit if vgic_v3_rdist_region_from_index() fails
> - return -EINVAL if legacy and new redist region API are mixed
> 
> v1 -> v2:
> - Rework the uapi. Only bits [51:16] of the redist region are
>   exposed. Also a new flags field was introduced
> - Do not store the last bit in the vgic_cpu struct anymore
> - remove dist->spis check in 1st patch
> - add last patch to bump VGIC_V3_MAX_CPUS to 512
> - advertise the new attribute
> 
> Eric Auger (12):
>   KVM: arm/arm64: Set dist->spis to NULL after kfree
>   KVM: arm/arm64: Document KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION
>   KVM: arm/arm64: Replace the single rdist region by a list
>   KVM: arm/arm64: Helper to locate free rdist index
>   KVM: arm/arm64: Revisit Redistributor TYPER last bit computation
>   KVM: arm/arm64: Adapt vgic_v3_check_base to multiple rdist regions
>   KVM: arm/arm64: Helper to register a new redistributor region
>   KVM: arm/arm64: Check vcpu redist base before registering an iodev
>   KVM: arm/arm64: Check all vcpu redistributors are set on map_resources
>   KVM: arm/arm64: Add KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION
>   KVM: arm/arm64: Implement KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION
>   KVM: arm/arm64: Bump VGIC_V3_MAX_CPUS to 512
> 
>  Documentation/virtual/kvm/devices/arm-vgic-v3.txt |  25 ++++-
>  arch/arm/include/uapi/asm/kvm.h                   |   1 +
>  arch/arm64/include/uapi/asm/kvm.h                 |   1 +
>  include/kvm/arm_vgic.h                            |  16 ++-
>  virt/kvm/arm/vgic/vgic-init.c                     |  20 +++-
>  virt/kvm/arm/vgic/vgic-kvm-device.c               |  55 ++++++++++-
>  virt/kvm/arm/vgic/vgic-mmio-v3.c                  | 114 +++++++++++++++++++---
>  virt/kvm/arm/vgic/vgic-v3.c                       | 101 +++++++++++++++----
>  virt/kvm/arm/vgic/vgic.h                          |  42 +++++++-
>  9 files changed, 330 insertions(+), 45 deletions(-)
>