Re: [PING PATCH v4 00/29] Add KVM LoongArch support

[Paolo Bonzini]

On 3/28/23 14:30, Tianrui Zhao wrote:
> Ping patch series, please help for reviewing the loongarch kvm patch
> set. Thanks very much.
>
> This series adds KVM LoongArch support. Loongson 3A5000 supports hardware
> assisted virtualization. With cpu virtualization, there are separate
> hw-supported user mode and kernel mode in guest mode. With memory
> virtualization, there are two-level hw mmu table for guest mode and host
> mode. Also there is separate hw cpu timer with consant frequency in
> guest mode, so that vm can migrate between hosts with different freq.
> Currently, we are able to boot LoongArch Linux Guests.
>
> Few key aspects of KVM LoongArch added by this series are:
> 1. Enable kvm hardware function when kvm module is loaded.
> 2. Implement VM and vcpu related ioctl interface such as vcpu create,
>     vcpu run etc. GET_ONE_REG/SET_ONE_REG ioctl commands are use to
>     get general registers one by one.
> 3. Hardware access about MMU, timer and csr are emulated in kernel.
> 4. Hardwares such as mmio and iocsr device are emulated in user space
>     such as APIC, IPI, pci devices etc.

Please check Documentation/virtual/kvm/api.rst and document the 
loongarch-specific parts of the API, in particular ioctls that have 
architecture-specific semantics (KVM_GET/SET_ONE_REG, KVM_INTERRUPT) and 
vcpu->run fields.

Code-wise what I could understand looked okay, I only made a suggestion 
on the handling of idle; thanks for going through the previous review 
carefully.

Paolo