Re: [PATCH v3 08/10] RISC-V: KVM: Expose APLIC registers as attributes of AIA irqchip

[Atish Patra]

On Thu, Jun 15, 2023 at 12:34 AM Anup Patel <apatel@xxxxxxxxxxxxxxxx> wrote:
>
> We expose APLIC registers as KVM device attributes of the in-kernel
> AIA irqchip device. This will allow KVM user-space to save/restore
> APLIC state using KVM device ioctls().
>
> Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> ---
>  arch/riscv/include/asm/kvm_aia.h  |  3 +++
>  arch/riscv/include/uapi/asm/kvm.h |  6 +++++
>  arch/riscv/kvm/aia_aplic.c        | 43 +++++++++++++++++++++++++++++++
>  arch/riscv/kvm/aia_device.c       | 25 ++++++++++++++++++
>  4 files changed, 77 insertions(+)
>
> diff --git a/arch/riscv/include/asm/kvm_aia.h b/arch/riscv/include/asm/kvm_aia.h
> index f6bd8523395f..ba939c0054aa 100644
> --- a/arch/riscv/include/asm/kvm_aia.h
> +++ b/arch/riscv/include/asm/kvm_aia.h
> @@ -129,6 +129,9 @@ static inline void kvm_riscv_vcpu_aia_imsic_cleanup(struct kvm_vcpu *vcpu)
>  {
>  }
>
> +int kvm_riscv_aia_aplic_set_attr(struct kvm *kvm, unsigned long type, u32 v);
> +int kvm_riscv_aia_aplic_get_attr(struct kvm *kvm, unsigned long type, u32 *v);
> +int kvm_riscv_aia_aplic_has_attr(struct kvm *kvm, unsigned long type);
>  int kvm_riscv_aia_aplic_inject(struct kvm *kvm, u32 source, bool level);
>  int kvm_riscv_aia_aplic_init(struct kvm *kvm);
>  void kvm_riscv_aia_aplic_cleanup(struct kvm *kvm);
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index 047c8fc5bd71..9ed822fc5589 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -249,6 +249,12 @@ enum KVM_RISCV_SBI_EXT_ID {
>  #define KVM_DEV_RISCV_AIA_GRP_CTRL             2
>  #define KVM_DEV_RISCV_AIA_CTRL_INIT            0
>
> +/*
> + * The device attribute type contains the memory mapped offset of the
> + * APLIC register (range 0x0000-0x3FFF) and it must be 4-byte aligned.
> + */
> +#define KVM_DEV_RISCV_AIA_GRP_APLIC            3
> +
>  /* One single KVM irqchip, ie. the AIA */
>  #define KVM_NR_IRQCHIPS                        1
>
> diff --git a/arch/riscv/kvm/aia_aplic.c b/arch/riscv/kvm/aia_aplic.c
> index eecd8f4abe21..39e72aa016a4 100644
> --- a/arch/riscv/kvm/aia_aplic.c
> +++ b/arch/riscv/kvm/aia_aplic.c
> @@ -501,6 +501,49 @@ static struct kvm_io_device_ops aplic_iodoev_ops = {
>         .write = aplic_mmio_write,
>  };
>
> +int kvm_riscv_aia_aplic_set_attr(struct kvm *kvm, unsigned long type, u32 v)
> +{
> +       int rc;
> +
> +       if (!kvm->arch.aia.aplic_state)
> +               return -ENODEV;
> +
> +       rc = aplic_mmio_write_offset(kvm, type, v);
> +       if (rc)
> +               return rc;
> +
> +       return 0;
> +}
> +
> +int kvm_riscv_aia_aplic_get_attr(struct kvm *kvm, unsigned long type, u32 *v)
> +{
> +       int rc;
> +
> +       if (!kvm->arch.aia.aplic_state)
> +               return -ENODEV;
> +
> +       rc = aplic_mmio_read_offset(kvm, type, v);
> +       if (rc)
> +               return rc;
> +
> +       return 0;
> +}
> +
> +int kvm_riscv_aia_aplic_has_attr(struct kvm *kvm, unsigned long type)
> +{
> +       int rc;
> +       u32 val;
> +
> +       if (!kvm->arch.aia.aplic_state)
> +               return -ENODEV;
> +
> +       rc = aplic_mmio_read_offset(kvm, type, &val);
> +       if (rc)
> +               return rc;
> +
> +       return 0;
> +}
> +
>  int kvm_riscv_aia_aplic_init(struct kvm *kvm)
>  {
>         int i, ret = 0;
> diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c
> index 7ab555121872..c649ad6e8e0a 100644
> --- a/arch/riscv/kvm/aia_device.c
> +++ b/arch/riscv/kvm/aia_device.c
> @@ -365,6 +365,15 @@ static int aia_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
>                         break;
>                 }
>
> +               break;
> +       case KVM_DEV_RISCV_AIA_GRP_APLIC:
> +               if (copy_from_user(&nr, uaddr, sizeof(nr)))
> +                       return -EFAULT;
> +
> +               mutex_lock(&dev->kvm->lock);
> +               r = kvm_riscv_aia_aplic_set_attr(dev->kvm, type, nr);
> +               mutex_unlock(&dev->kvm->lock);
> +
>                 break;
>         }
>
> @@ -412,6 +421,20 @@ static int aia_get_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
>                 if (copy_to_user(uaddr, &addr, sizeof(addr)))
>                         return -EFAULT;
>
> +               break;
> +       case KVM_DEV_RISCV_AIA_GRP_APLIC:
> +               if (copy_from_user(&nr, uaddr, sizeof(nr)))
> +                       return -EFAULT;
> +
> +               mutex_lock(&dev->kvm->lock);
> +               r = kvm_riscv_aia_aplic_get_attr(dev->kvm, type, &nr);
> +               mutex_unlock(&dev->kvm->lock);
> +               if (r)
> +                       return r;
> +
> +               if (copy_to_user(uaddr, &nr, sizeof(nr)))
> +                       return -EFAULT;
> +
>                 break;
>         }
>
> @@ -448,6 +471,8 @@ static int aia_has_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
>                         return 0;
>                 }
>                 break;
> +       case KVM_DEV_RISCV_AIA_GRP_APLIC:
> +               return kvm_riscv_aia_aplic_has_attr(dev->kvm, attr->attr);
>         }
>
>         return -ENXIO;
> --
> 2.34.1
>


Reviewed-by: Atish Patra <atishp@xxxxxxxxxxxx>
-- 
Regards,
Atish