diff mbox series

[5/9] RISC-V: KVM: Provide UAPI for Zicboz block size

Message ID 20221027130247.31634-6-ajones@ventanamicro.com (mailing list archive)
State Changes Requested
Delegated to: Palmer Dabbelt
Headers show
Series RISC-V: Apply Zicboz to clear_page and memset | expand

Commit Message

Andrew Jones Oct. 27, 2022, 1:02 p.m. UTC
We're about to allow guests to use the Zicboz extension. KVM
userspace needs to know the cache block size in order to
properly advertise it to the guest. Provide a virtual config
register for userspace to get it with the GET_ONE_REG API, but
setting it cannot be supported, so disallow SET_ONE_REG.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
---
 arch/riscv/include/uapi/asm/kvm.h | 1 +
 arch/riscv/kvm/vcpu.c             | 7 +++++++
 2 files changed, 8 insertions(+)

Comments

Conor Dooley Oct. 30, 2022, 9:23 p.m. UTC | #1
On Thu, Oct 27, 2022 at 03:02:43PM +0200, Andrew Jones wrote:
> We're about to allow guests to use the Zicboz extension. KVM
> userspace needs to know the cache block size in order to
> properly advertise it to the guest. Provide a virtual config
> register for userspace to get it with the GET_ONE_REG API, but
> setting it cannot be supported, so disallow SET_ONE_REG.

This all looks pretty formulaic..
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>

> 
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> ---
>  arch/riscv/include/uapi/asm/kvm.h | 1 +
>  arch/riscv/kvm/vcpu.c             | 7 +++++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index 8985ff234c01..4bbf55cb2b70 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -49,6 +49,7 @@ struct kvm_sregs {
>  struct kvm_riscv_config {
>  	unsigned long isa;
>  	unsigned long zicbom_block_size;
> +	unsigned long zicboz_block_size;
>  };
>  
>  /* CORE registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index 71ebbc4821f0..18a739070b51 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -270,6 +270,11 @@ static int kvm_riscv_vcpu_get_reg_config(struct kvm_vcpu *vcpu,
>  			return -EINVAL;
>  		reg_val = riscv_cbom_block_size;
>  		break;
> +	case KVM_REG_RISCV_CONFIG_REG(zicboz_block_size):
> +		if (!riscv_isa_extension_available(vcpu->arch.isa, ZICBOZ))
> +			return -EINVAL;
> +		reg_val = riscv_cboz_block_size;
> +		break;
>  	default:
>  		return -EINVAL;
>  	}
> @@ -329,6 +334,8 @@ static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu,
>  		break;
>  	case KVM_REG_RISCV_CONFIG_REG(zicbom_block_size):
>  		return -EOPNOTSUPP;
> +	case KVM_REG_RISCV_CONFIG_REG(zicboz_block_size):
> +		return -EOPNOTSUPP;
>  	default:
>  		return -EINVAL;
>  	}
> -- 
> 2.37.3
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
Anup Patel Nov. 27, 2022, 5:37 a.m. UTC | #2
On Thu, Oct 27, 2022 at 6:34 PM Andrew Jones <ajones@ventanamicro.com> wrote:
>
> We're about to allow guests to use the Zicboz extension. KVM
> userspace needs to know the cache block size in order to
> properly advertise it to the guest. Provide a virtual config
> register for userspace to get it with the GET_ONE_REG API, but
> setting it cannot be supported, so disallow SET_ONE_REG.
>
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>

Looks good to me.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

> ---
>  arch/riscv/include/uapi/asm/kvm.h | 1 +
>  arch/riscv/kvm/vcpu.c             | 7 +++++++
>  2 files changed, 8 insertions(+)
>
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index 8985ff234c01..4bbf55cb2b70 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -49,6 +49,7 @@ struct kvm_sregs {
>  struct kvm_riscv_config {
>         unsigned long isa;
>         unsigned long zicbom_block_size;
> +       unsigned long zicboz_block_size;
>  };
>
>  /* CORE registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index 71ebbc4821f0..18a739070b51 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -270,6 +270,11 @@ static int kvm_riscv_vcpu_get_reg_config(struct kvm_vcpu *vcpu,
>                         return -EINVAL;
>                 reg_val = riscv_cbom_block_size;
>                 break;
> +       case KVM_REG_RISCV_CONFIG_REG(zicboz_block_size):
> +               if (!riscv_isa_extension_available(vcpu->arch.isa, ZICBOZ))
> +                       return -EINVAL;
> +               reg_val = riscv_cboz_block_size;
> +               break;
>         default:
>                 return -EINVAL;
>         }
> @@ -329,6 +334,8 @@ static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu,
>                 break;
>         case KVM_REG_RISCV_CONFIG_REG(zicbom_block_size):
>                 return -EOPNOTSUPP;
> +       case KVM_REG_RISCV_CONFIG_REG(zicboz_block_size):
> +               return -EOPNOTSUPP;
>         default:
>                 return -EINVAL;
>         }
> --
> 2.37.3
>
>
> --
> kvm-riscv mailing list
> kvm-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kvm-riscv
diff mbox series

Patch

diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index 8985ff234c01..4bbf55cb2b70 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -49,6 +49,7 @@  struct kvm_sregs {
 struct kvm_riscv_config {
 	unsigned long isa;
 	unsigned long zicbom_block_size;
+	unsigned long zicboz_block_size;
 };
 
 /* CORE registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 71ebbc4821f0..18a739070b51 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -270,6 +270,11 @@  static int kvm_riscv_vcpu_get_reg_config(struct kvm_vcpu *vcpu,
 			return -EINVAL;
 		reg_val = riscv_cbom_block_size;
 		break;
+	case KVM_REG_RISCV_CONFIG_REG(zicboz_block_size):
+		if (!riscv_isa_extension_available(vcpu->arch.isa, ZICBOZ))
+			return -EINVAL;
+		reg_val = riscv_cboz_block_size;
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -329,6 +334,8 @@  static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu,
 		break;
 	case KVM_REG_RISCV_CONFIG_REG(zicbom_block_size):
 		return -EOPNOTSUPP;
+	case KVM_REG_RISCV_CONFIG_REG(zicboz_block_size):
+		return -EOPNOTSUPP;
 	default:
 		return -EINVAL;
 	}