Re: [PATCH v7 5/9] x86: spp: Introduce user-space SPP IOCTLs

From: Paolo Bonzini <pbonzini@redhat.com>
To: Yang Weijiang <weijiang.yang@intel.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	jmattson@google.com, sean.j.christopherson@intel.com
Cc: yu.c.zhang@linux.intel.com, alazar@bitdefender.com, edwin.zhai@intel.com
Subject: Re: [PATCH v7 5/9] x86: spp: Introduce user-space SPP IOCTLs
Date: Thu, 21 Nov 2019 11:03:52 +0100	[thread overview]
Message-ID: <f8cd7d7c-7ffd-3ee4-bf5f-203f9a030fef@redhat.com> (raw)
In-Reply-To: <20191119084949.15471-6-weijiang.yang@intel.com>

On 19/11/19 09:49, Yang Weijiang wrote:
> +	case KVM_INIT_SPP: {
> +		r = kvm_vm_ioctl_init_spp(kvm);
> +		break;
> +	}
>  	default:
>  		r = -ENOTTY;
>  	}
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 9460830de536..700f0825336d 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1257,6 +1257,9 @@ struct kvm_vfio_spapr_tce {
>  					struct kvm_userspace_memory_region)
>  #define KVM_SET_TSS_ADDR          _IO(KVMIO,   0x47)
>  #define KVM_SET_IDENTITY_MAP_ADDR _IOW(KVMIO,  0x48, __u64)
> +#define KVM_SUBPAGES_GET_ACCESS   _IOR(KVMIO,  0x49, __u64)
> +#define KVM_SUBPAGES_SET_ACCESS   _IOW(KVMIO,  0x4a, __u64)
> +#define KVM_INIT_SPP              _IOW(KVMIO,  0x4b, __u64)

You also need to define a capability and return a value for it in
kvm_vm_ioctl_check_extension.  We could return SUBPAGE_MAX_BITMAP (now
KVM_SUBPAGE_MAX_PAGES).  And instead of introducing KVM_INIT_SPP, you
can then use KVM_ENABLE_CAP on the new capability.

Paolo