Re: [PATCH 1/2] KVM: Unconditionally export KVM_CAP_READONLY_MEM

[Paolo Bonzini <pbonzini@redhat.com>]

Il 26/08/2014 14:00, Christoffer Dall ha scritto:
> The idea between capabilities and the KVM_CHECK_EXTENSION ioctl is that
> userspace can, at run-time, determine if a feature is supported or not.
> This allows KVM to being supporting a new feature with a new kernel
> version without any need to update user space.  Unfortunately, since the
> definition of KVM_CAP_READONLY_MEM was guarded by #ifdef
> __KVM_HAVE_READONLY_MEM, such discovery still required a user space
> update.
> 
> Therefore, unconditionally export KVM_CAP_READONLY_MEM and change the
> in-kernel conditional to rely on __KVM_HAVE_READONLY_MEM.
> 
> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
> ---
>  include/uapi/linux/kvm.h | 2 --
>  virt/kvm/kvm_main.c      | 2 +-
>  2 files changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index cf3a2ff..90d3eda 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -738,9 +738,7 @@ struct kvm_ppc_smmu_info {
>  #define KVM_CAP_PPC_GET_SMMU_INFO 78
>  #define KVM_CAP_S390_COW 79
>  #define KVM_CAP_PPC_ALLOC_HTAB 80
> -#ifdef __KVM_HAVE_READONLY_MEM
>  #define KVM_CAP_READONLY_MEM 81
> -#endif
>  #define KVM_CAP_IRQFD_RESAMPLE 82
>  #define KVM_CAP_PPC_BOOKE_WATCHDOG 83
>  #define KVM_CAP_PPC_HTAB_FD 84
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 5a0817e..1d03967 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -708,7 +708,7 @@ static int check_memory_region_flags(struct kvm_userspace_memory_region *mem)
>  {
>  	u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
>  
> -#ifdef KVM_CAP_READONLY_MEM
> +#ifdef __KVM_HAVE_READONLY_MEM
>  	valid_flags |= KVM_MEM_READONLY;
>  #endif
>  
> 

Thanks, applying both.  Next time please include a cover letter. :)

Paolo