On Fri, Aug 25, 2017 at 07:53:39PM +1000, Paul Mackerras wrote:
> This adds information about storage keys to the struct returned by
> the KVM_PPC_GET_SMMU_INFO ioctl.  The new fields replace a pad field,
> which was zeroed by previous kernel versions.  Thus userspace that
> knows about the new fields will see zeroes when running on an older
> kernel, indicating that storage keys are not supported.  The size of
> the structure has not changed.
> 
> The number of keys is hard-coded for the CPUs supported by HV KVM,
> which is just POWER7, POWER8 and POWER9.
> 
> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
> This is intended to go in after Ram Pai's patch fixing the H_ENTER
> code to not drop the top two bits of the key field.
> 
>  arch/powerpc/kvm/book3s_hv.c | 8 ++++++++
>  include/uapi/linux/kvm.h     | 3 ++-
>  2 files changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 359c79c..3d9b661 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -3325,6 +3325,14 @@ static int kvm_vm_ioctl_get_smmu_info_hv(struct kvm *kvm,
>  	if (radix_enabled())
>  		return -EINVAL;
>  
> +	/*
> +	 * POWER7, POWER8 and POWER9 all support 32 storage keys for data.
> +	 * POWER7 doesn't support keys for instruction accesses,
> +	 * POWER8 and POWER9 do.
> +	 */
> +	info->data_keys = 32;
> +	info->instr_keys = cpu_has_feature(CPU_FTR_ARCH_207S) ? 32 : 0;
> +
>  	info->flags = KVM_PPC_PAGE_SIZES_REAL;
>  	if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
>  		info->flags |= KVM_PPC_1T_SEGMENTS;
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 6cd63c1..8388875 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -711,7 +711,8 @@ struct kvm_ppc_one_seg_page_size {
>  struct kvm_ppc_smmu_info {
>  	__u64 flags;
>  	__u32 slb_size;
> -	__u32 pad;
> +	__u16 data_keys;	/* # storage keys supported for data */
> +	__u16 instr_keys;	/* # storage keys supported for instructions */
>  	struct kvm_ppc_one_seg_page_size sps[KVM_PPC_PAGE_SIZES_MAX_SZ];
>  };
>  

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson