Haren Myneni writes:
> The hypervisor supports user-mode NX from Power10. pseries_vas_dlpar_cpu()
> is called from lparcfg_write() to update VAS windows for DLPAR event in
> shared processor mode and the kernel gets -ENOTSUPP for HCALLs if the
> user-mode NX is not supported. The current VAS implementation also
> supports only with Radix page tables. Whereas in dedicated processor
> mode, pseries_vas_notifier() is registered only if the copy/paste
> feature is enabled. So instead of displaying HCALL error messages,
> update VAS capabilities if the copy/paste feature is available.
OK, so this prevents the code from making inappropriate hcalls and
logging useless errors, looks good.
>
> This patch ignores updating VAS capabilities in pseries_vas_dlpar_cpu()
> and returns success if the copy/paste feature is not enabled.
> Then lparcfg_write() completes the processor DLPAR operations
> without any failures.
>
> Fixes: 2147783d6bf0 ("powerpc/pseries: Use lparcfg to reconfig VAS windows
> for DLPAR CPU")
> Signed-off-by: Haren Myneni
Reviewed-by: Nathan Lynch
> ---
> v2: Use bool for copypaste_feat and expand commit message on handling failures
>
> arch/powerpc/platforms/pseries/vas.c | 8
> 1 file changed, 8 insertions(+)
>
> diff --git a/arch/powerpc/platforms/pseries/vas.c
> b/arch/powerpc/platforms/pseries/vas.c
> index 559112312810..513180467562 100644
> --- a/arch/powerpc/platforms/pseries/vas.c
> +++ b/arch/powerpc/platforms/pseries/vas.c
> @@ -856,6 +856,13 @@ int pseries_vas_dlpar_cpu(void)
> {
> int new_nr_creds, rc;
>
> + /*
> + * NX-GZIP is not enabled. Nothing to do for DLPAR event
> + */
> + if (!copypaste_feat)
> + return 0;
> +
> +
> rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES,
> vascaps[VAS_GZIP_DEF_FEAT_TYPE].feat,
> (u64)virt_to_phys(_cop_caps));
> @@ -1012,6 +1019,7 @@ static int __init pseries_vas_init(void)
>* Linux supports user space COPY/PASTE only with Radix
>*/
> if (!radix_enabled()) {
> + copypaste_feat = false;
> pr_err("API is supported only with radix page tables\n");
> return -ENOTSUPP;
> }
> --
> 2.26.3
