powerpc/pseries/vas: Ignore VAS update for DLPAR if copy/paste is not enabled

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.

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")
Cc: stable@vger.kernel.org # v6.1+
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/1d0e727e7dbd9a28627ef08ca9df9c86a50175e2.camel@linux.ibm.com

diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index 5591123..5131804 100644 (file)
--- 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(&hv_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;
        }