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: 2147783d6b ("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

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;
 	}