powerpc/pseries: fix plpks_read_var() code for different consumers

Even though plpks_read_var() is currently called to read variables
owned by different consumers, it internally supports only OS consumer.

Fix plpks_read_var() to handle different consumers correctly.

Fixes: 2454a7af ("powerpc/pseries: define driver for Platform KeyStore")
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221106205839.600442-7-nayna@linux.ibm.com

arch/powerpc/platforms/pseries/plpks.c

@@ -354,22 +354,24 @@ static int plpks_read_var(u8 consumer, struct plpks_var *var)
 {
 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
 	struct plpks_auth *auth;
-	struct label *label;
+	struct label *label = NULL;
 	u8 *output;
 	int rc;
 
 	if (var->namelen > MAX_NAME_SIZE)
 		return -EINVAL;
 
-	auth = construct_auth(PKS_OS_OWNER);
+	auth = construct_auth(consumer);
 	if (IS_ERR(auth))
 		return PTR_ERR(auth);
 
-	label = construct_label(var->component, var->os, var->name,
-				var->namelen);
-	if (IS_ERR(label)) {
-		rc = PTR_ERR(label);
-		goto out_free_auth;
+	if (consumer == PKS_OS_OWNER) {
+		label = construct_label(var->component, var->os, var->name,
+					var->namelen);
+		if (IS_ERR(label)) {
+			rc = PTR_ERR(label);
+			goto out_free_auth;
+		}
 	}
 
 	output = kzalloc(maxobjsize, GFP_KERNEL);
@@ -378,9 +380,15 @@ static int plpks_read_var(u8 consumer, struct plpks_var *var)
 		goto out_free_label;
 	}
 
-	rc = plpar_hcall(H_PKS_READ_OBJECT, retbuf, virt_to_phys(auth),
-			 virt_to_phys(label), label->size, virt_to_phys(output),
-			 maxobjsize);
+	if (consumer == PKS_OS_OWNER)
+		rc = plpar_hcall(H_PKS_READ_OBJECT, retbuf, virt_to_phys(auth),
+				 virt_to_phys(label), label->size, virt_to_phys(output),
+				 maxobjsize);
+	else
+		rc = plpar_hcall(H_PKS_READ_OBJECT, retbuf, virt_to_phys(auth),
+				 virt_to_phys(var->name), var->namelen, virt_to_phys(output),
+				 maxobjsize);
+
 
 	if (rc != H_SUCCESS) {
 		rc = pseries_status_to_err(rc);