hw: Add "loadparm" property to scsi disk devices for booting on s390x

While adding the new flexible boot order feature on s390x recently,
we missed to add the "loadparm" property to the scsi-hd and scsi-cd
devices. This property is required on s390x to pass the information
to the boot loader about which kernel should be started or whether
the boot menu should be shown. But even more serious: The missing
property is now causing trouble with the corresponding libvirt patches
that assume that the "loadparm" property is either settable for all
bootable devices (when the "boot order" feature is implemented in
QEMU), or none (meaning the behaviour of older QEMUs that only allowed
one "loadparm" at the machine level). To fix this broken situation,
let's implement the "loadparm" property in for the SCSI devices, too.

Message-ID: <20241115141202.1877294-1-thuth@redhat.com>
Acked-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index cb222da..8e55348 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -32,6 +32,7 @@
 #include "migration/vmstate.h"
 #include "hw/scsi/emulation.h"
 #include "scsi/constants.h"
+#include "sysemu/arch_init.h"
 #include "sysemu/block-backend.h"
 #include "sysemu/blockdev.h"
 #include "hw/block/block.h"
@@ -111,6 +112,7 @@ struct SCSIDiskState {
     char *vendor;
     char *product;
     char *device_id;
+    char *loadparm;     /* only for s390x */
     bool tray_open;
     bool tray_locked;
     /*
@@ -3135,6 +3137,43 @@ BlockAIOCB *scsi_dma_writev(int64_t offset, QEMUIOVector *iov,
     return blk_aio_pwritev(s->qdev.conf.blk, offset, iov, 0, cb, cb_opaque);
 }
 
+static char *scsi_property_get_loadparm(Object *obj, Error **errp)
+{
+    return g_strdup(SCSI_DISK_BASE(obj)->loadparm);
+}
+
+static void scsi_property_set_loadparm(Object *obj, const char *value,
+                                       Error **errp)
+{
+    void *lp_str;
+
+    if (object_property_get_int(obj, "bootindex", NULL) < 0) {
+        error_setg(errp, "'loadparm' is only valid for boot devices");
+        return;
+    }
+
+    lp_str = g_malloc0(strlen(value));
+    if (!qdev_prop_sanitize_s390x_loadparm(lp_str, value, errp)) {
+        g_free(lp_str);
+        return;
+    }
+    SCSI_DISK_BASE(obj)->loadparm = lp_str;
+}
+
+static void scsi_property_add_specifics(DeviceClass *dc)
+{
+    ObjectClass *oc = OBJECT_CLASS(dc);
+
+    /* The loadparm property is only supported on s390x */
+    if (arch_type & QEMU_ARCH_S390X) {
+        object_class_property_add_str(oc, "loadparm",
+                                      scsi_property_get_loadparm,
+                                      scsi_property_set_loadparm);
+        object_class_property_set_description(oc, "loadparm",
+                                              "load parameter (s390x only)");
+    }
+}
+
 static void scsi_disk_base_class_initfn(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
@@ -3218,6 +3257,8 @@ static void scsi_hd_class_initfn(ObjectClass *klass, void *data)
     dc->desc = "virtual SCSI disk";
     device_class_set_props(dc, scsi_hd_properties);
     dc->vmsd  = &vmstate_scsi_disk_state;
+
+    scsi_property_add_specifics(dc);
 }
 
 static const TypeInfo scsi_hd_info = {
@@ -3258,6 +3299,8 @@ static void scsi_cd_class_initfn(ObjectClass *klass, void *data)
     dc->desc = "virtual SCSI CD-ROM";
     device_class_set_props(dc, scsi_cd_properties);
     dc->vmsd  = &vmstate_scsi_disk_state;
+
+    scsi_property_add_specifics(dc);
 }
 
 static const TypeInfo scsi_cd_info = {