ide: Split error status from status register

When adding the werror=stop mode, some flags were added to s->status
which are used to determine what kind of operation should be restarted
when the VM is continued.

Unfortunately, it turns out that s->status is in fact a device register
and as such is visible to the guest (some of the abused bits are even
writable for the guest).

For migration we keep on using the old VMState field (renamed to
migration_compat_status) if the status register doesn't use any of the
previously abused bits. If it does, we use a subsection with a clean copy of
the status register.

The error status is always sent in a subsection if there is any error. It can't
use the old field because errors happen even without PCI.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 27 insertions, 1 deletions

diff --git a/hw/ide/core.c b/hw/ide/core.c
index 95beb175b3..da250ac39b 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -446,7 +446,7 @@ static int ide_handle_rw_error(IDEState *s, int error, int op)
     if ((error == ENOSPC && action == BLOCK_ERR_STOP_ENOSPC)
             || action == BLOCK_ERR_STOP_ANY) {
         s->bus->dma->ops->set_unit(s->bus->dma, s->unit);
-        s->bus->dma->ops->add_status(s->bus->dma, op);
+        s->bus->error_status = op;
         bdrv_mon_event(s->bs, BDRV_ACTION_STOP, is_read);
         vm_stop(VMSTOP_DISKFULL);
     } else {
@@ -1847,6 +1847,13 @@ static bool ide_atapi_gesn_needed(void *opaque)
     return s->events.new_media || s->events.eject_request;
 }
 
+static bool ide_error_needed(void *opaque)
+{
+    IDEBus *bus = opaque;
+
+    return (bus->error_status != 0);
+}
+
 /* Fields for GET_EVENT_STATUS_NOTIFICATION ATAPI command */
 const VMStateDescription vmstate_ide_atapi_gesn_state = {
     .name ="ide_drive/atapi/gesn_state",
@@ -1921,6 +1928,17 @@ const VMStateDescription vmstate_ide_drive = {
     }
 };
 
+const VMStateDescription vmstate_ide_error_status = {
+    .name ="ide_bus/error",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields = (VMStateField []) {
+        VMSTATE_INT32(error_status, IDEBus),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 const VMStateDescription vmstate_ide_bus = {
     .name = "ide_bus",
     .version_id = 1,
@@ -1930,6 +1948,14 @@ const VMStateDescription vmstate_ide_bus = {
         VMSTATE_UINT8(cmd, IDEBus),
         VMSTATE_UINT8(unit, IDEBus),
         VMSTATE_END_OF_LIST()
+    },
+    .subsections = (VMStateSubsection []) {
+        {
+            .vmsd = &vmstate_ide_error_status,
+            .needed = ide_error_needed,
+        }, {
+            /* empty */
+        }
     }
 };