From: John Snow <js...@redhat.com> When the AHCI HBA device is migrated, all of the information that led to the request being created is stored in the AHCIDevice structures, except for pointers into guest data where return information needs to be stored.
The "cur_cmd" field is usually responsible for this. To rebuild the cur_cmd pointer post-migration, we can utilize the busy_slot index to figure out where the command header we are still processing is. This allows a machine in a halted state from rerror=stop or werror=stop to be migrated and resume operations without issue. Signed-off-by: John Snow <js...@redhat.com> Message-id: 1424708286-16483-17-git-send-email-js...@redhat.com Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> --- hw/ide/ahci.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c index 56a4867..e1ae36f 100644 --- a/hw/ide/ahci.c +++ b/hw/ide/ahci.c @@ -1376,6 +1376,13 @@ static int ahci_state_post_load(void *opaque, int version_id) */ if (ad->busy_slot == -1) { check_cmd(s, i); + } else { + /* We are in the middle of a command, and may need to access + * the command header in guest memory again. */ + if (ad->busy_slot < 0 || ad->busy_slot >= AHCI_MAX_CMDS) { + return -1; + } + ad->cur_cmd = &((AHCICmdHdr *)ad->lst)[ad->busy_slot]; } } -- 2.1.0