From c1990468d5a13c8f1d9111fcca0a78a6adad062b Mon Sep 17 00:00:00 2001 From: Michael Roth Date: Wed, 22 May 2013 11:32:51 -0500 Subject: [PATCH] wdt_i6300esb: fix vmstate versioning When this VMSD was introduced it's version fields were set to sizeof(I6300State), making them essentially random from build to build, version to version. To fix this, we lock in a high version id and low minimum version id to support old->new migration from all prior versions of this device's state. This should work since the device state has not changed since its introduction. The potentially breaks migration from 1.5+ to 1.5, but since the versioning was essentially random prior to this patch, new->old migration was not consistently functional to begin with. Reported-by: Nicholas Thomas Suggested-by: Peter Maydell Cc: qemu-stable@nongnu.org Signed-off-by: Michael Roth Signed-off-by: Anthony Liguori --- hw/watchdog/wdt_i6300esb.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/hw/watchdog/wdt_i6300esb.c b/hw/watchdog/wdt_i6300esb.c index 1407fbadb2..05af0b1b68 100644 --- a/hw/watchdog/wdt_i6300esb.c +++ b/hw/watchdog/wdt_i6300esb.c @@ -374,9 +374,22 @@ static const MemoryRegionOps i6300esb_ops = { static const VMStateDescription vmstate_i6300esb = { .name = "i6300esb_wdt", - .version_id = sizeof(I6300State), - .minimum_version_id = sizeof(I6300State), - .minimum_version_id_old = sizeof(I6300State), + /* With this VMSD's introduction, version_id/minimum_version_id were + * erroneously set to sizeof(I6300State), causing a somewhat random + * version_id to be set for every build. This eventually broke + * migration. + * + * To correct this without breaking old->new migration for older versions + * of QEMU, we've set version_id to a value high enough to exceed all past + * values of sizeof(I6300State) across various build environments, and have + * reset minimum_version_id_old/minimum_version_id to 1, since this VMSD + * has never changed and thus can accept all past versions. + * + * For future changes we can treat these values as we normally would. + */ + .version_id = 10000, + .minimum_version_id = 1, + .minimum_version_id_old = 1, .fields = (VMStateField []) { VMSTATE_PCI_DEVICE(dev, I6300State), VMSTATE_INT32(reboot_enabled, I6300State), -- 2.11.4.GIT