On Thu, Aug 30, 2012 at 01:51:10PM -0400, Jason Baron wrote:
> While testing q35 live migration, I found that the migration would abort with
> the following error: "Unknown savevm section type 76".
>
> The error is due to this check failing in 'vmstate_load_state()':
>
> while(field->name) {
> if ((field->field_exists &&
> field->field_exists(opaque, version_id)) ||
> (!field->field_exists &&
> field->version_id <= version_id)) {
>
> The VMSTATE_PCIE_DEVICE() currently has a 'version_id' set to 2. However,
> 'version_id' in the above check is 1. And thus we fail to load the pcie device
> field. Further the code returns to 'qemu_loadvm_state()' which produces the
> error that I saw.
>
> I'm proposing to fix this by simply dropping the 'version_id' field from
> VMSTATE_PCIE_DEVICE(). VMSTATE_PCI_DEVICE() defines no such field and further
> the vmstate_pcie_device that VMSTATE_PCI_DEVICE() refers to is already
> versioned. Thus, any versioning issues could be detected at the vmsd level.
>
> Taking a step back, I think that the 'field->version_id' should be compared
> against a saved version number for the field not the 'version_id'. Futhermore,
> once vmstate_load_state() is called recursively on another vmsd, the check of:
>
> if (version_id > vmsd->version_id) {
> return -EINVAL;
> }
>
> Will never fail since version_id is always equal to vmsd->version_id. So I'm
> wondering why we aren't storing the vmsd version id of the source in the
> migration stream?
>
> This patch also renames the 'name' field of vmstate_pcie_device from:
> PCIDevice -> PCIEDevice to differentiate it from vmstate_pci_device.
>
> Signed-off-by: Jason Baron <jba...@redhat.com>
I have this queued to apply already - this is just a repost
or did I miss something?
I have no idea about the larger issues - Juan?
> ---
> hw/pci.c | 2 +-
> hw/pcie.h | 1 -
> 2 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/hw/pci.c b/hw/pci.c
> index 3727afa..5386a4f 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> @@ -439,7 +439,7 @@ const VMStateDescription vmstate_pci_device = {
> };
>
> const VMStateDescription vmstate_pcie_device = {
> - .name = "PCIDevice",
> + .name = "PCIEDevice",
> .version_id = 2,
> .minimum_version_id = 1,
> .minimum_version_id_old = 1,
> diff --git a/hw/pcie.h b/hw/pcie.h
> index b8ab0c7..4889194 100644
> --- a/hw/pcie.h
> +++ b/hw/pcie.h
> @@ -133,7 +133,6 @@ extern const VMStateDescription vmstate_pcie_device;
>
> #define VMSTATE_PCIE_DEVICE(_field, _state) { \
> .name = (stringify(_field)), \
> - .version_id = 2, \
> .size = sizeof(PCIDevice), \
> .vmsd = &vmstate_pcie_device, \
> .flags = VMS_STRUCT, \
> --
> 1.7.1
