Re: [PATCH v1 1/1] hw/pci: Disable PCI_ERR_UNCOR_MASK register for machine type < 8.0

[Peter Xu]

On Tue, May 02, 2023 at 09:27:02PM -0300, Leonardo Bras wrote:
> Since it's implementation on v8.0.0-rc0, having the PCI_ERR_UNCOR_MASK
> set for machine types < 8.0 will cause migration to fail if the target
> QEMU version is < 8.0.0 :
> 
> qemu-system-x86_64: get_pci_config_device: Bad config data: i=0x10a read: 40 
> device: 0 cmask: ff wmask: 0 w1cmask:0
> qemu-system-x86_64: Failed to load PCIDevice:config
> qemu-system-x86_64: Failed to load e1000e:parent_obj
> qemu-system-x86_64: error while loading state for instance 0x0 of device 
> '0000:00:02.0/e1000e'
> qemu-system-x86_64: load of migration failed: Invalid argument
> 
> The above test migrated a 7.2 machine type from QEMU master to QEMU 7.2.0,
> with this cmdline:
> 
> ./qemu-system-x86_64 -M pc-q35-7.2 [-incoming XXX]
> 
> In order to fix this, property x-pcie-err-unc-mask was introduced to
> control when PCI_ERR_UNCOR_MASK is enabled. This property is enabled by
> default, but is disabled if machine type <= 7.2.
> 
> Fixes: 010746ae1d ("hw/pci/aer: Implement PCI_ERR_UNCOR_MASK register")
> Suggested-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Leonardo Bras <leobras@redhat.com>

Since this one blocks mostly all backward migration for current master and
all the downstream trees, shall we consider pick it up sooner?

And I think we should make sure qemu-stable gets this too, I'm not pretty
sure how we normally do that and whether we need explicit CC: to stable
list, perhaps not..

Thanks!

-- 
Peter Xu