On Thu, 28 Jul 2022 16:04:58 +0100 Peter Maydell <peter.mayd...@linaro.org> wrote:
> On Thu, 28 Jul 2022 at 15:44, Dr. David Alan Gilbert > <dgilb...@redhat.com> wrote: > > > > * Igor Mammedov (imamm...@redhat.com) wrote: > > > QEMU crashes trying to save VMSTATE when only MIPS target are compiled in > > > $ qemu-system-mips -monitor stdio > > > (qemu) migrate "exec:gzip -c > STATEFILE.gz" > > > Segmentation fault (core dumped) > > > > > > It happens due to PIIX4_PM trying to parse hotplug vmstate structures > > > which are valid only for x86 and not for MIPS (as it requires ACPI > > > tables support which is not existent for ithe later) > > > > > > Issue was probably exposed by trying to cleanup/compile out unused > > > ACPI bits from MIPS target (but forgetting about migration bits). > > > > > > Disable compiled out features using compat properties as the least > > > risky way to deal with issue. > > > > Isn't the problem partially due to a 'stub' vmsd which isn't terminated? > > Yes, but setting these properties causes that vmsd > (vmstate_acpi_pcihp_pci_status) to not be used: > > * it is used only in VMSTATE_PCI_HOTPLUG() > * that macro is used only in hw/acpi/ich9.c (not relevant here) and > hw/acpi/piix4.c > * in piix4.c it is invoked passing it the test functions > vmstate_test_use_acpi_hotplug_bridge and > vmstate_test_migrate_acpi_index > * setting the properties on the device as this patch does > causes those test functions to return false, so the > vmstate_acpi_pcihp_pci_status is never examined it's not limited to VMSTATE_PCI_HOTPLUG but also memory hotplug and other x86 specific knobs that may cause crash. (I ignored cpu hotplug one for now since it doesn't cause crash) > > -- PMM >
