On 08/01/20 09:25, zhenwei pi wrote: > Hey, Paolo > > Currently, pvpapic only supports bit 0(PVPANIC_PANICKED). > We usually expect that guest writes ioport (typical 0x505) in panic_notifier_list callback > during handling panic, then we can handle pvpapic event PVPANIC_PANICKED in QEMU. > > On the other hand, guest wants to handle the crash by kdump-tools, and reboots without any > panic_notifier_list callback. So QEMU only knows that guest has rebooted (because guest > write 0xcf9 ioport for RCR request), but QEMU can't identify why guest resets. > > In production environment, we hit about 100+ guest reboot event everyday, sadly we > can't separate the abnormal reboot from normal operation. > > We want to add a new bit for pvpanic event(maybe PVPANIC_CRASHLOADED) to represent the guest has crashed, > and the panic is handled by the guest kernel. (here is the previous patch https://lkml.org/lkml/2019/12/14/265) > > What do you think about this solution? Or do you have any other suggestions? Hi Zhenwei, the kernel-side patch certainly makes sense. I assume that you want the event to propagate up from QEMU to Libvirt and so on? The QEMU patch would need to declare a new event (qapi/misc.json) and send it in handle_event (hw/misc/pvpanic.c). For Libvirt I'm not familiar, so I'm adding the respective list. Another possibility is to simply not write to pvpanic if kexec_crash_loaded() returns true; this would match what xen_panic_event does for example. The kexec kernel would then log the panic normally, without the need for MMIO at all. However, I have no problem with adding a new bit to the pvpanic I/O port so once you post the QEMU patch I will certainly ack the kernel side. Thanks, Paolo -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
