Paolo, Jiri, can I do something more for this patch to be accepted? On 05.11.2015 17:32, Paolo Bonzini wrote:
On 05/11/2015 14:54, Dmitry Andreev wrote:
Add crash CPU feature for Hyper-V. Hyper-V crash MSR's can be used by Hyper-V based guests to notify about occurred guest crash.
XML: <features> <hyperv> <crash state='on'/> </hyperv> </features> Sounds like this is related to an existing panic device we already support. So what does enabling hv_crash do in QEMU? Is it an additional channel to a panic device or is the panic device still needed even if hv_crash is enabled? In any case, I think we should map this somehow to the panic device instead of copying 1:1 the way QEMU enables hv_crash. pvpanic and Hyper-V crash are independent ways for guest to notify about OS crash. Both ways rise the 'qemu guest panicked' event. Domain can have both hv_crash and pvpanic enabled at the same time.
pvpanic is in <devices> section in domain configuration because it is an ISA device. Hyper-V crash is a hypervisor's feature, which enables a set of model-specific registers. Guest can use this registers to send notification and store additional information about a crash. This is a part of Microsoft hypervisor interface.
That's why I think hv_crash should be in <features> section. I agree.
Paolo