"Denis V. Lunev" <den@virtuozzo.com> writes:
On 11/10/2015 06:55 PM, Dmitry Andreev wrote:
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
Please.
This feature is very interesting for us for guest debugging especially during guest installation where specific drivers are not available or not ready or not that easy to supply.
+1 while I think it would make more sense to propagate crash information (HV_X64_MSR_CRASH_P0..P4 MSR) all the way up to libvirt (and even further to libvirt users) instead of just triggering 'guest panic', enabling the feature for Windows guests looks like a good starting point. -- Vitaly