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SubjectRe: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support
On 09/25/2015 09:59 AM, Konrad Rzeszutek Wilk wrote:
> On Fri, Sep 25, 2015 at 11:59:52AM +0200, Vitaly Kuznetsov wrote:
>> Currently there is a number of issues preventing PVHVM Xen guests from
>> doing successful kexec/kdump:
>> - Bound event channels.
>> - Registered vcpu_info.
>> - PIRQ/emuirq mappings.
>> - shared_info frame after XENMAPSPACE_shared_info operation.
>> - Active grant mappings.
>> Basically, newly booted kernel stumbles upon already set up Xen interfaces
>> and there is no way to reestablish them. In Xen-4.7 a new feature called
>> 'soft reset' is coming. A guest performing kexec/kdump operation is
>> supposed to call SCHEDOP_shutdown hypercall with SHUTDOWN_soft_reset reason
>> before jumping to new kernel. Hypervisor (with some help from toolstack)
>> will do full domain cleanup (but keeping its memory and vCPU contexts
>> intact) returning the guest to the state it had when it was first booted
>> and thus allowing it to start over.
>> Doing SHUTDOWN_soft_reset on Xen hypervisors which don't support it is
>> probably OK as by default all unknown shutdown reasons cause domain destroy
>> with a message in toolstack log:
>> 'Unknown shutdown reason code 5. Destroying domain.'
>> which gives a clue to what the problem is and eliminates false
>> expectations.
>> Signed-off-by: Vitaly Kuznetsov <>
> Reviewed-by: Konrad Rzeszutek Wilk <>
> with s/pvhvm/hvm/
> to match with the rest of the file.
> Thanks.
>> +static void xen_pvhvm_kexec_shutdown(void)
>> +{
>> + native_machine_shutdown();
>> + if (kexec_in_progress)
>> + xen_reboot(SHUTDOWN_soft_reset);
>> +}

This routine is not kexec-specific so "kexec_" should be dropped from
the name.

Also, I am not sure I see how this new op will be used in the hypervisor
--- currently AFAICS it is only processed under is_hardware_domain().
Are there other patches that will support HVM guests?


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