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Re: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support

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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 <vkuznets@redhat.com>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>
> with s/pvhvm/hvm/
>
> to match with the rest of the file.
>
> Thanks.
>>   
>> +#ifdef CONFIG_KEXEC_CORE
>> +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?


-boris

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[PATCH] xen/pvhvm: add soft reset on kexec/kdump support Vitaly Kuznetsov <vkuznets@redhat.com> - 2015-09-25 12:10 +0200
  Re: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2015-09-25 16:10 +0200
    Re: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2015-09-25 18:00 +0200
      Re: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support Vitaly Kuznetsov <vkuznets@redhat.com> - 2015-09-25 19:00 +0200
        Re: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2015-09-25 19:20 +0200
          Re: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2015-09-25 21:10 +0200
            Re: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2015-09-25 21:30 +0200
              Re: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2015-09-25 21:40 +0200
                Re: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2015-09-25 23:10 +0200
                Re: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support Vitaly Kuznetsov <vkuznets@redhat.com> - 2015-09-29 13:50 +0200
                Re: [PATCH] xen/pvhvm: add soft reset on kexec/kdump support Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2015-09-29 15:20 +0200
  Re: [Xen-devel] [PATCH] xen/pvhvm: add soft reset on kexec/kdump  support David Vrabel <david.vrabel@citrix.com> - 2015-09-28 16:20 +0200

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