Re: [Qemu-devel] [PATCH 11/17] pseries: savevm support for pseries machine

[Alexander Graf]

On 08.07.2013, at 20:45, Anthony Liguori wrote:

> Alexey Kardashevskiy <address@hidden> writes:
> 
>> From: David Gibson <address@hidden>
>> 
>> This adds the necessary pieces to implement savevm / migration for the
>> pseries machine.  The most complex part here is migrating the hash
>> table - for the paravirtualized pseries machine the guest's hash page
>> table is not stored within guest memory, but externally and the guest
>> accesses it via hypercalls.
>> 
>> This patch uses a hypervisor reserved bit of the HPTE as a dirty bit
>> (tracking changes to the HPTE itself, not the page it references).
>> This is used to implement a live migration style incremental save and
>> restore of the hash table contents.
>> 
>> In addition it adds VMStateDescription information to save and restore
>> the (few) remaining pieces of state information needed by the pseries
>> machine.
>> 
>> Signed-off-by: David Gibson <address@hidden>
>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
> 
> I vaguely recall making the suggestion to use a live section like this.
> How large is the HTAB typically?

The default for HV KVM is at 16MB IIRC.


Alex