Re: [Qemu-devel] [QEMU PATCH v2 0/2]: KVM: i386: Add support for save and restore nested state

[Dr. David Alan Gilbert]

* Liran Alon (address@hidden) wrote:
> 
> 
> > On 31 Oct 2018, at 20:19, Paolo Bonzini <address@hidden> wrote:
> > 
> > On 31/10/2018 19:17, Eduardo Habkost wrote:
> >> On Wed, Oct 31, 2018 at 03:03:34AM +0200, Liran Alon wrote:
> >>> Ping.
> >>> Patch was submitted almost two months ago and I haven’t seen any respond 
> >>> for the v2 of this series.
> >> Sorry for the long delay.  This was on my queue of patches to be
> >> reviewed, but I'm failing to keep up to the rate of incoming
> >> patches.  I will try to review the series next week.
> > 
> > I have already reviewed it; unfortunately I have missed the soft freeze
> > for posting the version I had also been working on when Liran posted
> > these patches.
> > 
> > Paolo
> 
> Paolo, note that this is v2 of this patch series. It’s not the one you have 
> already reviewed.
> It now correctly handles the case you mentioned in review of v1 of migrating 
> with various nested_state buffer sizes.
> The following scenarios were tested:
> (a) src and dest have same nested state size.
>       ==> Migration succeeds.
> (b) src don't have nested state while dest do.
>       ==> Migration succeed and src don't send it's nested state.
> (c) src have nested state while dest don't.
>       ==> Migration fails as it cannot restore nested state.
> (d) dest have bigger max nested state size than src
>       ==> Migration succeeds.
> (e) dest have smaller max nested state size than src but enough to store it's 
> saved nested state
>       ==> Migration succeeds
> (f) dest have smaller max nested state size than src but not enough to store 
> it's saved nested state
>       ==> Migration fails

Is it possible to tell these limits before the start of the migration,
or do we only find out that a nested migration won't work by trying it?

Dave

> -Liran
> 
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK