Re: [Qemu-devel] [RFC PATCH v1 0/2] spapr: Abort when HTAB size requirement can't be met

[David Gibson]

On Thu, Sep 24, 2015 at 01:52:46PM +0530, Bharata B Rao wrote:
> HTAB size is a factor of maximum memory size that is specified by maxmem=
> command line option. In cases where there is shortage of host memory, host
> will not be able to allocate contiguous memory for guest HTAB and will
> instead allocate a smaller HTAB. This usually is not a problem but when
> user starts hotplugging memory to the guest, we can run out of HTAB entries
> and hence memory hotplug fails. This failure should have been handled
> gracefully by the guest kernel, but currently it leads to guest kernel OOPS.
> This will eventually get fixed when the handling of memory hotplug is
> completely moved to kernel for PowerKVM.
> 
> Prevent such kernel failure by refusing to boot the guest when requested
> HTAB size can't be allocated. However HTAB allocation happens in the
> reset path from where it is too late to abort. Hence this patchset
> moves the HTAB allocation to machine init and aborts if HTAB size
> requirement isn't met.
> 
> This patchset applies against David Gibson's spapr-next. With this
> patchset, simple boot, reboot and migration tests pass with HV KVM guest.
> For PR KVM guest, boot and reboot tests were done since migration already
> appears broken for PR KVM.

This looks good.  Applied to spapr-next

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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