On Tue, Nov 10, 2015 at 08:38:57AM -0600, Michael Roth wrote: > Quoting Bharata B Rao (2015-11-09 23:24:54) > > KVM_PPC_ALLOCATE_HTAB ioctl can return -ENOMEM for KVM guests and QEMU > > never handled this correctly. But this didn't cause any problems till > > now as KVM_PPC_ALLOCATE_HTAB ioctl returned with smaller than requested > > HTAB when enough contiguous memory wasn't available in the host. > > After the proposed kernel change: > > https://patchwork.ozlabs.org/patch/530501/, > > KVM_PPC_ALLOCATE_HTAB ioctl will not fallback to lower sized HTAB > > allocation and will fail if requested HTAB size can't be met. > > > > Check for such failures in QEMU and abort appropriately. This will > > prevent guest kernel from hanging/freezing during early boot by doing > > graceful exit when host is unable to allocate requested HTAB. > > > > Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com> > > --- > > hw/ppc/spapr.c | 20 ++++++++++++++++---- > > 1 file changed, 16 insertions(+), 4 deletions(-) > > > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > > index e1202ce..a64a1b5 100644 > > --- a/hw/ppc/spapr.c > > +++ b/hw/ppc/spapr.c > > @@ -1021,9 +1021,19 @@ static void spapr_alloc_htab(sPAPRMachineState > > *spapr) > > * RAM */ > > > > shift = kvmppc_reset_htab(spapr->htab_shift); > > - > > - if (shift > 0) { > > - /* Kernel handles htab, we don't need to allocate one */ > > + if (shift < 0) { > > + /* > > + * For HV KVM, host kernel will return -ENOMEM when requested > > + * HTAB size can't be allocated. > > + */ > > + error_setg(&error_abort, "Failed to allocate HTAB of requested > > size, try with smaller maxmem"); > > Wording is appropriate, but maybe just "Failed to allocate HTAB, try with > smaller maxmem" to distinguish it from the error below where the call succeeds > but there's a size mismatch?
Possibly the message could be a little better, but I'm not going to
hold up the patches just for that. I've applied tentatively to
spapr-next, and I hope to send a pull req with it soon, assuming it
survives my tests.
--
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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