4.14-stable review patch. If anyone has any objections, please let me know.
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From: Christian Borntraeger borntraeger@de.ibm.com
commit 32aa144fc32abfcbf7140f473dfbd94c5b9b4105 upstream.
When multiple memory slots are present the cmma migration code does not allocate enough memory for the bitmap. The memory slots are sorted in reverse order, so we must use gfn and size of slot[0] instead of the last one.
Signed-off-by: Christian Borntraeger borntraeger@de.ibm.com Reviewed-by: Claudio Imbrenda imbrenda@linux.vnet.ibm.com Fixes: 190df4a212a7 (KVM: s390: CMMA tracking, ESSA emulation, migration mode) Reviewed-by: Cornelia Huck cohuck@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/s390/kvm/kvm-s390.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
--- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -794,11 +794,12 @@ static int kvm_s390_vm_start_migration(s
if (kvm->arch.use_cmma) { /* - * Get the last slot. They should be sorted by base_gfn, so the - * last slot is also the one at the end of the address space. - * We have verified above that at least one slot is present. + * Get the first slot. They are reverse sorted by base_gfn, so + * the first slot is also the one at the end of the address + * space. We have verified above that at least one slot is + * present. */ - ms = slots->memslots + slots->used_slots - 1; + ms = slots->memslots; /* round up so we only use full longs */ ram_pages = roundup(ms->base_gfn + ms->npages, BITS_PER_LONG); /* allocate enough bytes to store all the bits */