On 12/19/2017 11:41 AM, Cornelia Huck wrote:
> On Tue, 19 Dec 2017 09:19:21 +0100
> Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:
>
>> when multiple memory slots are present the cmma migration code
>
> s/when/When/
>
>> 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.
>
> I've spent way too much time looking at the memslot code, but this
> seems correct.
>
>>
>> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>> Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxxxxxxx>
>> Cc: stable@xxxxxxxxxxxxxxx # 4.13+
>> Fixes: 190df4a212a7 (KVM: s390: CMMA tracking, ESSA emulation, migration mode)
>> ---
>> arch/s390/kvm/kvm-s390.c | 9 +++++----
>> 1 file changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>> index 966ea611210a..3373d8dff131 100644
>> --- a/arch/s390/kvm/kvm-s390.c
>> +++ b/arch/s390/kvm/kvm-s390.c
>> @@ -792,11 +792,12 @@ static int kvm_s390_vm_start_migration(struct kvm *kvm)
>>
>> 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 */
>
> Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
>
> As you wrote, this is good as a minimal fix.
Paolo, Radim,
do you want a respin and/or pull request or can you take a fixed up version (
adding the Review and fixing when vs When/ for kvm/master?
