[V4, 1/4] KVM: PPC: Use READ_ONCE when dereferencing pte_t pointer

Aneesh Kumar K.V aneesh.kumar at linux.vnet.ibm.com
Mon Mar 30 03:46:52 AEDT 2015


Michael Ellerman <mpe at ellerman.id.au> writes:

> On Thu, 2015-26-03 at 13:13:39 UTC, "Aneesh Kumar K.V" wrote:
>> pte can get updated from other CPUs as part of multiple activities
>> like THP split, huge page collapse, unmap. We need to make sure we
>> don't reload the pte value again and again for different checks.
>> 
>> ---
>>  arch/powerpc/include/asm/kvm_book3s_64.h |  5 ++++-
>>  arch/powerpc/kvm/e500_mmu_host.c         | 20 ++++++++++++--------
>>  2 files changed, 16 insertions(+), 9 deletions(-)
>
> So this series is partly KVM but mostly powerpc.
>
> I assume you can't split it into two separate series easily?

Yes, will do. But before that I was looking for feedback from Ben or
Paul.

>
> You haven't sent it to the KVM lists or to Alex AFAICS. You'll need to do that
> for the KVM pieces at least. We can probably take it all via powerpc, but I'll
> need an ACK from Alex at least.
>

If I can get an ack from Ben, that makes it easy for the kvm list.

-aneesh



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