On 20.11.2012, at 10:01, Paul Mackerras wrote:
> This fixes a bug where adding a new guest HPT entry via the H_ENTER
> hcall would lose the "changed" bit in the reverse map information
> for the guest physical page being mapped. The result was that the
> KVM_GET_DIRTY_LOG could return a zero bit for the page even though
> the page had been modified by the guest.
>
> This fixes it by only modifying the index and present bits in the
> reverse map entry, thus preserving the reference and change bits.
> We were also unnecessarily setting the reference bit, and this
> fixes that too.
>
> Signed-off-by: Paul Mackerras <[email protected]>
Thanks, applied to kvm-ppc-next.
Alex
> ---
> This is against Alex Graf's kvm-ppc-next branch plus the series of three
> patches I just sent, but it should be independent of that series.
>
> arch/powerpc/kvm/book3s_hv_rm_mmu.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> index 2334000..fc3da32 100644
> --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> @@ -59,10 +59,10 @@ void kvmppc_add_revmap_chain(struct kvm *kvm, struct
> revmap_entry *rev,
> head->back = pte_index;
> } else {
> rev->forw = rev->back = pte_index;
> - i = pte_index;
> + *rmap = (*rmap & ~KVMPPC_RMAP_INDEX) |
> + pte_index | KVMPPC_RMAP_PRESENT;
> }
> - smp_wmb();
> - *rmap = i | KVMPPC_RMAP_REFERENCED | KVMPPC_RMAP_PRESENT; /* unlock */
> + unlock_rmap(rmap);
> }
> EXPORT_SYMBOL_GPL(kvmppc_add_revmap_chain);
>
> --
> 1.7.10.4
>
> --
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