On 15.12.2016 06:54, David Gibson wrote:
> The kvm_unmap_rmapp() function, called from certain MMU notifiers, is used
> to force all guest mappings of a particular host page to be set ABSENT, and
> removed from the reverse mappings.
>
> For HPT resizing, we will have some cases where we want to set just a
> single guest HPTE ABSENT and remove its reverse mappings. To prepare with
> this, we split out the logic from kvm_unmap_rmapp() to evict a single HPTE,
> moving it to a new helper function.
>
> Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> ---
> arch/powerpc/kvm/book3s_64_mmu_hv.c | 77 +++++++++++++++++++++----------------
> 1 file changed, 44 insertions(+), 33 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> index 8e5ac2f..cd145eb 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> @@ -740,13 +740,53 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
> return kvm_handle_hva_range(kvm, hva, hva + 1, handler);
> }
>
> +/* Must be called with both HPTE and rmap locked */
> +static void kvmppc_unmap_hpte(struct kvm *kvm, unsigned long i,
> + unsigned long *rmapp, unsigned long gfn)
> +{
> + __be64 *hptep = (__be64 *) (kvm->arch.hpt.virt + (i << 4));
> + struct revmap_entry *rev = kvm->arch.hpt.rev;
> + unsigned long j, h;
> + unsigned long ptel, psize, rcbits;
> +
> + j = rev[i].forw;
> + if (j == i) {
> + /* chain is now empty */
> + *rmapp &= ~(KVMPPC_RMAP_PRESENT | KVMPPC_RMAP_INDEX);
> + } else {
> + /* remove i from chain */
> + h = rev[i].back;
> + rev[h].forw = j;
> + rev[j].back = h;
> + rev[i].forw = rev[i].back = i;
> + *rmapp = (*rmapp & ~KVMPPC_RMAP_INDEX) | j;
> + }
> +
> + /* Now check and modify the HPTE */
> + ptel = rev[i].guest_rpte;
> + psize = hpte_page_size(be64_to_cpu(hptep[0]), ptel);
> + if ((be64_to_cpu(hptep[0]) & HPTE_V_VALID) &&
> + hpte_rpn(ptel, psize) == gfn) {
> + hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
> + kvmppc_invalidate_hpte(kvm, hptep, i);
> + hptep[1] &= ~cpu_to_be64(HPTE_R_KEY_HI | HPTE_R_KEY_LO);
> + /* Harvest R and C */
> + rcbits = be64_to_cpu(hptep[1]) & (HPTE_R_R | HPTE_R_C);
> + *rmapp |= rcbits << KVMPPC_RMAP_RC_SHIFT;
> + if (rcbits & HPTE_R_C)
> + kvmppc_update_rmap_change(rmapp, psize);
> + if (rcbits & ~rev[i].guest_rpte) {
> + rev[i].guest_rpte = ptel | rcbits;
> + note_hpte_modification(kvm, &rev[i]);
> + }
> + }
Superfluous TAB at the end of above line.
Apart from that, the patch looks fine to me.
Thomas
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