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 <da...@gibson.dropbear.id.au> > --- > 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