From 82ed36164c8a8ee685ea3fb3c4f741214ac070ca Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Thu, 15 Dec 2011 02:03:22 +0000 Subject: KVM: PPC: Book3s HV: Implement get_dirty_log using hardware changed bit This changes the implementation of kvm_vm_ioctl_get_dirty_log() for Book3s HV guests to use the hardware C (changed) bits in the guest hashed page table. Since this makes the implementation quite different from the Book3s PR case, this moves the existing implementation from book3s.c to book3s_pr.c and creates a new implementation in book3s_hv.c. That implementation calls kvmppc_hv_get_dirty_log() to do the actual work by calling kvm_test_clear_dirty on each page. It iterates over the HPTEs, clearing the C bit if set, and returns 1 if any C bit was set (including the saved C bit in the rmap entry). Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf Signed-off-by: Avi Kivity --- arch/powerpc/kvm/book3s_64_mmu_hv.c | 69 +++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) (limited to 'arch/powerpc/kvm/book3s_64_mmu_hv.c') diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 926e2b92bdab..783cd3510c93 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -870,6 +870,75 @@ void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte) kvm_handle_hva(kvm, hva, kvm_unmap_rmapp); } +static int kvm_test_clear_dirty(struct kvm *kvm, unsigned long *rmapp) +{ + struct revmap_entry *rev = kvm->arch.revmap; + unsigned long head, i, j; + unsigned long *hptep; + int ret = 0; + + retry: + lock_rmap(rmapp); + if (*rmapp & KVMPPC_RMAP_CHANGED) { + *rmapp &= ~KVMPPC_RMAP_CHANGED; + ret = 1; + } + if (!(*rmapp & KVMPPC_RMAP_PRESENT)) { + unlock_rmap(rmapp); + return ret; + } + + i = head = *rmapp & KVMPPC_RMAP_INDEX; + do { + hptep = (unsigned long *) (kvm->arch.hpt_virt + (i << 4)); + j = rev[i].forw; + + if (!(hptep[1] & HPTE_R_C)) + continue; + + if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) { + /* unlock rmap before spinning on the HPTE lock */ + unlock_rmap(rmapp); + while (hptep[0] & HPTE_V_HVLOCK) + cpu_relax(); + goto retry; + } + + /* Now check and modify the HPTE */ + if ((hptep[0] & HPTE_V_VALID) && (hptep[1] & HPTE_R_C)) { + /* need to make it temporarily absent to clear C */ + hptep[0] |= HPTE_V_ABSENT; + kvmppc_invalidate_hpte(kvm, hptep, i); + hptep[1] &= ~HPTE_R_C; + eieio(); + hptep[0] = (hptep[0] & ~HPTE_V_ABSENT) | HPTE_V_VALID; + rev[i].guest_rpte |= HPTE_R_C; + ret = 1; + } + hptep[0] &= ~HPTE_V_HVLOCK; + } while ((i = j) != head); + + unlock_rmap(rmapp); + return ret; +} + +long kvmppc_hv_get_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot) +{ + unsigned long i; + unsigned long *rmapp, *map; + + preempt_disable(); + rmapp = memslot->rmap; + map = memslot->dirty_bitmap; + for (i = 0; i < memslot->npages; ++i) { + if (kvm_test_clear_dirty(kvm, rmapp)) + __set_bit_le(i, map); + ++rmapp; + } + preempt_enable(); + return 0; +} + void *kvmppc_pin_guest_page(struct kvm *kvm, unsigned long gpa, unsigned long *nb_ret) { -- cgit v1.2.3-70-g09d2