From 82ed36164c8a8ee685ea3fb3c4f741214ac070ca Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Thu, 15 Dec 2011 02:03:22 +0000 Subject: [PATCH] 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/include/asm/kvm_book3s.h | 2 + arch/powerpc/kvm/book3s.c | 39 -------------------- arch/powerpc/kvm/book3s_64_mmu_hv.c | 69 +++++++++++++++++++++++++++++++++++ arch/powerpc/kvm/book3s_hv.c | 37 +++++++++++++++++++ arch/powerpc/kvm/book3s_pr.c | 39 ++++++++++++++++++++ 5 files changed, 147 insertions(+), 39 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h index 33fdc09..3c3edee 100644 --- a/arch/powerpc/include/asm/kvm_book3s.h +++ b/arch/powerpc/include/asm/kvm_book3s.h @@ -156,6 +156,8 @@ extern long kvmppc_virtmode_h_enter(struct kvm_vcpu *vcpu, unsigned long flags, long pte_index, unsigned long pteh, unsigned long ptel); extern long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags, long pte_index, unsigned long pteh, unsigned long ptel); +extern long kvmppc_hv_get_dirty_log(struct kvm *kvm, + struct kvm_memory_slot *memslot); extern void kvmppc_entry_trampoline(void); extern void kvmppc_hv_entry_trampoline(void); diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c index 6bf7e05..7d54f4e 100644 --- a/arch/powerpc/kvm/book3s.c +++ b/arch/powerpc/kvm/book3s.c @@ -477,45 +477,6 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu, return 0; } -/* - * Get (and clear) the dirty memory log for a memory slot. - */ -int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, - struct kvm_dirty_log *log) -{ - struct kvm_memory_slot *memslot; - struct kvm_vcpu *vcpu; - ulong ga, ga_end; - int is_dirty = 0; - int r; - unsigned long n; - - mutex_lock(&kvm->slots_lock); - - r = kvm_get_dirty_log(kvm, log, &is_dirty); - if (r) - goto out; - - /* If nothing is dirty, don't bother messing with page tables. */ - if (is_dirty) { - memslot = id_to_memslot(kvm->memslots, log->slot); - - ga = memslot->base_gfn << PAGE_SHIFT; - ga_end = ga + (memslot->npages << PAGE_SHIFT); - - kvm_for_each_vcpu(n, vcpu, kvm) - kvmppc_mmu_pte_pflush(vcpu, ga, ga_end); - - n = kvm_dirty_bitmap_bytes(memslot); - memset(memslot->dirty_bitmap, 0, n); - } - - r = 0; -out: - mutex_unlock(&kvm->slots_lock); - return r; -} - void kvmppc_decrementer_func(unsigned long data) { struct kvm_vcpu *vcpu = (struct kvm_vcpu *)data; diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 926e2b9..783cd35 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) { diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 86c4191..0f1ddf0 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -1072,6 +1072,43 @@ long kvm_vm_ioctl_allocate_rma(struct kvm *kvm, struct kvm_allocate_rma *ret) return fd; } +/* + * Get (and clear) the dirty memory log for a memory slot. + */ +int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log) +{ + struct kvm_memory_slot *memslot; + int r; + unsigned long n; + + mutex_lock(&kvm->slots_lock); + + r = -EINVAL; + if (log->slot >= KVM_MEMORY_SLOTS) + goto out; + + memslot = id_to_memslot(kvm->memslots, log->slot); + r = -ENOENT; + if (!memslot->dirty_bitmap) + goto out; + + n = kvm_dirty_bitmap_bytes(memslot); + memset(memslot->dirty_bitmap, 0, n); + + r = kvmppc_hv_get_dirty_log(kvm, memslot); + if (r) + goto out; + + r = -EFAULT; + if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n)) + goto out; + + r = 0; +out: + mutex_unlock(&kvm->slots_lock); + return r; +} + static unsigned long slb_pgsize_encoding(unsigned long psize) { unsigned long senc = 0; diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 2da6704..c193625 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -1056,6 +1056,45 @@ out: return ret; } +/* + * Get (and clear) the dirty memory log for a memory slot. + */ +int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, + struct kvm_dirty_log *log) +{ + struct kvm_memory_slot *memslot; + struct kvm_vcpu *vcpu; + ulong ga, ga_end; + int is_dirty = 0; + int r; + unsigned long n; + + mutex_lock(&kvm->slots_lock); + + r = kvm_get_dirty_log(kvm, log, &is_dirty); + if (r) + goto out; + + /* If nothing is dirty, don't bother messing with page tables. */ + if (is_dirty) { + memslot = id_to_memslot(kvm->memslots, log->slot); + + ga = memslot->base_gfn << PAGE_SHIFT; + ga_end = ga + (memslot->npages << PAGE_SHIFT); + + kvm_for_each_vcpu(n, vcpu, kvm) + kvmppc_mmu_pte_pflush(vcpu, ga, ga_end); + + n = kvm_dirty_bitmap_bytes(memslot); + memset(memslot->dirty_bitmap, 0, n); + } + + r = 0; +out: + mutex_unlock(&kvm->slots_lock); + return r; +} + int kvmppc_core_prepare_memory_region(struct kvm *kvm, struct kvm_userspace_memory_region *mem) { -- 2.7.4