diff options
| -rw-r--r-- | virt/kvm/kvm_main.c | 109 |
1 files changed, 66 insertions, 43 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 373079a03710..ec5567e8442b 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1549,6 +1549,69 @@ static void kvm_copy_memslots_arch(struct kvm_memslots *to, to->memslots[i].arch = from->memslots[i].arch; } +static int kvm_prepare_memory_region(struct kvm *kvm, + const struct kvm_memory_slot *old, + struct kvm_memory_slot *new, + enum kvm_mr_change change) +{ + int r; + + /* + * If dirty logging is disabled, nullify the bitmap; the old bitmap + * will be freed on "commit". If logging is enabled in both old and + * new, reuse the existing bitmap. If logging is enabled only in the + * new and KVM isn't using a ring buffer, allocate and initialize a + * new bitmap. + */ + if (!(new->flags & KVM_MEM_LOG_DIRTY_PAGES)) + new->dirty_bitmap = NULL; + else if (old->dirty_bitmap) + new->dirty_bitmap = old->dirty_bitmap; + else if (!kvm->dirty_ring_size) { + r = kvm_alloc_dirty_bitmap(new); + if (r) + return r; + + if (kvm_dirty_log_manual_protect_and_init_set(kvm)) + bitmap_set(new->dirty_bitmap, 0, new->npages); + } + + r = kvm_arch_prepare_memory_region(kvm, old, new, change); + + /* Free the bitmap on failure if it was allocated above. */ + if (r && new->dirty_bitmap && !old->dirty_bitmap) + kvm_destroy_dirty_bitmap(new); + + return r; +} + +static void kvm_commit_memory_region(struct kvm *kvm, + struct kvm_memory_slot *old, + const struct kvm_memory_slot *new, + enum kvm_mr_change change) +{ + /* + * Update the total number of memslot pages before calling the arch + * hook so that architectures can consume the result directly. + */ + if (change == KVM_MR_DELETE) + kvm->nr_memslot_pages -= old->npages; + else if (change == KVM_MR_CREATE) + kvm->nr_memslot_pages += new->npages; + + kvm_arch_commit_memory_region(kvm, old, new, change); + + /* + * Free the old memslot's metadata. On DELETE, free the whole thing, + * otherwise free the dirty bitmap as needed (the below effectively + * checks both the flags and whether a ring buffer is being used). + */ + if (change == KVM_MR_DELETE) + kvm_free_memslot(kvm, old); + else if (old->dirty_bitmap && !new->dirty_bitmap) + kvm_destroy_dirty_bitmap(old); +} + static int kvm_set_memslot(struct kvm *kvm, struct kvm_memory_slot *new, enum kvm_mr_change change) @@ -1635,27 +1698,14 @@ static int kvm_set_memslot(struct kvm *kvm, old.as_id = new->as_id; } - r = kvm_arch_prepare_memory_region(kvm, &old, new, change); + r = kvm_prepare_memory_region(kvm, &old, new, change); if (r) goto out_slots; update_memslots(slots, new, change); slots = install_new_memslots(kvm, new->as_id, slots); - /* - * Update the total number of memslot pages before calling the arch - * hook so that architectures can consume the result directly. - */ - if (change == KVM_MR_DELETE) - kvm->nr_memslot_pages -= old.npages; - else if (change == KVM_MR_CREATE) - kvm->nr_memslot_pages += new->npages; - - kvm_arch_commit_memory_region(kvm, &old, new, change); - - /* Free the old memslot's metadata. Note, this is the full copy!!! */ - if (change == KVM_MR_DELETE) - kvm_free_memslot(kvm, &old); + kvm_commit_memory_region(kvm, &old, new, change); kvfree(slots); return 0; @@ -1751,7 +1801,6 @@ int __kvm_set_memory_region(struct kvm *kvm, if (!old.npages) { change = KVM_MR_CREATE; - new.dirty_bitmap = NULL; /* * To simplify KVM internals, the total number of pages across @@ -1771,9 +1820,6 @@ int __kvm_set_memory_region(struct kvm *kvm, change = KVM_MR_FLAGS_ONLY; else /* Nothing to change. */ return 0; - - /* Copy dirty_bitmap from the current memslot. */ - new.dirty_bitmap = old.dirty_bitmap; } if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) { @@ -1787,30 +1833,7 @@ int __kvm_set_memory_region(struct kvm *kvm, } } - /* Allocate/free page dirty bitmap as needed */ - if (!(new.flags & KVM_MEM_LOG_DIRTY_PAGES)) - new.dirty_bitmap = NULL; - else if (!new.dirty_bitmap && !kvm->dirty_ring_size) { - r = kvm_alloc_dirty_bitmap(&new); - if (r) - return r; - - if (kvm_dirty_log_manual_protect_and_init_set(kvm)) - bitmap_set(new.dirty_bitmap, 0, new.npages); - } - - r = kvm_set_memslot(kvm, &new, change); - if (r) - goto out_bitmap; - - if (old.dirty_bitmap && !new.dirty_bitmap) - kvm_destroy_dirty_bitmap(&old); - return 0; - -out_bitmap: - if (new.dirty_bitmap && !old.dirty_bitmap) - kvm_destroy_dirty_bitmap(&new); - return r; + return kvm_set_memslot(kvm, &new, change); } EXPORT_SYMBOL_GPL(__kvm_set_memory_region); |