Split out the core functionality of setting a memslot into a separate
helper in preparation for moving memslot deletion into its own routine.

Signed-off-by: Sean Christopherson <sean.j.christopher...@intel.com>
---
 virt/kvm/kvm_main.c | 106 ++++++++++++++++++++++++++------------------
 1 file changed, 63 insertions(+), 43 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 8306ce3345a6..693f3d20e710 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -907,6 +907,66 @@ static struct kvm_memslots *install_new_memslots(struct 
kvm *kvm,
        return old_memslots;
 }
 
+static int kvm_set_memslot(struct kvm *kvm,
+                          const struct kvm_userspace_memory_region *mem,
+                          const struct kvm_memory_slot *old,
+                          struct kvm_memory_slot *new, int as_id,
+                          enum kvm_mr_change change)
+{
+       struct kvm_memory_slot *slot;
+       struct kvm_memslots *slots;
+       int r;
+
+       slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT);
+       if (!slots)
+               return -ENOMEM;
+       memcpy(slots, __kvm_memslots(kvm, as_id), sizeof(struct kvm_memslots));
+
+       if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
+               /*
+                * Note, the INVALID flag needs to be in the appropriate entry
+                * in the freshly allocated memslots, not in @old or @new.
+                */
+               slot = id_to_memslot(slots, old->id);
+               slot->flags |= KVM_MEMSLOT_INVALID;
+
+               /*
+                * We can re-use the old memslots, the only difference from the
+                * newly installed memslots is the invalid flag, which will get
+                * dropped by update_memslots anyway.  We'll also revert to the
+                * old memslots if preparing the new memory region fails.
+                */
+               slots = install_new_memslots(kvm, as_id, slots);
+
+               /* From this point no new shadow pages pointing to a deleted,
+                * or moved, memslot will be created.
+                *
+                * validation of sp->gfn happens in:
+                *      - gfn_to_hva (kvm_read_guest, gfn_to_pfn)
+                *      - kvm_is_visible_gfn (mmu_check_roots)
+                */
+               kvm_arch_flush_shadow_memslot(kvm, slot);
+       }
+
+       r = kvm_arch_prepare_memory_region(kvm, new, mem, change);
+       if (r)
+               goto out_slots;
+
+       update_memslots(slots, new, change);
+       slots = install_new_memslots(kvm, as_id, slots);
+
+       kvm_arch_commit_memory_region(kvm, mem, old, new, change);
+
+       kvfree(slots);
+       return 0;
+
+out_slots:
+       if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
+               slots = install_new_memslots(kvm, as_id, slots);
+       kvfree(slots);
+       return r;
+}
+
 /*
  * Allocate some memory and give it an address in the guest physical address
  * space.
@@ -923,7 +983,6 @@ int __kvm_set_memory_region(struct kvm *kvm,
        unsigned long npages;
        struct kvm_memory_slot *slot;
        struct kvm_memory_slot old, new;
-       struct kvm_memslots *slots;
        int as_id, id;
        enum kvm_mr_change change;
 
@@ -1010,58 +1069,19 @@ int __kvm_set_memory_region(struct kvm *kvm,
                        return r;
        }
 
-       slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT);
-       if (!slots) {
-               r = -ENOMEM;
-               goto out_bitmap;
-       }
-       memcpy(slots, __kvm_memslots(kvm, as_id), sizeof(struct kvm_memslots));
-
-       if ((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE)) {
-               slot = id_to_memslot(slots, id);
-               slot->flags |= KVM_MEMSLOT_INVALID;
-
-               /*
-                * We can re-use the old memslots, the only difference from the
-                * newly installed memslots is the invalid flag, which will get
-                * dropped by update_memslots anyway.  We'll also revert to the
-                * old memslots if preparing the new memory region fails.
-                */
-               slots = install_new_memslots(kvm, as_id, slots);
-
-               /* From this point no new shadow pages pointing to a deleted,
-                * or moved, memslot will be created.
-                *
-                * validation of sp->gfn happens in:
-                *      - gfn_to_hva (kvm_read_guest, gfn_to_pfn)
-                *      - kvm_is_visible_gfn (mmu_check_roots)
-                */
-               kvm_arch_flush_shadow_memslot(kvm, slot);
-       }
-
-       r = kvm_arch_prepare_memory_region(kvm, &new, mem, change);
-       if (r)
-               goto out_slots;
-
        /* actual memory is freed via old in kvm_free_memslot below */
        if (change == KVM_MR_DELETE) {
                new.dirty_bitmap = NULL;
                memset(&new.arch, 0, sizeof(new.arch));
        }
 
-       update_memslots(slots, &new, change);
-       slots = install_new_memslots(kvm, as_id, slots);
-
-       kvm_arch_commit_memory_region(kvm, mem, &old, &new, change);
+       r = kvm_set_memslot(kvm, mem, &old, &new, as_id, change);
+       if (r)
+               goto out_bitmap;
 
        kvm_free_memslot(kvm, &old, &new);
-       kvfree(slots);
        return 0;
 
-out_slots:
-       if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
-               slots = install_new_memslots(kvm, as_id, slots);
-       kvfree(slots);
 out_bitmap:
        if (new.dirty_bitmap && !old.dirty_bitmap)
                kvm_destroy_dirty_bitmap(&new);
-- 
2.22.0

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