diff options
| author | Sean Christopherson <seanjc@google.com> | 2021-12-06 20:54:22 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-12-08 04:24:28 -0500 |
| commit | 7cd08553ab103a7ebca79035eb35b73418b2f475 (patch) | |
| tree | 5af0292c8f44367b477b9a2050258c4200eee7d1 /virt/kvm | |
| parent | ec5c86976674d2f5c0f389903d956eda1dc54a78 (diff) | |
KVM: Don't make a full copy of the old memslot in __kvm_set_memory_region()
Stop making a full copy of the old memslot in __kvm_set_memory_region()
now that metadata updates are handled by kvm_set_memslot(), i.e. now that
the old memslot's dirty bitmap doesn't need to be referenced after the
memslot and its pointer is modified/invalidated by kvm_set_memslot().
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Message-Id: <5dce0946b41bba8c83f6e3424c6955c56bcc9f86.1638817640.git.maciej.szmigiero@oracle.com>
Diffstat (limited to 'virt/kvm')
| -rw-r--r-- | virt/kvm/kvm_main.c | 35 |
1 files changed, 13 insertions, 22 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index ec5567e8442b..8ccb1ac82d38 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1730,8 +1730,8 @@ out_slots: int __kvm_set_memory_region(struct kvm *kvm, const struct kvm_userspace_memory_region *mem) { - struct kvm_memory_slot old, new; - struct kvm_memory_slot *tmp; + struct kvm_memory_slot *old, *tmp; + struct kvm_memory_slot new; enum kvm_mr_change change; int as_id, id; int r; @@ -1761,25 +1761,16 @@ int __kvm_set_memory_region(struct kvm *kvm, return -EINVAL; /* - * Make a full copy of the old memslot, the pointer will become stale - * when the memslots are re-sorted by update_memslots(), and the old - * memslot needs to be referenced after calling update_memslots(), e.g. - * to free its resources and for arch specific behavior. + * Note, the old memslot (and the pointer itself!) may be invalidated + * and/or destroyed by kvm_set_memslot(). */ - tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id); - if (tmp) { - old = *tmp; - tmp = NULL; - } else { - memset(&old, 0, sizeof(old)); - old.id = id; - } + old = id_to_memslot(__kvm_memslots(kvm, as_id), id); if (!mem->memory_size) { - if (!old.npages) + if (!old || !old->npages) return -EINVAL; - if (WARN_ON_ONCE(kvm->nr_memslot_pages < old.npages)) + if (WARN_ON_ONCE(kvm->nr_memslot_pages < old->npages)) return -EIO; memset(&new, 0, sizeof(new)); @@ -1799,7 +1790,7 @@ int __kvm_set_memory_region(struct kvm *kvm, if (new.npages > KVM_MEM_MAX_NR_PAGES) return -EINVAL; - if (!old.npages) { + if (!old || !old->npages) { change = KVM_MR_CREATE; /* @@ -1809,14 +1800,14 @@ int __kvm_set_memory_region(struct kvm *kvm, if ((kvm->nr_memslot_pages + new.npages) < kvm->nr_memslot_pages) return -EINVAL; } else { /* Modify an existing slot. */ - if ((new.userspace_addr != old.userspace_addr) || - (new.npages != old.npages) || - ((new.flags ^ old.flags) & KVM_MEM_READONLY)) + if ((new.userspace_addr != old->userspace_addr) || + (new.npages != old->npages) || + ((new.flags ^ old->flags) & KVM_MEM_READONLY)) return -EINVAL; - if (new.base_gfn != old.base_gfn) + if (new.base_gfn != old->base_gfn) change = KVM_MR_MOVE; - else if (new.flags != old.flags) + else if (new.flags != old->flags) change = KVM_MR_FLAGS_ONLY; else /* Nothing to change. */ return 0; |