Commit 7cd08553 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

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: default avatarSean Christopherson <seanjc@google.com>
Reviewed-by: default avatarMaciej S. Szmigiero <maciej.szmigiero@oracle.com>
Signed-off-by: default avatarMaciej S. Szmigiero <maciej.szmigiero@oracle.com>
Message-Id: <5dce0946b41bba8c83f6e3424c6955c56bcc9f86.1638817640.git.maciej.szmigiero@oracle.com>
parent ec5c8697

virt/kvm/kvm_main.c

+13 −22
Original line number Diff line number Diff line
@@ -1730,8 +1730,8 @@ static int kvm_set_memslot(struct kvm *kvm, 
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;