Commit 71a4c30b authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: Refactor error handling for setting memory region 



Replace a big pile o' gotos with returns to make it more obvious what
error code is being returned, and to prepare for refactoring the
functional, i.e. post-checks, portion of __kvm_set_memory_region().

Reviewed-by: default avatarJanosch Frank <frankja@linux.ibm.com>
Reviewed-by: default avatarPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent bd0e96fd

virt/kvm/kvm_main.c

+18 −22
Original line number Diff line number Diff line
@@ -1005,34 +1005,33 @@ int __kvm_set_memory_region(struct kvm *kvm, 


	r = check_memory_region_flags(mem);

	if (r)

		goto out;

		return r;



	r = -EINVAL;

	as_id = mem->slot >> 16;

	id = (u16)mem->slot;



	/* General sanity checks */

	if (mem->memory_size & (PAGE_SIZE - 1))

		goto out;

		return -EINVAL;

	if (mem->guest_phys_addr & (PAGE_SIZE - 1))

		goto out;

		return -EINVAL;

	/* We can read the guest memory with __xxx_user() later on. */

	if ((id < KVM_USER_MEM_SLOTS) &&

	    ((mem->userspace_addr & (PAGE_SIZE - 1)) ||

	     !access_ok((void __user *)(unsigned long)mem->userspace_addr,

			mem->memory_size)))

		goto out;

		return -EINVAL;

	if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_MEM_SLOTS_NUM)

		goto out;

		return -EINVAL;

	if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)

		goto out;

		return -EINVAL;



	slot = id_to_memslot(__kvm_memslots(kvm, as_id), id);

	base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;

	npages = mem->memory_size >> PAGE_SHIFT;



	if (npages > KVM_MEM_MAX_NR_PAGES)

		goto out;

		return -EINVAL;



	new = old = *slot;
@@ -1049,20 +1048,18 @@ int __kvm_set_memory_region(struct kvm *kvm, 
			if ((new.userspace_addr != old.userspace_addr) ||

			    (npages != old.npages) ||

			    ((new.flags ^ old.flags) & KVM_MEM_READONLY))

				goto out;

				return -EINVAL;



			if (base_gfn != old.base_gfn)

				change = KVM_MR_MOVE;

			else if (new.flags != old.flags)

				change = KVM_MR_FLAGS_ONLY;

			else { /* Nothing to change. */

				r = 0;

				goto out;

			}

			else /* Nothing to change. */

				return 0;

		}

	} else {

		if (!old.npages)

			goto out;

			return -EINVAL;



		change = KVM_MR_DELETE;

		new.base_gfn = 0;
@@ -1071,29 +1068,29 @@ int __kvm_set_memory_region(struct kvm *kvm, 


	if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {

		/* Check for overlaps */

		r = -EEXIST;

		kvm_for_each_memslot(slot, __kvm_memslots(kvm, as_id)) {

			if (slot->id == id)

				continue;

			if (!((base_gfn + npages <= slot->base_gfn) ||

			      (base_gfn >= slot->base_gfn + slot->npages)))

				goto out;

				return -EEXIST;

		}

	}



	r = -ENOMEM;



	/* Allocate/free page dirty bitmap as needed */

	if (!(new.flags & KVM_MEM_LOG_DIRTY_PAGES))

		new.dirty_bitmap = NULL;

	else if (!new.dirty_bitmap) {

		if (kvm_create_dirty_bitmap(&new) < 0)

			goto out;

		r = kvm_create_dirty_bitmap(&new);

		if (r)

			return r;

	}



	slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT);

	if (!slots)

	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)) {
@@ -1144,7 +1141,6 @@ out_slots: 
out_bitmap:

	if (new.dirty_bitmap && !old.dirty_bitmap)

		kvm_destroy_dirty_bitmap(&new);

out:

	return r;

}

EXPORT_SYMBOL_GPL(__kvm_set_memory_region);

CRA Git | Maintained and supported by SUSTech CRA and CCSE