Commit 0f9bdef3 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: Wait 'til the bitter end to initialize the "new" memslot 



Initialize the "new" memslot in the !DELETE path only after the various
sanity checks have passed.  This will allow a future commit to allocate
@new dynamically without having to copy a memslot, and without having to
deal with freeing @new in error paths and in the "nothing to change" path
that's hiding in the sanity checks.

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: <a084d0531ca3a826a7f861eb2b08b5d1c06ef265.1638817641.git.maciej.szmigiero@oracle.com>
parent 44401a20

virt/kvm/kvm_main.c

+20 −17
Original line number Diff line number Diff line
@@ -1843,6 +1843,8 @@ int __kvm_set_memory_region(struct kvm *kvm, 
	struct kvm_memory_slot new;

	struct kvm_memslots *slots;

	enum kvm_mr_change change;

	unsigned long npages;

	gfn_t base_gfn;

	int as_id, id;

	int r;
@@ -1869,6 +1871,8 @@ int __kvm_set_memory_region(struct kvm *kvm, 
		return -EINVAL;

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

		return -EINVAL;

	if ((mem->memory_size >> PAGE_SHIFT) > KVM_MEM_MAX_NR_PAGES)

		return -EINVAL;



	slots = __kvm_memslots(kvm, as_id);
@@ -1892,15 +1896,8 @@ int __kvm_set_memory_region(struct kvm *kvm, 
		return kvm_set_memslot(kvm, old, &new, KVM_MR_DELETE);

	}



	new.as_id = as_id;

	new.id = id;

	new.base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;

	new.npages = mem->memory_size >> PAGE_SHIFT;

	new.flags = mem->flags;

	new.userspace_addr = mem->userspace_addr;



	if (new.npages > KVM_MEM_MAX_NR_PAGES)

		return -EINVAL;

	base_gfn = (mem->guest_phys_addr >> PAGE_SHIFT);

	npages = (mem->memory_size >> PAGE_SHIFT);



	if (!old || !old->npages) {

		change = KVM_MR_CREATE;
@@ -1909,27 +1906,33 @@ int __kvm_set_memory_region(struct kvm *kvm, 
		 * To simplify KVM internals, the total number of pages across

		 * all memslots must fit in an unsigned long.

		 */

		if ((kvm->nr_memslot_pages + new.npages) < kvm->nr_memslot_pages)

		if ((kvm->nr_memslot_pages + 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 ((mem->userspace_addr != old->userspace_addr) ||

		    (npages != old->npages) ||

		    ((mem->flags ^ old->flags) & KVM_MEM_READONLY))

			return -EINVAL;



		if (new.base_gfn != old->base_gfn)

		if (base_gfn != old->base_gfn)

			change = KVM_MR_MOVE;

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

		else if (mem->flags != old->flags)

			change = KVM_MR_FLAGS_ONLY;

		else /* Nothing to change. */

			return 0;

	}



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

	    kvm_check_memslot_overlap(slots, id, new.base_gfn,

				      new.base_gfn + new.npages))

	    kvm_check_memslot_overlap(slots, id, base_gfn, base_gfn + npages))

		return -EEXIST;



	new.as_id = as_id;

	new.id = id;

	new.base_gfn = base_gfn;

	new.npages = npages;

	new.flags = mem->flags;

	new.userspace_addr = mem->userspace_addr;



	return kvm_set_memslot(kvm, old, &new, change);

}

EXPORT_SYMBOL_GPL(__kvm_set_memory_region);