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Commit bb4945e6 authored by Radim Krčmář's avatar Radim Krčmář
Browse files

Merge tag 'kvm-s390-master-4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux 

KVM: s390: fixes for cmma migration

Two fixes for potential bitmap overruns in the cmma migration
code.
parents 0cb5b306 c2cf265d

arch/s390/kvm/kvm-s390.c

+5 −4
Original line number Diff line number Diff line
@@ -792,11 +792,12 @@ static int kvm_s390_vm_start_migration(struct kvm *kvm) 


	if (kvm->arch.use_cmma) {

		/*

		 * Get the last slot. They should be sorted by base_gfn, so the

		 * last slot is also the one at the end of the address space.

		 * We have verified above that at least one slot is present.

		 * Get the first slot. They are reverse sorted by base_gfn, so

		 * the first slot is also the one at the end of the address

		 * space. We have verified above that at least one slot is

		 * present.

		 */

		ms = slots->memslots + slots->used_slots - 1;

		ms = slots->memslots;

		/* round up so we only use full longs */

		ram_pages = roundup(ms->base_gfn + ms->npages, BITS_PER_LONG);

		/* allocate enough bytes to store all the bits */

arch/s390/kvm/priv.c

+1 −1
Original line number Diff line number Diff line
@@ -1006,7 +1006,7 @@ static inline int do_essa(struct kvm_vcpu *vcpu, const int orc) 
		cbrlo[entries] = gfn << PAGE_SHIFT;

	}



	if (orc) {

	if (orc && gfn < ms->bitmap_size) {

		/* increment only if we are really flipping the bit to 1 */

		if (!test_and_set_bit(gfn, ms->pgste_bitmap))

			atomic64_inc(&ms->dirty_pages);