From 32aa144fc32abfcbf7140f473dfbd94c5b9b4105 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Fri, 15 Dec 2017 13:14:31 +0100 Subject: KVM: s390: fix cmma migration for multiple memory slots When multiple memory slots are present the cmma migration code does not allocate enough memory for the bitmap. The memory slots are sorted in reverse order, so we must use gfn and size of slot[0] instead of the last one. Signed-off-by: Christian Borntraeger Reviewed-by: Claudio Imbrenda Cc: stable@vger.kernel.org # 4.13+ Fixes: 190df4a212a7 (KVM: s390: CMMA tracking, ESSA emulation, migration mode) Reviewed-by: Cornelia Huck --- arch/s390/kvm/kvm-s390.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'arch/s390/kvm') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index efa439f6ffb3..abcd24fdde3f 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -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 */ -- cgit v1.2.3 From c2cf265d860882b51a200e4a7553c17827f2b730 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Thu, 21 Dec 2017 09:18:22 +0100 Subject: KVM: s390: prevent buffer overrun on memory hotplug during migration We must not go beyond the pre-allocated buffer. This can happen when a new memory slot is added during migration. Reported-by: David Hildenbrand Signed-off-by: Christian Borntraeger Cc: stable@vger.kernel.org # 4.13+ Fixes: 190df4a212a7 (KVM: s390: CMMA tracking, ESSA emulation, migration mode) Reviewed-by: Cornelia Huck Reviewed-by: David Hildenbrand --- arch/s390/kvm/priv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/s390/kvm') diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 572496c688cc..0714bfa56da0 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -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); -- cgit v1.2.3