From b2740d3533a3f4aeb9553e872ce471ff73200a7f Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 23 Feb 2016 15:36:01 +0100 Subject: [PATCH] KVM: ensure __gfn_to_pfn_memslot initializes *writable For the kvm_is_error_hva, ubsan complains if the uninitialized writable is passed to __direct_map, even though the value itself is not used (__direct_map goes to mmu_set_spte->set_spte->set_mmio_spte but never looks at that argument). Ensuring that __gfn_to_pfn_memslot initializes *writable is cheap and avoids this kind of issue. Signed-off-by: Paolo Bonzini --- virt/kvm/kvm_main.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 39c36d4f4f5c..1eae05236347 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1434,11 +1434,17 @@ kvm_pfn_t __gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn, { unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault); - if (addr == KVM_HVA_ERR_RO_BAD) + if (addr == KVM_HVA_ERR_RO_BAD) { + if (writable) + *writable = false; return KVM_PFN_ERR_RO_FAULT; + } - if (kvm_is_error_hva(addr)) + if (kvm_is_error_hva(addr)) { + if (writable) + *writable = false; return KVM_PFN_NOSLOT; + } /* Do not map writable pfn in the readonly memslot. */ if (writable && memslot_is_readonly(slot)) { -- 2.20.1