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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 <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2016-02-23 15:36:01 +01:00
parent 107d44a2c5
commit b2740d3533
1 changed files with 8 additions and 2 deletions
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10
virt/kvm/kvm_main.c
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@ -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)) {