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>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 39c36d4..1eae052 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1434,11 +1434,17 @@
{
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)) {