KVM: ensure __gfn_to_pfn_memslot initializes *writable (b2740d35) · Commits · 戴 / test

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>

virt/kvm/kvm_main.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -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)) {

Admin message