Commit e0135a10 authored Jun 11, 2020 by Paolo Bonzini

KVM: x86: do not pass poisoned hva to __kvm_set_memory_region



__kvm_set_memory_region does not use the hva at all, so trying to
catch use-after-delete is pointless and, worse, it fails access_ok
now that we apply it to all memslots including private kernel ones.
This fixes an AVIC regression.

Fixes: 09d952c9 ("KVM: check userspace_addr for all memslots")
Reported-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent cfb65c15

arch/x86/kvm/x86.c

+1 −6

Original line number	Diff line number	Diff line
		@@ -9951,13 +9951,8 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size)
		if (!slot \|\| !slot->npages)
		return 0;

		/*
		* Stuff a non-canonical value to catch use-after-delete. This
		* ends up being 0 on 32-bit KVM, but there's no better
		* alternative.
		*/
		hva = (unsigned long)(0xdeadull << 48);
		old_npages = slot->npages;
		hva = 0;
		}

		for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {

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