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KVM: x86: do not pass poisoned hva to __kvm_set_memory_region

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__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: 09d952c971 ("KVM: check userspace_addr for all memslots")
Reported-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2020-06-11 14:01:51 -04:00
parent cfb65c15d7
commit e0135a104c
1 changed files with 1 additions and 6 deletions
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7
arch/x86/kvm/x86.c
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@ -9951,13 +9951,8 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size)
if (!slot || !slot->npages) if (!slot || !slot->npages)
return 0; 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; old_npages = slot->npages;
hva = 0;
} }
for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {