From 345ff079a8ac212417be800746961a6ce929c3ba Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 11 Jun 2020 14:01:51 -0400 Subject: [PATCH] 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: eafc16c93920 ("KVM: check userspace_addr for all memslots") Reported-by: Maxim Levitsky Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 290784ba63e41..00c88c2f34e44 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -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++) { -- 2.39.5