Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH] KVM: x86: fix a typo in __try_cmpxchg_user that caused cmpxchg to be not atomic | Date | Thu, 12 May 2022 14:45:42 +0200 |
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Maxim Levitsky <mlevitsk@redhat.com> writes:
> Fixes: 1c2361f667f36 ("KVM: x86: Use __try_cmpxchg_user() to emulate atomic accesses") > Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> > --- > arch/x86/kvm/x86.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Yes, this is the root cause of the TDP mmu leak I was doing debug of in the last week. > Non working cmpxchg on which TDP mmu relies makes it install two differnt shadow pages > under same spte.
In case the fix is not squashed with 1c2361f667f36, the above should really go before '---'.
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 8ee8c91fa7625..79cabd3d97d22 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -7329,7 +7329,7 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt, > goto emul_write; > > hva = kvm_vcpu_gfn_to_hva(vcpu, gpa_to_gfn(gpa)); > - if (kvm_is_error_hva(addr)) > + if (kvm_is_error_hva(hva))
Looks like a typo indeed, so
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> goto emul_write; > > hva += offset_in_page(gpa);
-- Vitaly
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