Messages in this thread | | | Date | Fri, 3 Dec 2021 23:48:42 +0000 | From | Sean Christopherson <> | Subject | Re: [PATCH v2 7/8] KVM: x86: Reject fixeds-size Hyper-V hypercalls with non-zero "var_cnt" |
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On Mon, Nov 01, 2021, Vitaly Kuznetsov wrote: > Sean Christopherson <seanjc@google.com> writes: > > @@ -2331,6 +2331,11 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu) > > ret = HV_STATUS_OPERATION_DENIED; > > break; > > } > > + if (unlikely(hc.var_cnt)) { > > + ret = HV_STATUS_INVALID_HYPERCALL_INPUT; > > + break; > > + } > > + > > Probably true for HVCALL_RESET_DEBUG_SESSION but I'm not sure about > HVCALL_POST_DEBUG_DATA/HVCALL_RETRIEVE_DEBUG_DATA (note 'fallthrough' > above) -- these are not described well in TLFS.
I'll drop the check for all the DEBUG hypercalls and add a note in the changelog to call out that they're probably not supposed to use var_cnt, but that the TLFS documentation isn't clear one way or the other.
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