Re: [PATCH v3 00/26] KVM: x86: Halt and APICv overhaul

[Paolo Bonzini]

On 12/9/21 01:02, Sean Christopherson wrote:
> RDX, a.k.a. ir_data is NULL.  This check in svm_ir_list_add()
>
> 	if (pi->ir_data && (pi->prev_ga_tag != 0)) {
>
> implies pi->ir_data can be NULL, but neither avic_update_iommu_vcpu_affinity()
> nor amd_iommu_update_ga() check ir->data for NULL.
>
> amd_ir_set_vcpu_affinity() returns "success" without clearing pi.is_guest_mode
>
> 	/* Note:
> 	 * This device has never been set up for guest mode.
> 	 * we should not modify the IRTE
> 	 */
> 	if (!dev_data || !dev_data->use_vapic)
> 		return 0;
>
> so it's plausible svm_ir_list_add() could add to the list with a NULL pi->ir_data.
>
> But none of the relevant code has seen any meaningful changes since 5.15, so odds
> are good I broke something :-/

Ok, I'll take this.

Paolo