When the destination mode of an interrupt is physical APICID, the interrupt is delivered only to the single CPU of which the physical APICID is specified in the destination ID field. Therefore, the redirection hint is meaningless.
Furthermore, on certain processors, the IOMMU does not deliver the interrupt when the delivery mode is NMI, the redirection hint is set, and the destination mode is physical. Clearing the redirection hint ensures that the NMI is delivered. Cc: Andi Kleen <[email protected]> Cc: David Woodhouse <[email protected]> Cc: "Ravi V. Shankar" <[email protected]> Cc: Lu Baolu <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Suggested-by: Ashok Raj <[email protected]> Reviewed-by: Lu Baolu <[email protected]> Signed-off-by: Ricardo Neri <[email protected]> --- Changes since v5: * Introduced this patch. Changes since v4: * N/A Changes since v3: * N/A Changes since v2: * N/A Changes since v1: * N/A --- drivers/iommu/intel/irq_remapping.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel/irq_remapping.c b/drivers/iommu/intel/irq_remapping.c index a67319597884..d2764a71f91a 100644 --- a/drivers/iommu/intel/irq_remapping.c +++ b/drivers/iommu/intel/irq_remapping.c @@ -1128,7 +1128,17 @@ static void prepare_irte(struct irte *irte, int vector, unsigned int dest) irte->dlvry_mode = apic->delivery_mode; irte->vector = vector; irte->dest_id = IRTE_DEST(dest); - irte->redir_hint = 1; + + /* + * When using the destination mode of physical APICID, only the + * processor specified in @dest receives the interrupt. Thus, the + * redirection hint is meaningless. + * + * Furthermore, on some processors, NMIs with physical delivery mode + * and the redirection hint set are delivered as regular interrupts + * or not delivered at all. + */ + irte->redir_hint = apic->dest_mode_logical; } struct irq_remap_ops intel_irq_remap_ops = { -- 2.17.1 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
