Messages in this thread | | | Date | Mon, 25 May 2015 10:38:21 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [v7 4/8] iommu, x86: No need to migrating irq for VT-d Posted-Interrupts |
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On Mon, 25 May 2015, Feng Wu wrote:
> We don't need to migrate the irqs for VT-d Posted-Interrupts here. > When 'pst' is set in IRTE, the associated irq will be posted to > guests instead of interrupt remapping. The destination of the > interrupt is set in Posted-Interrupts Descriptor, and the migration > happens during vCPU scheduling. > > However, we still update the cached irte here, which can be used > when changing back to remapping mode. > > Signed-off-by: Feng Wu <feng.wu@intel.com> > Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com> > Acked-by: David Woodhouse <David.Woodhouse@intel.com> > --- > drivers/iommu/intel_irq_remapping.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c > index 1955b09..646f4cf 100644 > --- a/drivers/iommu/intel_irq_remapping.c > +++ b/drivers/iommu/intel_irq_remapping.c > @@ -994,7 +994,10 @@ intel_ir_set_affinity(struct irq_data *data, const struct cpumask *mask, > */ > irte->vector = cfg->vector; > irte->dest_id = IRTE_DEST(cfg->dest_apicid); > - modify_irte(&ir_data->irq_2_iommu, irte); > + > + /* We don't need to modify irte if the interrupt is for posting. */ > + if (irte->pst != 1) > + modify_irte(&ir_data->irq_2_iommu, irte);
I don't think this is correct. ir_data->irte_entry contains the non posted version, which has pst == 0.
You need some other way to store whether you are in posted mode or not.
Thanks,
tglx
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