Re: [Xen-devel] [PATCH v10 1/3] vt-d: add a timeout parameter for Queued Invalidation

["Xu, Quan" <quan.xu@xxxxxxxxx>]

On May 19, 2016 2:13 PM, Jan Beulich <jbeulich@xxxxxxxx> wrote:
> >>> "Xu, Quan" <quan.xu@xxxxxxxxx> 05/19/16 3:35 AM >>>
> >On May 19, 2016 8:33 AM, Tian, Kevin <kevin.tian@xxxxxxxxx> wrote:
> >> A single default value for both IOMMU-side and device-side is anyway
> >> not optimal. What about introducing a new knob e.g.
> >> vtd_qi_device_timeout specifically for device-side flush while using
> >> vtd_qi_timeout for other places? If device-side timeout is not specified, 
> >> it is
> then default to vtd_qi_timeout.
> 
> There should imo be a single command line option, allowing for two values to
> be passed (e.g. comma-separated).
> 

As mentioned, 1 ms is enough for VT-d IOTLB/Context/IEC invalidation, so we are 
no need to increasing the value of timeout or introduce a boot-time changed 
parameter.
What about a constant (e.g. a macro), 1 ms, for VT-d IOTLB/Context/IEC 
invalidation timeout.

For Device-TLB invalidation, we can introduce 'vtd_qi_device_timeout', which is 
boot-time changed, and 1 ms by default.

Quan

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