Re: [PATCH v5 09/11] iommu/vt-d: Add iotlb flush for nested domain

On 2023/9/27 14:53, Tian, Kevin wrote:

...

From: Liu, Yi L yi.l.liu@intel.com Sent: Thursday, September 21, 2023 3:54 PM

• /* REVISIT:

• * VT-d has defined ITE, ICE, IQE for invalidation failure per hardware,
  

• * but no error code yet, so just set the error code to be 0.
  

• */
  

• *cerror_idx = 0;

Is it "hardware doesn't provide error code now though it's defined in spec" or "intel-iommu driver doesn't retrieve the error code though it's provided by the hardware"?

I didn't see vtd spec defines error code for cache invalidation. :(

Is there guarantee that '0' isn't used for an existing error code or won't be used for any new error code later?

may need to check it.