Re: dmar pte read access not set error messages on hp dl388 gen8 systems

[Lu Baolu <baolu.lu@linux.intel.com>]

Hi,

On 12/2/19 2:34 PM, Jerry Snitselaar wrote:
> We are seeing DMAR PTE read access not set errors when booting a
> kernel with default passthrough, both with a test kernel and with
> a 5.4.0 kernel. Previously we would see a number of identity mappings
> being set related to the rmrrs, and now they aren't seen and we get
> the dmar pte errors as devices touch those regions. From what I can tell
> currently df4f3c603aeb ("iommu/vt-d: Remove static identity map code")
> removed the bit of code in init_dmars that used to set up those
> mappings:
> 
> -       /*
> -        * For each rmrr
> -        *   for each dev attached to rmrr
> -        *   do
> -        *     locate drhd for dev, alloc domain for dev
> -        *     allocate free domain
> -        *     allocate page table entries for rmrr
> -        *     if context not allocated for bus
> -        *           allocate and init context
> -        *           set present in root table for this bus
> -        *     init context with domain, translation etc
> -        *    endfor
> -        * endfor
> -        */
> -       pr_info("Setting RMRR:\n");
> -       for_each_rmrr_units(rmrr) {
> -               /* some BIOS lists non-exist devices in DMAR table. */
> -               for_each_active_dev_scope(rmrr->devices, rmrr->devices_cnt,
> -                                         i, dev) {
> -                       ret = iommu_prepare_rmrr_dev(rmrr, dev);
> -                       if (ret)
> -                               pr_err("Mapping reserved region failed\n");
> -               }
> -       }
> 
> si_domain_init now has code that sets identity maps for devices in 
> rmrrs, but
> only for certain devices.

On which device, are you seeing this error? Is it a rmrr locked device?

Best regards,
baolu

> 
> With iommu=nopt, the system boots up without issue.
> 
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