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

From: Jerry Snitselaar <jsnitsel@redhat.com>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: iommu@lists.linux-foundation.org
Subject: Re: dmar pte read access not set error messages on hp dl388 gen8 systems
Date: Tue, 3 Dec 2019 02:56:36 -0700	[thread overview]
Message-ID: <20191203095636.epmuinnrpykecfda@cantor> (raw)
In-Reply-To: <14bbe41c-61e9-d2b6-31cb-67c0b1ad11da@linux.intel.com>

On Tue Dec 03 19, Lu Baolu wrote:
>Hi,
>
>On 12/3/19 12:13 AM, Jerry Snitselaar wrote:
>>On Mon Dec 02 19, Jerry Snitselaar wrote:
>>>On Mon Dec 02 19, Lu Baolu wrote:
>>>>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
>>>>
>>>
>>>Almost all of the messages are for the ilo, but there also is a 
>>>message for
>>>the smart array raid bus controller.
>>>
>>
>>Also seeing it with a dl380 gen9 system, where the raid bus controller
>>is getting the error.
>
>Does it help if you remove
>
>                        if (device_is_rmrr_locked(dev))
>                                continue;
>
>in si_domain_init()?
>

Unfortunately it still spits out a bunch of error messages.

>Best regards,
>baolu
>

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