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

From: Lu Baolu <baolu.lu@linux.intel.com>
To: Jerry Snitselaar <jsnitsel@redhat.com>
Cc: iommu@lists.linux-foundation.org
Subject: Re: dmar pte read access not set error messages on hp dl388 gen8 systems
Date: Wed, 4 Dec 2019 08:17:53 +0800	[thread overview]
Message-ID: <5ce8d57e-25f0-5d28-7408-92c650ba54aa@linux.intel.com> (raw)
In-Reply-To: <20191203095636.epmuinnrpykecfda@cantor>

Hi,

On 12/3/19 5:56 PM, Jerry Snitselaar wrote:
> 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.

Can you please show me the whole dmesg?

Best regards,
-baolu
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