Re: [PATCH] iommu/intel-iommu: set as DUMMY_DEVICE_DOMAIN_INFO if no IOMMU

From: Jian-Hong Pan
Date: Wed Feb 05 2020 - 05:07:42 EST

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Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> æ 2020å2æ5æ éä äå9:28åéï
>
> Hi,
>
> On 2020/2/4 17:25, Jian-Hong Pan wrote:
> > Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> æ 2020å2æ4æ éä äå2:11åéï
> >>
> >> Hi,
> >>
> >> On 2020/2/3 17:10, Jian-Hong Pan wrote:
> >>> If the device has no IOMMU, it still invokes iommu_need_mapping during
> >>> intel_alloc_coherent. However, iommu_need_mapping can only check the
> >>> device is DUMMY_DEVICE_DOMAIN_INFO or not. This patch marks the device
> >>> is a DUMMY_DEVICE_DOMAIN_INFO if the device has no IOMMU.
> >>>
> >>> Signed-off-by: Jian-Hong Pan <jian-hong@xxxxxxxxxxxx>
> >>> ---
> >>> drivers/iommu/intel-iommu.c | 4 +++-
> >>> 1 file changed, 3 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> >>> index 35a4a3abedc6..878bc986a015 100644
> >>> --- a/drivers/iommu/intel-iommu.c
> >>> +++ b/drivers/iommu/intel-iommu.c
> >>> @@ -5612,8 +5612,10 @@ static int intel_iommu_add_device(struct device *dev)
> >>> int ret;
> >>>
> >>> iommu = device_to_iommu(dev, &bus, &devfn);
> >>> - if (!iommu)
> >>> + if (!iommu) {
> >>> + dev->archdata.iommu = DUMMY_DEVICE_DOMAIN_INFO;
> >>
> >> Is this a DMA capable device?
> >
> > Do you mean is the device in DMA Remapping table?
> > Dump DMAR from ACPI table. The device is not in the table.
> > So, it does not support DMAR, Intel IOMMU.
> >
> > Or, should device_to_iommu be invoked in iommu_need_mapping to check
> > IOMMU feature again?
> >
>
> Normally intel_iommu_add_device() should only be called for PCI devices
> and APCI name space devices (reported in ACPI/DMAR table). In both
> cases, device_to_iommu() should always return a corresponding iommu. I
> just tried to understand why it failed for your case.

We found all of the DMAR featured devices's PCI Segment Number is *0000*.
But the devices locating under segment/domain *0001* hit the issue,
until the patch is applied.

Because of different segment numbers, none of iommu will be matched by
for_each_active_iommu(iommu, drhd) loop in function device_to_iommu()
and it will return NULL. So, intel_iommu_add_device() returns no
device.

I can share the DMAR:
/*
* Intel ACPI Component Architecture
* AML/ASL+ Disassembler version 20200110 (64-bit version)
* Copyright (c) 2000 - 2020 Intel Corporation
*
* Disassembly of dmar.dat, Wed Jan 22 11:41:50 2020
*
* ACPI Data Table [DMAR]
*
* Format: [HexOffset DecimalOffset ByteLength] FieldName : FieldValue
*/

[000h 0000 4] Signature : "DMAR" [DMA Remapping table]
[004h 0004 4] Table Length : 000000A8
[008h 0008 1] Revision : 01
[009h 0009 1] Checksum : 5E
[00Ah 0010 6] Oem ID : "INTEL "
[010h 0016 8] Oem Table ID : "EDK2 "
[018h 0024 4] Oem Revision : 00000002
[01Ch 0028 4] Asl Compiler ID : " "
[020h 0032 4] Asl Compiler Revision : 01000013

[024h 0036 1] Host Address Width : 26
[025h 0037 1] Flags : 05
[026h 0038 10] Reserved : 00 00 00 00 00 00 00 00 00 00

[030h 0048 2] Subtable Type : 0000 [Hardware Unit Definition]
[032h 0050 2] Length : 0018

[034h 0052 1] Flags : 00
[035h 0053 1] Reserved : 00
[036h 0054 2] PCI Segment Number : 0000
[038h 0056 8] Register Base Address : 00000000FED90000

[040h 0064 1] Device Scope Type : 01 [PCI Endpoint Device]
[041h 0065 1] Entry Length : 08
[042h 0066 2] Reserved : 0000
[044h 0068 1] Enumeration ID : 00
[045h 0069 1] PCI Bus Number : 00

[046h 0070 2] PCI Path : 02,00

[048h 0072 2] Subtable Type : 0000 [Hardware Unit Definition]
[04Ah 0074 2] Length : 0020

[04Ch 0076 1] Flags : 01
[04Dh 0077 1] Reserved : 00
[04Eh 0078 2] PCI Segment Number : 0000
[050h 0080 8] Register Base Address : 00000000FED91000

[058h 0088 1] Device Scope Type : 03 [IOAPIC Device]
[059h 0089 1] Entry Length : 08
[05Ah 0090 2] Reserved : 0000
[05Ch 0092 1] Enumeration ID : 02
[05Dh 0093 1] PCI Bus Number : 00

[05Eh 0094 2] PCI Path : 1E,07

[060h 0096 1] Device Scope Type : 04 [Message-capable HPET Device]
[061h 0097 1] Entry Length : 08
[062h 0098 2] Reserved : 0000
[064h 0100 1] Enumeration ID : 00
[065h 0101 1] PCI Bus Number : 00

[066h 0102 2] PCI Path : 1E,06

[068h 0104 2] Subtable Type : 0001 [Reserved Memory Region]
[06Ah 0106 2] Length : 0020

[06Ch 0108 2] Reserved : 0000
[06Eh 0110 2] PCI Segment Number : 0000
[070h 0112 8] Base Address : 000000006F58B000
[078h 0120 8] End Address (limit) : 000000006F7D4FFF

[080h 0128 1] Device Scope Type : 01 [PCI Endpoint Device]
[081h 0129 1] Entry Length : 08
[082h 0130 2] Reserved : 0000
[084h 0132 1] Enumeration ID : 00
[085h 0133 1] PCI Bus Number : 00

[086h 0134 2] PCI Path : 14,00

[088h 0136 2] Subtable Type : 0001 [Reserved Memory Region]
[08Ah 0138 2] Length : 0020

[08Ch 0140 2] Reserved : 0000
[08Eh 0142 2] PCI Segment Number : 0000
[090h 0144 8] Base Address : 0000000079800000
[098h 0152 8] End Address (limit) : 000000007DFFFFFF

[0A0h 0160 1] Device Scope Type : 01 [PCI Endpoint Device]
[0A1h 0161 1] Entry Length : 08
[0A2h 0162 2] Reserved : 0000
[0A4h 0164 1] Enumeration ID : 00
[0A5h 0165 1] PCI Bus Number : 00

[0A6h 0166 2] PCI Path : 02,00

Raw Table Data: Length 168 (0xA8)

0000: 44 4D 41 52 A8 00 00 00 01 5E 49 4E 54 45 4C 20 // DMAR.....^INTEL
0010: 45 44 4B 32 20 20 20 20 02 00 00 00 20 20 20 20 // EDK2 ....
0020: 13 00 00 01 26 05 00 00 00 00 00 00 00 00 00 00 // ....&...........
0030: 00 00 18 00 00 00 00 00 00 00 D9 FE 00 00 00 00 // ................
0040: 01 08 00 00 00 00 02 00 00 00 20 00 01 00 00 00 // .......... .....
0050: 00 10 D9 FE 00 00 00 00 03 08 00 00 02 00 1E 07 // ................
0060: 04 08 00 00 00 00 1E 06 01 00 20 00 00 00 00 00 // .......... .....
0070: 00 B0 58 6F 00 00 00 00 FF 4F 7D 6F 00 00 00 00 // ..Xo.....O}o....
0080: 01 08 00 00 00 00 14 00 01 00 20 00 00 00 00 00 // .......... .....
0090: 00 00 80 79 00 00 00 00 FF FF FF 7D 00 00 00 00 // ...y.......}....
00A0: 01 08 00 00 00 00 02 00 // ........

Here is the lspci:
0000:00:00.0 Host bridge: Intel Corporation Device 9b61 (rev 0c)
0000:00:02.0 VGA compatible controller: Intel Corporation Device 9b41 (rev 02)
0000:00:04.0 Signal processing controller: Intel Corporation Skylake
Processor Thermal Subsystem (rev 0c)
0000:00:08.0 System peripheral: Intel Corporation Skylake Gaussian Mixture Model
0000:00:12.0 Signal processing controller: Intel Corporation Device 02f9
0000:00:13.0 Serial controller: Intel Corporation Device 02fc
0000:00:14.0 USB controller: Intel Corporation Device 02ed
0000:00:14.2 RAM memory: Intel Corporation Device 02ef
0000:00:14.3 Network controller: Intel Corporation Device 02f0
0000:00:15.0 Serial bus controller [0c80]: Intel Corporation Device 02e8
0000:00:15.1 Serial bus controller [0c80]: Intel Corporation Device 02e9
0000:00:15.2 Serial bus controller [0c80]: Intel Corporation Device 02ea
0000:00:16.0 Communication controller: Intel Corporation Device 02e0
0000:00:17.0 RAID bus controller: Intel Corporation Device 02d7
0000:00:1c.0 PCI bridge: Intel Corporation Device 02b8 (rev f0)
0000:00:1e.0 Communication controller: Intel Corporation Device 02a8
0000:00:1e.2 Serial bus controller [0c80]: Intel Corporation Device 02aa
0000:00:1f.0 ISA bridge: Intel Corporation Device 0284
0000:00:1f.3 Audio device: Intel Corporation Device 02c8
0000:00:1f.4 SMBus: Intel Corporation Device 02a3
0000:00:1f.5 Serial bus controller [0c80]: Intel Corporation Device 02a4
0000:00:1f.6 Ethernet controller: Intel Corporation Device 0d4f
0000:01:00.0 PCI bridge: Intel Corporation JHL7540 Thunderbolt 3
Bridge [Titan Ridge 4C 2018] (rev 06)
0000:02:00.0 PCI bridge: Intel Corporation JHL7540 Thunderbolt 3
Bridge [Titan Ridge 4C 2018] (rev 06)
0000:02:01.0 PCI bridge: Intel Corporation JHL7540 Thunderbolt 3
Bridge [Titan Ridge 4C 2018] (rev 06)
0000:02:02.0 PCI bridge: Intel Corporation JHL7540 Thunderbolt 3
Bridge [Titan Ridge 4C 2018] (rev 06)
0000:02:04.0 PCI bridge: Intel Corporation JHL7540 Thunderbolt 3
Bridge [Titan Ridge 4C 2018] (rev 06)
0000:03:00.0 System peripheral: Intel Corporation JHL7540 Thunderbolt
3 NHI [Titan Ridge 4C 2018] (rev 06)
0000:37:00.0 USB controller: Intel Corporation JHL7540 Thunderbolt 3
USB Controller [Titan Ridge 4C 2018] (rev 06)
0001:00:00.0 SATA controller: Intel Corporation Device 02d7
0001:00:01.0 Non-Volatile memory controller: Intel Corporation Device 0000
0001:00:02.0 Non-Volatile memory controller: Intel Corporation Device 0000

Best regards,
Jian-Hong Pan

Next message: Tomeu Vizoso: "[PATCH] drm/panfrost: Don't try to map on error faults"
Previous message: Wei Yang: "Re: [PATCH v6 09/10] mm/memory_hotplug: Drop local variables in shrink_zone_span()"
In reply to: Lu Baolu: "Re: [PATCH] iommu/intel-iommu: set as DUMMY_DEVICE_DOMAIN_INFO if no IOMMU"
Next in thread: Jian-Hong Pan: "Re: [PATCH] iommu/intel-iommu: set as DUMMY_DEVICE_DOMAIN_INFO if no IOMMU"
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