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In-Reply-To: <948da337-128f-22ae-7b2e-730b4b8da446@linux.intel.com>
From:   Jian-Hong Pan <jian-hong@endlessm.com>
Date:   Wed, 5 Feb 2020 18:06:55 +0800
Message-ID: <CAPpJ_ecM0oCUjYLbG+uTprRk0=OTUBTxZc-d2BGBRDSYWk4uSQ@mail.gmail.com>
Subject: Re: [PATCH] iommu/intel-iommu: set as DUMMY_DEVICE_DOMAIN_INFO if no IOMMU
To:     Lu Baolu <baolu.lu@linux.intel.com>
Cc:     David Woodhouse <dwmw2@infradead.org>,
        Joerg Roedel <joro@8bytes.org>,
        iommu@lists.linux-foundation.org,
        Linux Kernel <linux-kernel@vger.kernel.org>,
        Linux Upstreaming Team <linux@endlessm.com>
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Lu Baolu <baolu.lu@linux.intel.com> =E6=96=BC 2020=E5=B9=B42=E6=9C=885=E6=
=97=A5 =E9=80=B1=E4=B8=89 =E4=B8=8A=E5=8D=889:28=E5=AF=AB=E9=81=93=EF=BC=9A
>
> Hi,
>
> On 2020/2/4 17:25, Jian-Hong Pan wrote:
> > Lu Baolu <baolu.lu@linux.intel.com> =E6=96=BC 2020=E5=B9=B42=E6=9C=884=
=E6=97=A5 =E9=80=B1=E4=BA=8C =E4=B8=8B=E5=8D=882:11=E5=AF=AB=E9=81=93=EF=BC=
=9A
> >>
> >> Hi,
> >>
> >> On 2020/2/3 17:10, Jian-Hong Pan wrote:
> >>> If the device has no IOMMU, it still invokes iommu_need_mapping durin=
g
> >>> intel_alloc_coherent. However, iommu_need_mapping can only check the
> >>> device is DUMMY_DEVICE_DOMAIN_INFO or not. This patch marks the devic=
e
> >>> is a DUMMY_DEVICE_DOMAIN_INFO if the device has no IOMMU.
> >>>
> >>> Signed-off-by: Jian-Hong Pan <jian-hong@endlessm.com>
> >>> ---
> >>>    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 devic=
e *dev)
> >>>        int ret;
> >>>
> >>>        iommu =3D device_to_iommu(dev, &bus, &devfn);
> >>> -     if (!iommu)
> >>> +     if (!iommu) {
> >>> +             dev->archdata.iommu =3D 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 tab=
le]
[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 0=
0

[030h 0048   2]                Subtable Type : 0000 [Hardware Unit Definiti=
on]
[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 Definiti=
on]
[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 Dev=
ice]
[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.....^INT=
EL
    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