I'm working on getting a system to reproduce this, and verify it also occurs
with 5.5, but I have a report of a case where the kdump kernel gives
warnings like the following on a hp dl360 gen9:
[ 2.830589] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 2.832615] ehci-pci: EHCI PCI platform driver
[ 2.834190] ehci-pci 0000:00:1a.0: EHCI Host Controller
[ 2.835974] ehci-pci 0000:00:1a.0: new USB bus registered, assigned bus number 1
[ 2.838276] ehci-pci 0000:00:1a.0: debug port 2
[ 2.839700] WARNING: CPU: 0 PID: 1 at drivers/iommu/intel-iommu.c:598 domain_get_iommu+0x55/0x60
[ 2.840671] Modules linked in:
[ 2.840671] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.0-170.el8.kdump2.x86_64 #1
[ 2.840671] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 07/21/2019
[ 2.840671] RIP: 0010:domain_get_iommu+0x55/0x60
[ 2.840671] Code: c2 01 eb 0b 48 83 c0 01 8b 34 87 85 f6 75 0b 48 63 c8 48 39 c2 75 ed 31 c0 c3 48 c1 e1 03 48 8b 05 70 f3 91 01 48 8b 04 08 c3 <0f> 0b 31 c0 c3 31 c9 eb eb 66 90 0f 1f 44 00 00 41 55 40 0f b6 f6
[ 2.840671] RSP: 0018:ffffc900000dfab8 EFLAGS: 00010202
[ 2.840671] RAX: ffff88ec7f1c8000 RBX: 0000006c7c867000 RCX: 0000000000000000
[ 2.840671] RDX: 00000000fffffff0 RSI: 0000000000000000 RDI: ffff88ec7f1c8000
[ 2.840671] RBP: ffff88ec6f7000b0 R08: ffff88ec7f19d000 R09: ffff88ec7cbfcd00
[ 2.840671] R10: 0000000000000095 R11: ffffc900000df928 R12: 0000000000000000
[ 2.840671] R13: ffff88ec7f1c8000 R14: 0000000000001000 R15: 00000000ffffffff
[ 2.840671] FS: 0000000000000000(0000) GS:ffff88ec7f600000(0000) knlGS:0000000000000000
[ 2.840671] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2.840671] CR2: 00007ff3e1713000 CR3: 0000006c7de0a004 CR4: 00000000001606b0
[ 2.840671] Call Trace:
[ 2.840671] __intel_map_single+0x62/0x140
[ 2.840671] intel_alloc_coherent+0xa6/0x130
[ 2.840671] dma_pool_alloc+0xd8/0x1e0
[ 2.840671] e_qh_alloc+0x55/0x130
[ 2.840671] ehci_setup+0x284/0x7b0
[ 2.840671] ehci_pci_setup+0xa3/0x530
[ 2.840671] usb_add_hcd+0x2b6/0x800
[ 2.840671] usb_hcd_pci_probe+0x375/0x460
[ 2.840671] local_pci_probe+0x41/0x90
[ 2.840671] pci_device_probe+0x105/0x1b0
[ 2.840671] driver_probe_device+0x12d/0x460
[ 2.840671] device_driver_attach+0x50/0x60
[ 2.840671] __driver_attach+0x61/0x130
[ 2.840671] ? device_driver_attach+0x60/0x60
[ 2.840671] bus_for_each_dev+0x77/0xc0
[ 2.840671] ? klist_add_tail+0x3b/0x70
[ 2.840671] bus_add_driver+0x14d/0x1e0
[ 2.840671] ? ehci_hcd_init+0xaa/0xaa
[ 2.840671] ? do_early_param+0x91/0x91
[ 2.840671] driver_register+0x6b/0xb0
[ 2.840671] ? ehci_hcd_init+0xaa/0xaa
[ 2.840671] do_one_initcall+0x46/0x1c3
[ 2.840671] ? do_early_param+0x91/0x91
[ 2.840671] kernel_init_freeable+0x1af/0x258
[ 2.840671] ? rest_init+0xaa/0xaa
[ 2.840671] kernel_init+0xa/0xf9
[ 2.840671] ret_from_fork+0x35/0x40
[ 2.840671] ---[ end trace e87b0d9a1c8135c4 ]---
[ 3.010848] ehci-pci 0000:00:1a.0: Using iommu dma mapping
[ 3.012551] ehci-pci 0000:00:1a.0: 32bit DMA uses non-identity mapping
[ 3.018537] ehci-pci 0000:00:1a.0: cache line size of 64 is not supported
[ 3.021188] ehci-pci 0000:00:1a.0: irq 18, io mem 0x93002000
[ 3.029006] ehci-pci 0000:00:1a.0: USB 2.0 started, EHCI 1.00
[ 3.030918] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 4.18
[ 3.033491] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 3.035900] usb usb1: Product: EHCI Host Controller
[ 3.037423] usb usb1: Manufacturer: Linux 4.18.0-170.el8.kdump2.x86_64 ehci_hcd
[ 3.039691] usb usb1: SerialNumber: 0000:00:1a.0
It looks like the device finishes initializing once it figures out it
needs dma mapping instead of the default
passthrough. intel_alloc_coherent calls iommu_need_mapping, before it
calls __intel_map_single, so I'm not sure why it is tripping over the
WARN_ON in domain_get_iommu.
one thing I noticed while looking at this is that domain_get_iommu can
return NULL. So should there be something like the following in
__intel_map_single after the domain_get_iommu call?
if (!iommu)
goto error;
It is possible to deref the null pointer later otherwise.
Regards,
Jerry
On Tue Feb 04 20, Jerry Snitselaar wrote:
>I'm working on getting a system to reproduce this, and verify it also occurs
>with 5.5, but I have a report of a case where the kdump kernel gives
>warnings like the following on a hp dl360 gen9:
>
>[ 2.830589] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
>[ 2.832615] ehci-pci: EHCI PCI platform driver
>[ 2.834190] ehci-pci 0000:00:1a.0: EHCI Host Controller
>[ 2.835974] ehci-pci 0000:00:1a.0: new USB bus registered, assigned bus number 1
>[ 2.838276] ehci-pci 0000:00:1a.0: debug port 2
>[ 2.839700] WARNING: CPU: 0 PID: 1 at drivers/iommu/intel-iommu.c:598 domain_get_iommu+0x55/0x60
>[ 2.840671] Modules linked in:
>[ 2.840671] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.0-170.el8.kdump2.x86_64 #1
>[ 2.840671] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 07/21/2019
>[ 2.840671] RIP: 0010:domain_get_iommu+0x55/0x60
>[ 2.840671] Code: c2 01 eb 0b 48 83 c0 01 8b 34 87 85 f6 75 0b 48 63 c8 48 39 c2 75 ed 31 c0 c3 48 c1 e1 03 48 8b 05 70 f3 91 01 48 8b 04 08 c3 <0f> 0b 31 c0 c3 31 c9 eb eb 66 90 0f 1f 44 00 00 41 55 40 0f b6 f6
>[ 2.840671] RSP: 0018:ffffc900000dfab8 EFLAGS: 00010202
>[ 2.840671] RAX: ffff88ec7f1c8000 RBX: 0000006c7c867000 RCX: 0000000000000000
>[ 2.840671] RDX: 00000000fffffff0 RSI: 0000000000000000 RDI: ffff88ec7f1c8000
>[ 2.840671] RBP: ffff88ec6f7000b0 R08: ffff88ec7f19d000 R09: ffff88ec7cbfcd00
>[ 2.840671] R10: 0000000000000095 R11: ffffc900000df928 R12: 0000000000000000
>[ 2.840671] R13: ffff88ec7f1c8000 R14: 0000000000001000 R15: 00000000ffffffff
>[ 2.840671] FS: 0000000000000000(0000) GS:ffff88ec7f600000(0000) knlGS:0000000000000000
>[ 2.840671] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>[ 2.840671] CR2: 00007ff3e1713000 CR3: 0000006c7de0a004 CR4: 00000000001606b0
>[ 2.840671] Call Trace:
>[ 2.840671] __intel_map_single+0x62/0x140
>[ 2.840671] intel_alloc_coherent+0xa6/0x130
>[ 2.840671] dma_pool_alloc+0xd8/0x1e0
>[ 2.840671] e_qh_alloc+0x55/0x130
>[ 2.840671] ehci_setup+0x284/0x7b0
>[ 2.840671] ehci_pci_setup+0xa3/0x530
>[ 2.840671] usb_add_hcd+0x2b6/0x800
>[ 2.840671] usb_hcd_pci_probe+0x375/0x460
>[ 2.840671] local_pci_probe+0x41/0x90
>[ 2.840671] pci_device_probe+0x105/0x1b0
>[ 2.840671] driver_probe_device+0x12d/0x460
>[ 2.840671] device_driver_attach+0x50/0x60
>[ 2.840671] __driver_attach+0x61/0x130
>[ 2.840671] ? device_driver_attach+0x60/0x60
>[ 2.840671] bus_for_each_dev+0x77/0xc0
>[ 2.840671] ? klist_add_tail+0x3b/0x70
>[ 2.840671] bus_add_driver+0x14d/0x1e0
>[ 2.840671] ? ehci_hcd_init+0xaa/0xaa
>[ 2.840671] ? do_early_param+0x91/0x91
>[ 2.840671] driver_register+0x6b/0xb0
>[ 2.840671] ? ehci_hcd_init+0xaa/0xaa
>[ 2.840671] do_one_initcall+0x46/0x1c3
>[ 2.840671] ? do_early_param+0x91/0x91
>[ 2.840671] kernel_init_freeable+0x1af/0x258
>[ 2.840671] ? rest_init+0xaa/0xaa
>[ 2.840671] kernel_init+0xa/0xf9
>[ 2.840671] ret_from_fork+0x35/0x40
>[ 2.840671] ---[ end trace e87b0d9a1c8135c4 ]---
>[ 3.010848] ehci-pci 0000:00:1a.0: Using iommu dma mapping
>[ 3.012551] ehci-pci 0000:00:1a.0: 32bit DMA uses non-identity mapping
>[ 3.018537] ehci-pci 0000:00:1a.0: cache line size of 64 is not supported
>[ 3.021188] ehci-pci 0000:00:1a.0: irq 18, io mem 0x93002000
>[ 3.029006] ehci-pci 0000:00:1a.0: USB 2.0 started, EHCI 1.00
>[ 3.030918] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 4.18
>[ 3.033491] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
>[ 3.035900] usb usb1: Product: EHCI Host Controller
>[ 3.037423] usb usb1: Manufacturer: Linux 4.18.0-170.el8.kdump2.x86_64 ehci_hcd
>[ 3.039691] usb usb1: SerialNumber: 0000:00:1a.0
>
>It looks like the device finishes initializing once it figures out it
>needs dma mapping instead of the default
>passthrough. intel_alloc_coherent calls iommu_need_mapping, before it
>calls __intel_map_single, so I'm not sure why it is tripping over the
>WARN_ON in domain_get_iommu.
>
>one thing I noticed while looking at this is that domain_get_iommu can
>return NULL. So should there be something like the following in
>__intel_map_single after the domain_get_iommu call?
>
>if (!iommu)
> goto error;
>
>It is possible to deref the null pointer later otherwise.
>
>Regards,
>Jerry
I reproduced the warning with a 5.5 kernel on an Intel NUC5i5MYBE.
On Thu Feb 06 20, Jerry Snitselaar wrote:
>On Tue Feb 04 20, Jerry Snitselaar wrote:
>>I'm working on getting a system to reproduce this, and verify it also occurs
>>with 5.5, but I have a report of a case where the kdump kernel gives
>>warnings like the following on a hp dl360 gen9:
>>
>>[ 2.830589] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
>>[ 2.832615] ehci-pci: EHCI PCI platform driver
>>[ 2.834190] ehci-pci 0000:00:1a.0: EHCI Host Controller
>>[ 2.835974] ehci-pci 0000:00:1a.0: new USB bus registered, assigned bus number 1
>>[ 2.838276] ehci-pci 0000:00:1a.0: debug port 2
>>[ 2.839700] WARNING: CPU: 0 PID: 1 at drivers/iommu/intel-iommu.c:598 domain_get_iommu+0x55/0x60
>>[ 2.840671] Modules linked in:
>>[ 2.840671] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.0-170.el8.kdump2.x86_64 #1
>>[ 2.840671] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 07/21/2019
>>[ 2.840671] RIP: 0010:domain_get_iommu+0x55/0x60
>>[ 2.840671] Code: c2 01 eb 0b 48 83 c0 01 8b 34 87 85 f6 75 0b 48 63 c8 48 39 c2 75 ed 31 c0 c3 48 c1 e1 03 48 8b 05 70 f3 91 01 48 8b 04 08 c3 <0f> 0b 31 c0 c3 31 c9 eb eb 66 90 0f 1f 44 00 00 41 55 40 0f b6 f6
>>[ 2.840671] RSP: 0018:ffffc900000dfab8 EFLAGS: 00010202
>>[ 2.840671] RAX: ffff88ec7f1c8000 RBX: 0000006c7c867000 RCX: 0000000000000000
>>[ 2.840671] RDX: 00000000fffffff0 RSI: 0000000000000000 RDI: ffff88ec7f1c8000
>>[ 2.840671] RBP: ffff88ec6f7000b0 R08: ffff88ec7f19d000 R09: ffff88ec7cbfcd00
>>[ 2.840671] R10: 0000000000000095 R11: ffffc900000df928 R12: 0000000000000000
>>[ 2.840671] R13: ffff88ec7f1c8000 R14: 0000000000001000 R15: 00000000ffffffff
>>[ 2.840671] FS: 0000000000000000(0000) GS:ffff88ec7f600000(0000) knlGS:0000000000000000
>>[ 2.840671] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>[ 2.840671] CR2: 00007ff3e1713000 CR3: 0000006c7de0a004 CR4: 00000000001606b0
>>[ 2.840671] Call Trace:
>>[ 2.840671] __intel_map_single+0x62/0x140
>>[ 2.840671] intel_alloc_coherent+0xa6/0x130
>>[ 2.840671] dma_pool_alloc+0xd8/0x1e0
>>[ 2.840671] e_qh_alloc+0x55/0x130
>>[ 2.840671] ehci_setup+0x284/0x7b0
>>[ 2.840671] ehci_pci_setup+0xa3/0x530
>>[ 2.840671] usb_add_hcd+0x2b6/0x800
>>[ 2.840671] usb_hcd_pci_probe+0x375/0x460
>>[ 2.840671] local_pci_probe+0x41/0x90
>>[ 2.840671] pci_device_probe+0x105/0x1b0
>>[ 2.840671] driver_probe_device+0x12d/0x460
>>[ 2.840671] device_driver_attach+0x50/0x60
>>[ 2.840671] __driver_attach+0x61/0x130
>>[ 2.840671] ? device_driver_attach+0x60/0x60
>>[ 2.840671] bus_for_each_dev+0x77/0xc0
>>[ 2.840671] ? klist_add_tail+0x3b/0x70
>>[ 2.840671] bus_add_driver+0x14d/0x1e0
>>[ 2.840671] ? ehci_hcd_init+0xaa/0xaa
>>[ 2.840671] ? do_early_param+0x91/0x91
>>[ 2.840671] driver_register+0x6b/0xb0
>>[ 2.840671] ? ehci_hcd_init+0xaa/0xaa
>>[ 2.840671] do_one_initcall+0x46/0x1c3
>>[ 2.840671] ? do_early_param+0x91/0x91
>>[ 2.840671] kernel_init_freeable+0x1af/0x258
>>[ 2.840671] ? rest_init+0xaa/0xaa
>>[ 2.840671] kernel_init+0xa/0xf9
>>[ 2.840671] ret_from_fork+0x35/0x40
>>[ 2.840671] ---[ end trace e87b0d9a1c8135c4 ]---
>>[ 3.010848] ehci-pci 0000:00:1a.0: Using iommu dma mapping
>>[ 3.012551] ehci-pci 0000:00:1a.0: 32bit DMA uses non-identity mapping
>>[ 3.018537] ehci-pci 0000:00:1a.0: cache line size of 64 is not supported
>>[ 3.021188] ehci-pci 0000:00:1a.0: irq 18, io mem 0x93002000
>>[ 3.029006] ehci-pci 0000:00:1a.0: USB 2.0 started, EHCI 1.00
>>[ 3.030918] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 4.18
>>[ 3.033491] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
>>[ 3.035900] usb usb1: Product: EHCI Host Controller
>>[ 3.037423] usb usb1: Manufacturer: Linux 4.18.0-170.el8.kdump2.x86_64 ehci_hcd
>>[ 3.039691] usb usb1: SerialNumber: 0000:00:1a.0
>>
>>It looks like the device finishes initializing once it figures out it
>>needs dma mapping instead of the default
>>passthrough. intel_alloc_coherent calls iommu_need_mapping, before it
>>calls __intel_map_single, so I'm not sure why it is tripping over the
>>WARN_ON in domain_get_iommu.
>>
>>one thing I noticed while looking at this is that domain_get_iommu can
>>return NULL. So should there be something like the following in
>>__intel_map_single after the domain_get_iommu call?
>>
>>if (!iommu)
>> goto error;
>>
>>It is possible to deref the null pointer later otherwise.
>>
>>Regards,
>>Jerry
>
>I reproduced the warning with a 5.5 kernel on an Intel NUC5i5MYBE.
Hi Baolu,
I think I understand what is happening here. With the kdump boot
translation is pre-enabled, so in intel_iommu_add_device things are
getting set to DEFER_DEVICE_DOMAIN_INFO. When intel_alloc_coherent
calls iommu_need_mapping it returns true, but doesn't do the dma
domain switch because of DEFER_DEVICE_DOMAIN_INFO. Then
__intel_map_single gets called and it calls deferred_attach_domain,
which sets the domain to the group domain, which in this case is the
identity domain. Then it calls domain_get_iommu, which spits out the
warning because the domain type was dma and returns null. My
workaround was to add a call to iommu_need_mapping and find_domain
after the deferred_attach_domain, but I don't know if that is the
correct solution. There are a couple other spots like intel_map_sg
that have the deferred_attach_domain after iommu_need_mapping that
possibly will suffer from the same problem.
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index b5c5ab58d395..063f45323cfc 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3515,6 +3515,10 @@ static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr,
if (!domain)
return DMA_MAPPING_ERROR;
+ if (!iommu_need_mapping(dev))
+ return paddr;
+
+ domain = find_domain(dev);
iommu = domain_get_iommu(domain);
size = aligned_nrpages(paddr, size);
I finally got a git repo over to one of these systems, and was
able to reproduce the issue with the head of linus's tree. With commit
9235cb13d7d1 ("iommu/vt-d: Allow devices with RMRRs to use identity domain")
there are more of the warnings, because devices are using identity that
weren't before.
Regards,
Jerry
Hi Jerry,
On 2020/2/7 17:34, Jerry Snitselaar wrote:
> On Thu Feb 06 20, Jerry Snitselaar wrote:
>> On Tue Feb 04 20, Jerry Snitselaar wrote:
>>> I'm working on getting a system to reproduce this, and verify it also
>>> occurs
>>> with 5.5, but I have a report of a case where the kdump kernel gives
>>> warnings like the following on a hp dl360 gen9:
>>>
>>> [ 2.830589] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI)
>>> Driver
>>> [ 2.832615] ehci-pci: EHCI PCI platform driver
>>> [ 2.834190] ehci-pci 0000:00:1a.0: EHCI Host Controller
>>> [ 2.835974] ehci-pci 0000:00:1a.0: new USB bus registered,
>>> assigned bus number 1
>>> [ 2.838276] ehci-pci 0000:00:1a.0: debug port 2
>>> [ 2.839700] WARNING: CPU: 0 PID: 1 at
>>> drivers/iommu/intel-iommu.c:598 domain_get_iommu+0x55/0x60
>>> [ 2.840671] Modules linked in:
>>> [ 2.840671] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
>>> 4.18.0-170.el8.kdump2.x86_64 #1
>>> [ 2.840671] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360
>>> Gen9, BIOS P89 07/21/2019
>>> [ 2.840671] RIP: 0010:domain_get_iommu+0x55/0x60
>>> [ 2.840671] Code: c2 01 eb 0b 48 83 c0 01 8b 34 87 85 f6 75 0b 48
>>> 63 c8 48 39 c2 75 ed 31 c0 c3 48 c1 e1 03 48 8b 05 70 f3 91 01 48 8b
>>> 04 08 c3 <0f> 0b 31 c0 c3 31 c9 eb eb 66 90 0f 1f 44 00 00 41 55 40
>>> 0f b6 f6
>>> [ 2.840671] RSP: 0018:ffffc900000dfab8 EFLAGS: 00010202
>>> [ 2.840671] RAX: ffff88ec7f1c8000 RBX: 0000006c7c867000 RCX:
>>> 0000000000000000
>>> [ 2.840671] RDX: 00000000fffffff0 RSI: 0000000000000000 RDI:
>>> ffff88ec7f1c8000
>>> [ 2.840671] RBP: ffff88ec6f7000b0 R08: ffff88ec7f19d000 R09:
>>> ffff88ec7cbfcd00
>>> [ 2.840671] R10: 0000000000000095 R11: ffffc900000df928 R12:
>>> 0000000000000000
>>> [ 2.840671] R13: ffff88ec7f1c8000 R14: 0000000000001000 R15:
>>> 00000000ffffffff
>>> [ 2.840671] FS: 0000000000000000(0000) GS:ffff88ec7f600000(0000)
>>> knlGS:0000000000000000
>>> [ 2.840671] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> [ 2.840671] CR2: 00007ff3e1713000 CR3: 0000006c7de0a004 CR4:
>>> 00000000001606b0
>>> [ 2.840671] Call Trace:
>>> [ 2.840671] __intel_map_single+0x62/0x140
>>> [ 2.840671] intel_alloc_coherent+0xa6/0x130
>>> [ 2.840671] dma_pool_alloc+0xd8/0x1e0
>>> [ 2.840671] e_qh_alloc+0x55/0x130
>>> [ 2.840671] ehci_setup+0x284/0x7b0
>>> [ 2.840671] ehci_pci_setup+0xa3/0x530
>>> [ 2.840671] usb_add_hcd+0x2b6/0x800
>>> [ 2.840671] usb_hcd_pci_probe+0x375/0x460
>>> [ 2.840671] local_pci_probe+0x41/0x90
>>> [ 2.840671] pci_device_probe+0x105/0x1b0
>>> [ 2.840671] driver_probe_device+0x12d/0x460
>>> [ 2.840671] device_driver_attach+0x50/0x60
>>> [ 2.840671] __driver_attach+0x61/0x130
>>> [ 2.840671] ? device_driver_attach+0x60/0x60
>>> [ 2.840671] bus_for_each_dev+0x77/0xc0
>>> [ 2.840671] ? klist_add_tail+0x3b/0x70
>>> [ 2.840671] bus_add_driver+0x14d/0x1e0
>>> [ 2.840671] ? ehci_hcd_init+0xaa/0xaa
>>> [ 2.840671] ? do_early_param+0x91/0x91
>>> [ 2.840671] driver_register+0x6b/0xb0
>>> [ 2.840671] ? ehci_hcd_init+0xaa/0xaa
>>> [ 2.840671] do_one_initcall+0x46/0x1c3
>>> [ 2.840671] ? do_early_param+0x91/0x91
>>> [ 2.840671] kernel_init_freeable+0x1af/0x258
>>> [ 2.840671] ? rest_init+0xaa/0xaa
>>> [ 2.840671] kernel_init+0xa/0xf9
>>> [ 2.840671] ret_from_fork+0x35/0x40
>>> [ 2.840671] ---[ end trace e87b0d9a1c8135c4 ]---
>>> [ 3.010848] ehci-pci 0000:00:1a.0: Using iommu dma mapping
>>> [ 3.012551] ehci-pci 0000:00:1a.0: 32bit DMA uses non-identity
>>> mapping
>>> [ 3.018537] ehci-pci 0000:00:1a.0: cache line size of 64 is not
>>> supported
>>> [ 3.021188] ehci-pci 0000:00:1a.0: irq 18, io mem 0x93002000
>>> [ 3.029006] ehci-pci 0000:00:1a.0: USB 2.0 started, EHCI 1.00
>>> [ 3.030918] usb usb1: New USB device found, idVendor=1d6b,
>>> idProduct=0002, bcdDevice= 4.18
>>> [ 3.033491] usb usb1: New USB device strings: Mfr=3, Product=2,
>>> SerialNumber=1
>>> [ 3.035900] usb usb1: Product: EHCI Host Controller
>>> [ 3.037423] usb usb1: Manufacturer: Linux
>>> 4.18.0-170.el8.kdump2.x86_64 ehci_hcd
>>> [ 3.039691] usb usb1: SerialNumber: 0000:00:1a.0
>>>
>>> It looks like the device finishes initializing once it figures out it
>>> needs dma mapping instead of the default
>>> passthrough. intel_alloc_coherent calls iommu_need_mapping, before it
>>> calls __intel_map_single, so I'm not sure why it is tripping over the
>>> WARN_ON in domain_get_iommu.
>>>
>>> one thing I noticed while looking at this is that domain_get_iommu can
>>> return NULL. So should there be something like the following in
>>> __intel_map_single after the domain_get_iommu call?
>>>
>>> if (!iommu)
>>> goto error;
>>>
>>> It is possible to deref the null pointer later otherwise.
>>>
>>> Regards,
>>> Jerry
>>
>> I reproduced the warning with a 5.5 kernel on an Intel NUC5i5MYBE.
>
> Hi Baolu,
>
> I think I understand what is happening here. With the kdump boot
> translation is pre-enabled, so in intel_iommu_add_device things are
> getting set to DEFER_DEVICE_DOMAIN_INFO. When intel_alloc_coherent
> calls iommu_need_mapping it returns true, but doesn't do the dma
> domain switch because of DEFER_DEVICE_DOMAIN_INFO. Then
> __intel_map_single gets called and it calls deferred_attach_domain,
> which sets the domain to the group domain, which in this case is the
> identity domain. Then it calls domain_get_iommu, which spits out the
> warning because the domain type was dma and returns null. My
> workaround was to add a call to iommu_need_mapping and find_domain
> after the deferred_attach_domain, but I don't know if that is the
> correct solution. There are a couple other spots like intel_map_sg
> that have the deferred_attach_domain after iommu_need_mapping that
> possibly will suffer from the same problem.
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index b5c5ab58d395..063f45323cfc 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -3515,6 +3515,10 @@ static dma_addr_t __intel_map_single(struct
> device *dev, phys_addr_t paddr,
> if (!domain)
> return DMA_MAPPING_ERROR;
>
> + if (!iommu_need_mapping(dev))
> + return paddr;
> +
> + domain = find_domain(dev);
> iommu = domain_get_iommu(domain);
> size = aligned_nrpages(paddr, size);
>
>
> I finally got a git repo over to one of these systems, and was
> able to reproduce the issue with the head of linus's tree. With commit
> 9235cb13d7d1 ("iommu/vt-d: Allow devices with RMRRs to use identity
> domain")
> there are more of the warnings, because devices are using identity that
> weren't before.
>
Is it possible to move deferred domain attachment to identity_mapping()?
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 9dc37672bf89..234ab346198e 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2913,13 +2913,11 @@ static int __init si_domain_init(int hw)
static int identity_mapping(struct device *dev)
{
- struct device_domain_info *info;
+ struct dmar_domain *domain;
- info = dev->archdata.iommu;
- if (info && info != DUMMY_DEVICE_DOMAIN_INFO && info !=
DEFER_DEVICE_DOMAIN_INFO)
- return (info->domain == si_domain);
+ domain = deferred_attach_domain(dev);
- return 0;
+ return (!domain || domain_type_is_si(domain));
}
static int domain_add_dev_info(struct dmar_domain *domain, struct
device *dev)
Best regards,
baolu
On Sat Feb 08 20, Lu Baolu wrote:
>Hi Jerry,
>
>On 2020/2/7 17:34, Jerry Snitselaar wrote:
>>On Thu Feb 06 20, Jerry Snitselaar wrote:
>>>On Tue Feb 04 20, Jerry Snitselaar wrote:
>>>>I'm working on getting a system to reproduce this, and verify it
>>>>also occurs
>>>>with 5.5, but I have a report of a case where the kdump kernel gives
>>>>warnings like the following on a hp dl360 gen9:
>>>>
>>>>[ 2.830589] ehci_hcd: USB 2.0 'Enhanced' Host Controller
>>>>(EHCI) Driver
>>>>[ 2.832615] ehci-pci: EHCI PCI platform driver
>>>>[ 2.834190] ehci-pci 0000:00:1a.0: EHCI Host Controller
>>>>[ 2.835974] ehci-pci 0000:00:1a.0: new USB bus registered,
>>>>assigned bus number 1
>>>>[ 2.838276] ehci-pci 0000:00:1a.0: debug port 2
>>>>[ 2.839700] WARNING: CPU: 0 PID: 1 at
>>>>drivers/iommu/intel-iommu.c:598 domain_get_iommu+0x55/0x60
>>>>[ 2.840671] Modules linked in:
>>>>[ 2.840671] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
>>>>4.18.0-170.el8.kdump2.x86_64 #1
>>>>[ 2.840671] Hardware name: HP ProLiant DL360 Gen9/ProLiant
>>>>DL360 Gen9, BIOS P89 07/21/2019
>>>>[ 2.840671] RIP: 0010:domain_get_iommu+0x55/0x60
>>>>[ 2.840671] Code: c2 01 eb 0b 48 83 c0 01 8b 34 87 85 f6 75
>>>>0b 48 63 c8 48 39 c2 75 ed 31 c0 c3 48 c1 e1 03 48 8b 05 70 f3
>>>>91 01 48 8b 04 08 c3 <0f> 0b 31 c0 c3 31 c9 eb eb 66 90 0f 1f 44
>>>>00 00 41 55 40 0f b6 f6
>>>>[ 2.840671] RSP: 0018:ffffc900000dfab8 EFLAGS: 00010202
>>>>[ 2.840671] RAX: ffff88ec7f1c8000 RBX: 0000006c7c867000 RCX:
>>>>0000000000000000
>>>>[ 2.840671] RDX: 00000000fffffff0 RSI: 0000000000000000 RDI:
>>>>ffff88ec7f1c8000
>>>>[ 2.840671] RBP: ffff88ec6f7000b0 R08: ffff88ec7f19d000 R09:
>>>>ffff88ec7cbfcd00
>>>>[ 2.840671] R10: 0000000000000095 R11: ffffc900000df928 R12:
>>>>0000000000000000
>>>>[ 2.840671] R13: ffff88ec7f1c8000 R14: 0000000000001000 R15:
>>>>00000000ffffffff
>>>>[ 2.840671] FS: 0000000000000000(0000)
>>>>GS:ffff88ec7f600000(0000) knlGS:0000000000000000
>>>>[ 2.840671] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>[ 2.840671] CR2: 00007ff3e1713000 CR3: 0000006c7de0a004 CR4:
>>>>00000000001606b0
>>>>[ 2.840671] Call Trace:
>>>>[ 2.840671] __intel_map_single+0x62/0x140
>>>>[ 2.840671] intel_alloc_coherent+0xa6/0x130
>>>>[ 2.840671] dma_pool_alloc+0xd8/0x1e0
>>>>[ 2.840671] e_qh_alloc+0x55/0x130
>>>>[ 2.840671] ehci_setup+0x284/0x7b0
>>>>[ 2.840671] ehci_pci_setup+0xa3/0x530
>>>>[ 2.840671] usb_add_hcd+0x2b6/0x800
>>>>[ 2.840671] usb_hcd_pci_probe+0x375/0x460
>>>>[ 2.840671] local_pci_probe+0x41/0x90
>>>>[ 2.840671] pci_device_probe+0x105/0x1b0
>>>>[ 2.840671] driver_probe_device+0x12d/0x460
>>>>[ 2.840671] device_driver_attach+0x50/0x60
>>>>[ 2.840671] __driver_attach+0x61/0x130
>>>>[ 2.840671] ? device_driver_attach+0x60/0x60
>>>>[ 2.840671] bus_for_each_dev+0x77/0xc0
>>>>[ 2.840671] ? klist_add_tail+0x3b/0x70
>>>>[ 2.840671] bus_add_driver+0x14d/0x1e0
>>>>[ 2.840671] ? ehci_hcd_init+0xaa/0xaa
>>>>[ 2.840671] ? do_early_param+0x91/0x91
>>>>[ 2.840671] driver_register+0x6b/0xb0
>>>>[ 2.840671] ? ehci_hcd_init+0xaa/0xaa
>>>>[ 2.840671] do_one_initcall+0x46/0x1c3
>>>>[ 2.840671] ? do_early_param+0x91/0x91
>>>>[ 2.840671] kernel_init_freeable+0x1af/0x258
>>>>[ 2.840671] ? rest_init+0xaa/0xaa
>>>>[ 2.840671] kernel_init+0xa/0xf9
>>>>[ 2.840671] ret_from_fork+0x35/0x40
>>>>[ 2.840671] ---[ end trace e87b0d9a1c8135c4 ]---
>>>>[ 3.010848] ehci-pci 0000:00:1a.0: Using iommu dma mapping
>>>>[ 3.012551] ehci-pci 0000:00:1a.0: 32bit DMA uses
>>>>non-identity mapping
>>>>[ 3.018537] ehci-pci 0000:00:1a.0: cache line size of 64 is
>>>>not supported
>>>>[ 3.021188] ehci-pci 0000:00:1a.0: irq 18, io mem 0x93002000
>>>>[ 3.029006] ehci-pci 0000:00:1a.0: USB 2.0 started, EHCI 1.00
>>>>[ 3.030918] usb usb1: New USB device found, idVendor=1d6b,
>>>>idProduct=0002, bcdDevice= 4.18
>>>>[ 3.033491] usb usb1: New USB device strings: Mfr=3,
>>>>Product=2, SerialNumber=1
>>>>[ 3.035900] usb usb1: Product: EHCI Host Controller
>>>>[ 3.037423] usb usb1: Manufacturer: Linux
>>>>4.18.0-170.el8.kdump2.x86_64 ehci_hcd
>>>>[ 3.039691] usb usb1: SerialNumber: 0000:00:1a.0
>>>>
>>>>It looks like the device finishes initializing once it figures out it
>>>>needs dma mapping instead of the default
>>>>passthrough. intel_alloc_coherent calls iommu_need_mapping, before it
>>>>calls __intel_map_single, so I'm not sure why it is tripping over the
>>>>WARN_ON in domain_get_iommu.
>>>>
>>>>one thing I noticed while looking at this is that domain_get_iommu can
>>>>return NULL. So should there be something like the following in
>>>>__intel_map_single after the domain_get_iommu call?
>>>>
>>>>if (!iommu)
>>>> goto error;
>>>>
>>>>It is possible to deref the null pointer later otherwise.
>>>>
>>>>Regards,
>>>>Jerry
>>>
>>>I reproduced the warning with a 5.5 kernel on an Intel NUC5i5MYBE.
>>
>>Hi Baolu,
>>
>>I think I understand what is happening here. With the kdump boot
>>translation is pre-enabled, so in intel_iommu_add_device things are
>>getting set to DEFER_DEVICE_DOMAIN_INFO. When intel_alloc_coherent
>>calls iommu_need_mapping it returns true, but doesn't do the dma
>>domain switch because of DEFER_DEVICE_DOMAIN_INFO. Then
>>__intel_map_single gets called and it calls deferred_attach_domain,
>>which sets the domain to the group domain, which in this case is the
>>identity domain. Then it calls domain_get_iommu, which spits out the
>>warning because the domain type was dma and returns null. My
>>workaround was to add a call to iommu_need_mapping and find_domain
>>after the deferred_attach_domain, but I don't know if that is the
>>correct solution. There are a couple other spots like intel_map_sg
>>that have the deferred_attach_domain after iommu_need_mapping that
>>possibly will suffer from the same problem.
>>
>>diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>>index b5c5ab58d395..063f45323cfc 100644
>>--- a/drivers/iommu/intel-iommu.c
>>+++ b/drivers/iommu/intel-iommu.c
>>@@ -3515,6 +3515,10 @@ static dma_addr_t __intel_map_single(struct
>>device *dev, phys_addr_t paddr,
>> if (!domain)
>> return DMA_MAPPING_ERROR;
>>
>>+ if (!iommu_need_mapping(dev))
>>+ return paddr;
>>+
>>+ domain = find_domain(dev);
>> iommu = domain_get_iommu(domain);
>> size = aligned_nrpages(paddr, size);
>>
>>
>>I finally got a git repo over to one of these systems, and was
>>able to reproduce the issue with the head of linus's tree. With commit
>>9235cb13d7d1 ("iommu/vt-d: Allow devices with RMRRs to use identity
>>domain")
>>there are more of the warnings, because devices are using identity that
>>weren't before.
>>
>
>Is it possible to move deferred domain attachment to identity_mapping()?
>
>diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>index 9dc37672bf89..234ab346198e 100644
>--- a/drivers/iommu/intel-iommu.c
>+++ b/drivers/iommu/intel-iommu.c
>@@ -2913,13 +2913,11 @@ static int __init si_domain_init(int hw)
>
> static int identity_mapping(struct device *dev)
> {
>- struct device_domain_info *info;
>+ struct dmar_domain *domain;
>
>- info = dev->archdata.iommu;
>- if (info && info != DUMMY_DEVICE_DOMAIN_INFO && info !=
>DEFER_DEVICE_DOMAIN_INFO)
>- return (info->domain == si_domain);
>+ domain = deferred_attach_domain(dev);
>
>- return 0;
>+ return (!domain || domain_type_is_si(domain));
> }
>
> static int domain_add_dev_info(struct dmar_domain *domain, struct
>device *dev)
>
>Best regards,
>baolu
Hi Baolu,
I think that would work, and then change the deferred_attach_domain
calls in __intel_map_single and intel_map_sg to find_domain?
I did a quick test with it on the system where I've been looking at this.
Regards,
Jerry
>_______________________________________________
>iommu mailing list
>[email protected]
>https://lists.linuxfoundation.org/mailman/listinfo/iommu
Hi,
On 2020/2/8 18:19, Jerry Snitselaar wrote:
> On Sat Feb 08 20, Lu Baolu wrote:
>> Hi Jerry,
>>
>> On 2020/2/7 17:34, Jerry Snitselaar wrote:
>>> On Thu Feb 06 20, Jerry Snitselaar wrote:
>>>> On Tue Feb 04 20, Jerry Snitselaar wrote:
>>>>> I'm working on getting a system to reproduce this, and verify it
>>>>> also occurs
>>>>> with 5.5, but I have a report of a case where the kdump kernel gives
>>>>> warnings like the following on a hp dl360 gen9:
>>>>>
>>>>> [ 2.830589] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI)
>>>>> Driver
>>>>> [ 2.832615] ehci-pci: EHCI PCI platform driver
>>>>> [ 2.834190] ehci-pci 0000:00:1a.0: EHCI Host Controller
>>>>> [ 2.835974] ehci-pci 0000:00:1a.0: new USB bus registered,
>>>>> assigned bus number 1
>>>>> [ 2.838276] ehci-pci 0000:00:1a.0: debug port 2
>>>>> [ 2.839700] WARNING: CPU: 0 PID: 1 at
>>>>> drivers/iommu/intel-iommu.c:598 domain_get_iommu+0x55/0x60
>>>>> [ 2.840671] Modules linked in:
>>>>> [ 2.840671] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
>>>>> 4.18.0-170.el8.kdump2.x86_64 #1
>>>>> [ 2.840671] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360
>>>>> Gen9, BIOS P89 07/21/2019
>>>>> [ 2.840671] RIP: 0010:domain_get_iommu+0x55/0x60
>>>>> [ 2.840671] Code: c2 01 eb 0b 48 83 c0 01 8b 34 87 85 f6 75 0b
>>>>> 48 63 c8 48 39 c2 75 ed 31 c0 c3 48 c1 e1 03 48 8b 05 70 f3 91 01
>>>>> 48 8b 04 08 c3 <0f> 0b 31 c0 c3 31 c9 eb eb 66 90 0f 1f 44 00 00 41
>>>>> 55 40 0f b6 f6
>>>>> [ 2.840671] RSP: 0018:ffffc900000dfab8 EFLAGS: 00010202
>>>>> [ 2.840671] RAX: ffff88ec7f1c8000 RBX: 0000006c7c867000 RCX:
>>>>> 0000000000000000
>>>>> [ 2.840671] RDX: 00000000fffffff0 RSI: 0000000000000000 RDI:
>>>>> ffff88ec7f1c8000
>>>>> [ 2.840671] RBP: ffff88ec6f7000b0 R08: ffff88ec7f19d000 R09:
>>>>> ffff88ec7cbfcd00
>>>>> [ 2.840671] R10: 0000000000000095 R11: ffffc900000df928 R12:
>>>>> 0000000000000000
>>>>> [ 2.840671] R13: ffff88ec7f1c8000 R14: 0000000000001000 R15:
>>>>> 00000000ffffffff
>>>>> [ 2.840671] FS: 0000000000000000(0000)
>>>>> GS:ffff88ec7f600000(0000) knlGS:0000000000000000
>>>>> [ 2.840671] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>> [ 2.840671] CR2: 00007ff3e1713000 CR3: 0000006c7de0a004 CR4:
>>>>> 00000000001606b0
>>>>> [ 2.840671] Call Trace:
>>>>> [ 2.840671] __intel_map_single+0x62/0x140
>>>>> [ 2.840671] intel_alloc_coherent+0xa6/0x130
>>>>> [ 2.840671] dma_pool_alloc+0xd8/0x1e0
>>>>> [ 2.840671] e_qh_alloc+0x55/0x130
>>>>> [ 2.840671] ehci_setup+0x284/0x7b0
>>>>> [ 2.840671] ehci_pci_setup+0xa3/0x530
>>>>> [ 2.840671] usb_add_hcd+0x2b6/0x800
>>>>> [ 2.840671] usb_hcd_pci_probe+0x375/0x460
>>>>> [ 2.840671] local_pci_probe+0x41/0x90
>>>>> [ 2.840671] pci_device_probe+0x105/0x1b0
>>>>> [ 2.840671] driver_probe_device+0x12d/0x460
>>>>> [ 2.840671] device_driver_attach+0x50/0x60
>>>>> [ 2.840671] __driver_attach+0x61/0x130
>>>>> [ 2.840671] ? device_driver_attach+0x60/0x60
>>>>> [ 2.840671] bus_for_each_dev+0x77/0xc0
>>>>> [ 2.840671] ? klist_add_tail+0x3b/0x70
>>>>> [ 2.840671] bus_add_driver+0x14d/0x1e0
>>>>> [ 2.840671] ? ehci_hcd_init+0xaa/0xaa
>>>>> [ 2.840671] ? do_early_param+0x91/0x91
>>>>> [ 2.840671] driver_register+0x6b/0xb0
>>>>> [ 2.840671] ? ehci_hcd_init+0xaa/0xaa
>>>>> [ 2.840671] do_one_initcall+0x46/0x1c3
>>>>> [ 2.840671] ? do_early_param+0x91/0x91
>>>>> [ 2.840671] kernel_init_freeable+0x1af/0x258
>>>>> [ 2.840671] ? rest_init+0xaa/0xaa
>>>>> [ 2.840671] kernel_init+0xa/0xf9
>>>>> [ 2.840671] ret_from_fork+0x35/0x40
>>>>> [ 2.840671] ---[ end trace e87b0d9a1c8135c4 ]---
>>>>> [ 3.010848] ehci-pci 0000:00:1a.0: Using iommu dma mapping
>>>>> [ 3.012551] ehci-pci 0000:00:1a.0: 32bit DMA uses non-identity
>>>>> mapping
>>>>> [ 3.018537] ehci-pci 0000:00:1a.0: cache line size of 64 is not
>>>>> supported
>>>>> [ 3.021188] ehci-pci 0000:00:1a.0: irq 18, io mem 0x93002000
>>>>> [ 3.029006] ehci-pci 0000:00:1a.0: USB 2.0 started, EHCI 1.00
>>>>> [ 3.030918] usb usb1: New USB device found, idVendor=1d6b,
>>>>> idProduct=0002, bcdDevice= 4.18
>>>>> [ 3.033491] usb usb1: New USB device strings: Mfr=3, Product=2,
>>>>> SerialNumber=1
>>>>> [ 3.035900] usb usb1: Product: EHCI Host Controller
>>>>> [ 3.037423] usb usb1: Manufacturer: Linux
>>>>> 4.18.0-170.el8.kdump2.x86_64 ehci_hcd
>>>>> [ 3.039691] usb usb1: SerialNumber: 0000:00:1a.0
>>>>>
>>>>> It looks like the device finishes initializing once it figures out it
>>>>> needs dma mapping instead of the default
>>>>> passthrough. intel_alloc_coherent calls iommu_need_mapping, before it
>>>>> calls __intel_map_single, so I'm not sure why it is tripping over the
>>>>> WARN_ON in domain_get_iommu.
>>>>>
>>>>> one thing I noticed while looking at this is that domain_get_iommu can
>>>>> return NULL. So should there be something like the following in
>>>>> __intel_map_single after the domain_get_iommu call?
>>>>>
>>>>> if (!iommu)
>>>>> goto error;
>>>>>
>>>>> It is possible to deref the null pointer later otherwise.
>>>>>
>>>>> Regards,
>>>>> Jerry
>>>>
>>>> I reproduced the warning with a 5.5 kernel on an Intel NUC5i5MYBE.
>>>
>>> Hi Baolu,
>>>
>>> I think I understand what is happening here. With the kdump boot
>>> translation is pre-enabled, so in intel_iommu_add_device things are
>>> getting set to DEFER_DEVICE_DOMAIN_INFO. When intel_alloc_coherent
>>> calls iommu_need_mapping it returns true, but doesn't do the dma
>>> domain switch because of DEFER_DEVICE_DOMAIN_INFO. Then
>>> __intel_map_single gets called and it calls deferred_attach_domain,
>>> which sets the domain to the group domain, which in this case is the
>>> identity domain. Then it calls domain_get_iommu, which spits out the
>>> warning because the domain type was dma and returns null. My
>>> workaround was to add a call to iommu_need_mapping and find_domain
>>> after the deferred_attach_domain, but I don't know if that is the
>>> correct solution. There are a couple other spots like intel_map_sg
>>> that have the deferred_attach_domain after iommu_need_mapping that
>>> possibly will suffer from the same problem.
>>>
>>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>>> index b5c5ab58d395..063f45323cfc 100644
>>> --- a/drivers/iommu/intel-iommu.c
>>> +++ b/drivers/iommu/intel-iommu.c
>>> @@ -3515,6 +3515,10 @@ static dma_addr_t __intel_map_single(struct
>>> device *dev, phys_addr_t paddr,
>>> if (!domain)
>>> return DMA_MAPPING_ERROR;
>>>
>>> + if (!iommu_need_mapping(dev))
>>> + return paddr;
>>> +
>>> + domain = find_domain(dev);
>>> iommu = domain_get_iommu(domain);
>>> size = aligned_nrpages(paddr, size);
>>>
>>>
>>> I finally got a git repo over to one of these systems, and was
>>> able to reproduce the issue with the head of linus's tree. With commit
>>> 9235cb13d7d1 ("iommu/vt-d: Allow devices with RMRRs to use identity
>>> domain")
>>> there are more of the warnings, because devices are using identity that
>>> weren't before.
>>>
>>
>> Is it possible to move deferred domain attachment to identity_mapping()?
>>
>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>> index 9dc37672bf89..234ab346198e 100644
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -2913,13 +2913,11 @@ static int __init si_domain_init(int hw)
>>
>> static int identity_mapping(struct device *dev)
>> {
>> - struct device_domain_info *info;
>> + struct dmar_domain *domain;
>>
>> - info = dev->archdata.iommu;
>> - if (info && info != DUMMY_DEVICE_DOMAIN_INFO && info !=
>> DEFER_DEVICE_DOMAIN_INFO)
>> - return (info->domain == si_domain);
>> + domain = deferred_attach_domain(dev);
>>
>> - return 0;
>> + return (!domain || domain_type_is_si(domain));
>> }
>>
>> static int domain_add_dev_info(struct dmar_domain *domain, struct
>> device *dev)
>>
>> Best regards,
>> baolu
>
> Hi Baolu,
>
> I think that would work, and then change the deferred_attach_domain
> calls in __intel_map_single and intel_map_sg to find_domain?
>
Yes.
> I did a quick test with it on the system where I've been looking at this.
>
Thanks!
Best regards,
baolu