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Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device
From: |
Klaus Jensen |
Subject: |
Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device |
Date: |
Thu, 2 Jul 2020 12:31:27 +0200 |
On Jul 2 12:13, Klaus Jensen wrote:
> On Jul 1 14:48, Andrzej Jakowski wrote:
> > So far it was not possible to have CMB and PMR emulated on the same
> > device, because BAR2 was used exclusively either of PMR or CMB. This
> > patch places CMB at BAR4 offset so it not conflicts with MSI-X vectors.
> >
>
> Linux craps out when I test this (1MB CMB):
>
> Misaligned __add_pages start: 0xfdd00 end: #fdeff
>
> I tracked it down to check_pfn_span (mm/memory_hotplug.c) failing
> because it's not on a 2MB boundary. I then tried to monkey patch the
> cmb_offset to be 2MB instead and it succeeds in registering the cmb:
>
> [ 8.384565] memmap_init_zone_device initialised 512 pages in 0ms
> [ 8.385715] nvme 0000:03:00.0: added peer-to-peer DMA memory [mem
> 0xfd200000-0xfd3fffff 64bit
> pref]
> [ 8.419372] nvme nvme0: 1/0/0 default/read/poll queues
>
> But the kernel then continues to really crap out with a kernel panic:
>
> [ 8.440891] DMAR: DRHD: handling fault status reg 2
> [ 8.440934] BUG: kernel NULL pointer dereference, address: 0000000000000120
> [ 8.441713] DMAR: [DMA Read] Request device [03:00.0] PASID ffffffff fault
> addr fd200000 [faul
> t reason 06] PTE Read access is not set
> [ 8.442630] #PF: supervisor write access in kernel mode
> [ 8.444972] #PF: error_code(0x0002) - not-present page
> [ 8.445640] PGD 0 P4D 0
> [ 8.445965] Oops: 0002 [#1] PREEMPT SMP PTI
> [ 8.446499] CPU: 3 PID: 0 Comm: swapper/3 Not tainted
> 5.8.0-rc1-00034-gb6cf9836d07f-dirty #19
> [ 8.447547] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
> rel-1.13.0-0-gf21b5a4aeb0
> 2-prebuilt.qemu.org 04/01/2014
> [ 8.448898] RIP: 0010:nvme_process_cq+0xc4/0x200 [nvme]
> [ 8.449525] Code: cf 00 00 00 48 8b 57 70 48 8b 7c c2 f8 e8 14 e9 32 c1 49
> 89 c7 0f 1f 44 00 0
> 0 41 0f b7 44 24 0e 49 8b 14 24 4c 89 ff 66 d1 e8 <49> 89 97 20 01 00 00 66
> 41 89 87 2a 01 00 00
> e8 28 04 33 c1 0f b7
> [ 8.451662] RSP: 0018:ffffc9000015cf20 EFLAGS: 00010803
> [ 8.452321] RAX: 000000000000400b RBX: ffff88826faad0c0 RCX:
> 0000000000000000
> [ 8.453293] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
> 0000000000000000
> [ 8.454312] RBP: ffff8882725d38e4 R08: 00000001f71e225c R09:
> 0000000000000000
> [ 8.455319] R10: 0000000000000000 R11: 0000000000000000 R12:
> ffff888270bb0000
> [ 8.456334] R13: 0000000000000000 R14: ffffc9000015cfac R15:
> 0000000000000000
> [ 8.457311] FS: 0000000000000000(0000) GS:ffff888277d80000(0000)
> knlGS:0000000000000000
> [ 8.458441] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 8.459380] CR2: 0000000000000120 CR3: 0000000271c8c006 CR4:
> 0000000000360ee0
> [ 8.460507] Call Trace:
> [ 8.460906] <IRQ>
> [ 8.461272] nvme_irq+0x10/0x20 [nvme]
> [ 8.461951] __handle_irq_event_percpu+0x45/0x1b0
> [ 8.462803] ? handle_fasteoi_irq+0x210/0x210
> [ 8.463585] handle_irq_event+0x58/0xb0
> [ 8.464312] handle_edge_irq+0xae/0x270
> [ 8.465027] asm_call_on_stack+0x12/0x20
> [ 8.465686] </IRQ>
> [ 8.466053] common_interrupt+0x120/0x1f0
> [ 8.466717] asm_common_interrupt+0x1e/0x40
> [ 8.467429] RIP: 0010:default_idle+0x21/0x170
> [ 8.468140] Code: eb a6 e8 82 27 ff ff cc cc 0f 1f 44 00 00 41 54 55 53 e8
> e2 2e ff ff 0f 1f 4
> 4 00 00 e9 07 00 00 00 0f 00 2d f3 d4 44 00 fb f4 <e8> ca 2e ff ff 89 c5 0f
> 1f 44 00 00 5b 5d 41
> 5c c3 89 c5 65 8b 05
> [ 8.471286] RSP: 0018:ffffc9000009fec8 EFLAGS: 00000282
> [ 8.472202] RAX: 0000000000000003 RBX: ffff888276ff0000 RCX:
> 0000000000000001
> [ 8.473405] RDX: 0000000000000001 RSI: ffffffff8212355f RDI:
> ffffffff8212d699
> [ 8.474571] RBP: 0000000000000003 R08: ffff888277d9e4a0 R09:
> 0000000000000020
> [ 8.475717] R10: 0000000000000000 R11: 0000000000000000 R12:
> 0000000000000000
> [ 8.476921] R13: 0000000000000000 R14: 0000000000000000 R15:
> 0000000000000000
> [ 8.478110] ? default_idle+0xe/0x170
> [ 8.478728] do_idle+0x1e1/0x240
> [ 8.479283] ? _raw_spin_lock_irqsave+0x19/0x40
> [ 8.480040] cpu_startup_entry+0x19/0x20
> [ 8.480705] start_secondary+0x153/0x190
> [ 8.481400] secondary_startup_64+0xb6/0xc0
> [ 8.482114] Modules linked in: libata nvme nvme_core scsi_mod t10_pi
> crc_t10dif crct10dif_gene
> ric crct10dif_common virtio_net net_failover failover virtio_rng rng_core
> [ 8.484675] CR2: 0000000000000120
> [ 8.485264] ---[ end trace ff1849437c76af12 ]---
> [ 8.486065] RIP: 0010:nvme_process_cq+0xc4/0x200 [nvme]
> [ 8.486953] Code: cf 00 00 00 48 8b 57 70 48 8b 7c c2 f8 e8 14 e9 32 c1 49
> 89 c7 0f 1f 44 00 0
> 0 41 0f b7 44 24 0e 49 8b 14 24 4c 89 ff 66 d1 e8 <49> 89 97 20 01 00 00 66
> 41 89 87 2a 01 00 00
> e8 28 04 33 c1 0f b7
> [ 8.490234] RSP: 0018:ffffc9000015cf20 EFLAGS: 00010803
> [ 8.491144] RAX: 000000000000400b RBX: ffff88826faad0c0 RCX:
> 0000000000000000
> [ 8.492445] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
> 0000000000000000
> [ 8.493681] RBP: ffff8882725d38e4 R08: 00000001f71e225c R09:
> 0000000000000000
> [ 8.494907] R10: 0000000000000000 R11: 0000000000000000 R12:
> ffff888270bb0000
> [ 8.496130] R13: 0000000000000000 R14: ffffc9000015cfac R15:
> 0000000000000000
> [ 8.497363] FS: 0000000000000000(0000) GS:ffff888277d80000(0000)
> knlGS:0000000000000000
> [ 8.498726] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 8.499713] CR2: 0000000000000120 CR3: 0000000271c8c006 CR4:
> 0000000000360ee0
> [ 8.500935] Kernel panic - not syncing: Fatal exception in interrupt
> [ 8.502113] Kernel Offset: disabled
> [ 8.502728] ---[ end Kernel panic - not syncing: Fatal exception in
> interrupt ]---
>
> I'm out of my depth here, but the CMB/BAR offsets/setup seems sane enough -
> could this be a kernel bug?
>
> Keith, any thoughts on this?
>
Aight, an update here. This only happens when QEMU is run with a virtual
IOMMU. Otherwise, the kernel is happy.
With the vIOMMU, qemu also craps out a bit:
qemu-system-x86_64: vtd_iova_to_slpte: detected slpte permission error
(iova=0xfd200000, level=0x2, slpte=0x0, write=0)
qemu-system-x86_64: vtd_iommu_translate: detected translation failure
(dev=03:00:00, iova=0xfd200000)
So I think we are back in QEMU land for the bug.
- [PATCH v4] nvme: allow cmb and pmr emulation on same device, Andrzej Jakowski, 2020/07/01
- [PATCH v4 1/2] nvme: indicate CMB support through controller capabilities register, Andrzej Jakowski, 2020/07/01
- [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Andrzej Jakowski, 2020/07/01
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Klaus Jensen, 2020/07/02
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device,
Klaus Jensen <=
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Andrzej Jakowski, 2020/07/02
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Klaus Jensen, 2020/07/02
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Andrzej Jakowski, 2020/07/02
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Klaus Jensen, 2020/07/06
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Andrzej Jakowski, 2020/07/08
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Klaus Jensen, 2020/07/15
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Klaus Jensen, 2020/07/15
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Andrzej Jakowski, 2020/07/21
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Klaus Jensen, 2020/07/22
- Re: [PATCH v4 2/2] nvme: allow cmb and pmr to be enabled on same device, Andrzej Jakowski, 2020/07/22