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.
