Re: [dpdk-stable] [PATCH v2] igb_uio: prevent reset for a list of devices

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 11/7/2017 12:47 PM, Chas Williams wrote:
> I will confess I haven't looked into the issue too hard since I have a
> workaround.  My first guess is that there is something going on with the IOMMU
> and quiescing a PCI pass-through device/function from the guest (since I don't
> think the IOMMU is "visible" to the guest) seems iffy.
> 
> Most devices have some sort of reset to put the device into a known state for
> setup/configuration (or enable/disable for the DMA engines).  If this is done at
> .dev_close(), shouldn't that be as sufficient as resetting the function?

This is for the cases DPDK app terminated unexpectedly, proper exit path already
does cleanup.

> 
> On Tue, Nov 7, 2017 at 1:49 PM, Ferruh Yigit <ferruh.yigit@intel.com
> <mailto:ferruh.yigit@intel.com>> wrote:
> 
>     On 11/7/2017 10:12 AM, Chas Williams wrote:
>     > Environment: Dell PowerEdge R730, Intel Corporation 82599ES 10-Gigabit
>     SFI/SFP+
>     > Network Connection shared via PCI pass-through
>     > Host: Debian 8
>     > Guest: Custom Debian 8 with DPDK application based on 17.11
>     >
>     > When we shutdown the guest, the kernel panics with:
>     >
>     > [  279.021818] Do you have a strange power saving mode enabled?
>     > [  279.021819] Dazed and confused, but trying to continue
>     > [  279.021847] {1}[Hardware Error]: Hardware error from APEI Generic Hardware
>     > Error Source: 3
>     > [  279.021849] {1}[Hardware Error]: event severity: fatal
>     > [  279.021850] {1}[Hardware Error]:  Error 0, type: fatal
>     > [  279.021851] {1}[Hardware Error]:   section_type: PCIe error
>     > [  279.021852] {1}[Hardware Error]:   port_type: 0, PCIe end point
>     > [  279.021853] {1}[Hardware Error]:   version: 1.16
>     > [  279.021854] {1}[Hardware Error]:   command: 0x0507, status: 0x4010
>     > [  279.021855] {1}[Hardware Error]:   device_id: 0000:03:00.0
>     > [  279.021855] {1}[Hardware Error]:   slot: 0
>     > [  279.021856] {1}[Hardware Error]:   secondary_bus: 0x00
>     > [  279.021857] {1}[Hardware Error]:   vendor_id: 0x8086, device_id: 0x10fb
>     > [  279.021858] {1}[Hardware Error]:   class_code: 000002
>     > [  279.021859] Kernel panic - not syncing: Fatal hardware error!
>     > [  279.021977] sched: Unexpected reschedule of offline CPU#1!
>     > [  279.021984] ------------[ cut here ]------------
>     > [  279.021992] WARNING: CPU: 43 PID: 2807 at
>     > /build/linux-fHlJSJ/linux-4.12.6/arch/x86/kernel/smp.c:128
>     > native_smp_send_reschedule+0x34/0x40
>     > [  279.021993] Modules linked in: vfio_pci vfio_virqfd vfio_iommu_type1 vfio
>     > openvswitch nf_conntrack_ipv6 nf_nat_ipv6 nf_conntrack_ipv4 nf_defrag_ipv4
>     > nf_nat_ipv4 nf_defrag_ipv6 nf_nat nf_conntrack libcrc32c crc32c_generic nfsd
>     > nfs_aclr
>     > pcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace sunrpc
>     fscache tun
>     > intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp
>     kvm_intel kvm
>     > irqbypass mgag200 ttm drm_kms_helper drm joydev crct10dif_pclmul crc32_pclmu
>     > l ghash_clmulni_intel i2c_algo_bit ipmi_si ipmi_devintf iTCO_wdt intel_cstate
>     > iTCO_vendor_support evdev intel_uncore mxm_wmi lpc_ich ipmi_msghandler
>     mfd_core
>     > ioatdma intel_rapl_perf dcdbas pcspkr shpchp mei_me button wmi mei
>     acpi_power_m
>     > eter tpm_crb autofs4 ext4 crc16 jbd2 fscrypto mbcache sr_mod cdrom sg
>     > hid_generic usbhid hid sd_mod
>     > [  279.022044]  crc32c_intel aesni_intel aes_x86_64 crypto_simd cryptd
>     > glue_helper ahci ehci_pci libahci ehci_hcd ixgbe libata megaraid_sas
>     usbcore dca
>     > i40e usb_common ptp pps_core scsi_mod mdio
>     > [  279.022060] CPU: 43 PID: 2807 Comm: revalidator85 Not tainted
>     4.12.0-1-amd64
>     > #1 Debian 4.12.6-1
>     > [  279.022061] Hardware name: Dell Inc. PowerEdge R730/0WCJNT, BIOS 2.3.4
>     11/08/2016
>     > [  279.022062] task: ffff91d0473f7100 task.stack: ffffafef8f4a4000
>     > [  279.022066] RIP: 0010:native_smp_send_reschedule+0x34/0x40
>     > [  279.022067] RSP: 0018:ffffafef8f4a7c98 EFLAGS: 00010082
>     > [  279.022069] RAX: 000000000000002e RBX: ffff91d059d24080 RCX:
>     0000000000000001
>     > [  279.022070] RDX: 0000000000000000 RSI: 0000000000000002 RDI:
>     0000000000000046
>     > [  279.022071] RBP: ffff91d04691d100 R08: 0000000000000000 R09:
>     000000000000002e
>     > [  279.022072] R10: ffffafef8f4a7c90 R11: 00000000001cbb78 R12:
>     ffff91d85d21ae80
>     > [  279.022073] R13: ffff91d059d24000 R14: 0000000000000002 R15:
>     0000000000000008
>     > [  279.022075] FS:  00007f726affd700(0000) GS:ffff91d85d740000(0000)
>     > knlGS:0000000000000000
>     > [  279.022076] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>     > [  279.022077] CR2: 00007fd422a52c48 CR3: 000000042d90f000 CR4:
>     00000000003426e0
>     > [  279.022078] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
>     0000000000000000
>     > [  279.022079] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
>     0000000000000400
>     > [  279.022080] Call Trace:
>     > [  279.022086]  ? check_preempt_wakeup+0x181/0x220
>     > [  279.022091]  ? check_preempt_curr+0x74/0x80
>     > [  279.022094]  ? ttwu_do_wakeup+0x19/0x140
>     > [  279.022098]  ? try_to_wake_up+0x1b8/0x470
>     > [  279.022101]  ? wake_up_q+0x3f/0x70
>     > [  279.022106]  ? futex_wake+0x15a/0x170
>     > [  279.022108]  ? do_futex+0x2df/0xa90
>     > [  279.022111]  ? SyS_futex+0x7a/0x170
>     > [  279.022113]  ? SyS_read+0x76/0xc0
>     > [  279.022118]  ? system_call_fast_compare_end+0xc/0x97
>     > [  279.022119] Code: a3 05 51 fb cc 00 73 15 48 8b 05 28 74 a3 00 be fd 00
>     00 00
>     > 48 8b 80 a0 00 00 00 ff e0 89 fe 48 c7 c7 88 5c de b6 e8 e2 c9 13 00 <0f>
>     ff c3
>     > 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 5d 00
>     > [  279.022151] ---[ end trace eddc980dc8648163 ]---
>     > [  279.454274] Kernel Offset: 0x35400000 from 0xffffffff81000000 (relocation
>     > range: 0xffffffff80000000-0xffffffffbfffffff)
>     >
>     > The test engineer says this doesn't happen if we use SRIOV (which makes sense
>     > since the device isn't directly shared between the guest and the host).  If I
>     > remove the pci_reset_function() from igb_uio's .release, then all is well.
> 
>     This was tougher than expected, so many unexpected behavior. Why resetting
>     pass-through device in guest cause a crash in the host?
> 
>     Finally, I will send a patch to remove the reset. Hopefully no more surprises
>     for release.
> 
>     Still there will remain two improvement in igb_uio for better security,
>     disabling device interrupt on exit and clear master on exit.
> 
>     >
>     >
>     > On Tue, Nov 7, 2017 at 8:02 AM, Thomas Monjalon <thomas@monjalon.net <mailto:thomas@monjalon.net>
>     > <mailto:thomas@monjalon.net <mailto:thomas@monjalon.net>>> wrote:
>     >
>     >     07/11/2017 12:50, Chas Williams:
>     >     > We still have an issue with this and PCI pass-through.  If a guest is
>     >     > restarted while using PCI pass-through and igb_uio issues a
>     >     > pci_reset_function(), this causes the host to crash.
>     >
>     >     Please, could you better explain the exact scenario and the cause of
>     the crash?
>     >     Thanks
>     >
>     >
> 
>