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[Qemu-devel] [Question] Seabios HANGs when mmio wirte in a nested vmware
From: |
Xulei (Stone) |
Subject: |
[Qemu-devel] [Question] Seabios HANGs when mmio wirte in a nested vmware host wtih virito-scsi controller |
Date: |
Mon, 17 Jul 2017 03:13:05 +0000 |
Hello all,
Recently, I met a werid question when i run a VM in the following platfrom:
Vmware Vsphere 6.0/6.5
|-- centos 7.3 nested VM (with qemu 2.8, kmod 4.4.11, seabios 1.10)
|-- VM (with virtio-scsi controller, modern mode)
VM MUST hang in seabios when try to mmio write during virtio-scsi init.
I deeply analyze the code, and i found that:
Seabios calltrace:
scsi_drive_setup
|-- cdb_get_inquiry
|-- virtio_scsi_process_op
|-- vring_kick
|-- writew (hang here, mmio write, never return...)
Kmod calltrace:
handle_EPT_MISCONFIG
|--kvm_io_bus_write
|-- kvm_iodevice_write (fast mmio through ioeventfd to trigger qemu)
|-- vcpu_run
|-- vcpu_enter_guest
Qemu calltrace:
os_host_main_loop_wait
|--glib_pollfds_poll
|-- aio_dispatch
|-- vritio_scsi_handle_cmd_vq
|--virtio_scsi_pop_req
|-- virtqueue_pop
|--virtio_queue_empty
Then, kmod falls in infinite loop in handle EPT_MISCONFIG.
As far as i know, when kvm enters guest after handling EPT_MISCONFIG, seabios
should return
from mmio write and wait for virtio backend(qemu) to handle this mmio writing.
What puzzles me:
1) i can not understand why kvm runs in infinite loop and seabios does not
return from writew.
2) kvm nested kvm is ok. But vmware nested kvm is not ok. This problem has
anything related
with vmware?
Looking forward for directions...
Attached Kmod ftrace:
CPU 0/KVM-9435 [008] .... 241968.479572: kvm_exit: reason EPT_MISCONFIG
rip 0xee696 info 0 0
CPU 0/KVM-9435 [008] .... 241968.479573: kvm_fast_mmio: fast mmio at
gpa 0xfe003008
CPU 0/KVM-9435 [008] d... 241968.479573: kvm_entry: vcpu 0
CPU 0/KVM-9435 [008] .... 241968.479583: kvm_exit: reason EPT_MISCONFIG
rip 0xee696 info 0 0
CPU 0/KVM-9435 [008] .... 241968.479589: kvm_fast_mmio: fast mmio at
gpa 0xfe003008
CPU 0/KVM-9435 [008] d... 241968.479589: kvm_entry: vcpu 0
CPU 0/KVM-9435 [008] .... 241968.479599: kvm_exit: reason EPT_MISCONFIG
rip 0xee696 info 0 0
CPU 0/KVM-9435 [008] .... 241968.479600: kvm_fast_mmio: fast mmio at
gpa 0xfe003008
CPU 0/KVM-9435 [008] d... 241968.479601: kvm_entry: vcpu 0
CPU 0/KVM-9435 [008] .... 241968.479610: kvm_exit: reason EPT_MISCONFIG
rip 0xee696 info 0 0
CPU 0/KVM-9435 [008] .... 241968.479616: kvm_fast_mmio: fast mmio at
gpa 0xfe003008
CPU 0/KVM-9435 [008] d... 241968.479617: kvm_entry: vcpu 0
CPU 0/KVM-9435 [008] .... 241968.479627: kvm_exit: reason EPT_MISCONFIG
rip 0xee696 info 0 0
CPU 0/KVM-9435 [008] .... 241968.479628: kvm_fast_mmio: fast mmio at
gpa 0xfe003008
CPU 0/KVM-9435 [008] d... 241968.479628: kvm_entry: vcpu 0
CPU 0/KVM-9435 [008] .... 241968.479638: kvm_exit: reason EPT_MISCONFIG
rip 0xee696 info 0 0
CPU 0/KVM-9435 [008] .... 241968.479644: kvm_fast_mmio: fast mmio at
gpa 0xfe003008
CPU 0/KVM-9435 [008] d... 241968.479644: kvm_entry: vcpu 0
CPU 0/KVM-9435 [008] .... 241968.479655: kvm_exit: reason EPT_MISCONFIG
rip 0xee696 info 0 0
CPU 0/KVM-9435 [008] .... 241968.479656: kvm_fast_mmio: fast mmio at
gpa 0xfe003008
CPU 0/KVM-9435 [008] d... 241968.479656: kvm_entry: vcpu 0
________________________________
- [Qemu-devel] [Question] Seabios HANGs when mmio wirte in a nested vmware host wtih virito-scsi controller,
Xulei (Stone) <=