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    SubjectRe: [PATCH] KVM: nVMX: Fix IRQs inject to L2 which belong to L1 since race
    On Fri, Jul 04, 2014 at 07:43:14AM +0200, Jan Kiszka wrote:
    >On 2014-07-04 04:52, Wanpeng Li wrote:
    >> On Thu, Jul 03, 2014 at 01:27:05PM -0400, Bandan Das wrote:
    >> [...]
    >>> # modprobe kvm_intel ept=0 nested=1 enable_shadow_vmcs=0
    >>>
    >>> The Host CPU - Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz
    >>> qemu cmd to run L1 -
    >>> # qemu-system-x86_64 -drive file=level1.img,if=virtio,id=disk0,format=raw,cache=none,werror=stop,rerror=stop,aio=threads -drive file=level2.img,if=virtio,id=disk1,format=raw,cache=none,werror=stop,rerror=stop,aio=threads -vnc :2 --enable-kvm -monitor stdio -m 4G -net nic,macaddr=00:23:32:45:89:10 -net tap,ifname=tap0,script=/etc/qemu-ifup,downscript=no -smp 4 -cpu Nehalem,+vmx -serial pty
    >>>
    >>> qemu cmd to run L2 -
    >>> # sudo qemu-system-x86_64 -hda VM/level2.img -vnc :0 --enable-kvm -monitor stdio -m 2G -smp 2 -cpu Nehalem -redir tcp:5555::22
    >>>
    >>> Additionally,
    >>> L0 is FC19 with 3.16-rc3
    >>> L1 and L2 are Ubuntu 14.04 with 3.13.0-24-generic
    >>>
    >>> Then start a kernel compilation inside L2 with "make -j3"
    >>>
    >>> There's no call trace on L0, both L0 and L1 are hung (or rather really slow) and
    >>> L1 serial spews out CPU softlock up errors. Enabling panic on softlockup on L1 will give
    >>> a trace with smp_call_function_many() I think the corresponding code in kernel/smp.c that
    >>> triggers this is
    >>>
    >>> WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
    >>> && !oops_in_progress && !early_boot_irqs_disabled);
    >>>
    >>> I know in most cases this is usually harmless, but in this specific case,
    >>> it seems it's stuck here forever.
    >>>
    >>> Sorry, I don't have a L1 call trace handy atm, I can post that if you are interested.
    >>>
    >>> Note that this can take as much as 30 to 40 minutes to appear but once it does,
    >>> you will know because both L1 and L2 will be stuck with the serial messages as I mentioned
    >>> before. From my side, let me try this on another system to rule out any machine specific
    >>> weirdness going on..
    >>>
    >>
    >> Thanks for your pointing out.
    >>
    >>> Please let me know if you need any further information.
    >>>
    >>
    >> I just run kvm-unit-tests w/ vmx.flat and eventinj.flat.
    >>
    >>
    >> w/ vmx.flat and w/o my patch applied
    >>
    >> [...]
    >>
    >> Test suite : interrupt
    >> FAIL: direct interrupt while running guest
    >> PASS: intercepted interrupt while running guest
    >> FAIL: direct interrupt + hlt
    >> FAIL: intercepted interrupt + hlt
    >> FAIL: direct interrupt + activity state hlt
    >> FAIL: intercepted interrupt + activity state hlt
    >> PASS: running a guest with interrupt acknowledgement set
    >> SUMMARY: 69 tests, 6 failures
    >>
    >> w/ vmx.flat and w/ my patch applied
    >>
    >> [...]
    >>
    >> Test suite : interrupt
    >> PASS: direct interrupt while running guest
    >> PASS: intercepted interrupt while running guest
    >> PASS: direct interrupt + hlt
    >> FAIL: intercepted interrupt + hlt
    >> PASS: direct interrupt + activity state hlt
    >> PASS: intercepted interrupt + activity state hlt
    >> PASS: running a guest with interrupt acknowledgement set
    >>
    >> SUMMARY: 69 tests, 2 failures
    >
    >Which version (hash) of kvm-unit-tests are you using? All tests up to
    >307621765a are running fine here, but since a0e30e712d not much is
    >completing successfully anymore:
    >

    I just git pull my kvm-unit-tests to latest, the last commit is daeec9795d.

    >enabling apic
    >paging enabled
    >cr0 = 80010011
    >cr3 = 7fff000
    >cr4 = 20
    >PASS: test vmxon with FEATURE_CONTROL cleared
    >PASS: test vmxon without FEATURE_CONTROL lock
    >PASS: test enable VMX in FEATURE_CONTROL
    >PASS: test FEATURE_CONTROL lock bit
    >PASS: test vmxon
    >FAIL: test vmptrld
    >PASS: test vmclear
    >init_vmcs : make_vmcs_current error
    >FAIL: test vmptrst
    >init_vmcs : make_vmcs_current error
    >vmx_run : vmlaunch failed.
    >FAIL: test vmlaunch
    >FAIL: test vmlaunch
    >
    >SUMMARY: 10 tests, 4 unexpected failures


    /opt/qemu/bin/qemu-system-x86_64 -enable-kvm -device pc-testdev -serial stdio
    -device isa-debug-exit,iobase=0xf4,iosize=0x4 -kernel ./x86/vmx.flat -cpu host

    Test suite : interrupt
    PASS: direct interrupt while running guest
    PASS: intercepted interrupt while running guest
    PASS: direct interrupt + hlt
    FAIL: intercepted interrupt + hlt
    PASS: direct interrupt + activity state hlt
    PASS: intercepted interrupt + activity state hlt
    PASS: running a guest with interrupt acknowledgement set

    SUMMARY: 69 tests, 2 failures

    However, interrupted interrupt + hlt always fail w/ and w/o my patch.

    Regards,
    Wanpeng Li

    >
    >
    >Jan
    >
    >--
    >Siemens AG, Corporate Technology, CT RTC ITP SES-DE
    >Corporate Competence Center Embedded Linux


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