From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [RFC PATCH v3 0/4] Real mode interrupt injection
Date: Mon, 16 Aug 2010 11:51:57 +0300
Message-ID: <4C68FC2D.5070208@redhat.com>
References: <1281908823-4505-1-git-send-email-m.gamal005@gmail.com> <AANLkTik5ZQ5cRu6JmHN8HAN3mu-m9EgKh=UHRPndzmUq@mail.gmail.com>
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Cc: kvm@vger.kernel.org, mtosatti@redhat.com
To: Mohammed Gamal <m.gamal005@gmail.com>
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  On 08/16/2010 02:37 AM, Mohammed Gamal wrote:
>
> Here is a full trace of a MINIX guest since bootup. Looks like we get
> stuck somewhere in the BIOS.
> https://docs.google.com/leaf?id=0B9UodZT1IuENMzJhNWQxM2YtYzE3YS00YWY4LTk2YTgtZWY3ODNhMWUxMDkx&sort=name&layout=list&num=50

>  qemu-system-x86-28953 [000]  1927.399942: kvm_inj_virq: irq 16
>  qemu-system-x86-28953 [000]  1927.399949: 
> kvm_inject_realmode_interrupt: cs=c000
>  qemu-system-x86-28953 [000]  1927.399951: 
> kvm_inject_realmode_interrupt: eip=40a3
>  qemu-system-x86-28953 [000]  1927.399957: 
> kvm_inject_realmode_interrupt: cs=c000
>  qemu-system-x86-28953 [000]  1927.399958: 
> kvm_inject_realmode_interrupt: eip=8339
>  qemu-system-x86-28953 [000]  1927.399960: kvm_entry: vcpu 0
>  qemu-system-x86-28953 [000]  1927.399965: kvm_exit: reason 
> EXCEPTION_NMI rip 0x8339
>  qemu-system-x86-28953 [000]  1927.399966: kvm_page_fault: address 
> c8339 error_code 1d
>  qemu-system-x86-28953 [000]  1927.399970: kvm_entry: vcpu 0
>  qemu-system-x86-28953 [000]  1927.399975: kvm_exit: reason 
> IO_INSTRUCTION rip 0x67d9
>  qemu-system-x86-28953 [000]  1927.399976: kvm_pio: pio_read at 0x3c4 
> size 2 count 1
>  qemu-system-x86-28953 [000]  1927.399985: kvm_entry: vcpu 0
>  qemu-system-x86-28953 [000]  1927.399991: kvm_exit: reason 
> EXCEPTION_NMI rip 0x3d4

This is bogus, it's in the middle of an instruction:

    f93d1:       2e 67 8b 9a 00 00 f1    addr32 mov %cs:-0xf0000(%edx),%bx
    f93d8:       ff
    f93d9:       66 0f b7 eb             movzwl %bx,%ebp

Everything after that is invalid.

So we need to know how we got to rip = 0x3d4, it looks like an I/O port 
used by vga.  Please rerun with emulation on all real mode instructions.

>  qemu-system-x86-28953 [000]  1927.399992: kvm_page_fault: address 
> f93d4 error_code 1d
>  qemu-system-x86-28953 [000]  1927.399996: kvm_entry: vcpu 0
>  qemu-system-x86-28953 [000]  1927.400000: kvm_exit: reason 
> EXCEPTION_NMI rip 0x0
>  qemu-system-x86-28953 [000]  1927.400003: kvm_inj_exception: #DB (0x0)
>  qemu-system-x86-28953 [000]  1927.400005: 
> kvm_inject_realmode_interrupt: cs=fff1
>  qemu-system-x86-28953 [000]  1927.400006: 
> kvm_inject_realmode_interrupt: eip=0
>  qemu-system-x86-28953 [000]  1927.400011: 
> kvm_inject_realmode_interrupt: cs=f000
>  qemu-system-x86-28953 [000]  1927.400012: 
> kvm_inject_realmode_interrupt: eip=ff53
>  qemu-system-x86-28953 [000]  1927.400014: kvm_entry: vcpu 0

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.