Re: [Xen-devel] xl serial console 'o' crashes Xen.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 11.01.13 at 21:30, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote:
> This is a non-debug built of Xen 4.3-unstable and after having
> one HVM guest launched I pressed 'o' for fun on the serial console
> and go this:
> 
> This is a SandyBridge ES-1220 CPU (Lenovo ThinkServer (TS130 11051CU))
> 
> (XEN) domain1 IOMMU p2m table: 
> (XEN) p2m table has 4 levels
> (XEN) Assertion 'pfn_to_pdx(ma >> PAGE_SHIFT) < (DIRECTMAP_SIZE >> 
> PAGE_SHIFT)' 
> failed at /home/konrad/ssd/konrad/xtt-x86_64/bootstrap/xen/x:101
> (XEN) ----[ Xen-4.3-unstable  x86_64  debug=y  Not tainted ]----
> (XEN) CPU:    0
> (XEN) RIP:    e008:[<ffff82c48014c2e8>] map_vtd_domain_page+0x38/0x6d
> (XEN) RFLAGS: 0000000000010216   CONTEXT: hypervisor
> (XEN) rax: 0000000000000000   rbx: f000eef3f000e000   rcx: 0000000000000000
> (XEN) rdx: 000f000eef3f000e   rsi: 000f000eef3f000e   rdi: f000eef3f000e000
> (XEN) rbp: ffff82c4802bfd60   rsp: ffff82c4802bfd60   r8:  f000eef3f000e2c3
> (XEN) r9:  00000000a589c275   r10: 00000000fffffffd   r11: ffff82c480224e40
> (XEN) r12: 00000000000001ff   r13: ffff830000000000   r14: 0000000000000003
> (XEN) r15: 0000008000000000   cr0: 000000008005003b   cr4: 00000000000426f0
> (XEN) cr3: 00000000c6a70000   cr2: ffffffffff600400
> (XEN) ds: 0000   es: 0000   fs: 0000   gs: 0000   ss: 0000   cs: e008
> (XEN) Xen stack trace from rsp=ffff82c4802bfd60:
> (XEN)    ffff82c4802bfdb0 ffff82c4801453b2 00000001802bfe00 0000000000000000
> (XEN)    0000000000000200 0000000000000001 00000000000001ff ffff830000000000
> (XEN)    0000000000000003 0000000000000000 ffff82c4802bfe00 ffff82c48014542f
> (XEN)    0000000080303a20 0000002700000001 0000000000000004 ffff83022d9fa000
> (XEN)    ffff82c480263180 ffff82c48023f16e ffff82c480248ea0 ffff82c480303a48
> (XEN)    ffff82c4802bfe20 ffff82c4801454c8 ffff82c48023f16e ffff83022d9fa000
> (XEN)    ffff82c4802bfe50 ffff82c4801421da ffff82c480277d40 000000000000006f
> (XEN)    0000000000000000 ffff82c480303a60 ffff82c4802bfe80 ffff82c48011042c
> (XEN)    ffff82c4802bfe80 ffff82c480277620 ffff82c480277620 0000000000000000
> (XEN)    ffff82c4802bfe90 ffff82c48011046d ffff82c4802bfeb0 ffff82c4801272af
> (XEN)    ffff82c480303ad0 ffff82c480303af0 ffff82c4802bfee0 ffff82c4801273d9
> (XEN)    ffff82c480260f80 ffff82c4802b8000 ffff82c480260f80 ffff82c4802b8000
> (XEN)    ffff82c4802bff10 ffff82c48015b5d5 0000000000026c00 ffff8300c6d4a000
> (XEN)    ffff8300c6d4a000 ffffffffffffffff ffff82c4802bfdf0 0000000000026c00
> (XEN)    0000000000000000 ffffffff81a00000 0000000000000000 ffffffff81a01ea8
> (XEN)    ffffffff81a00010 ffffffff81a01e08 0000001931fed8c8 ffff880079a0e800
> (XEN)    0000000000000000 0000000000000000 0000000000000000 0000000000000000
> (XEN)    0140000000000000 0000000000000082 0000beef0000beef ffffffff8107b3a6
> (XEN)    0000beef0000beef 0000000000000246 ffffffff81a01ea8 000000000000beef
> (XEN)    000000000000beef 000000000000beef 000000000000beef 000000000000beef
> (XEN) Xen call trace:
> (XEN)    [<ffff82c48014c2e8>] map_vtd_domain_page+0x38/0x6d
> (XEN)    [<ffff82c4801453b2>] vtd_dump_p2m_table_level+0x2a/0xef
> (XEN)    [<ffff82c48014542f>] vtd_dump_p2m_table_level+0xa7/0xef
> (XEN)    [<ffff82c4801454c8>] vtd_dump_p2m_table+0x51/0x58
> (XEN)    [<ffff82c4801421da>] iommu_dump_p2m_table+0xb8/0xca
> (XEN)    [<ffff82c48011042c>] handle_keypress+0x70/0x9c
> (XEN)    [<ffff82c48011046d>] keypress_action+0x15/0x17
> (XEN)    [<ffff82c4801272af>] do_tasklet_work+0x8e/0xc6
> (XEN)    [<ffff82c4801273d9>] do_tasklet+0x66/0x96
> (XEN)    [<ffff82c48015b5d5>] idle_loop+0x6e/0x75
> (XEN)    
> (XEN) 
> (XEN) ****************************************
> (XEN) Panic on CPU 0:
> (XEN) Assertion 'pfn_to_pdx(ma >> PAGE_SHIFT) < (DIRECTMAP_SIZE >> 
> PAGE_SHIFT)' 
> failed at 
> /home/konrad/ssd/konrad/xtt-x86_64/bootstra*********************************
> *******
> (XEN) 
> (XEN) Manual reset required ('noreboot' specified)
> 
> Any ideas?

Was that with the guest still running or already terminated?

In any case - the register values suggest that the page at MFN 0
got looked at and used for traversing the page table hierarchy,
and the question therefore mainly at what level this MFN 0 got
read and used.

Jan 

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