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  1. Sep 08, 2015
    • Juergen Gross's avatar
      xen: avoid another early crash of memory limited dom0 · ab24507c
      Juergen Gross authored
      
      
      Commit b1c9f169047b ("xen: split counting of extra memory pages...")
      introduced an error when dom0 was started with limited memory occurring
      only on some hardware.
      
      The problem arises in case dom0 is started with initial memory and
      maximum memory being the same. The kernel must be configured without
      CONFIG_XEN_BALLOON_MEMORY_HOTPLUG for the problem to happen. If all
      of this is true and the E820 map of the machine is sparse (some areas
      are not covered) then the machine might crash early in the boot
      process.
      
      An example E820 map triggering the problem looks like this:
      
      [    0.000000] e820: BIOS-provided physical RAM map:
      [    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009d7ff] usable
      [    0.000000] BIOS-e820: [mem 0x000000000009d800-0x000000000009ffff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved
      [    0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000cf7fafff] usable
      [    0.000000] BIOS-e820: [mem 0x00000000cf7fb000-0x00000000cf95ffff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000cf960000-0x00000000cfb62fff] ACPI NVS
      [    0.000000] BIOS-e820: [mem 0x00000000cfb63000-0x00000000cfd14fff] usable
      [    0.000000] BIOS-e820: [mem 0x00000000cfd15000-0x00000000cfd61fff] ACPI NVS
      [    0.000000] BIOS-e820: [mem 0x00000000cfd62000-0x00000000cfd6cfff] ACPI data
      [    0.000000] BIOS-e820: [mem 0x00000000cfd6d000-0x00000000cfd6ffff] ACPI NVS
      [    0.000000] BIOS-e820: [mem 0x00000000cfd70000-0x00000000cfd70fff] usable
      [    0.000000] BIOS-e820: [mem 0x00000000cfd71000-0x00000000cfea8fff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000cfea9000-0x00000000cfeb9fff] ACPI NVS
      [    0.000000] BIOS-e820: [mem 0x00000000cfeba000-0x00000000cfecafff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000cfecb000-0x00000000cfecbfff] ACPI NVS
      [    0.000000] BIOS-e820: [mem 0x00000000cfecc000-0x00000000cfedbfff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000cfedc000-0x00000000cfedcfff] ACPI NVS
      [    0.000000] BIOS-e820: [mem 0x00000000cfedd000-0x00000000cfeddfff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000cfede000-0x00000000cfee3fff] ACPI NVS
      [    0.000000] BIOS-e820: [mem 0x00000000cfee4000-0x00000000cfef6fff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000cfef7000-0x00000000cfefffff] usable
      [    0.000000] BIOS-e820: [mem 0x00000000e0000000-0x00000000efffffff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000fec00000-0x00000000fec00fff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000fec10000-0x00000000fec10fff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000fed00000-0x00000000fed00fff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000fed40000-0x00000000fed44fff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000fed61000-0x00000000fed70fff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000fed80000-0x00000000fed8ffff] reserved
      [    0.000000] BIOS-e820: [mem 0x00000000ff000000-0x00000000ffffffff] reserved
      [    0.000000] BIOS-e820: [mem 0x0000000100001000-0x000000020effffff] usable
      
      In this case the area a0000-dffff isn't present in the map. This will
      confuse the memory setup of the domain when remapping the memory from
      such holes to populated areas.
      
      To avoid the problem the accounting of to be remapped memory has to
      count such holes in the E820 map as well.
      
      Reported-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
      Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
      Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      ab24507c
    • Juergen Gross's avatar
      xen: avoid early crash of memory limited dom0 · eafd72e0
      Juergen Gross authored
      
      
      Commit b1c9f169047b ("xen: split counting of extra memory pages...")
      introduced an error when dom0 was started with limited memory.
      
      The problem arises in case dom0 is started with initial memory and
      maximum memory being the same and exactly a multiple of 1 GB. The
      kernel must be configured without CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
      for the problem to happen. In this case it will crash very early
      during boot due to the virtual mapped p2m list not being large
      enough to be able to remap any memory:
      
      (XEN) Freed 304kB init memory.
      mapping kernel into physical memory
      about to get started...
      (XEN) traps.c:459:d0v0 Unhandled invalid opcode fault/trap [#6] on VCPU 0 [ec=0000]
      (XEN) domain_crash_sync called from entry.S: fault at ffff82d080229a93 create_bounce_frame+0x12b/0x13a
      (XEN) Domain 0 (vcpu#0) crashed on cpu#0:
      (XEN) ----[ Xen-4.5.2-pre  x86_64  debug=n Not tainted ]----
      (XEN) CPU:    0
      (XEN) RIP:    e033:[<ffffffff81d120cb>]
      (XEN) RFLAGS: 0000000000000206   EM: 1 CONTEXT: pv guest (d0v0)
      (XEN) rax: ffffffff81db2000   rbx: 000000004d000000   rcx: 0000000000000000
      (XEN) rdx: 000000004d000000   rsi: 0000000000063000   rdi: 000000004d063000
      (XEN) rbp: ffffffff81c03d78   rsp: ffffffff81c03d28   r8:  0000000000023000
      (XEN) r9:  00000001040ff000   r10: 0000000000007ff0   r11: 0000000000000000
      (XEN) r12: 0000000000063000   r13: 000000000004d000   r14: 0000000000000063
      (XEN) r15: 0000000000000063   cr0: 0000000080050033   cr4: 00000000000006f0
      (XEN) cr3: 0000000105c0f000   cr2: ffffc90000268000
      (XEN) ds: 0000   es: 0000   fs: 0000   gs: 0000   ss: e02b   cs: e033
      (XEN) Guest stack trace from rsp=ffffffff81c03d28:
      (XEN)   0000000000000000 0000000000000000 ffffffff81d120cb 000000010000e030
      (XEN)   0000000000010006 ffffffff81c03d68 000000000000e02b ffffffffffffffff
      (XEN)   0000000000000063 000000000004d063 ffffffff81c03de8 ffffffff81d130a7
      (XEN)   ffffffff81c03de8 000000000004d000 00000001040ff000 0000000000105db1
      (XEN)   00000001040ff001 000000000004d062 ffff8800092d6ff8 0000000002027000
      (XEN)   ffff8800094d8340 ffff8800092d6ff8 00003ffffffff000 ffff8800092d7ff8
      (XEN)   ffffffff81c03e48 ffffffff81d13c43 ffff8800094d8000 ffff8800094d9000
      (XEN)   0000000000000000 ffff8800092d6000 00000000092d6000 000000004cfbf000
      (XEN)   00000000092d6000 00000000052d5442 0000000000000000 0000000000000000
      (XEN)   ffffffff81c03ed8 ffffffff81d185c1 0000000000000000 0000000000000000
      (XEN)   ffffffff81c03e78 ffffffff810f8ca4 ffffffff81c03ed8 ffffffff8171a15d
      (XEN)   0000000000000010 ffffffff81c03ee8 0000000000000000 0000000000000000
      (XEN)   ffffffff81f0e402 ffffffffffffffff ffffffff81dae900 0000000000000000
      (XEN)   0000000000000000 0000000000000000 ffffffff81c03f28 ffffffff81d0cf0f
      (XEN)   0000000000000000 0000000000000000 0000000000000000 ffffffff81db82e0
      (XEN)   0000000000000000 0000000000000000 0000000000000000 0000000000000000
      (XEN)   ffffffff81c03f38 ffffffff81d0c603 ffffffff81c03ff8 ffffffff81d11c86
      (XEN)   0300000100000032 0000000000000005 0000000000000020 0000000000000000
      (XEN)   0000000000000000 0000000000000000 0000000000000000 0000000000000000
      (XEN)   0000000000000000 0000000000000000 0000000000000000 0000000000000000
      (XEN) Domain 0 crashed: rebooting machine in 5 seconds.
      
      This can be avoided by allocating aneough space for the p2m to cover
      the maximum memory of dom0 plus the identity mapped holes required
      for PCI space, BIOS etc.
      
      Reported-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
      Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
      Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      eafd72e0
  2. Aug 20, 2015
  3. Aug 17, 2015
  4. Aug 16, 2015