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  1. 20 12月, 2011 1 次提交
  3. 17 12月, 2011 3 次提交
  5. 17 11月, 2011 1 次提交
  7. 01 11月, 2011 2 次提交
  9. 20 10月, 2011 1 次提交
  11. 14 10月, 2011 2 次提交
  13. 30 9月, 2011 1 次提交
  15. 27 9月, 2011 1 次提交
  17. 23 9月, 2011 1 次提交
    • O
      xen/pv-on-hvm kexec: add xs_reset_watches to shutdown watches from old kernel · ddacf5ef
      由 Olaf Hering 提交于 
      Add new xs_reset_watches function to shutdown watches from old kernel after
kexec boot.  The old kernel does not unregister all watches in the
shutdown path.  They are still active, the double registration can not
be detected by the new kernel.  When the watches fire, unexpected events
will arrive and the xenwatch thread will crash (jumps to NULL).  An
orderly reboot of a hvm guest will destroy the entire guest with all its
resources (including the watches) before it is rebuilt from scratch, so
the missing unregister is not an issue in that case.

With this change the xenstored is instructed to wipe all active watches
for the guest.  However, a patch for xenstored is required so that it
accepts the XS_RESET_WATCHES request from a client (see changeset
23839:42a45baf037d in xen-unstable.hg). Without the patch for xenstored
the registration of watches will fail and some features of a PVonHVM
guest are not available. The guest is still able to boot, but repeated
kexec boots will fail.

[v5: use xs_single instead of passing a dummy string to xs_talkv]
[v4: ignore -EEXIST in xs_reset_watches]
[v3: use XS_RESET_WATCHES instead of XS_INTRODUCE]
[v2: move all code which deals with XS_INTRODUCE into xs_introduce()
    (based on feedback from Ian Campbell); remove casts from kvec assignment]
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
[v1: Redid the git description a bit]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      ddacf5ef
  19. 01 9月, 2011 2 次提交
    • O
      xen/pv-on-hvm kexec+kdump: reset PV devices in kexec or crash kernel · 116df6f0
      由 Olaf Hering 提交于 
      After triggering a crash dump in a HVM guest, the PV backend drivers
will remain in Connected state. When the kdump kernel starts the PV
drivers will skip such devices. As a result, no root device is found and
the vmcore cant be saved.

A similar situation happens after a kexec boot, here the devices will be
in the Closed state.

With this change all frontend devices with state XenbusStateConnected or
XenbusStateClosed will be reset by changing the state file to Closing ->
Closed -> Initializing.  This will trigger a disconnect in the backend
drivers. Now the frontend drivers will find the backend drivers in state
Initwait and can connect.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
[v2:
  - add timeout when waiting for backend state change
  (based on feedback from Ian Campell)
  - extent printk message to include backend string
  - add comment to fall-through case in xenbus_reset_frontend]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      116df6f0
    • O
      xen/pv-on-hvm kexec: prevent crash in xenwatch_thread() when stale watch events arrive · c4c303c7
      由 Olaf Hering 提交于 
      During repeated kexec boots xenwatch_thread() can crash because
xenbus_watch->callback is cleared by xenbus_watch_path() if a node/token
combo for a new watch happens to match an already registered watch from
an old kernel.  In this case xs_watch returns -EEXISTS, then
register_xenbus_watch() does not remove the to-be-registered watch from
the list of active watches but returns the -EEXISTS to the caller
anyway.

Because the watch is still active in xenstored it will cause an event
which will arrive in the new kernel. process_msg() will find the
encapsulated struct xenbus_watch in its list of registered watches and
puts the "empty" watch handle in the queue for xenwatch_thread().
xenwatch_thread() then calls ->callback which was cleared earlier by
xenbus_watch_path().

To prevent that crash in a guest running on an old xen toolstack remove
the special -EEXIST handling.

v2:
 - remove the EEXIST handing in register_xenbus_watch() instead of
   checking for ->callback in process_msg()
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
      c4c303c7
  21. 27 7月, 2011 2 次提交
  23. 01 7月, 2011 2 次提交
  25. 17 3月, 2011 2 次提交
  27. 06 1月, 2011 12 次提交
  29. 23 10月, 2010 1 次提交
  31. 21 10月, 2010 1 次提交
  33. 18 10月, 2010 1 次提交
  35. 05 10月, 2010 1 次提交
  37. 08 8月, 2010 1 次提交
    • D
      xenbus: Make xenbus_switch_state transactional · 5b61cb90
      由 Daniel Stodden 提交于 
      According to the comments, this was how it's been done years ago, but
apparently took an xbt pointer from elsewhere back then. The code was
removed because of consistency issues: cancellation wont't roll back
the saved xbdev->state.

Still, unsolicited writes to the state field remain an issue,
especially if device shutdown takes thread synchronization, and subtle
races cause accidental recreation of the device node.

Fixed by reintroducing the transaction. An internal one is sufficient,
so the xbdev->state value remains consistent.

Also fixes the original hack to prevent infinite recursion. Instead of
bailing out on the first attempt to switch to Closing, checks call
depth now.
Signed-off-by: NDaniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
      5b61cb90
  39. 05 8月, 2010 1 次提交
  41. 27 7月, 2010 1 次提交