linux-stable.git/drivers/xen, branch v3.16.7

xen/manage: Always freeze/thaw processes when suspend/resuming

2014-10-05T20:41:03+00:00

commit 61a734d305e16944b42730ef582a7171dc733321 upstream.

Always freeze processes when suspending and thaw processes when resuming
to prevent a race noticeable with HVM guests.

This prevents a deadlock where the khubd kthread (which is designed to
be freezable) acquires a usb device lock and then tries to allocate
memory which requires the disk which hasn't been resumed yet.
Meanwhile, the xenwatch thread deadlocks waiting for the usb device
lock.

Freezing processes fixes this because the khubd thread is only thawed
after the xenwatch thread finishes resuming all the devices.

Signed-off-by: Ross Lagerwall 
Signed-off-by: David Vrabel 
Signed-off-by: Greg Kroah-Hartman

xen/events/fifo: reset control block and local HEADs on resume

2014-09-17T16:22:11+00:00

commit c12784c3d14a2110468ec4d1383f60cfd2665576 upstream.

When using the FIFO-based event channel ABI, if the control block or
the local HEADs are not reset after resuming the guest may see stale
HEAD values and will fail to traverse the FIFO correctly.

This may prevent one or more VCPUs from receiving any events following
a resume.

Signed-off-by: David Vrabel 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Greg Kroah-Hartman

xen/events/fifo: ensure all bitops are properly aligned even on x86

2014-09-05T23:36:35+00:00

commit dcecb8fd93a65787130a74e61fdf29932c8d85eb upstream.

When using the FIFO-based ABI on x86_64, if the last port is at the
end of an event array page then sync_test_bit() on this port's event
word will read beyond the end of the page and in certain circumstances
this may fault.

The fault requires the following page in the kernel's direct mapping
to be not present, which would mean:

a) the array page is the last page of RAM; or

b) the following page is ballooned out /and/ it has been used for a
   foreign mapping by a kernel driver (such as netback or blkback)
   /and/ the grant has been unmapped.

Use the infrastructure added for arm64 to ensure that all bitops
operating on event words are unsigned long aligned.

Signed-off-by: David Vrabel 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'stable/for-linus-3.16-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2014-07-30T16:00:20+00:00

Pull Xen fix from David Vrabel:
 "Fix BUG when trying to expand the grant table.  This seems to occur
  often during boot with Ubuntu 14.04 PV guests"

* tag 'stable/for-linus-3.16-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  x86/xen: safely map and unmap grant frames when in atomic context

x86/xen: safely map and unmap grant frames when in atomic context

2014-07-30T13:22:47+00:00

arch_gnttab_map_frames() and arch_gnttab_unmap_frames() are called in
atomic context but were calling alloc_vm_area() which might sleep.

Also, if a driver attempts to allocate a grant ref from an interrupt
and the table needs expanding, then the CPU may already by in lazy MMU
mode and apply_to_page_range() will BUG when it tries to re-enable
lazy MMU mode.

These two functions are only used in PV guests.

Introduce arch_gnttab_init() to allocates the virtual address space in
advance.

Avoid the use of apply_to_page_range() by using saving and using the
array of PTE addresses from the alloc_vm_area() call (which ensures
that the required page tables are pre-allocated).

Signed-off-by: David Vrabel 
Signed-off-by: Konrad Rzeszutek Wilk

Merge tag 'stable/for-linus-3.16-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2014-07-17T18:02:35+00:00

Pull Xen fixes from Konrad Rzeszutek Wilk:
 "Two fixes found during migration of PV guests.  David would be the one
  doing this pull but he is on vacation.

  Fixes:
   - fix console deadlock when resuming PV guests
   - fix regression hit when ballooning and resuming PV guests"

* tag 'stable/for-linus-3.16-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/balloon: set ballooned out pages as invalid in p2m
  xen/manage: fix potential deadlock when resuming the console

xen/balloon: set ballooned out pages as invalid in p2m

2014-07-04T14:17:43+00:00

Since cd9151e26d31048b2b5e00fd02e110e07d2200c9 (xen/balloon: set a
mapping for ballooned out pages), a ballooned out page had its entry
in the p2m set to the MFN of one of the scratch pages.  This means
that the p2m will contain many entries pointing to the same MFN.

During a domain save, these many-to-one entries are not identified as
such and the scratch page is saved multiple times. On restore the
ballooned pages are populated with new frames and the domain may use
up its allocation before all pages can be restored.

Since the original fix only needed to keep a mapping for the ballooned
page it is safe to set ballooned out pages as INVALID_P2M_ENTRY in the
p2m (as they were before). Thus preventing them from being saved and
re-populated on restore.

Signed-off-by: David Vrabel 
Reported-by: Marek Marczykowski 
Tested-by: Marek Marczykowski 
Acked-by: Stefano Stabellini 
Cc:

xen/manage: fix potential deadlock when resuming the console

2014-07-03T10:02:28+00:00

Calling xen_console_resume() in xen_suspend() causes a warning because
it locks irq_mapping_update_lock (a mutex) and this may sleep.  If a
userspace process is using the evtchn device then this mutex may be
locked at the point of the stop_machine() call and
xen_console_resume() would then deadlock.

Resuming the console after stop_machine() returns avoids this
deadlock.

Signed-off-by: David Vrabel 
Reviewed-by: Boris Ostrovsky 
Cc:

Merge tag 'stable/for-linus-3.16-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2014-06-19T17:53:27+00:00

Pull Xen fixes from David Vrabel:
 "Xen regression and PVH fixes for 3.16-rc1

   - fix dom0 PVH memory setup on latest unstable Xen releases
   - fix 64-bit x86 PV guest boot failure on Xen 3.1 and earlier
   - fix resume regression on non-PV (auto-translated physmap) guests"

* tag 'stable/for-linus-3.16-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/grant-table: fix suspend for non-PV guests
  x86/xen: no need to explicitly register an NMI callback
  Revert "xen/pvh: Update E820 to work with PVH (v2)"
  x86/xen: fix memory setup for PVH dom0

xen/grant-table: fix suspend for non-PV guests

2014-06-18T09:58:01+00:00

Commit aa8532c32216ae07c3813b9aeb774517878a7573 (xen: refactor suspend
pre/post hooks) broke resuming PVHVM (auto-translated physmap) guests.

The gnttab_suspend() would clear the mapping for the grant table
frames, but the ->unmap_frames() call is only applicable to PV guests.

Signed-off-by: David Vrabel 
Reported-by: Konrad Rzeszutek Wilk 
Tested-by: Konrad Rzeszutek Wilk