23 Jul, 2010

1 commit

  • Add the xen pci platform device driver that is responsible
    for initializing the grant table and xenbus in PV on HVM mode.
    Few changes to xenbus and grant table are necessary to allow the delayed
    initialization in HVM mode.
    Grant table needs few additional modifications to work in HVM mode.

    The Xen PCI platform device raises an irq every time an event has been
    delivered to us. However these interrupts are only delivered to vcpu 0.
    The Xen PCI platform interrupt handler calls xen_hvm_evtchn_do_upcall
    that is a little wrapper around __xen_evtchn_do_upcall, the traditional
    Xen upcall handler, the very same used with traditional PV guests.

    When running on HVM the event channel upcall is never called while in
    progress because it is a normal Linux irq handler (and we cannot switch
    the irq chip wholesale to the Xen PV ones as we are running QEMU and
    might have passed in PCI devices), therefore we cannot be sure that
    evtchn_upcall_pending is 0 when returning.
    For this reason if evtchn_upcall_pending is set by Xen we need to loop
    again on the event channels set pending otherwise we might loose some
    event channel deliveries.

    Signed-off-by: Stefano Stabellini
    Signed-off-by: Sheng Yang
    Signed-off-by: Jeremy Fitzhardinge

    Stefano Stabellini
     

30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

05 Nov, 2009

1 commit


17 Dec, 2008

1 commit


20 Aug, 2008

1 commit

  • There are four operating modes Xen code may find itself running in:
    - native
    - hvm domain
    - pv dom0
    - pv domU

    Clean up predicates for testing for these states to make them more consistent.

    Signed-off-by: Jeremy Fitzhardinge
    Cc: Xen-devel
    Signed-off-by: Ingo Molnar

    Jeremy Fitzhardinge
     

27 May, 2008

1 commit

  • This patch implements Xen save/restore and migration.

    Saving is triggered via xenbus, which is polled in
    drivers/xen/manage.c. When a suspend request comes in, the kernel
    prepares itself for saving by:

    1 - Freeze all processes. This is primarily to prevent any
    partially-completed pagetable updates from confusing the suspend
    process. If CONFIG_PREEMPT isn't defined, then this isn't necessary.

    2 - Suspend xenbus and other devices

    3 - Stop_machine, to make sure all the other vcpus are quiescent. The
    Xen tools require the domain to run its save off vcpu0.

    4 - Within the stop_machine state, it pins any unpinned pgds (under
    construction or destruction), performs canonicalizes various other
    pieces of state (mostly converting mfns to pfns), and finally

    5 - Suspend the domain

    Restore reverses the steps used to save the domain, ending when all
    the frozen processes are thawed.

    Signed-off-by: Jeremy Fitzhardinge
    Signed-off-by: Thomas Gleixner

    Jeremy Fitzhardinge
     

25 Apr, 2008

3 commits

  • split out x86 specific part from grant-table.c and
    allow ia64/xen specific initialization.
    ia64/xen grant table is based on pseudo physical address
    (guest physical address) unlike x86/xen. On ia64 init_mm
    doesn't map identity straight mapped area.
    ia64/xen specific grant table initialization is necessary.

    Signed-off-by: Isaku Yamahata
    Signed-off-by: Ingo Molnar
    Signed-off-by: Thomas Gleixner

    Isaku Yamahata
     
  • Don't use alloc_vm_area()/free_vm_area() directly, instead define
    xen_alloc_vm_area()/xen_free_vm_area() and use them.

    alloc_vm_area()/free_vm_area() are used to allocate/free area which
    are for grant table mapping. Xen/x86 grant table is based on virtual
    address so that alloc_vm_area()/free_vm_area() are suitable.
    On the other hand Xen/ia64 (and Xen/powerpc) grant table is based on
    pseudo physical address (guest physical address) so that allocation
    should be done differently.
    The original version of xenified Linux/IA64 have its own
    allocate_vm_area()/free_vm_area() definitions which don't allocate vm area
    contradictory to those names.
    Now vanilla Linux already has its definitions so that it's impossible
    to have IA64 definitions of allocate_vm_area()/free_vm_area().
    Instead introduce xen_allocate_vm_area()/xen_free_vm_area() and use them.

    Signed-off-by: Isaku Yamahata
    Signed-off-by: Jeremy Fitzhardinge
    Signed-off-by: Ingo Molnar
    Signed-off-by: Thomas Gleixner

    Isaku Yamahata
     
  • Add xen handles realted definitions for grant table which ia64/xen
    needs.
    Pointer argumsnts for ia64/xen hypercall are passed in pseudo physical
    address (guest physical address) so that it is required to convert
    guest kernel virtual address into pseudo physical address right before
    issuing hypercall.
    The xen guest handle represents such arguments.
    Define necessary handles and helper functions.

    Signed-off-by: Isaku Yamahata
    Signed-off-by: Jeremy Fitzhardinge
    Signed-off-by: Ingo Molnar
    Signed-off-by: Thomas Gleixner

    Isaku Yamahata
     

05 Apr, 2008

1 commit

  • fix memory corruption and crash due to mis-sized grant table.

    A PV OS has two grant table data structures: the grant table itself
    and a free list. The free list is composed of an array of pages,
    which grow dynamically as the guest OS requires more grants. While
    the grant table contains 8-byte entries, the free list contains 4-byte
    entries. So we have half as many pages in the free list than in the
    grant table.

    There was a bug in the free list allocation code. The free list was
    indexed as if it was the same size as the grant table. But it's only
    half as large. So memory got corrupted, and I was seeing crashes in
    the slab allocator later on.

    Taken from:

    http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/4018c0da3360

    Signed-off-by: Michael Abd-El-Malek
    Signed-off-by: Mark McLoughlin
    Signed-off-by: Jeremy Fitzhardinge
    Signed-off-by: Ingo Molnar

    Michael Abd-El-Malek
     

18 Jul, 2007

1 commit

  • Add Xen 'grant table' driver which allows granting of access to
    selected local memory pages by other virtual machines and,
    symmetrically, the mapping of remote memory pages which other virtual
    machines have granted access to.

    This driver is a prerequisite for many of the Xen virtual device
    drivers, which grant the 'device driver domain' restricted and
    temporary access to only those memory pages that are currently
    involved in I/O operations.

    Signed-off-by: Jeremy Fitzhardinge
    Signed-off-by: Ian Pratt
    Signed-off-by: Christian Limpach
    Signed-off-by: Chris Wright

    Jeremy Fitzhardinge