Drop the arguments from the macro and adjust all callers with the
following script:

  perl -pi -e 's/DEFINE_TIMER\((.*), 0, 0\);/DEFINE_TIMER($1);/g;' \
    $(git grep DEFINE_TIMER | cut -d: -f1 | sort -u | grep -v timer.h)
Signed-off-by: NKees Cook <keescook@chromium.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # for m68k parts
Acked-by: Guenter Roeck <linux@roeck-us.net> # for watchdog parts
Acked-by: David S. Miller <davem@davemloft.net> # for networking parts
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Kalle Valo <kvalo@codeaurora.org> # for wireless parts
Acked-by: NArnd Bergmann <arnd@arndb.de>
Cc: linux-mips@linux-mips.org
Cc: Petr Mladek <pmladek@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Kalle Valo <kvalo@qca.qualcomm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: linux1394-devel@lists.sourceforge.net
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: linux-s390@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ursula Braun <ubraun@linux.vnet.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Harish Patil <harish.patil@cavium.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Michael Reed <mdr@sgi.com>
Cc: Manish Chopra <manish.chopra@cavium.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-pm@vger.kernel.org
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mark Gross <mark.gross@intel.com>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: netdev@vger.kernel.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Link: https://lkml.kernel.org/r/1507159627-127660-11-git-send-email-keescook@chromium.orgSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

log a message when we enter this situation:
1) we already allocated the max number of available grants from hypervisor
and
2) we still need more (but the request fails because of 1)).

Sometimes the lack of grants causes IO hangs in xen_blkfront devices.
Adding this log would help debuging.
Signed-off-by: NWengang Wang <wen.gang.wang@oracle.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NJunxiao Bi <junxiao.bi@oracle.com>
Reviewed-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>

Like PV guests, PVH does not have PCI devices and therefore cannot
use MMIO space to store grants. Instead it balloons out memory and
keeps grants there.
Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: NJuergen Gross <jgross@suse.com>

Code that uses no modular facilities whatsoever should not be
sourcing module.h at all, since that header drags in a bunch
of other headers with it.

Similarly, code that is not explicitly using modular facilities
like module_init() but only is declaring module_param setup
variables should be using moduleparam.h and not the larger
module.h file for that.

In making this change, we also uncover an implicit use of BUG()
in inline fcns within arch/arm/include/asm/xen/hypercall.h so
we explicitly source <linux/bug.h> for that file now.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

The gnttab_ops structure is never modified, so declare it as const.

Done with the help of Coccinelle.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

With the 64KB page granularity support on ARM64, a Linux page may be
split accross multiple grant.

Currently we have the helper gnttab_foreach_grant_in_grant to break a
Linux page based on an offset and a len, but it doesn't fit when we only
have a number of grants in hand.

Introduce a new helper which take an array of Linux page and a number of
grant and will figure out the address of each grant.
Signed-off-by: NJulien Grall <julien.grall@citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

The Xen interface is using 4KB page granularity. This means that each
grant is 4KB.

The current implementation allocates a Linux page per grant. On Linux
using 64KB page granularity, only the first 4KB of the page will be
used.

We could decrease the memory wasted by sharing the page with multiple
grant. It will require some care with the {Set,Clear}ForeignPage macro.

Note that no changes has been made in the x86 code because both Linux
and Xen will only use 4KB page granularity.
Signed-off-by: NJulien Grall <julien.grall@citrix.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

Currently, a grant is always based on the Xen page granularity (i.e
4KB). When Linux is using a different page granularity, a single page
will be split between multiple grants.

The new helpers will be in charge of splitting the Linux page into grants
and call a function given by the caller on each grant.

Also provide an helper to count the number of grants within a given
contiguous region.

Note that the x86/include/asm/xen/page.h is now including
xen/interface/grant_table.h rather than xen/grant_table.h. It's
necessary because xen/grant_table.h depends on asm/xen/page.h and will
break the compilation. Furthermore, only definition in
interface/grant_table.h is required.
Signed-off-by: NJulien Grall <julien.grall@citrix.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

All users of alloc_xenballoon_pages() wanted low memory pages, so
remove the option for high memory.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: NDaniel Kiper <daniel.kiper@oracle.com>

SPP was used by the grant table v2 code which has been removed in
commit 438b33c7 "xen/grant-table:
remove support for V2 tables".
Signed-off-by: NJulien Grall <julien.grall@citrix.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

There are several place using gnttab async unmap and wait for
completion, so move the common code to a function
gnttab_unmap_refs_sync().
Signed-off-by: NBob Liu <bob.liu@oracle.com>
Acked-by: NRoger Pau Monné <roger.pau@citrix.com>
Acked-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

Introduce gnttab_unmap_refs_async() that can be used to safely unmap
pages that may be in use (ref count > 1).  If the pages are in use the
unmap is deferred and retried later.  This polling is not very clever
but it should be good enough if the cases where the delay is necessary
are rare.

The initial delay is 5 ms and is increased linearly on each subsequent
retry (to reduce load if the page is in use for a long time).

This is needed to allow block backends using grant mapping to safely
use network storage (block or filesystem based such as iSCSI or NFS).

The network storage driver may complete a block request whilst there
is a queued network packet retry (because the ack from the remote end
races with deciding to queue the retry).  The pages for the retried
packet would be grant unmapped and the network driver (or hardware)
would access the unmapped page.
Signed-off-by: NJennifer Herbert <jennifer.herbert@citrix.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

Use the "foreign" page flag to mark pages that have a grant map.  Use
page->private to store information of the grant (the granting domain
and the grant reference).
Signed-off-by: NJennifer Herbert <jennifer.herbert@citrix.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

Add gnttab_alloc_pages() and gnttab_free_pages() to allocate/free pages
suitable to for granted maps.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

When unmapping grants, instead of converting the kernel map ops to
unmap ops on the fly, pre-populate the set of unmap ops.

This allows the grant unmap for the kernel mappings to be trivially
batched in the future.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

The cleanup loop in grow_gnttab_list() is safe from the underflow of
the unsigned 'i' since nr_glist_frames is >= 1, but refactor it
anyway.
Signed-off-by: NChen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

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: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Since 11c7ff17 (xen/grant-table: Force
to use v1 of grants.) the code for V2 grant tables is not used.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

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.

N.B. 'alloc_vm_area' pre-allocates the pagetable so there is no need
to worry about having to do a PGD/PUD/PMD walk (like apply_to_page_range
does) and we can instead do set_pte.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
----
[v2: Add comment about alloc_vm_area]
[v3: Fix compile error found by 0-day bot]

Commit aa8532c3 (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: NDavid Vrabel <david.vrabel@citrix.com>
Reported-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The grant mapping API does m2p_override unnecessarily: only gntdev needs it,
for blkback and future netback patches it just cause a lock contention, as
those pages never go to userspace. Therefore this series does the following:
- the bulk of the original function (everything after the mapping hypercall)
  is moved to arch-dependent set/clear_foreign_p2m_mapping
- the "if (xen_feature(XENFEAT_auto_translated_physmap))" branch goes to ARM
- therefore the ARM function could be much smaller, the m2p_override stubs
  could be also removed
- on x86 the set_phys_to_machine calls were moved up to this new funcion
  from m2p_override functions
- and m2p_override functions are only called when there is a kmap_ops param

It also removes a stray space from arch/x86/include/asm/xen/page.h.
Signed-off-by: NZoltan Kiss <zoltan.kiss@citrix.com>
Suggested-by: NAnthony Liguori <aliguori@amazon.com>
Suggested-by: NDavid Vrabel <david.vrabel@citrix.com>
Suggested-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

This reverts commit 08ece5bb.

As it breaks ARM builds and needs more attention
on the ARM side.
Acked-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The grant mapping API does m2p_override unnecessarily: only gntdev needs it,
for blkback and future netback patches it just cause a lock contention, as
those pages never go to userspace. Therefore this series does the following:
- the original functions were renamed to __gnttab_[un]map_refs, with a new
  parameter m2p_override
- based on m2p_override either they follow the original behaviour, or just set
  the private flag and call set_phys_to_machine
- gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with
  m2p_override false
- a new function gnttab_[un]map_refs_userspace provides the old behaviour

It also removes a stray space from page.h and change ret to 0 if
XENFEAT_auto_translated_physmap, as that is the only possible return value
there.

v2:
- move the storing of the old mfn in page->index to gnttab_map_refs
- move the function header update to a separate patch

v3:
- a new approach to retain old behaviour where it needed
- squash the patches into one

v4:
- move out the common bits from m2p* functions, and pass pfn/mfn as parameter
- clear page->private before doing anything with the page, so m2p_find_override
  won't race with this

v5:
- change return value handling in __gnttab_[un]map_refs
- remove a stray space in page.h
- add detail why ret = 0 now at some places

v6:
- don't pass pfn to m2p* functions, just get it locally
Signed-off-by: NZoltan Kiss <zoltan.kiss@citrix.com>
Suggested-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

On ARM, address size can be 32 bits or 64 bits (if CONFIG_ARCH_PHYS_ADDR_T_64BIT
is enabled).
We can't assume that the grant frame base address will always fits in an
unsigned long. Use phys_addr_t instead of unsigned long as argument for
gnttab_setup_auto_xlat_frames.
Signed-off-by: NJulien Grall <julien.grall@linaro.org>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NIan Campbell <ian.campbell@citrix.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>

We have the framework to use v2, but there are no backends that
actually use it. The end result is that on PV we use v2 grants
and on PVHVM v1. The v1 has a capacity of 512 grants per page while
the v2 has 256 grants per page. This means we lose about 50%
capacity - and if we want more than 16 VIFs (each VIF takes
512 grants), then we are hitting the max per guest of 32.

Oracle-bug: 16039922
CC: annie.li@oracle.com
CC: msw@amazon.com
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>

In PVH the shared grant frame is the PFN and not MFN,
hence its mapped via the same code path as HVM.

The allocation of the grant frame is done differently - we
do not use the early platform-pci driver and have an
ioremap area - instead we use balloon memory and stitch
all of the non-contingous pages in a virtualized area.

That means when we call the hypervisor to replace the GMFN
with a XENMAPSPACE_grant_table type, we need to lookup the
old PFN for every iteration instead of assuming a flat
contingous PFN allocation.

Lastly, we only use v1 for grants. This is because PVHVM
is not able to use v2 due to no XENMEM_add_to_physmap
calls on the error status page (see commit
69e8f430
 xen/granttable: Disable grant v2 for HVM domains.)

Until that is implemented this workaround has to
be in place.

Also per suggestions by Stefano utilize the PVHVM paths
as they share common functionality.

v2 of this patch moves most of the PVH code out in the
arch/x86/xen/grant-table driver and touches only minimally
the generic driver.

v3, v4: fixes us some of the code due to earlier patches.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

The 'xen_hvm_resume_frames' used to be an 'unsigned long'
and contain the virtual address of the grants. That was OK
for most architectures (PVHVM, ARM) were the grants are contiguous
in memory. That however is not the case for PVH - in which case
we will have to do a lookup for each virtual address for the PFN.

Instead of doing that, lets make it a structure which will contain
the array of PFNs, the virtual address and the count of said PFNs.

Also provide a generic functions: gnttab_setup_auto_xlat_frames and
gnttab_free_auto_xlat_frames to populate said structure with
appropriate values for PVHVM and ARM.

To round it off, change the name from 'xen_hvm_resume_frames' to
a more descriptive one - 'xen_auto_xlat_grant_frames'.

For PVH, in patch "xen/pvh: Piggyback on PVHVM for grant driver"
we will populate the 'xen_auto_xlat_grant_frames' by ourselves.

v2 moves the xen_remap in the gnttab_setup_auto_xlat_frames
and also introduces xen_unmap for gnttab_free_auto_xlat_frames.
Suggested-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v3: Based on top of 'asm/xen/page.h: remove redundant semicolon']
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

We have this odd scenario of where for PV paths we take a shortcut
but for the HVM paths we first ioremap xen_hvm_resume_frames, then
assign it to gnttab_shared.addr. This is needed because gnttab_map
uses gnttab_shared.addr.

Instead of having:
	if (pv)
		return gnttab_map
	if (hvm)
		...

	gnttab_map

Lets move the HVM part before the gnttab_map and remove the
first call to gnttab_map.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

The function gnttab_max_grant_frames() returns the maximum amount
of frames (pages) of grants we can have. Unfortunatly it was
dependent on gnttab_init() having been run before to initialize
the boot max value (boot_max_nr_grant_frames).

This meant that users of gnttab_max_grant_frames would always
get a zero value if they called before gnttab_init() - such as
'platform_pci_init' (drivers/xen/platform-pci.c).
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

From: Eric Trudeau <etrudeau@broadcom.com>

xen_hvm_resume_frames stores the physical address of the grant table.
englighten.c was incorrectly setting it as if it was a page frame number.
This caused the table to be mapped into the guest at an unexpected physical
address.

Additionally, a warning is improved to include the grant table address which
failed in xen_remap.
Signed-off-by: NEric Trudeau <etrudeau@broadcom.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Commit f62805f1 introduced a bug where lazy MMU mode isn't exited if a
m2p_add/remove_override call fails.
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: NAnthony Liguori <aliguori@amazon.com>
Cc: xen-devel@lists.xenproject.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NMatt Wilson <msw@amazon.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: stable@vger.kernel.org

When mapping/unmapping grant refs, call
set_phys_to_machine to update the P2M with the new mappings for
autotranslate guests.
This is (almost) a nop on x86.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Changes in v9:
- add in-code comments.

With the current implementation, the callback in the tail of the list
can be added twice, because the check done in
gnttab_request_free_callback is bogus, callback->next can be NULL if
it is the last callback in the list. If we add the same callback twice
we end up with an infinite loop, were callback == callback->next.

Replace this check with a proper one that iterates over the list to
see if the callback has already been added.
Signed-off-by: NRoger Pau Monné <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NMatt Wilson <msw@amazon.com>
Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com>
CC: stable@vger.kernel.org

Convert printks to pr_<level> (excludes printk(KERN_DEBUG...)
to be more consistent throughout the xen subsystem.

Add pr_fmt with KBUILD_MODNAME or "xen:" KBUILD_MODNAME
Coalesce formats and add missing word spaces
Add missing newlines
Align arguments and reflow to 80 columns
Remove DRV_NAME from formats as pr_fmt adds the same content

This does change some of the prefixes of these messages
but it also does make them more consistent.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

ioremap can't be used to map ring pages on ARM because it uses device
memory caching attributes (MT_DEVICE*).

Introduce a Xen specific abstraction to map ring pages, called
xen_remap, that is defined as ioremap on x86 (no behavioral changes).
On ARM it explicitly calls __arm_ioremap with the right caching
attributes: MT_MEMORY.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Commit 85ff6acb (xen/granttable: Grant
tables V2 implementation) changed the GREFS_PER_GRANT_FRAME macro from
a constant to a conditional expression. The expression depends on
grant_table_version being appropriately set. Unfortunately, at init
time grant_table_version will be 0. The GREFS_PER_GRANT_FRAME
conditional expression checks for "grant_table_version == 1", and
therefore returns the number of grant references per frame for v2.

This causes gnttab_init() to allocate fewer pages for gnttab_list, as
a frame can old half the number of v2 entries than v1 entries. After
gnttab_resume() is called, grant_table_version is appropriately
set. nr_init_grefs will then be miscalculated and gnttab_free_count
will hold a value larger than the actual number of free gref entries.

If a guest is heavily utilizing improperly initialized v1 grant
tables, memory corruption can occur. One common manifestation is
corruption of the vmalloc list, resulting in a poisoned pointer
derefrence when accessing /proc/meminfo or /proc/vmallocinfo:

[   40.770064] BUG: unable to handle kernel paging request at 0000200200001407
[   40.770083] IP: [<ffffffff811a6fb0>] get_vmalloc_info+0x70/0x110
[   40.770102] PGD 0
[   40.770107] Oops: 0000 [#1] SMP
[   40.770114] CPU 10

This patch introduces a static variable, grefs_per_grant_frame, to
cache the calculated value. gnttab_init() now calls
gnttab_request_version() early so that grant_table_version and
grefs_per_grant_frame can be appropriately set. A few BUG_ON()s have
been added to prevent this type of bug from reoccurring in the future.
Signed-off-by: NMatt Wilson <msw@amazon.com>
Reviewed-and-Tested-by: NSteven Noonan <snoonan@amazon.com>
Acked-by: NIan Campbell <Ian.Campbell@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Annie Li <annie.li@oracle.com>
Cc: xen-devel@lists.xen.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org # v3.3 and newer
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

CONFIG_HOTPLUG is going away as an option.  As a result, the __dev*
markings need to be removed.

This change removes the use of __devinit, and __devinitdata from these
drivers.

Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.

Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This correctly sizes it as 64 bit on ARM but leaves it as unsigned
long on x86 (therefore no intended change on x86).

The long and ulong guest handles are now unused (and a bit dangerous)
so remove them.
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Since Xen-4.2, hvm domains may have portions of their memory paged out. When a
foreign domain (such as dom0) attempts to map these frames, the map will
initially fail. The hypervisor returns a suitable errno, and kicks an
asynchronous page-in operation carried out by a helper. The foreign domain is
expected to retry the mapping operation until it eventually succeeds. The
foreign domain is not put to sleep because itself could be the one running the
pager assist (typical scenario for dom0).

This patch adds support for this mechanism for backend drivers using grant
mapping and copying operations. Specifically, this covers the blkback and
gntdev drivers (which map foreign grants), and the netback driver (which copies
foreign grants).

* Add a retry method for grants that fail with GNTST_eagain (i.e. because the
  target foreign frame is paged out).
* Insert hooks with appropriate wrappers in the aforementioned drivers.

The retry loop is only invoked if the grant operation status is GNTST_eagain.
It guarantees to leave a new status code different from GNTST_eagain. Any other
status code results in identical code execution as before.

The retry loop performs 256 attempts with increasing time intervals through a
32 second period. It uses msleep to yield while waiting for the next retry.

V2 after feedback from David Vrabel:
* Explicit MAX_DELAY instead of wrap-around delay into zero
* Abstract GNTST_eagain check into core grant table code for netback module.

V3 after feedback from Ian Campbell:
* Add placeholder in array of grant table error descriptions for unrelated
  error code we jump over.
* Eliminate single map and retry macro in favor of a generic batch flavor.
* Some renaming.
* Bury most implementation in grant_table.c, cleaner interface.

V4 rebased on top of sync of Xen grant table interface headers.
Signed-off-by: NAndres Lagar-Cavilla <andres@lagarcavilla.org>
Acked-by: NIan Campbell <ian.campbell@citrix.com>
[v5: Fixed whitespace issues]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

If the caller passes a valid kmap_op to m2p_add_override, we use
kmap_op->dev_bus_addr to store the original mfn, but dev_bus_addr is
part of the interface with Xen and if we are batching the hypercalls it
might not have been written by the hypervisor yet. That means that later
on Xen will write to it and we'll think that the original mfn is
actually what Xen has written to it.

Rather than "stealing" struct members from kmap_op, keep using
page->index to store the original mfn and add another parameter to
m2p_remove_override to get the corresponding kmap_op instead.
It is now responsibility of the caller to keep track of which kmap_op
corresponds to a particular page in the m2p_override (gntdev, the only
user of this interface that passes a valid kmap_op, is already doing that).

CC: stable@kernel.org
Reported-and-Tested-By: NSander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>