IOCTL_GNTDEV_GRANT_COPY batches copy operations to reduce the number
of hypercalls. The stack is used to avoid a memory allocation in a
hot path. However, a batch size of 24 requires more than 1024 bytes of
stack which in some configurations causes a compiler warning.
xen/gntdev.c: In function ‘gntdev_ioctl_grant_copy’:
xen/gntdev.c:949:1: warning: the frame size of 1248 bytes is
larger than 1024 bytes [-Wframe-larger-than=]
This is a harmless warning as there is still plenty of stack spare,
but people keep trying to "fix" it. Reduce the batch size to 16 to
reduce stack usage to less than 1024 bytes. This should have minimal
impact on performance.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Add IOCTL_GNTDEV_GRANT_COPY to allow applications to copy between user
space buffers and grant references.
This interface is similar to the GNTTABOP_copy hypercall ABI except
the local buffers are provided using a virtual address (instead of a
GFN and offset). To avoid userspace from having to page align its
buffers the driver will use two or more ops if required.
If the ioctl returns 0, the application must check the status of each
segment with the segments status field. If the ioctl returns a -ve
error code (EINVAL or EFAULT), the status of individual ops is
undefined.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This mmu_notifier_ops structure is never modified, so declare it as
const, like the other mmu_notifier_ops structures.
Done with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Doing so will cause the grant to be unmapped and then, during
fault handling, the fault to be mistakenly treated as NUMA hint
fault.
In addition, even if those maps could partcipate in NUMA
balancing, it wouldn't provide any benefit since we are unable
to determine physical page's node (even if/when VNUMA is
implemented).
Marking grant maps' VMAs as VM_IO will exclude them from being
part of NUMA balancing.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
While gntdev_release() is called the MMU notifier is still registered
and can traverse priv->maps list even if no pages are mapped (which is
the case -- gntdev_release() is called after all). But
gntdev_release() will clear that list, so make sure that only one of
those things happens at the same time.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: David 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: Bob Liu <bob.liu@oracle.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
For a PV guest, use the find_special_page op to find the right page.
To handle VMAs being split, remember the start of the original VMA so
the correct index in the pages array can be calculated.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
In an x86 PV guest, get_user_pages_fast() on a userspace address range
containing foreign mappings does not work correctly because the M2P
lookup of the MFN from a userspace PTE may return the wrong page.
Force get_user_pages_fast() to fail on such addresses by marking the PTEs
as special.
If Xen has XENFEAT_gnttab_map_avail_bits (available since at least
4.0), we can do so efficiently in the grant map hypercall. Otherwise,
it needs to be done afterwards. This is both inefficient and racy
(the mapping is visible to the task before we fixup the PTEs), but
will be fine for well-behaved applications that do not use the mapping
until after the mmap() system call returns.
Guests with XENFEAT_auto_translated_physmap (ARM and x86 HVM or PVH)
do not need this since get_user_pages() has always worked correctly
for them.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Use gnttab_unmap_refs_async() to wait until the mapped pages are no
longer in use before unmapping them.
This allows userspace programs to safely use Direct I/O and AIO to a
network filesystem which may retain refs to pages in queued skbs after
the filesystem I/O has completed.
Signed-off-by: Jennifer Herbert <jennifer.herbert@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David 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: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Stefano 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: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.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: Zoltan Kiss <zoltan.kiss@citrix.com>
Suggested-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.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
69e8f430e2
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: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
GNTTABOP_unmap_grant_ref unmaps a grant and replaces it with a 0
mapping instead of reinstating the original mapping.
Doing so separately would be racy.
To unmap a grant and reinstate the original mapping atomically we use
GNTTABOP_unmap_and_replace.
GNTTABOP_unmap_and_replace doesn't work with GNTMAP_contains_pte, so
don't use it for kmaps. GNTTABOP_unmap_and_replace zeroes the mapping
passed in new_addr so we have to reinstate it, however that is a
per-cpu mapping only used for balloon scratch pages, so we can be sure that
it's not going to be accessed while the mapping is not valid.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: alex@alex.org.uk
CC: dcrisan@flexiant.com
[v1: Konrad fixed up the conflicts]
Conflicts:
arch/x86/xen/p2m.c
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: Joe Perches <joe@perches.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Since there is now a mapping of granted pages in kernel address space in
both PV and HVM, use it for UNMAP_NOTIFY_CLEAR_BYTE instead of accessing
memory via copy_to_user and triggering sleep-in-atomic warnings.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
If gntdev_ioctl_unmap_grant_ref is called on a range before unmapping
it, the entry is removed from priv->maps and the later call to
mn_invl_range_start won't find it to do the unmapping. Fix this by
creating another list of freeable maps that the mmu notifier can search
and use to unmap grants.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
In gntdev_ioctl_get_offset_for_vaddr, we need to hold mmap_sem while
calling find_vma() to avoid potentially having the result freed out from
under us. Similarly, the MMU notifier functions need to synchronize with
gntdev_vma_close to avoid map->vma being freed during their iteration.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
map->kmap_ops allocated in gntdev_alloc_map() wasn't freed by
gntdev_put_map().
Add a gntdev_free_map() helper function to free everything allocated
by gntdev_alloc_map().
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: stable@vger.kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
A long time ago, in v2.4, VM_RESERVED kept swapout process off VMA,
currently it lost original meaning but still has some effects:
| effect | alternative flags
-+------------------------+---------------------------------------------
1| account as reserved_vm | VM_IO
2| skip in core dump | VM_IO, VM_DONTDUMP
3| do not merge or expand | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
4| do not mlock | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
This patch removes reserved_vm counter from mm_struct. Seems like nobody
cares about it, it does not exported into userspace directly, it only
reduces total_vm showed in proc.
Thus VM_RESERVED can be replaced with VM_IO or pair VM_DONTEXPAND | VM_DONTDUMP.
remap_pfn_range() and io_remap_pfn_range() set VM_IO|VM_DONTEXPAND|VM_DONTDUMP.
remap_vmalloc_range() set VM_DONTEXPAND | VM_DONTDUMP.
[akpm@linux-foundation.org: drivers/vfio/pci/vfio_pci.c fixup]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull Xen update from Konrad Rzeszutek Wilk:
"Features:
- When hotplugging PCI devices in a PV guest we can allocate
Xen-SWIOTLB later.
- Cleanup Xen SWIOTLB.
- Support pages out grants from HVM domains in the backends.
- Support wild cards in xen-pciback.hide=(BDF) arguments.
- Update grant status updates with upstream hypervisor.
- Boot PV guests with more than 128GB.
- Cleanup Xen MMU code/add comments.
- Obtain XENVERS using a preferred method.
- Lay out generic changes to support Xen ARM.
- Allow privcmd ioctl for HVM (used to do only PV).
- Do v2 of mmap_batch for privcmd ioctls.
- If hypervisor saves the LED keyboard light - we will now instruct
the kernel about its state.
Fixes:
- More fixes to Xen PCI backend for various calls/FLR/etc.
- With more than 4GB in a 64-bit PV guest disable native SWIOTLB.
- Fix up smatch warnings.
- Fix up various return values in privmcmd and mm."
* tag 'stable/for-linus-3.7-x86-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: (48 commits)
xen/pciback: Restore the PCI config space after an FLR.
xen-pciback: properly clean up after calling pcistub_device_find()
xen/vga: add the xen EFI video mode support
xen/x86: retrieve keyboard shift status flags from hypervisor.
xen/gndev: Xen backend support for paged out grant targets V4.
xen-pciback: support wild cards in slot specifications
xen/swiotlb: Fix compile warnings when using plain integer instead of NULL pointer.
xen/swiotlb: Remove functions not needed anymore.
xen/pcifront: Use Xen-SWIOTLB when initting if required.
xen/swiotlb: For early initialization, return zero on success.
xen/swiotlb: Use the swiotlb_late_init_with_tbl to init Xen-SWIOTLB late when PV PCI is used.
xen/swiotlb: Move the error strings to its own function.
xen/swiotlb: Move the nr_tbl determination in its own function.
xen/arm: compile and run xenbus
xen: resynchronise grant table status codes with upstream
xen/privcmd: return -EFAULT on error
xen/privcmd: Fix mmap batch ioctl error status copy back.
xen/privcmd: add PRIVCMD_MMAPBATCH_V2 ioctl
xen/mm: return more precise error from xen_remap_domain_range()
xen/mmu: If the revector fails, don't attempt to revector anything else.
...
David Vrabel
Julia Lawall
Boris Ostrovsky
Kirill A. Shutemov
Marek Marczykowski-Górecki
Julien Grall
Bob Liu
Jennifer Herbert
Konrad Rzeszutek Wilk
Zoltan Kiss
Stefano Stabellini
Joe Perches
Daniel De Graaf
Konstantin Khlebnikov
Linus Torvalds