Hypercalls submitted by user space tools via the privcmd driver can
take a long time (potentially many 10s of seconds) if the hypercall
has many sub-operations.
A fully preemptible kernel may deschedule such as task in any upcall
called from a hypercall continuation.
However, in a kernel with voluntary or no preemption, hypercall
continuations in Xen allow event handlers to be run but the task
issuing the hypercall will not be descheduled until the hypercall is
complete and the ioctl returns to user space. These long running
tasks may also trigger the kernel's soft lockup detection.
Add xen_preemptible_hcall_begin() and xen_preemptible_hcall_end() to
bracket hypercalls that may be preempted. Use these in the privcmd
driver.
When returning from an upcall, call xen_maybe_preempt_hcall() which
adds a schedule point if if the current task was within a preemptible
hypercall.
Since _cond_resched() can move the task to a different CPU, clear and
set xen_in_preemptible_hcall around the call.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This failure represents a hypervisor issue, but if it does occur then nothing
good can come of returning pages which still refer to a foreign owned page
into the general allocation pool.
Instead we are forced to leak them. Log that we have done so.
The potential for failure only exists for autotranslated guest (e.g. ARM and
x86 PVH).
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
When a foreign mapper attempts to map guest frames that are paged out,
the mapper receives an ENOENT response and will have to try again
while a helper process pages the target frame back in.
Gating checks on PRIVCMD_MMAPBATCH* ioctl args were preventing retries
of mapping calls.
Permit subsequent calls to update a sub-range of the VMA, iff nothing
is yet mapped in that range.
Since it is now valid to call PRIVCMD_MMAPBATCH* multiple times, only
set vma->vm_private_data if the parameters are valid and (if
necessary) the pages for the auto_translated_physmap case have been
allocated. This prevents subsequent calls from incorrectly entering
the 'retry' path when there are no pages allocated etc.
Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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>
The parenthesis are in the wrong place so the original code is
equivalent to:
if (!xen_feature(XENFEAT_writable_descriptor_tables)) { ...
Which obviously was not intended.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
1. If any individual mapping error happens, the V1 case will mark *all*
operations as failed. Fixed.
2. The err_array was allocated with kcalloc, resulting in potentially O(n) page
allocations. Refactor code to not use this array.
Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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Merge tag 'v3.7' into stable/for-linus-3.8
Linux 3.7
* tag 'v3.7': (833 commits)
Linux 3.7
Input: matrix-keymap - provide proper module license
Revert "revert "Revert "mm: remove __GFP_NO_KSWAPD""" and associated damage
ipv4: ip_check_defrag must not modify skb before unsharing
Revert "mm: avoid waking kswapd for THP allocations when compaction is deferred or contended"
inet_diag: validate port comparison byte code to prevent unsafe reads
inet_diag: avoid unsafe and nonsensical prefix matches in inet_diag_bc_run()
inet_diag: validate byte code to prevent oops in inet_diag_bc_run()
inet_diag: fix oops for IPv4 AF_INET6 TCP SYN-RECV state
mm: vmscan: fix inappropriate zone congestion clearing
vfs: fix O_DIRECT read past end of block device
net: gro: fix possible panic in skb_gro_receive()
tcp: bug fix Fast Open client retransmission
tmpfs: fix shared mempolicy leak
mm: vmscan: do not keep kswapd looping forever due to individual uncompactable zones
mm: compaction: validate pfn range passed to isolate_freepages_block
mmc: sh-mmcif: avoid oops on spurious interrupts (second try)
Revert misapplied "mmc: sh-mmcif: avoid oops on spurious interrupts"
mmc: sdhci-s3c: fix missing clock for gpio card-detect
lib/Makefile: Fix oid_registry build dependency
...
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Conflicts:
arch/arm/xen/enlighten.c
drivers/xen/Makefile
[We need to have the v3.7 base as the 'for-3.8' was based off v3.7-rc3
and there are some patches in v3.7-rc6 that we to have in our branch]
In the privcmd Linux driver two checks in the functions
privcmd_ioctl_mmap and privcmd_ioctl_mmap_batch are not needed as they
are trying to enforce hypervisor-level access control. They should be
removed as they break secondary control domains when performing dom0
disaggregation. Xen itself provides adequate security controls around
these hypercalls and these checks prevent those controls from
functioning as intended.
Signed-off-by: Tamas K Lengyel <tamas.lengyel@zentific.com>
Cc: Daniel De Graaf <dgdegra@tycho.nsa.gov>
[v1: Fixed up the patch and commit description]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
PVH and ARM only support the batch interface. To map a foreign page to
a process, the PFN must be allocated and the autotranslated path uses
ballooning for that purpose.
The returned PFN is then mapped to the foreign page.
xen_unmap_domain_mfn_range() is introduced to unmap these pages via the
privcmd close call.
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
[v1: Fix up privcmd_close]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
[v2: used for ARM too]
Also introduce xen_unmap_domain_mfn_range. These are the parts of
Mukesh's "xen/pvh: Implement MMU changes for PVH" which are also
needed as a baseline for ARM privcmd support.
The original patch was:
Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This derivative is also:
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
This is a regression introduced by ceb90fa0 (xen/privcmd: add
PRIVCMD_MMAPBATCH_V2 ioctl). It broke xentrace as it used
xc_map_foreign() instead of xc_map_foreign_bulk().
Most code-paths prefer the MMAPBATCH_V2, so this wasn't very obvious
that it broke. The return value is set early on to -EINVAL, and if all
goes well, the "set top bits of the MFN's" never gets called, so the
return value is still EINVAL when the function gets to the end, causing
the caller to think it went wrong (which it didn't!)
Now also including Andres "move the ret = -EINVAL into the error handling
path, as this avoids other similar errors in future.
Signed-off-by: Mats Petersson <mats.petersson@citrix.com>
Acked-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Acked-by: David Vrabel <david.vrabel@citrix.com>
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>
__copy_to_user() returns the number of bytes remaining to be copied but
we want to return a negative error code here.
Acked-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Copy back of per-slot error codes is only necessary for V2. V1 does not provide
an error array, so copyback will unconditionally set the global rc to EFAULT.
Only copyback for V2.
Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
PRIVCMD_MMAPBATCH_V2 extends PRIVCMD_MMAPBATCH with an additional
field for reporting the error code for every frame that could not be
mapped. libxc prefers PRIVCMD_MMAPBATCH_V2 over PRIVCMD_MMAPBATCH.
Also expand PRIVCMD_MMAPBATCH to return appropriate error-encoding top nibble
in the mfn array.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This patch removes the "return -ENOSYS" for auto_translated_physmap
guests from privcmd_mmap, thus it allows ARM guests to issue privcmd
mmap calls. However privcmd mmap calls are still going to fail for HVM
and hybrid guests on x86 because the xen_remap_domain_mfn_range
implementation is currently PV only.
Changes in v2:
- better commit message;
- return -EINVAL from xen_remap_domain_mfn_range if
auto_translated_physmap.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This was used for ia64. But there is no working ia64 support in sight,
so remove it for now.
Signed-off-by: Bastian Blank <waldi@debian.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Access to arbitrary hypercalls is currently provided via xenfs. This
adds a standard character device to handle this. The support in xenfs
remains for backward compatibility and uses the device driver code.
Signed-off-by: Bastian Blank <waldi@debian.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
