Commit Graph

20 Commits

Author SHA1 Message Date
Matthew Wilcox 620b4e9031 s390: use _refcount for pgtables
Patch series "Rearrange struct page", v6.

As presented at LSFMM, this patch-set rearranges struct page to give
more contiguous usable space to users who have allocated a struct page
for their own purposes.  For a graphical view of before-and-after, see
the first two tabs of

  https://docs.google.com/spreadsheets/d/1tvCszs_7FXrjei9_mtFiKV6nW1FLnYyvPvW-qNZhdog/edit?usp=sharing

Highlights:
 - deferred_list now really exists in struct page instead of just a comment.
 - hmm_data also exists in struct page instead of being a nasty hack.
 - x86's PGD pages have a real pointer to the mm_struct.
 - VMalloc pages now have all sorts of extra information stored in them
   to help with debugging and tuning.
 - rcu_head is no longer tied to slab in case anyone else wants to
   free pages by RCU.
 - slub's counters no longer share space with _refcount.
 - slub's freelist+counters are now naturally dword aligned.
 - slub loses a parameter to a lot of functions and a sysfs file.

This patch (of 17):

s390 borrows the storage used for _mapcount in struct page in order to
account whether the bottom or top half is being used for 2kB page tables.
I want to use that for something else, so use the top byte of _refcount
instead of the bottom byte of _mapcount.  _refcount may temporarily be
incremented by other CPUs that see a stale pointer to this page in the
page cache, but each CPU can only increment it by one, and there are no
systems with 2^24 CPUs today, so they will not change the upper byte of
_refcount.  We do have to be a little careful not to lose any of their
writes (as they will subsequently decrement the counter).

Link: http://lkml.kernel.org/r/20180518194519.3820-2-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07 17:34:37 -07:00
Heiko Carstens 1caf170df9 s390/mm: provide base_asce_alloc() / base_asce_free() helper functions
Provide base_asce_alloc() and base_asce_free() helper functions which
can be used to allocate an ASCE and all required region, segment and
page tables required to access memory regions of the virtual kernel
address space.

Both, the ASCE and all tables, do not use any features that correspond
to e.g. enhanced DAT features. This is required for some I/O functions
that pass an ASCE, like e.g. some service call requests, but which may
not use any enhanced features.

Acked-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Acked-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-02-22 15:31:23 +01:00
Heiko Carstens 8d306f53b6 s390/mm: fix off-by-one bug in 5-level page table handling
Martin Cermak reported that setting a uprobe doesn't work. Reason for
this is that the common uprobes code tries to get an unmapped area at
the last possible page within an address space.

This broke with commit 1aea9b3f92 ("s390/mm: implement 5 level pages
tables") which introduced an off-by-one bug which prevents to map
anything at the last possible page within an address space.

The check with the off-by-one bug however can be removed since with
commit 8ab867cb08 ("s390/mm: fix BUG_ON in crst_table_upgrade") the
necessary check is done at both call sites.

Reported-by: Martin Cermak <mcermak@redhat.com>
Bisected-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Fixes: 1aea9b3f92 ("s390/mm: implement 5 level pages tables")
Cc: <stable@vger.kernel.org> # v4.13+
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-12-05 07:51:09 +01:00
Martin Schwidefsky 0aaba41b58 s390: remove all code using the access register mode
The vdso code for the getcpu() and the clock_gettime() call use the access
register mode to access the per-CPU vdso data page with the current code.

An alternative to the complicated AR mode is to use the secondary space
mode. This makes the vdso faster and quite a bit simpler. The downside is
that the uaccess code has to be changed quite a bit.

Which instructions are used depends on the machine and what kind of uaccess
operation is requested. The instruction dictates which ASCE value needs
to be loaded into %cr1 and %cr7.

The different cases:

* User copy with MVCOS for z10 and newer machines
  The MVCOS instruction can copy between the primary space (aka user) and
  the home space (aka kernel) directly. For set_fs(KERNEL_DS) the kernel
  ASCE is loaded into %cr1. For set_fs(USER_DS) the user space is already
  loaded in %cr1.

* User copy with MVCP/MVCS for older machines
  To be able to execute the MVCP/MVCS instructions the kernel needs to
  switch to primary mode. The control register %cr1 has to be set to the
  kernel ASCE and %cr7 to either the kernel ASCE or the user ASCE dependent
  on set_fs(KERNEL_DS) vs set_fs(USER_DS).

* Data access in the user address space for strnlen / futex
  To use "normal" instruction with data from the user address space the
  secondary space mode is used. The kernel needs to switch to primary mode,
  %cr1 has to contain the kernel ASCE and %cr7 either the user ASCE or the
  kernel ASCE, dependent on set_fs.

To load a new value into %cr1 or %cr7 is an expensive operation, the kernel
tries to be lazy about it. E.g. for multiple user copies in a row with
MVCP/MVCS the replacement of the vdso ASCE in %cr7 with the user ASCE is
done only once. On return to user space a CPU bit is checked that loads the
vdso ASCE again.

To enable and disable the data access via the secondary space two new
functions are added, enable_sacf_uaccess and disable_sacf_uaccess. The fact
that a context is in secondary space uaccess mode is stored in the
mm_segment_t value for the task. The code of an interrupt may use set_fs
as long as it returns to the previous state it got with get_fs with another
call to set_fs. The code in finish_arch_post_lock_switch simply has to do a
set_fs with the current mm_segment_t value for the task.

For CPUs with MVCOS:

CPU running in                        | %cr1 ASCE | %cr7 ASCE |
--------------------------------------|-----------|-----------|
user space                            |  user     |  vdso     |
kernel, USER_DS, normal-mode          |  user     |  vdso     |
kernel, USER_DS, normal-mode, lazy    |  user     |  user     |
kernel, USER_DS, sacf-mode            |  kernel   |  user     |
kernel, KERNEL_DS, normal-mode        |  kernel   |  vdso     |
kernel, KERNEL_DS, normal-mode, lazy  |  kernel   |  kernel   |
kernel, KERNEL_DS, sacf-mode          |  kernel   |  kernel   |

For CPUs without MVCOS:

CPU running in                        | %cr1 ASCE | %cr7 ASCE |
--------------------------------------|-----------|-----------|
user space                            |  user     |  vdso     |
kernel, USER_DS, normal-mode          |  user     |  vdso     |
kernel, USER_DS, normal-mode lazy     |  kernel   |  user     |
kernel, USER_DS, sacf-mode            |  kernel   |  user     |
kernel, KERNEL_DS, normal-mode        |  kernel   |  vdso     |
kernel, KERNEL_DS, normal-mode, lazy  |  kernel   |  kernel   |
kernel, KERNEL_DS, sacf-mode          |  kernel   |  kernel   |

The lines with "lazy" refer to the state after a copy via the secondary
space with a delayed reload of %cr1 and %cr7.

There are three hardware address spaces that can cause a DAT exception,
primary, secondary and home space. The exception can be related to
four different fault types: user space fault, vdso fault, kernel fault,
and the gmap faults.

Dependent on the set_fs state and normal vs. sacf mode there are a number
of fault combinations:

1) user address space fault via the primary ASCE
2) gmap address space fault via the primary ASCE
3) kernel address space fault via the primary ASCE for machines with
   MVCOS and set_fs(KERNEL_DS)
4) vdso address space faults via the secondary ASCE with an invalid
   address while running in secondary space in problem state
5) user address space fault via the secondary ASCE for user-copy
   based on the secondary space mode, e.g. futex_ops or strnlen_user
6) kernel address space fault via the secondary ASCE for user-copy
   with secondary space mode with set_fs(KERNEL_DS)
7) kernel address space fault via the primary ASCE for user-copy
   with secondary space mode with set_fs(USER_DS) on machines without
   MVCOS.
8) kernel address space fault via the home space ASCE

Replace user_space_fault() with a new function get_fault_type() that
can distinguish all four different fault types.

With these changes the futex atomic ops from the kernel and the
strnlen_user will get a little bit slower, as well as the old style
uaccess with MVCP/MVCS. All user accesses based on MVCOS will be as
fast as before. On the positive side, the user space vdso code is a
lot faster and Linux ceases to use the complicated AR mode.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2017-11-14 11:01:47 +01:00
Linus Torvalds d60a540ac5 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Heiko Carstens:
 "Since Martin is on vacation you get the s390 pull request for the
  v4.15 merge window this time from me.

  Besides a lot of cleanups and bug fixes these are the most important
  changes:

   - a new regset for runtime instrumentation registers

   - hardware accelerated AES-GCM support for the aes_s390 module

   - support for the new CEX6S crypto cards

   - support for FORTIFY_SOURCE

   - addition of missing z13 and new z14 instructions to the in-kernel
     disassembler

   - generate opcode tables for the in-kernel disassembler out of a
     simple text file instead of having to manually maintain those
     tables

   - fast memset16, memset32 and memset64 implementations

   - removal of named saved segment support

   - hardware counter support for z14

   - queued spinlocks and queued rwlocks implementations for s390

   - use the stack_depth tracking feature for s390 BPF JIT

   - a new s390_sthyi system call which emulates the sthyi (store
     hypervisor information) instruction

   - removal of the old KVM virtio transport

   - an s390 specific CPU alternatives implementation which is used in
     the new spinlock code"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (88 commits)
  MAINTAINERS: add virtio-ccw.h to virtio/s390 section
  s390/noexec: execute kexec datamover without DAT
  s390: fix transactional execution control register handling
  s390/bpf: take advantage of stack_depth tracking
  s390: simplify transactional execution elf hwcap handling
  s390/zcrypt: Rework struct ap_qact_ap_info.
  s390/virtio: remove unused header file kvm_virtio.h
  s390: avoid undefined behaviour
  s390/disassembler: generate opcode tables from text file
  s390/disassembler: remove insn_to_mnemonic()
  s390/dasd: avoid calling do_gettimeofday()
  s390: vfio-ccw: Do not attempt to free no-op, test and tic cda.
  s390: remove named saved segment support
  s390/archrandom: Reconsider s390 arch random implementation
  s390/pci: do not require AIS facility
  s390/qdio: sanitize put_indicator
  s390/qdio: use atomic_cmpxchg
  s390/nmi: avoid using long-displacement facility
  s390: pass endianness info to sparse
  s390/decompressor: remove informational messages
  ...
2017-11-13 11:47:01 -08:00
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Heiko Carstens 41879ff65d s390/mm: use memset64 instead of clear_table
Use memset64 instead of the (now) open-coded variant clear_table.
Performance wise there is no difference.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-10-09 11:18:06 +02:00
Martin Schwidefsky f28a4b4ddf s390/mm: use a single lock for the fields in mm_context_t
The three locks 'lock', 'pgtable_lock' and 'gmap_lock' in the
mm_context_t can be reduced to a single lock.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-09-06 09:24:43 +02:00
Martin Schwidefsky 2fc4876ea8 s390/mm: use VM_BUG_ON in crst_table_[upgrade|downgrade]
The BUG_ON in crst_table_[upgrade|downgrade] is a debugging aid,
replace it with VM_BUG_ON.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-09-06 09:24:41 +02:00
Heiko Carstens f1c1174fa0 s390/mm: use new mm defines instead of magic values
Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-07-26 08:25:09 +02:00
Martin Schwidefsky c9b5ad546e s390/mm: tag normal pages vs pages used in page tables
The ESSA instruction has a new option that allows to tag pages that
are not used as a page table. Without the tag the hypervisor has to
assume that any guest page could be used in a page table inside the
guest. This forces the hypervisor to flush all guest TLB entries
whenever a host page table entry is invalidated. With the tag
the host can skip the TLB flush if the page is tagged as normal page.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-07-25 06:55:28 +02:00
Martin Schwidefsky 1aea9b3f92 s390/mm: implement 5 level pages tables
Add the logic to upgrade the page table for a 64-bit process to
five levels. This increases the TASK_SIZE from 8PB to 16EB-4K.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-06-12 16:25:54 +02:00
Martin Schwidefsky ee71d16d22 s390/mm: make TASK_SIZE independent from the number of page table levels
The TASK_SIZE for a process should be maximum possible size of the address
space, 2GB for a 31-bit process and 8PB for a 64-bit process. The number
of page table levels required for a given memory layout is a consequence
of the mapped memory areas and their location.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-04-25 07:47:32 +02:00
Michal Hocko faee35a57b s390: get rid of superfluous __GFP_REPEAT
__GFP_REPEAT has a rather weak semantic but since it has been introduced
around 2.6.12 it has been ignored for low order allocations.

page_table_alloc then uses the flag for a single page allocation. This
means that this flag has never been actually useful here because it has
always been used only for PAGE_ALLOC_COSTLY requests.

An earlier attempt to remove the flag 10d58bf297 ("s390: get rid of
superfluous __GFP_REPEAT") has missed this one but the situation is very
same here.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-03-22 08:29:04 +01:00
Linus Torvalds 221bb8a46e - ARM: GICv3 ITS emulation and various fixes. Removal of the old
VGIC implementation.
 
 - s390: support for trapping software breakpoints, nested virtualization
 (vSIE), the STHYI opcode, initial extensions for CPU model support.
 
 - MIPS: support for MIPS64 hosts (32-bit guests only) and lots of cleanups,
 preliminary to this and the upcoming support for hardware virtualization
 extensions.
 
 - x86: support for execute-only mappings in nested EPT; reduced vmexit
 latency for TSC deadline timer (by about 30%) on Intel hosts; support for
 more than 255 vCPUs.
 
 - PPC: bugfixes.
 
 The ugly bit is the conflicts.  A couple of them are simple conflicts due
 to 4.7 fixes, but most of them are with other trees. There was definitely
 too much reliance on Acked-by here.  Some conflicts are for KVM patches
 where _I_ gave my Acked-by, but the worst are for this pull request's
 patches that touch files outside arch/*/kvm.  KVM submaintainers should
 probably learn to synchronize better with arch maintainers, with the
 latter providing topic branches whenever possible instead of Acked-by.
 This is what we do with arch/x86.  And I should learn to refuse pull
 requests when linux-next sends scary signals, even if that means that
 submaintainers have to rebase their branches.
 
 Anyhow, here's the list:
 
 - arch/x86/kvm/vmx.c: handle_pcommit and EXIT_REASON_PCOMMIT was removed
 by the nvdimm tree.  This tree adds handle_preemption_timer and
 EXIT_REASON_PREEMPTION_TIMER at the same place.  In general all mentions
 of pcommit have to go.
 
 There is also a conflict between a stable fix and this patch, where the
 stable fix removed the vmx_create_pml_buffer function and its call.
 
 - virt/kvm/kvm_main.c: kvm_cpu_notifier was removed by the hotplug tree.
 This tree adds kvm_io_bus_get_dev at the same place.
 
 - virt/kvm/arm/vgic.c: a few final bugfixes went into 4.7 before the
 file was completely removed for 4.8.
 
 - include/linux/irqchip/arm-gic-v3.h: this one is entirely our fault;
 this is a change that should have gone in through the irqchip tree and
 pulled by kvm-arm.  I think I would have rejected this kvm-arm pull
 request.  The KVM version is the right one, except that it lacks
 GITS_BASER_PAGES_SHIFT.
 
 - arch/powerpc: what a mess.  For the idle_book3s.S conflict, the KVM
 tree is the right one; everything else is trivial.  In this case I am
 not quite sure what went wrong.  The commit that is causing the mess
 (fd7bacbca4, "KVM: PPC: Book3S HV: Fix TB corruption in guest exit
 path on HMI interrupt", 2016-05-15) touches both arch/powerpc/kernel/
 and arch/powerpc/kvm/.  It's large, but at 396 insertions/5 deletions
 I guessed that it wasn't really possible to split it and that the 5
 deletions wouldn't conflict.  That wasn't the case.
 
 - arch/s390: also messy.  First is hypfs_diag.c where the KVM tree
 moved some code and the s390 tree patched it.  You have to reapply the
 relevant part of commits 6c22c98637, plus all of e030c1125e, to
 arch/s390/kernel/diag.c.  Or pick the linux-next conflict
 resolution from http://marc.info/?l=kvm&m=146717549531603&w=2.
 Second, there is a conflict in gmap.c between a stable fix and 4.8.
 The KVM version here is the correct one.
 
 I have pushed my resolution at refs/heads/merge-20160802 (commit
 3d1f53419842) at git://git.kernel.org/pub/scm/virt/kvm/kvm.git.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.22 (GNU/Linux)
 
 iQEcBAABAgAGBQJXoGm7AAoJEL/70l94x66DugQIAIj703ePAFepB/fCrKHkZZia
 SGrsBdvAtNsOhr7FQ5qvvjLxiv/cv7CymeuJivX8H+4kuUHUllDzey+RPHYHD9X7
 U6n1PdCH9F15a3IXc8tDjlDdOMNIKJixYuq1UyNZMU6NFwl00+TZf9JF8A2US65b
 x/41W98ilL6nNBAsoDVmCLtPNWAqQ3lajaZELGfcqRQ9ZGKcAYOaLFXHv2YHf2XC
 qIDMf+slBGSQ66UoATnYV2gAopNlWbZ7n0vO6tE2KyvhHZ1m399aBX1+k8la/0JI
 69r+Tz7ZHUSFtmlmyByi5IAB87myy2WQHyAPwj+4vwJkDGPcl0TrupzbG7+T05Y=
 =42ti
 -----END PGP SIGNATURE-----

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:

 - ARM: GICv3 ITS emulation and various fixes.  Removal of the
   old VGIC implementation.

 - s390: support for trapping software breakpoints, nested
   virtualization (vSIE), the STHYI opcode, initial extensions
   for CPU model support.

 - MIPS: support for MIPS64 hosts (32-bit guests only) and lots
   of cleanups, preliminary to this and the upcoming support for
   hardware virtualization extensions.

 - x86: support for execute-only mappings in nested EPT; reduced
   vmexit latency for TSC deadline timer (by about 30%) on Intel
   hosts; support for more than 255 vCPUs.

 - PPC: bugfixes.

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (302 commits)
  KVM: PPC: Introduce KVM_CAP_PPC_HTM
  MIPS: Select HAVE_KVM for MIPS64_R{2,6}
  MIPS: KVM: Reset CP0_PageMask during host TLB flush
  MIPS: KVM: Fix ptr->int cast via KVM_GUEST_KSEGX()
  MIPS: KVM: Sign extend MFC0/RDHWR results
  MIPS: KVM: Fix 64-bit big endian dynamic translation
  MIPS: KVM: Fail if ebase doesn't fit in CP0_EBase
  MIPS: KVM: Use 64-bit CP0_EBase when appropriate
  MIPS: KVM: Set CP0_Status.KX on MIPS64
  MIPS: KVM: Make entry code MIPS64 friendly
  MIPS: KVM: Use kmap instead of CKSEG0ADDR()
  MIPS: KVM: Use virt_to_phys() to get commpage PFN
  MIPS: Fix definition of KSEGX() for 64-bit
  KVM: VMX: Add VMCS to CPU's loaded VMCSs before VMPTRLD
  kvm: x86: nVMX: maintain internal copy of current VMCS
  KVM: PPC: Book3S HV: Save/restore TM state in H_CEDE
  KVM: PPC: Book3S HV: Pull out TM state save/restore into separate procedures
  KVM: arm64: vgic-its: Simplify MAPI error handling
  KVM: arm64: vgic-its: Make vgic_its_cmd_handle_mapi similar to other handlers
  KVM: arm64: vgic-its: Turn device_id validation into generic ID validation
  ...
2016-08-02 16:11:27 -04:00
Michal Hocko 10d58bf297 s390: get rid of superfluous __GFP_REPEAT
__GFP_REPEAT has a rather weak semantic but since it has been introduced
around 2.6.12 it has been ignored for low order allocations.

page_table_alloc then uses the flag for a single page allocation.  This
means that this flag has never been actually useful here because it has
always been used only for PAGE_ALLOC_COSTLY requests.

Link: http://lkml.kernel.org/r/1464599699-30131-14-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-24 17:23:52 -07:00
Martin Schwidefsky 4be130a084 s390/mm: add shadow gmap support
For a nested KVM guest the outer KVM host needs to create shadow
page tables for the nested guest. This patch adds the basic support
to the guest address space (gmap) code.

For each guest address space the inner KVM host creates, the first
outer KVM host needs to create shadow page tables. The address space
is identified by the ASCE loaded into the control register 1 at the
time the inner SIE instruction for the second nested KVM guest is
executed. The outer KVM host creates the shadow tables starting with
the table identified by the ASCE on a on-demand basis. The outer KVM
host will get repeated faults for all the shadow tables needed to
run the second KVM guest.

While a shadow page table for the second KVM guest is active the access
to the origin region, segment and page tables needs to be restricted
for the first KVM guest. For region and segment and page tables the first
KVM guest may read the memory, but write attempt has to lead to an
unshadow.  This is done using the page invalid and read-only bits in the
page table of the first KVM guest. If the first guest re-accesses one of
the origin pages of a shadow, it gets a fault and the affected parts of
the shadow page table hierarchy needs to be removed again.

PGSTE tables don't have to be shadowed, as all interpretation assist can't
deal with the invalid bits in the shadow pte being set differently than
the original ones provided by the first KVM guest.

Many bug fixes and improvements by David Hildenbrand.

Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2016-06-20 09:54:04 +02:00
Martin Schwidefsky 8ecb1a59d6 s390/mm: use RCU for gmap notifier list and the per-mm gmap list
The gmap notifier list and the gmap list in the mm_struct change rarely.
Use RCU to optimize the reader of these lists.

Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2016-06-20 09:46:49 +02:00
Gerald Schaefer 723cacbd9d s390/mm: fix asce_bits handling with dynamic pagetable levels
There is a race with multi-threaded applications between context switch and
pagetable upgrade. In switch_mm() a new user_asce is built from mm->pgd and
mm->context.asce_bits, w/o holding any locks. A concurrent mmap with a
pagetable upgrade on another thread in crst_table_upgrade() could already
have set new asce_bits, but not yet the new mm->pgd. This would result in a
corrupt user_asce in switch_mm(), and eventually in a kernel panic from a
translation exception.

Fix this by storing the complete asce instead of just the asce_bits, which
can then be read atomically from switch_mm(), so that it either sees the
old value or the new value, but no mixture. Both cases are OK. Having the
old value would result in a page fault on access to the higher level memory,
but the fault handler would see the new mm->pgd, if it was a valid access
after the mmap on the other thread has completed. So as worst-case scenario
we would have a page fault loop for the racing thread until the next time
slice.

Also remove dead code and simplify the upgrade/downgrade path, there are no
upgrades from 2 levels, and only downgrades from 3 levels for compat tasks.
There are also no concurrent upgrades, because the mmap_sem is held with
down_write() in do_mmap, so the flush and table checks during upgrade can
be removed.

Reported-by: Michael Munday <munday@ca.ibm.com>
Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-04-21 09:50:09 +02:00
Martin Schwidefsky 1e133ab296 s390/mm: split arch/s390/mm/pgtable.c
The pgtable.c file is quite big, before it grows any larger split it
into pgtable.c, pgalloc.c and gmap.c. In addition move the gmap related
header definitions into the new gmap.h header and all of the pgste
helpers from pgtable.h to pgtable.c.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-03-08 15:00:15 +01:00