linux-toradex.git/include/xen, branch v4.17-rc1

xen/pvh: Indicate XENFEAT_linux_rsdp_unrestricted to Xen

2018-04-10T13:22:22+00:00

Pre-4.17 kernels ignored start_info's rsdp_paddr pointer and instead
relied on finding RSDP in standard location in BIOS RO memory. This
has worked since that's where Xen used to place it.

However, with recent Xen change (commit 4a5733771e6f ("libxl: put RSDP
for PVH guest near 4GB")) it prefers to keep RSDP at a "non-standard"
address. Even though as of commit b17d9d1df3c3 ("x86/xen: Add pvh
specific rsdp address retrieval function") Linux is able to find RSDP,
for back-compatibility reasons we need to indicate to Xen that we can
handle this, an we do so by setting XENFEAT_linux_rsdp_unrestricted
flag in ELF notes.

(Also take this opportunity and sync features.h header file with Xen)

Signed-off-by: Boris Ostrovsky 
Reviewed-by: Juergen Gross 
Reviewed-by: Wei Liu

Merge tag 'for-linus-4.15-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2017-12-22T20:30:10+00:00

Pull xen fixes from Juergen Gross:
 "This contains two fixes for running under Xen:

   - a fix avoiding resource conflicts between adding mmio areas and
     memory hotplug

   - a fix setting NX bits in page table entries copied from Xen when
     running a PV guest"

* tag 'for-linus-4.15-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/balloon: Mark unallocated host memory as UNUSABLE
  x86-64/Xen: eliminate W+X mappings

xen/balloon: Mark unallocated host memory as UNUSABLE

2017-12-20T18:16:20+00:00

Commit f5775e0b6116 ("x86/xen: discard RAM regions above the maximum
reservation") left host memory not assigned to dom0 as available for
memory hotplug.

Unfortunately this also meant that those regions could be used by
others. Specifically, commit fa564ad96366 ("x86/PCI: Enable a 64bit BAR
on AMD Family 15h (Models 00-1f, 30-3f, 60-7f)") may try to map those
addresses as MMIO.

To prevent this mark unallocated host memory as E820_TYPE_UNUSABLE (thus
effectively reverting f5775e0b6116) and keep track of that region as
a hostmem resource that can be used for the hotplug.

Signed-off-by: Boris Ostrovsky 
Reviewed-by: Juergen Gross

Merge tag 'for-linus-4.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2017-11-16T21:06:27+00:00

Pull xen updates from Juergen Gross:
 "Xen features and fixes for v4.15-rc1

  Apart from several small fixes it contains the following features:

   - a series by Joao Martins to add vdso support of the pv clock
     interface

   - a series by Juergen Gross to add support for Xen pv guests to be
     able to run on 5 level paging hosts

   - a series by Stefano Stabellini adding the Xen pvcalls frontend
     driver using a paravirtualized socket interface"

* tag 'for-linus-4.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (34 commits)
  xen/pvcalls: fix potential endless loop in pvcalls-front.c
  xen/pvcalls: Add MODULE_LICENSE()
  MAINTAINERS: xen, kvm: track pvclock-abi.h changes
  x86/xen/time: setup vcpu 0 time info page
  x86/xen/time: set pvclock flags on xen_time_init()
  x86/pvclock: add setter for pvclock_pvti_cpu0_va
  ptp_kvm: probe for kvm guest availability
  xen/privcmd: remove unused variable pageidx
  xen: select grant interface version
  xen: update arch/x86/include/asm/xen/cpuid.h
  xen: add grant interface version dependent constants to gnttab_ops
  xen: limit grant v2 interface to the v1 functionality
  xen: re-introduce support for grant v2 interface
  xen: support priv-mapping in an HVM tools domain
  xen/pvcalls: remove redundant check for irq >= 0
  xen/pvcalls: fix unsigned less than zero error check
  xen/time: Return -ENODEV from xen_get_wallclock()
  xen/pvcalls-front: mark expected switch fall-through
  xen: xenbus_probe_frontend: mark expected switch fall-throughs
  xen/time: do not decrease steal time after live migration on xen
  ...

x86/xen/time: setup vcpu 0 time info page

2017-11-08T21:33:14+00:00

In order to support pvclock vdso on xen we need to setup the time
info page for vcpu 0 and register the page with Xen using the
VCPUOP_register_vcpu_time_memory_area hypercall. This hypercall
will also forcefully update the pvti which will set some of the
necessary flags for vdso. Afterwards we check if it supports the
PVCLOCK_TSC_STABLE_BIT flag which is mandatory for having
vdso/vsyscall support. And if so, it will set the cpu 0 pvti that
will be later on used when mapping the vdso image.

The xen headers are also updated to include the new hypercall for
registering the secondary vcpu_time_info struct.

Signed-off-by: Joao Martins 
Reviewed-by: Juergen Gross 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky

xen: limit grant v2 interface to the v1 functionality

2017-11-06T20:50:17+00:00

As there is currently no user for sub-page grants or transient grants
remove that functionality. This at once makes it possible to switch
from grant v2 to grant v1 without restrictions, as there is no loss of
functionality other than the limited frame number width related to
the switch.

Signed-off-by: Juergen Gross 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky

xen: re-introduce support for grant v2 interface

2017-11-06T20:50:17+00:00

The grant v2 support was removed from the kernel with
commit 438b33c7145ca8a5131a30c36d8f59bce119a19a ("xen/grant-table:
remove support for V2 tables") as the higher memory footprint of v2
grants resulted in less grants being possible for a kernel compared
to the v1 grant interface.

As machines with more than 16TB of memory are expected to be more
common in the near future support of grant v2 is mandatory in order
to be able to run a Xen pv domain at any memory location.

So re-add grant v2 support basically by reverting above commit.

Signed-off-by: Juergen Gross 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky

xen: support priv-mapping in an HVM tools domain

2017-11-03T20:53:53+00:00

If the domain has XENFEAT_auto_translated_physmap then use of the PV-
specific HYPERVISOR_mmu_update hypercall is clearly incorrect.

This patch adds checks in xen_remap_domain_gfn_array() and
xen_unmap_domain_gfn_array() which call through to the approprate
xlate_mmu function if the feature is present. A check is also added
to xen_remap_domain_gfn_range() to fail with -EOPNOTSUPP since this
should not be used in an HVM tools domain.

Signed-off-by: Paul Durrant 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky

xen/time: do not decrease steal time after live migration on xen

2017-11-02T20:49:41+00:00

After guest live migration on xen, steal time in /proc/stat
(cpustat[CPUTIME_STEAL]) might decrease because steal returned by
xen_steal_lock() might be less than this_rq()->prev_steal_time which is
derived from previous return value of xen_steal_clock().

For instance, steal time of each vcpu is 335 before live migration.

cpu  198 0 368 200064 1962 0 0 1340 0 0
cpu0 38 0 81 50063 492 0 0 335 0 0
cpu1 65 0 97 49763 634 0 0 335 0 0
cpu2 38 0 81 50098 462 0 0 335 0 0
cpu3 56 0 107 50138 374 0 0 335 0 0

After live migration, steal time is reduced to 312.

cpu  200 0 370 200330 1971 0 0 1248 0 0
cpu0 38 0 82 50123 500 0 0 312 0 0
cpu1 65 0 97 49832 634 0 0 312 0 0
cpu2 39 0 82 50167 462 0 0 312 0 0
cpu3 56 0 107 50207 374 0 0 312 0 0

Since runstate times are cumulative and cleared during xen live migration
by xen hypervisor, the idea of this patch is to accumulate runstate times
to global percpu variables before live migration suspend. Once guest VM is
resumed, xen_get_runstate_snapshot_cpu() would always return the sum of new
runstate times and previously accumulated times stored in global percpu
variables.

Comment above HYPERVISOR_suspend() has been removed as it is inaccurate:
the call can return an error code (e.g., possibly -EPERM in the future).

Similar and more severe issue would impact prior linux 4.8-4.10 as
discussed by Michael Las at
https://0xstubs.org/debugging-a-flaky-cpu-steal-time-counter-on-a-paravirtualized-xen-guest,
which would overflow steal time and lead to 100% st usage in top command
for linux 4.8-4.10. A backport of this patch would fix that issue.

[boris: added linux/slab.h to driver/xen/time.c, slightly reformatted
        commit message]

References: https://0xstubs.org/debugging-a-flaky-cpu-steal-time-counter-on-a-paravirtualized-xen-guest
Signed-off-by: Dongli Zhang 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

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 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman