xen/grant-dma-iommu: Introduce stub IOMMU driver

In order to reuse generic IOMMU device tree bindings by Xen grant
DMA-mapping layer we need to add this stub driver from a fw_devlink
perspective (gr

xen/grant-dma-iommu: Introduce stub IOMMU driver

In order to reuse generic IOMMU device tree bindings by Xen grant
DMA-mapping layer we need to add this stub driver from a fw_devlink
perspective (grant-dma-ops cannot be converted into the proper
IOMMU driver).

Otherwise, just reusing IOMMU bindings (without having a corresponding
driver) leads to the deferred probe timeout afterwards, because
the IOMMU device never becomes available.

This stub driver does nothing except registering empty iommu_ops,
the upper layer "of_iommu" will treat this as NO_IOMMU condition
and won't return -EPROBE_DEFER.

As this driver is quite different from the most hardware IOMMU
implementations and only needed in Xen guests, place it in drivers/xen
directory. The subsequent commit will make use of it.

Signed-off-by: Oleksandr Tyshchenko <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen/grant-dma-ops: Add option to restrict memory access under Xen

Introduce Xen grant DMA-mapping layer which contains special DMA-mapping
routines for providing grant references as DMA addresses to

xen/grant-dma-ops: Add option to restrict memory access under Xen

Introduce Xen grant DMA-mapping layer which contains special DMA-mapping
routines for providing grant references as DMA addresses to be used by
frontends (e.g. virtio) in Xen guests.

Add the needed functionality by providing a special set of DMA ops
handling the needed grant operations for the I/O pages.

The subsequent commit will introduce the use case for xen-grant DMA ops
layer to enable using virtio devices in Xen guests in a safe manner.

Signed-off-by: Juergen Gross <[email protected]>
Signed-off-by: Oleksandr Tyshchenko <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen-pciback: allow compiling on other archs than x86

Xen-pciback driver was designed to be built for x86 only. But it
can also be used by other architectures, e.g. Arm.

Currently PCI backend implem

xen-pciback: allow compiling on other archs than x86

Xen-pciback driver was designed to be built for x86 only. But it
can also be used by other architectures, e.g. Arm.

Currently PCI backend implements multiple functionalities at a time,
such as:
1. It is used as a database for assignable PCI devices, e.g. xl
pci-assignable-{add|remove|list} manipulates that list. So, whenever
the toolstack needs to know which PCI devices can be passed through
it reads that from the relevant sysfs entries of the pciback.
2. It is used to hold the unbound PCI devices list, e.g. when passing
through a PCI device it needs to be unbound from the relevant device
driver and bound to pciback (strictly speaking it is not required
that the device is bound to pciback, but pciback is again used as a
database of the passed through PCI devices, so we can re-bind the
devices back to their original drivers when guest domain shuts down)
3. Device reset for the devices being passed through
4. Para-virtualised use-cases support

The para-virtualised part of the driver is not always needed as some
architectures, e.g. Arm or x86 PVH Dom0, are not using backend-frontend
model for PCI device passthrough.

For such use-cases make the very first step in splitting the
xen-pciback driver into two parts: Xen PCI stub and PCI PV backend
drivers.

For that add new configuration options CONFIG_XEN_PCI_STUB and
CONFIG_XEN_PCIDEV_STUB, so the driver can be limited in its
functionality, e.g. no support for para-virtualised scenario.
x86 platform will continue using CONFIG_XEN_PCIDEV_BACKEND for the
fully featured backend driver.

Signed-off-by: Oleksandr Andrushchenko <[email protected]>
Signed-off-by: Anastasiia Lukianenko <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Boris Ostrovsky <[email protected]>

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xen: Remove support for PV ACPI cpu/memory hotplug

Commit 76fc253723ad ("xen/acpi-stub: Disable it b/c the acpi_processor_add
is no longer called.") declared as BROKEN support for Xen ACPI stub (whi

xen: Remove support for PV ACPI cpu/memory hotplug

Commit 76fc253723ad ("xen/acpi-stub: Disable it b/c the acpi_processor_add
is no longer called.") declared as BROKEN support for Xen ACPI stub (which
is required for xen-acpi-{cpu|memory}-hotplug) and suggested that this
is temporary and will be soon fixed. This was in March 2013.

Further, commit cfafae940381 ("xen: rename dom0_op to platform_op")
renamed an interface used by memory hotplug code without updating that
code (as it was BROKEN and therefore not compiled). This was
in November 2015 and has gone unnoticed for over 5 year.

It is now clear that this code is of no interest to anyone and therefore
should be removed.

Signed-off-by: Boris Ostrovsky <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen: Remove Xen PVH/PVHVM dependency on PCI

A Xen PVH domain doesn't have a PCI bus or devices, so it doesn't need
PCI support built in. Currently, XEN_PVH depends on XEN_PVHVM which
depends on PCI

xen: Remove Xen PVH/PVHVM dependency on PCI

A Xen PVH domain doesn't have a PCI bus or devices, so it doesn't need
PCI support built in. Currently, XEN_PVH depends on XEN_PVHVM which
depends on PCI.

Introduce XEN_PVHVM_GUEST as a toplevel item and change XEN_PVHVM to a
hidden variable. This allows XEN_PVH to depend on XEN_PVHVM without PCI
while XEN_PVHVM_GUEST depends on PCI.

In drivers/xen, compile platform-pci depending on XEN_PVHVM_GUEST since
that pulls in the PCI dependency for linking.

Signed-off-by: Jason Andryuk <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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xen: add helpers to allocate unpopulated memory

To be used in order to create foreign mappings. This is based on the
ZONE_DEVICE facility which is used by persistent memory devices in
order to creat

xen: add helpers to allocate unpopulated memory

To be used in order to create foreign mappings. This is based on the
ZONE_DEVICE facility which is used by persistent memory devices in
order to create struct pages and kernel virtual mappings for the IOMEM
areas of such devices. Note that on kernels without support for
ZONE_DEVICE Xen will fallback to use ballooned pages in order to
create foreign mappings.

The newly added helpers use the same parameters as the existing
{alloc/free}_xenballooned_pages functions, which allows for in-place
replacement of the callers. Once a memory region has been added to be
used as scratch mapping space it will no longer be released, and pages
returned are kept in a linked list. This allows to have a buffer of
pages and prevents resorting to frequent additions and removals of
regions.

If enabled (because ZONE_DEVICE is supported) the usage of the new
functionality untangles Xen balloon and RAM hotplug from the usage of
unpopulated physical memory ranges to map foreign pages, which is the
correct thing to do in order to avoid mappings of foreign pages depend
on memory hotplug.

Note the driver is currently not enabled on Arm platforms because it
would interfere with the identity mapping required on some platforms.

Signed-off-by: Roger Pau Monné <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Juergen Gross <[email protected]>

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kbuild: remove cc-option test of -fno-stack-protector

Some Makefiles already pass -fno-stack-protector unconditionally.
For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile.

No probl

kbuild: remove cc-option test of -fno-stack-protector

Some Makefiles already pass -fno-stack-protector unconditionally.
For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile.

No problem report so far about hard-coding this option. So, we can
assume all supported compilers know -fno-stack-protector.

GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN)

Get rid of cc-option from -fno-stack-protector.

Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which is always 'y'.

Note:
arch/mips/vdso/Makefile adds -fno-stack-protector twice, first
unconditionally, and second conditionally. I removed the second one.

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Acked-by: Ard Biesheuvel <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>

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x86/entry: Switch XEN/PV hypercall entry to IDTENTRY

Convert the XEN/PV hypercall to IDTENTRY:

- Emit the ASM stub with DECLARE_IDTENTRY
- Remove the ASM idtentry in 64-bit
- Remove the open

x86/entry: Switch XEN/PV hypercall entry to IDTENTRY

Convert the XEN/PV hypercall to IDTENTRY:

- Emit the ASM stub with DECLARE_IDTENTRY
- Remove the ASM idtentry in 64-bit
- Remove the open coded ASM entry code in 32-bit
- Remove the old prototypes

The handler stubs need to stay in ASM code as they need corner case handling
and adjustment of the stack pointer.

Provide a new C function which invokes the entry/exit handling and calls
into the XEN handler on the interrupt stack if required.

The exit code is slightly different from the regular idtentry_exit() on
non-preemptible kernels. If the hypercall is preemptible and need_resched()
is set then XEN provides a preempt hypercall scheduling function.

Move this functionality into the entry code so it can use the existing
idtentry functionality.

[ mingo: Build fixes. ]

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Acked-by: Juergen Gross <[email protected]>
Tested-by: Juergen Gross <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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xen: remove tmem driver

The Xen tmem (transcendent memory) driver can be removed, as the
related Xen hypervisor feature never made it past the "experimental"
state and will be removed in future Xen

xen: remove tmem driver

The Xen tmem (transcendent memory) driver can be removed, as the
related Xen hypervisor feature never made it past the "experimental"
state and will be removed in future Xen versions (>= 4.13).

The xen-selfballoon driver depends on tmem, so it can be removed, too.

Signed-off-by: Juergen Gross <[email protected]>
Acked-by: Boris Ostrovsky <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>

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xen: remove pre-xen3 fallback handlers

The legacy hypercall handlers were originally added with
a comment explaining that "copying the argument structures in
HYPERVISOR_event_channel_op() and HYPERV

xen: remove pre-xen3 fallback handlers

The legacy hypercall handlers were originally added with
a comment explaining that "copying the argument structures in
HYPERVISOR_event_channel_op() and HYPERVISOR_physdev_op() into the local
variable is sufficiently safe" and only made sure to not write
past the end of the argument structure, the checks in linux/string.h
disagree with that, when link-time optimizations are used:

In function 'memcpy',
inlined from 'pirq_query_unmask' at drivers/xen/fallback.c:53:2,
inlined from '__startup_pirq' at drivers/xen/events/events_base.c:529:2,
inlined from 'restore_pirqs' at drivers/xen/events/events_base.c:1439:3,
inlined from 'xen_irq_resume' at drivers/xen/events/events_base.c:1581:2:
include/linux/string.h:350:3: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter
__read_overflow2();
^

Further research turned out that only Xen 3.0.2 or earlier required the
fallback at all, while all versions in use today don't need it.
As far as I can tell, it is not even possible to run a mainline kernel
on those old Xen releases, at the time when they were in use, only
a patched kernel was supported anyway.

Fixes: cf47a83fb06e ("xen/hypercall: fix hypercall fallback code for very old hypervisors")
Reviewed-by: Boris Ostrovsky <[email protected]>
Cc: Jan Beulich <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>

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xen: Introduce shared buffer helpers for page directory...

based frontends. Currently the frontends which implement
similar code for sharing big buffers between frontend and
backend are para-virtual

xen: Introduce shared buffer helpers for page directory...

based frontends. Currently the frontends which implement
similar code for sharing big buffers between frontend and
backend are para-virtualized DRM and sound drivers.
Both define the same way to share grant references of a
data buffer with the corresponding backend with little
differences.

Move shared code into a helper module, so there is a single
implementation of the same functionality for all.

This patch introduces code which is used by sound and display
frontend drivers without functional changes with the intention
to remove shared code from the corresponding drivers.

Signed-off-by: Oleksandr Andrushchenko <[email protected]>
Acked-by: Boris Ostrovsky <[email protected]>
Signed-off-by: Boris Ostrovsky <[email protected]>

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xen/gntdev: Add initial support for dma-buf UAPI

Add UAPI and IOCTLs for dma-buf grant device driver extension:
the extension allows userspace processes and kernel modules to
use Xen backed dma-buf

xen/gntdev: Add initial support for dma-buf UAPI

Add UAPI and IOCTLs for dma-buf grant device driver extension:
the extension allows userspace processes and kernel modules to
use Xen backed dma-buf implementation. With this extension grant
references to the pages of an imported dma-buf can be exported
for other domain use and grant references coming from a foreign
domain can be converted into a local dma-buf for local export.
Implement basic initialization and stubs for Xen DMA buffers'
support.

Signed-off-by: Oleksandr Andrushchenko <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Signed-off-by: Boris Ostrovsky <[email protected]>

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xen/balloon: Share common memory reservation routines

Memory {increase|decrease}_reservation and VA mappings update/reset
code used in balloon driver can be made common, so other drivers can
also re

xen/balloon: Share common memory reservation routines

Memory {increase|decrease}_reservation and VA mappings update/reset
code used in balloon driver can be made common, so other drivers can
also re-use the same functionality without open-coding.
Create a dedicated file for the shared code and export corresponding
symbols for other kernel modules.

Signed-off-by: Oleksandr Andrushchenko <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Signed-off-by: Boris Ostrovsky <[email protected]>

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xen: add new hypercall buffer mapping device

For passing arbitrary data from user land to the Xen hypervisor the
Xen tools today are using mlock()ed buffers. Unfortunately the kernel
might change ac

xen: add new hypercall buffer mapping device

For passing arbitrary data from user land to the Xen hypervisor the
Xen tools today are using mlock()ed buffers. Unfortunately the kernel
might change access rights of such buffers for brief periods of time
e.g. for page migration or compaction, leading to access faults in the
hypervisor, as the hypervisor can't use the locks of the kernel.

In order to solve this problem add a new device node to the Xen privcmd
driver to easily allocate hypercall buffers via mmap(). The memory is
allocated in the kernel and just mapped into user space. Marked as
VM_IO the user mapping will not be subject to page migration et al.

Signed-off-by: Juergen Gross <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>

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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

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 <[email protected]>
Reviewed-by: Philippe Ombredanne <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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xen: introduce a Kconfig option to enable the pvcalls frontend

Also add pvcalls-front to the Makefile.

Signed-off-by: Stefano Stabellini <[email protected]>
Reviewed-by: Boris Ostrovsky <boris.os

xen: introduce a Kconfig option to enable the pvcalls frontend

Also add pvcalls-front to the Makefile.

Signed-off-by: Stefano Stabellini <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
CC: [email protected]
CC: [email protected]
Signed-off-by: Boris Ostrovsky <[email protected]>

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xen: introduce a Kconfig option to enable the pvcalls backend

Also add pvcalls-back to the Makefile.

Signed-off-by: Stefano Stabellini <[email protected]>
Reviewed-by: Juergen Gross <jgross@suse.

xen: introduce a Kconfig option to enable the pvcalls backend

Also add pvcalls-back to the Makefile.

Signed-off-by: Stefano Stabellini <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
CC: [email protected]
CC: [email protected]
Signed-off-by: Boris Ostrovsky <[email protected]>

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Kbuild: use -fshort-wchar globally

Commit 971a69db7dc0 ("Xen: don't warn about 2-byte wchar_t in efi")
added the --no-wchar-size-warning to the Makefile to avoid this
harmless warning:

arm-linux-gn

Kbuild: use -fshort-wchar globally

Commit 971a69db7dc0 ("Xen: don't warn about 2-byte wchar_t in efi")
added the --no-wchar-size-warning to the Makefile to avoid this
harmless warning:

arm-linux-gnueabi-ld: warning: drivers/xen/efi.o uses 2-byte wchar_t yet the output is to use 4-byte wchar_t; use of wchar_t values across objects may fail

Changing kbuild to use thin archives instead of recursive linking
unfortunately brings the same warning back during the final link.

The kernel does not use wchar_t string literals at this point, and
xen does not use wchar_t at all (only efi_char16_t), so the flag
has no effect, but as pointed out by Jan Beulich, adding a wchar_t
string literal would be bad here.

Since wchar_t is always defined as u16, independent of the toolchain
default, always passing -fshort-wchar is correct and lets us
remove the Xen specific hack along with fixing the warning.

Link: https://patchwork.kernel.org/patch/9275217/
Fixes: 971a69db7dc0 ("Xen: don't warn about 2-byte wchar_t in efi")
Signed-off-by: Arnd Bergmann <[email protected]>
Acked-by: David Vrabel <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>

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Xen: ARM: Add support for mapping platform device mmio

Add a bus_notifier for platform bus device in order to map the device
mmio regions when DOM0 booting with ACPI.

Signed-off-by: Shannon Zhao <s

Xen: ARM: Add support for mapping platform device mmio

Add a bus_notifier for platform bus device in order to map the device
mmio regions when DOM0 booting with ACPI.

Signed-off-by: Shannon Zhao <[email protected]>
Acked-by: Stefano Stabellini <[email protected]>
Tested-by: Julien Grall <[email protected]>

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Xen: don't warn about 2-byte wchar_t in efi

The XEN UEFI code has become available on the ARM architecture
recently, but now causes a link-time warning:

ld: warning: drivers/xen/efi.o uses 2-byte w

Xen: don't warn about 2-byte wchar_t in efi

The XEN UEFI code has become available on the ARM architecture
recently, but now causes a link-time warning:

ld: warning: drivers/xen/efi.o uses 2-byte wchar_t yet the output is to use 4-byte wchar_t; use of wchar_t values across objects may fail

This seems harmless, because the efi code only uses 2-byte
characters when interacting with EFI, so we don't pass on those
strings to elsewhere in the system, and we just need to
silence the warning.

It is not clear to me whether we actually need to build the file
with the -fshort-wchar flag, but if we do, then we should also
pass --no-wchar-size-warning to the linker, to avoid the warning.

Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Fixes: 37060935dc04 ("ARM64: XEN: Add a function to initialize Xen specific UEFI runtime services")

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xen: move xen_setup_runstate_info and get_runstate_snapshot to drivers/xen/time.c

Signed-off-by: Stefano Stabellini <[email protected]>
Acked-by: Ian Campbell <[email protected]

xen: move xen_setup_runstate_info and get_runstate_snapshot to drivers/xen/time.c

Signed-off-by: Stefano Stabellini <[email protected]>
Acked-by: Ian Campbell <[email protected]>
Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>

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xen/arm: Enable cpu_hotplug.c

Build cpu_hotplug for ARM and ARM64 guests.

Rename arch_(un)register_cpu to xen_(un)register_cpu and provide an
empty implementation on ARM and ARM64. On x86 just call

xen/arm: Enable cpu_hotplug.c

Build cpu_hotplug for ARM and ARM64 guests.

Rename arch_(un)register_cpu to xen_(un)register_cpu and provide an
empty implementation on ARM and ARM64. On x86 just call
arch_(un)register_cpu as we are already doing.

Initialize cpu_hotplug on ARM.

Signed-off-by: Stefano Stabellini <[email protected]>
Reviewed-by: Julien Grall <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>

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XEN / ACPI: Make XEN ACPI depend on X86

When ACPI is enabled on ARM64, XEN ACPI will also compiled
into the kernel, but XEN ACPI is x86 dependent, so introduce
CONFIG_XEN_ACPI to make it depend on x

XEN / ACPI: Make XEN ACPI depend on X86

When ACPI is enabled on ARM64, XEN ACPI will also compiled
into the kernel, but XEN ACPI is x86 dependent, so introduce
CONFIG_XEN_ACPI to make it depend on x86 before XEN ACPI is
functional on ARM64.

CC: Julien Grall <[email protected]>
CC: Konrad Rzeszutek Wilk <[email protected]>
CC: Boris Ostrovsky <[email protected]>
CC: David Vrabel <[email protected]>
Acked-by: Stefano Stabellini <[email protected]>
Signed-off-by: Hanjun Guo <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

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xen: unify foreign GFN map/unmap for auto-xlated physmap guests

Auto-translated physmap guests (arm, arm64 and x86 PVHVM/PVH) map and
unmap foreign GFNs using the same method (updating the physmap).

xen: unify foreign GFN map/unmap for auto-xlated physmap guests

Auto-translated physmap guests (arm, arm64 and x86 PVHVM/PVH) map and
unmap foreign GFNs using the same method (updating the physmap).
Unify the two arm and x86 implementations into one commont one.

Note that on arm and arm64, the correct error code will be returned
(instead of always -EFAULT) and map/unmap failure warnings are no
longer printed. These changes are required if the foreign domain is
paging (-ENOENT failures are expected and must be propagated up to the
caller).

Signed-off-by: David Vrabel <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>

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x86/xen: allow privcmd hypercalls to be preempted

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

x86/xen: allow privcmd hypercalls to be preempted

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 <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>

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