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2019-07-17xen: remove tmem driverJuergen Gross
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 <jgross@suse.com> Acked-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2019-03-05xen: remove pre-xen3 fallback handlersArnd Bergmann
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 <boris.ostrovsky@oracle.com> Cc: Jan Beulich <JBeulich@suse.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Juergen Gross <jgross@suse.com>
2018-12-18xen: Introduce shared buffer helpers for page directory...Oleksandr Andrushchenko
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 <oleksandr_andrushchenko@epam.com> Acked-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-07-26xen/gntdev: Add initial support for dma-buf UAPIOleksandr Andrushchenko
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 <oleksandr_andrushchenko@epam.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-07-26xen/balloon: Share common memory reservation routinesOleksandr Andrushchenko
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 <oleksandr_andrushchenko@epam.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-06-22xen: add new hypercall buffer mapping deviceJuergen Gross
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 <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-11-16Merge tag 'for-linus-4.15-rc1-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip 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 ...
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
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>
2017-10-31xen: introduce a Kconfig option to enable the pvcalls frontendStefano Stabellini
Also add pvcalls-front to the Makefile. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-09-07Merge tag 'for-linus-4.14b-rc1-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen updates from Juergen Gross: - the new pvcalls backend for routing socket calls from a guest to dom0 - some cleanups of Xen code - a fix for wrong usage of {get,put}_cpu() * tag 'for-linus-4.14b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (27 commits) xen/mmu: set MMU_NORMAL_PT_UPDATE in remap_area_mfn_pte_fn xen: Don't try to call xen_alloc_p2m_entry() on autotranslating guests xen/events: events_fifo: Don't use {get,put}_cpu() in xen_evtchn_fifo_init() xen/pvcalls: use WARN_ON(1) instead of __WARN() xen: remove not used trace functions xen: remove unused function xen_set_domain_pte() xen: remove tests for pvh mode in pure pv paths xen-platform: constify pci_device_id. xen: cleanup xen.h xen: introduce a Kconfig option to enable the pvcalls backend xen/pvcalls: implement write xen/pvcalls: implement read xen/pvcalls: implement the ioworker functions xen/pvcalls: disconnect and module_exit xen/pvcalls: implement release command xen/pvcalls: implement poll command xen/pvcalls: implement accept command xen/pvcalls: implement listen command xen/pvcalls: implement bind command xen/pvcalls: implement connect command ...
2017-08-31xen: introduce a Kconfig option to enable the pvcalls backendStefano Stabellini
Also add pvcalls-back to the Makefile. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Juergen Gross <jgross@suse.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2017-08-21Kbuild: use -fshort-wchar globallyArnd Bergmann
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 <arnd@arndb.de> Acked-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2016-07-06Xen: ARM: Add support for mapping platform device mmioShannon Zhao
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 <shannon.zhao@linaro.org> Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Tested-by: Julien Grall <julien.grall@arm.com>
2016-05-24Xen: don't warn about 2-byte wchar_t in efiArnd Bergmann
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 <arnd@arndb.de> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Fixes: 37060935dc04 ("ARM64: XEN: Add a function to initialize Xen specific UEFI runtime services")
2015-12-21xen: move xen_setup_runstate_info and get_runstate_snapshot to ↵Stefano Stabellini
drivers/xen/time.c Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2015-10-23xen/arm: Enable cpu_hotplug.cStefano Stabellini
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 <stefano.stabellini@eu.citrix.com> Reviewed-by: Julien Grall <julien.grall@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2015-04-24Merge tag 'arm64-upstream' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull initial ACPI support for arm64 from Will Deacon: "This series introduces preliminary ACPI 5.1 support to the arm64 kernel using the "hardware reduced" profile. We don't support any peripherals yet, so it's fairly limited in scope: - MEMORY init (UEFI) - ACPI discovery (RSDP via UEFI) - CPU init (FADT) - GIC init (MADT) - SMP boot (MADT + PSCI) - ACPI Kconfig options (dependent on EXPERT) ACPI for arm64 has been in development for a while now and hardware has been available that can boot with either FDT or ACPI tables. This has been made possible by both changes to the ACPI spec to cater for ARM-based machines (known as "hardware-reduced" in ACPI parlance) but also a Linaro-driven effort to get this supported on top of the Linux kernel. This pull request is the result of that work. These changes allow us to initialise the CPUs, interrupt controller, and timers via ACPI tables, with memory information and cmdline coming from EFI. We don't support a hybrid ACPI/FDT scheme. Of course, there is still plenty of work to do (a serial console would be nice!) but I expect that to happen on a per-driver basis after this core series has been merged. Anyway, the diff stat here is fairly horrible, but splitting this up and merging it via all the different subsystems would have been extremely painful. Instead, we've got all the relevant Acks in place and I've not seen anything other than trivial (Kconfig) conflicts in -next (for completeness, I've included my resolution below). Nearly half of the insertions fall under Documentation/. So, we'll see how this goes. Right now, it all depends on EXPERT and I fully expect people to use FDT by default for the immediate future" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (31 commits) ARM64 / ACPI: make acpi_map_gic_cpu_interface() as void function ARM64 / ACPI: Ignore the return error value of acpi_map_gic_cpu_interface() ARM64 / ACPI: fix usage of acpi_map_gic_cpu_interface ARM64: kernel: acpi: honour acpi=force command line parameter ARM64: kernel: acpi: refactor ACPI tables init and checks ARM64: kernel: psci: let ACPI probe PSCI version ARM64: kernel: psci: factor out probe function ACPI: move arm64 GSI IRQ model to generic GSI IRQ layer ARM64 / ACPI: Don't unflatten device tree if acpi=force is passed ARM64 / ACPI: additions of ACPI documentation for arm64 Documentation: ACPI for ARM64 ARM64 / ACPI: Enable ARM64 in Kconfig XEN / ACPI: Make XEN ACPI depend on X86 ARM64 / ACPI: Select ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64 clocksource / arch_timer: Parse GTDT to initialize arch timer irqchip: Add GICv2 specific ACPI boot support ARM64 / ACPI: Introduce ACPI_IRQ_MODEL_GIC and register device's gsi ACPI / processor: Make it possible to get CPU hardware ID via GICC ACPI / processor: Introduce phys_cpuid_t for CPU hardware ID ARM64 / ACPI: Parse MADT for SMP initialization ...
2015-03-26XEN / ACPI: Make XEN ACPI depend on X86Hanjun Guo
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 <julien.grall@linaro.org> CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: David Vrabel <david.vrabel@citrix.com> Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-16xen: unify foreign GFN map/unmap for auto-xlated physmap guestsDavid Vrabel
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 <david.vrabel@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2015-02-23x86/xen: allow privcmd hypercalls to be preemptedDavid Vrabel
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>
2014-09-23xen-scsiback: Add Xen PV SCSI backend driverJuergen Gross
Introduces the Xen pvSCSI backend. With pvSCSI it is possible for a Xen domU to issue SCSI commands to a SCSI LUN assigned to that domU. The SCSI commands are passed to the pvSCSI backend in a driver domain (usually Dom0) which is owner of the physical device. This allows e.g. to use SCSI tape drives in a Xen domU. The code is taken from the pvSCSI implementation in Xen done by Fujitsu based on Linux kernel 2.6.18. Changes from the original version are: - port to upstream kernel - put all code in just one source file - adapt to Linux style guide - use target core infrastructure instead doing pure pass-through - enable module unloading - support SG-list in grant page(s) - support task abort - remove redundant struct backend - allocate resources dynamically - correct minor error in scsiback_fast_flush_area - free allocated resources in case of error during I/O preparation - remove CDB emulation, now handled by target core infrastructure Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-07-18xen: Put EFI machinery in placeDaniel Kiper
This patch enables EFI usage under Xen dom0. Standard EFI Linux Kernel infrastructure cannot be used because it requires direct access to EFI data and code. However, in dom0 case it is not possible because above mentioned EFI stuff is fully owned and controlled by Xen hypervisor. In this case all calls from dom0 to EFI must be requested via special hypercall which in turn executes relevant EFI code in behalf of dom0. When dom0 kernel boots it checks for EFI availability on a machine. If it is detected then artificial EFI system table is filled. Native EFI callas are replaced by functions which mimics them by calling relevant hypercall. Later pointer to EFI system table is passed to standard EFI machinery and it continues EFI subsystem initialization taking into account that there is no direct access to EFI boot services, runtime, tables, structures, etc. After that system runs as usual. This patch is based on Jan Beulich and Tang Liang work. Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Tang Liang <liang.tang@oracle.com> Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2014-02-11ia64/xen: Remove Xen support for ia64 even morePaul Bolle
Commit d52eefb47d4e ("ia64/xen: Remove Xen support for ia64") removed the Kconfig symbol XEN_XENCOMM. But it didn't remove the code depending on that symbol. Remove that code now. Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Acked-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2014-01-06xen/events: move drivers/xen/events.c into drivers/xen/events/David Vrabel
events.c will be split into multiple files so move it into its own directory. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2013-07-29xen/arm: enable PV control for ARMJulien Grall
Enable lifecyle management (reboot, shutdown...) from the toolstack for ARM guests. Signed-off-by: Julien Grall <julien.grall@linaro.org> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2013-07-29xen/arm64: Don't compile cpu hotplugJulien Grall
On ARM64, when CONFIG_XEN=y, the compilation will fail because CPU hotplug is not yet supported with XEN. For now, disable it. Signed-off-by: Julien Grall <julien.grall@linaro.org> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Mark Rutland <mark.rutland@arm.com>
2013-02-19xen/acpi: ACPI cpu hotplugLiu Jinsong
This patch implement real Xen ACPI cpu hotplug driver as module. When loaded, it replaces Xen stub driver. For booting existed cpus, the driver enumerates them. For hotadded cpus, which added at runtime and notify OS via device or container event, the driver is invoked to add them, parsing cpu information, hypercalling to Xen hypervisor to add them, and finally setting up new /sys interface for them. Signed-off-by: Liu Jinsong <jinsong.liu@intel.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-02-19xen/acpi: ACPI memory hotplugLiu Jinsong
This patch implements real Xen acpi memory hotplug driver as module. When loaded, it replaces Xen stub driver. When an acpi memory device hotadd event occurs, it notifies OS and invokes notification callback, adding related memory device and parsing memory information, finally hypercall to xen hypervisor to add memory. Signed-off-by: Liu Jinsong <jinsong.liu@intel.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-02-19xen/stub: driver for memory hotplugLiu Jinsong
This patch create a file (xen-stub.c) for Xen stub drivers. Xen stub drivers are used to reserve space for Xen drivers, i.e. memory hotplug and cpu hotplug, and to block native drivers loaded, so that real Xen drivers can be modular and loaded on demand. This patch is specific for Xen memory hotplug (other Xen logic can add stub drivers on their own). The xen stub driver will occupied earlier via subsys_initcall (than native memory hotplug driver via module_init and so blocking native). Later real Xen memory hotplug logic will unregister the stub driver and register itself to take effect on demand. Signed-off-by: Liu Jinsong <jinsong.liu@intel.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-12-13Merge tag 'stable/for-linus-3.8-rc0-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen Pull Xen updates from Konrad Rzeszutek Wilk: - Add necessary infrastructure to make balloon driver work under ARM. - Add /dev/xen/privcmd interfaces to work with ARM and PVH. - Improve Xen PCIBack wild-card parsing. - Add Xen ACPI PAD (Processor Aggregator) support - so can offline/ online sockets depending on the power consumption. - PVHVM + kexec = use an E820_RESV region for the shared region so we don't overwrite said region during kexec reboot. - Cleanups, compile fixes. Fix up some trivial conflicts due to the balloon driver now working on ARM, and there were changes next to the previous work-arounds that are now gone. * tag 'stable/for-linus-3.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: xen/PVonHVM: fix compile warning in init_hvm_pv_info xen: arm: implement remap interfaces needed for privcmd mappings. xen: correctly use xen_pfn_t in remap_domain_mfn_range. xen: arm: enable balloon driver xen: balloon: allow PVMMU interfaces to be compiled out xen: privcmd: support autotranslated physmap guests. xen: add pages parameter to xen_remap_domain_mfn_range xen/acpi: Move the xen_running_on_version_or_later function. xen/xenbus: Remove duplicate inclusion of asm/xen/hypervisor.h xen/acpi: Fix compile error by missing decleration for xen_domain. xen/acpi: revert pad config check in xen_check_mwait xen/acpi: ACPI PAD driver xen-pciback: reject out of range inputs xen-pciback: simplify and tighten parsing of device IDs xen PVonHVM: use E820_Reserved area for shared_info
2012-11-30Merge branch 'arm-privcmd-for-3.8' of ↵Konrad Rzeszutek Wilk
git://xenbits.xen.org/people/ianc/linux into stable/for-linus-3.8 * 'arm-privcmd-for-3.8' of git://xenbits.xen.org/people/ianc/linux: xen: arm: implement remap interfaces needed for privcmd mappings. xen: correctly use xen_pfn_t in remap_domain_mfn_range. xen: arm: enable balloon driver xen: balloon: allow PVMMU interfaces to be compiled out xen: privcmd: support autotranslated physmap guests. xen: add pages parameter to xen_remap_domain_mfn_range Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-11-29xen: arm: enable balloon driverIan Campbell
The code is now in a state where can just enable it. Drop the *_xenballloned_pages duplicates since these are now supplied by the balloon code. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-11-26xen/acpi: ACPI PAD driverLiu, Jinsong
PAD is acpi Processor Aggregator Device which provides a control point that enables the platform to perform specific processor configuration and control that applies to all processors in the platform. This patch is to implement Xen acpi pad logic. When running under Xen virt platform, native pad driver would not work. Instead Xen pad driver, a self-contained and thin logic level, would take over acpi pad logic. When acpi pad notify OSPM, xen pad logic intercept and parse _PUR object to get the expected idle cpu number, and then hypercall to hypervisor. Xen hypervisor would then do the rest work, say, core parking, to idle specific number of cpus on its own policy. Signed-off-by: Jan Beulich <JBeulich@suse.com> Signed-off-by: Liu Jinsong <jinsong.liu@intel.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-11-07xen/generic: Disable fallback build on ARM.Konrad Rzeszutek Wilk
As there is no need for it (the fallback code is for older hypervisors and they only run under x86), and also b/c we get: drivers/xen/fallback.c: In function 'xen_event_channel_op_compat': drivers/xen/fallback.c:10:19: error: storage size of 'op' isn't known drivers/xen/fallback.c:15:2: error: implicit declaration of function '_hypercall1' [-Werror=implicit-function-declaration] drivers/xen/fallback.c:15:19: error: expected expression before 'int' drivers/xen/fallback.c:18:7: error: 'EVTCHNOP_close' undeclared (first use in this function) drivers/xen/fallback.c:18:7: note: each undeclared identifier is reported only once for each function it appears in .. and more [v1: Moved the enablement to be covered by CONFIG_X86 per Ian's suggestion] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-11-04xen/hypercall: fix hypercall fallback code for very old hypervisorsJan Beulich
While copying the argument structures in HYPERVISOR_event_channel_op() and HYPERVISOR_physdev_op() into the local variable is sufficiently safe even if the actual structure is smaller than the container one, copying back eventual output values the same way isn't: This may collide with on-stack variables (particularly "rc") which may change between the first and second memcpy() (i.e. the second memcpy() could discard that change). Move the fallback code into out-of-line functions, and handle all of the operations known by this old a hypervisor individually: Some don't require copying back anything at all, and for the rest use the individual argument structures' sizes rather than the container's. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> [v2: Reduce #define/#undef usage in HYPERVISOR_physdev_op_compat().] [v3: Fix compile errors when modules use said hypercalls] [v4: Add xen_ prefix to the HYPERCALL_..] [v5: Alter the name and only EXPORT_SYMBOL_GPL one of them] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-10-07Merge tag 'stable/for-linus-3.7-arm-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen Pull ADM Xen support from Konrad Rzeszutek Wilk: Features: * Allow a Linux guest to boot as initial domain and as normal guests on Xen on ARM (specifically ARMv7 with virtualized extensions). PV console, block and network frontend/backends are working. Bug-fixes: * Fix compile linux-next fallout. * Fix PVHVM bootup crashing. The Xen-unstable hypervisor (so will be 4.3 in a ~6 months), supports ARMv7 platforms. The goal in implementing this architecture is to exploit the hardware as much as possible. That means use as little as possible of PV operations (so no PV MMU) - and use existing PV drivers for I/Os (network, block, console, etc). This is similar to how PVHVM guests operate in X86 platform nowadays - except that on ARM there is no need for QEMU. The end result is that we share a lot of the generic Xen drivers and infrastructure. Details on how to compile/boot/etc are available at this Wiki: http://wiki.xen.org/wiki/Xen_ARMv7_with_Virtualization_Extensions and this blog has links to a technical discussion/presentations on the overall architecture: http://blog.xen.org/index.php/2012/09/21/xensummit-sessions-new-pvh-virtualisation-mode-for-arm-cortex-a15arm-servers-and-x86/ * tag 'stable/for-linus-3.7-arm-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: (21 commits) xen/xen_initial_domain: check that xen_start_info is initialized xen: mark xen_init_IRQ __init xen/Makefile: fix dom-y build arm: introduce a DTS for Xen unprivileged virtual machines MAINTAINERS: add myself as Xen ARM maintainer xen/arm: compile netback xen/arm: compile blkfront and blkback xen/arm: implement alloc/free_xenballooned_pages with alloc_pages/kfree xen/arm: receive Xen events on ARM xen/arm: initialize grant_table on ARM xen/arm: get privilege status xen/arm: introduce CONFIG_XEN on ARM xen: do not compile manage, balloon, pci, acpi, pcpu and cpu_hotplug on ARM xen/arm: Introduce xen_ulong_t for unsigned long xen/arm: Xen detection and shared_info page mapping docs: Xen ARM DT bindings xen/arm: empty implementation of grant_table arch specific functions xen/arm: sync_bitops xen/arm: page.h definitions xen/arm: hypercalls ...
2012-10-02xen/Makefile: fix dom-y buildStefano Stabellini
We need to add $(dom0-y) to obj-$(CONFIG_XEN_DOM0) after dom0-y is defined otherwise we end up adding nothing. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-09-18USB EHCI/Xen: propagate controller reset information to hypervisorJan Beulich
Just like for the in-tree early console debug port driver, the hypervisor - when using a debug port based console - also needs to be told about controller resets, so it can suppress using and then re-initialize the debug port accordingly. Other than the in-tree driver, the hypervisor driver actually cares about doing this only for the device where the debug is port actually in use, i.e. it needs to be told the coordinates of the device being reset (quite obviously, leveraging the addition done for that would likely benefit the in-tree driver too). Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-13xen: do not compile manage, balloon, pci, acpi, pcpu and cpu_hotplug on ARMStefano Stabellini
Changes in v4: - compile pcpu only on x86; - use "+=" instead of ":=" for dom0- targets. Changes in v2: - make pci.o depend on CONFIG_PCI and acpi.o depend on CONFIG_ACPI. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-07-19xen/pcpu: Xen physical cpus online/offline sys interfaceLiu, Jinsong
This patch provide Xen physical cpus online/offline sys interface. User can use it for their own purpose, like power saving: by offlining some cpus when light workload it save power greatly. Its basic workflow is, user online/offline cpu via sys interface, then hypercall xen to implement, after done xen inject virq back to dom0, and then dom0 sync cpu status. Signed-off-by: Jiang, Yunhong <yunhong.jiang@intel.com> Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-07-19xen/mce: Add mcelog support for Xen platformLiu, Jinsong
When MCA error occurs, it would be handled by Xen hypervisor first, and then the error information would be sent to initial domain for logging. This patch gets error information from Xen hypervisor and convert Xen format error into Linux format mcelog. This logic is basically self-contained, not touching other kernel components. By using tools like mcelog tool users could read specific error information, like what they did under native Linux. To test follow directions outlined in Documentation/acpi/apei/einj.txt Acked-and-tested-by: Borislav Petkov <borislav.petkov@amd.com> Signed-off-by: Ke, Liping <liping.ke@intel.com> Signed-off-by: Jiang, Yunhong <yunhong.jiang@intel.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-05-07xen/acpi/sleep: Enable ACPI sleep via the __acpi_os_prepare_sleepKonrad Rzeszutek Wilk
Provide the registration callback to call in the Xen's ACPI sleep functionality. This means that during S3/S5 we make a hypercall XENPF_enter_acpi_sleep with the proper PM1A/PM1B registers. Based of Ke Yu's <ke.yu@intel.com> initial idea. [ From http://xenbits.xensource.com/linux-2.6.18-xen.hg change c68699484a65 ] [v1: Added Copyright and license] [v2: Added check if PM1A/B the 16-bits MSB contain something. The spec only uses 16-bits but might have more in future] Signed-off-by: Liang Tang <liang.tang@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-03-14xen/acpi-processor: C and P-state driver that uploads said data to hypervisor.Konrad Rzeszutek Wilk
This driver solves three problems: 1). Parse and upload ACPI0007 (or PROCESSOR_TYPE) information to the hypervisor - aka P-states (cpufreq data). 2). Upload the the Cx state information (cpuidle data). 3). Inhibit CPU frequency scaling drivers from loading. The reason for wanting to solve 1) and 2) is such that the Xen hypervisor is the only one that knows the CPU usage of different guests and can make the proper decision of when to put CPUs and packages in proper states. Unfortunately the hypervisor has no support to parse ACPI DSDT tables, hence it needs help from the initial domain to provide this information. The reason for 3) is that we do not want the initial domain to change P-states while the hypervisor is doing it as well - it causes rather some funny cases of P-states transitions. For this to work, the driver parses the Power Management data and uploads said information to the Xen hypervisor. It also calls acpi_processor_notify_smm() to inhibit the other CPU frequency scaling drivers from being loaded. Everything revolves around the 'struct acpi_processor' structure which gets updated during the bootup cycle in different stages. At the startup, when the ACPI parser starts, the C-state information is processed (processor_idle) and saved in said structure as 'power' element. Later on, the CPU frequency scaling driver (powernow-k8 or acpi_cpufreq), would call the the acpi_processor_* (processor_perflib functions) to parse P-states information and populate in the said structure the 'performance' element. Since we do not want the CPU frequency scaling drivers from loading we have to call the acpi_processor_* functions to parse the P-states and call "acpi_processor_notify_smm" to stop them from loading. There is also one oddity in this driver which is that under Xen, the physical online CPU count can be different from the virtual online CPU count. Meaning that the macros 'for_[online|possible]_cpu' would process only up to virtual online CPU count. We on the other hand want to process the full amount of physical CPUs. For that, the driver checks if the ACPI IDs count is different from the APIC ID count - which can happen if the user choose to use dom0_max_vcpu argument. In such a case a backup of the PM structure is used and uploaded to the hypervisor. [v1-v2: Initial RFC implementations that were posted] [v3: Changed the name to passthru suggested by Pasi Kärkkäinen <pasik@iki.fi>] [v4: Added vCPU != pCPU support - aka dom0_max_vcpus support] [v5: Cleaned up the driver, fix bug under Athlon XP] [v6: Changed the driver to a CPU frequency governor] [v7: Jan Beulich <jbeulich@suse.com> suggestion to make it a cpufreq scaling driver made me rework it as driver that inhibits cpufreq scaling driver] [v8: Per Jan's review comments, fixed up the driver] [v9: Allow to continue even if acpi_processor_preregister_perf.. fails] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-12-16xen: Add privcmd device driverBastian Blank
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>
2011-09-29xen: remove XEN_PLATFORM_PCI config optionStefano Stabellini
Xen PVHVM needs xen-platform-pci, on the other hand xen-platform-pci is useless in any other cases. Therefore remove the XEN_PLATFORM_PCI config option and compile xen-platform-pci built-in if XEN_PVHVM is selected. Changes to v1: - remove xen-platform-pci.o and just use platform-pci.o since it is not externally visible anymore. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-07-20Merge branch 'stable/xen-pciback-0.6.3' into stable/driversKonrad Rzeszutek Wilk
* stable/xen-pciback-0.6.3: xen/pciback: Have 'passthrough' option instead of XEN_PCIDEV_BACKEND_PASS and XEN_PCIDEV_BACKEND_VPCI xen/pciback: Remove the DEBUG option. xen/pciback: Drop two backends, squash and cleanup some code. xen/pciback: Print out the MSI/MSI-X (PIRQ) values xen/pciback: Don't setup an fake IRQ handler for SR-IOV devices. xen: rename pciback module to xen-pciback. xen/pciback: Fine-grain the spinlocks and fix BUG: scheduling while atomic cases. xen/pciback: Allocate IRQ handler for device that is shared with guest. xen/pciback: Disable MSI/MSI-X when reseting a device xen/pciback: guest SR-IOV support for PV guest xen/pciback: Register the owner (domain) of the PCI device. xen/pciback: Cleanup the driver based on checkpatch warnings and errors. xen/pciback: xen pci backend driver. Conflicts: drivers/xen/Kconfig
2011-07-19xen/pciback: xen pci backend driver.Konrad Rzeszutek Wilk
This is the host side counterpart to the frontend driver in drivers/pci/xen-pcifront.c. The PV protocol is also implemented by frontend drivers in other OSes too, such as the BSDs. The PV protocol is rather simple. There is page shared with the guest, which has the 'struct xen_pci_sharedinfo' embossed in it. The backend has a thread that is kicked every-time the structure is changed and based on the operation field it performs specific tasks: XEN_PCI_OP_conf_[read|write]: Read/Write 0xCF8/0xCFC filtered data. (conf_space*.c) Based on which field is probed, we either enable/disable the PCI device, change power state, read VPD, etc. The major goal of this call is to provide a Physical IRQ (PIRQ) to the guest. The PIRQ is Xen hypervisor global IRQ value irrespective of the IRQ is tied in to the IO-APIC, or is a vector. For GSI type interrupts, the PIRQ==GSI holds. For MSI/MSI-X the PIRQ value != Linux IRQ number (thought PIRQ==vector). Please note, that with Xen, all interrupts (except those level shared ones) are injected directly to the guest - there is no host interaction. XEN_PCI_OP_[enable|disable]_msi[|x] (pciback_ops.c) Enables/disables the MSI/MSI-X capability of the device. These operations setup the MSI/MSI-X vectors for the guest and pass them to the frontend. When the device is activated, the interrupts are directly injected in the guest without involving the host. XEN_PCI_OP_aer_[detected|resume|mmio|slotreset]: In case of failure, perform the appropriate AER commands on the guest. Right now that is a cop-out - we just kill the guest. Besides implementing those commands, it can also - hide a PCI device from the host. When booting up, the user can specify xen-pciback.hide=(1:0:0)(BDF..) so that host does not try to use the device. The driver was lifted from linux-2.6.18.hg tree and fixed up so that it could compile under v3.0. Per suggestion from Jesse Barnes moved the driver to drivers/xen/xen-pciback. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2011-07-08Merge branch 'xen-tmem-selfballoon-v8' of ↵Konrad Rzeszutek Wilk
git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem into stable/drivers * 'xen-tmem-selfballoon-v8' of git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem: xen: tmem: self-ballooning and frontswap-selfshrinking
2011-07-08xen: tmem: self-ballooning and frontswap-selfshrinkingDan Magenheimer
This patch introduces two in-kernel drivers for Xen transcendent memory ("tmem") functionality that complement cleancache and frontswap. Both use control theory to dynamically adjust and optimize memory utilization. Selfballooning controls the in-kernel Xen balloon driver, targeting a goal value (vm_committed_as), thus pushing less frequently used clean page cache pages (through the cleancache code) into Xen tmem where Xen can balance needs across all VMs residing on the physical machine. Frontswap-selfshrinking controls the number of pages in frontswap, driving it towards zero (effectively doing a partial swapoff) when in-kernel memory pressure subsides, freeing up RAM for other VMs. More detail is provided in the header comment of xen-selfballooning.c. Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> [v8: konrad.wilk@oracle.com: set default enablement depending on frontswap] [v7: konrad.wilk@oracle.com: fix capitalization and punctuation in comments] [v6: fix frontswap-selfshrinking initialization] [v6: konrad.wilk@oracle.com: fix init pr_infos; add comments about swap] [v5: konrad.wilk@oracle.com: add NULL to attr list; move inits up to decls] [v4: dkiper@net-space.pl: use strict_strtoul plus a few syntactic nits] [v3: konrad.wilk@oracle.com: fix potential divides-by-zero] [v3: konrad.wilk@oracle.com: add many more comments, fix nits] [v2: rebased to linux-3.0-rc1] [v2: Ian.Campbell@citrix.com: reorganize as new file (xen-selfballoon.c)] [v2: dkiper@net-space.pl: proper access to vm_committed_as] [v2: dkiper@net-space.pl: accounting fixes] Cc: Jan Beulich <JBeulich@novell.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: <xen-devel@lists.xensource.com>
2011-06-17xen: prepare tmem shim to handle frontswapDan Magenheimer
Provide the shim code for frontswap for Xen tmem even if the frontswap patchset is not present yet. (The egg is before the chicken.) Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Reviewed-by: Konrad Wilk <konrad.wilk@oracle.com>