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2020-07-24entry: Provide infrastructure for work before transitioning to guest modeThomas Gleixner
Entering a guest is similar to exiting to user space. Pending work like handling signals, rescheduling, task work etc. needs to be handled before that. Provide generic infrastructure to avoid duplication of the same handling code all over the place. The transfer to guest mode handling is different from the exit to usermode handling, e.g. vs. rseq and live patching, so a separate function is used. The initial list of work items handled is: TIF_SIGPENDING, TIF_NEED_RESCHED, TIF_NOTIFY_RESUME Architecture specific TIF flags can be added via defines in the architecture specific include files. The calling convention is also different from the syscall/interrupt entry functions as KVM invokes this from the outer vcpu_run() loop with interrupts and preemption enabled. To prevent missing a pending work item it invokes a check for pending TIF work from interrupt disabled code right before transitioning to guest mode. The lockdep, RCU and tracing state handling is also done directly around the switch to and from guest mode. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200722220519.833296398@linutronix.de
2019-04-26KVM: polling: add architecture backend to disable pollingChristian Borntraeger
There are cases where halt polling is unwanted. For example when running KVM on an over committed LPAR we rather want to give back the CPU to neighbour LPARs instead of polling. Let us provide a callback that allows architectures to disable polling. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2018-06-21KVM: arm64: Prevent KVM_COMPAT from being selectedMarc Zyngier
There is very little point in trying to support the 32bit KVM/arm API on arm64, and this was never an anticipated use case. Let's make it clear by not selecting KVM_COMPAT. Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-05-25KVM: arm/arm64: Introduce kvm_arch_vcpu_run_pid_changeChristoffer Dall
KVM/ARM differs from other architectures in having to maintain an additional virtual address space from that of the host and the guest, because we split the execution of KVM across both EL1 and EL2. This results in a need to explicitly map data structures into EL2 (hyp) which are accessed from the hyp code. As we are about to be more clever with our FPSIMD handling on arm64, which stores data in the task struct and uses thread_info flags, we will have to map parts of the currently executing task struct into the EL2 virtual address space. However, we don't want to do this on every KVM_RUN, because it is a fairly expensive operation to walk the page tables, and the common execution mode is to map a single thread to a VCPU. By introducing a hook that architectures can select with HAVE_KVM_VCPU_RUN_PID_CHANGE, we do not introduce overhead for other architectures, but have a simple way to only map the data we need when required for arm64. This patch introduces the framework only, and wires it up in the arm/arm64 KVM common code. No functional change. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-12-14KVM: introduce kvm_arch_vcpu_async_ioctlPaolo Bonzini
After the vcpu_load/vcpu_put pushdown, the handling of asynchronous VCPU ioctl is already much clearer in that it is obvious that they bypass vcpu_load and vcpu_put. However, it is still not perfect in that the different state of the VCPU mutex is still hidden in the caller. Separate those ioctls into a new function kvm_arch_vcpu_async_ioctl that returns -ENOIOCTLCMD for more "traditional" synchronous ioctls. Cc: James Hogan <jhogan@kernel.org> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Suggested-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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>
2016-06-16KVM: remove kvm_vcpu_compatiblePaolo Bonzini
The new created_vcpus field makes it possible to avoid the race between irqchip and VCPU creation in a much nicer way; just check under kvm->lock whether a VCPU has already been created. We can then remove KVM_APIC_ARCHITECTURE too, because at this point the symbol is only governing the default definition of kvm_vcpu_compatible. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-13KVM: halt_polling: provide a way to qualify wakeups during pollChristian Borntraeger
Some wakeups should not be considered a sucessful poll. For example on s390 I/O interrupts are usually floating, which means that _ALL_ CPUs would be considered runnable - letting all vCPUs poll all the time for transactional like workload, even if one vCPU would be enough. This can result in huge CPU usage for large guests. This patch lets architectures provide a way to qualify wakeups if they should be considered a good/bad wakeups in regard to polls. For s390 the implementation will fence of halt polling for anything but known good, single vCPU events. The s390 implementation for floating interrupts does a wakeup for one vCPU, but the interrupt will be delivered by whatever CPU checks first for a pending interrupt. We prefer the woken up CPU by marking the poll of this CPU as "good" poll. This code will also mark several other wakeup reasons like IPI or expired timers as "good". This will of course also mark some events as not sucessful. As KVM on z runs always as a 2nd level hypervisor, we prefer to not poll, unless we are really sure, though. This patch successfully limits the CPU usage for cases like uperf 1byte transactional ping pong workload or wakeup heavy workload like OLTP while still providing a proper speedup. This also introduced a new vcpu stat "halt_poll_no_tuning" that marks wakeups that are considered not good for polling. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Radim Krčmář <rkrcmar@redhat.com> (for an earlier version) Cc: David Matlack <dmatlack@google.com> Cc: Wanpeng Li <kernellwp@gmail.com> [Rename config symbol. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: don't pointlessly leave KVM_COMPAT=y in non-KVM configsJan Beulich
The symbol was missing a KVM dependency. Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-01KVM: introduce kvm_arch functions for IRQ bypassEric Auger
This patch introduces - kvm_arch_irq_bypass_add_producer - kvm_arch_irq_bypass_del_producer - kvm_arch_irq_bypass_stop - kvm_arch_irq_bypass_start They make possible to specialize the KVM IRQ bypass consumer in case CONFIG_KVM_HAVE_IRQ_BYPASS is set. Signed-off-by: Eric Auger <eric.auger@linaro.org> [Add weak implementations of the callbacks. - Feng] Signed-off-by: Feng Wu <feng.wu@intel.com> Reviewed-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-09KVM: Disable compat ioctl for s390Christian Borntraeger
We never had a 31bit QEMU/kuli running. We would need to review several ioctls to check if this creates holes, bugs or whatever to make it work. Lets just disable compat support for KVM on s390. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-23KVM: Remove unused config symbolChristoffer Dall
The dirty patch logging series introduced both HAVE_KVM_ARCH_DIRTY_LOG_PROTECT and KVM_GENERIC_DIRTYLOG_READ_PROTECT config symbols, but only KVM_GENERIC_DIRTYLOG_READ_PROTECT is used. Just remove the unused one. (The config symbol was renamed during the development of the patch series and the old name just creeped in by accident.() Reported-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-01-16KVM: Add generic support for dirty page loggingMario Smarduch
kvm_get_dirty_log() provides generic handling of dirty bitmap, currently reused by several architectures. Building on that we intrdoduce kvm_get_dirty_log_protect() adding write protection to mark these pages dirty for future write access, before next KVM_GET_DIRTY_LOG ioctl call from user space. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
2015-01-16KVM: Add architecture-defined TLB flush supportMario Smarduch
Allow architectures to override the generic kvm_flush_remote_tlbs() function via HAVE_KVM_ARCH_TLB_FLUSH_ALL. ARMv7 will need this to provide its own TLB flush interface. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
2014-08-05KVM: Give IRQFD its own separate enabling Kconfig optionPaul Mackerras
Currently, the IRQFD code is conditional on CONFIG_HAVE_KVM_IRQ_ROUTING. So that we can have the IRQFD code compiled in without having the IRQ routing code, this creates a new CONFIG_HAVE_KVM_IRQFD, makes the IRQFD code conditional on it instead of CONFIG_HAVE_KVM_IRQ_ROUTING, and makes all the platforms that currently select HAVE_KVM_IRQ_ROUTING also select HAVE_KVM_IRQFD. Signed-off-by: Paul Mackerras <paulus@samba.org> Tested-by: Eric Auger <eric.auger@linaro.org> Tested-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-01-30KVM: async_pf: Provide additional direct page notificationDominik Dingel
By setting a Kconfig option, the architecture can control when guest notifications will be presented by the apf backend. There is the default batch mechanism, working as before, where the vcpu thread should pull in this information. Opposite to this, there is now the direct mechanism, that will push the information to the guest. This way s390 can use an already existing architecture interface. Still the vcpu thread should call check_completion to cleanup leftovers. Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2013-10-30kvm: Add VFIO deviceAlex Williamson
So far we've succeeded at making KVM and VFIO mostly unaware of each other, but areas are cropping up where a connection beyond eventfds and irqfds needs to be made. This patch introduces a KVM-VFIO device that is meant to be a gateway for such interaction. The user creates the device and can add and remove VFIO groups to it via file descriptors. When a group is added, KVM verifies the group is valid and gets a reference to it via the VFIO external user interface. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-04-26KVM: Introduce CONFIG_HAVE_KVM_IRQ_ROUTINGAlexander Graf
Quite a bit of code in KVM has been conditionalized on availability of IOAPIC emulation. However, most of it is generically applicable to platforms that don't have an IOPIC, but a different type of irq chip. Make code that only relies on IRQ routing, not an APIC itself, on CONFIG_HAVE_KVM_IRQ_ROUTING, so that we can reuse it later. Signed-off-by: Alexander Graf <agraf@suse.de> Acked-by: Michael S. Tsirkin <mst@redhat.com>
2012-07-23KVM: Add config to support ple or cpu relax optimzationRaghavendra K T
Suggested-by: Avi Kivity <avi@redhat.com> Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> # on s390x Signed-off-by: Avi Kivity <avi@redhat.com>
2012-04-24KVM: Introduce direct MSI message injection for in-kernel irqchipsJan Kiszka
Currently, MSI messages can only be injected to in-kernel irqchips by defining a corresponding IRQ route for each message. This is not only unhandy if the MSI messages are generated "on the fly" by user space, IRQ routes are a limited resource that user space has to manage carefully. By providing a direct injection path, we can both avoid using up limited resources and simplify the necessary steps for user land. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-01-12KVM: Halt vcpu if page it tries to access is swapped outGleb Natapov
If a guest accesses swapped out memory do not swap it in from vcpu thread context. Schedule work to do swapping and put vcpu into halted state instead. Interrupts will still be delivered to the guest and if interrupt will cause reschedule guest will continue to run another task. [avi: remove call to get_user_pages_noio(), nacked by Linus; this makes everything synchrnous again] Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-03-01KVM: Add KVM_MMIO kconfig itemAvi Kivity
s390 doesn't have mmio, this will simplify ifdefing it out. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Break dependency between vcpu index in vcpus array and vcpu_id.Gleb Natapov
Archs are free to use vcpu_id as they see fit. For x86 it is used as vcpu's apic id. New ioctl is added to configure boot vcpu id that was assumed to be 0 till now. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: irqfdGregory Haskins
KVM provides a complete virtual system environment for guests, including support for injecting interrupts modeled after the real exception/interrupt facilities present on the native platform (such as the IDT on x86). Virtual interrupts can come from a variety of sources (emulated devices, pass-through devices, etc) but all must be injected to the guest via the KVM infrastructure. This patch adds a new mechanism to inject a specific interrupt to a guest using a decoupled eventfd mechnanism: Any legal signal on the irqfd (using eventfd semantics from either userspace or kernel) will translate into an injected interrupt in the guest at the next available interrupt window. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Move common KVM Kconfig items to new file virt/kvm/KconfigAvi Kivity
Reduce Kconfig code duplication. Signed-off-by: Avi Kivity <avi@redhat.com>