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2022-11-07KVM: s390: pv: don't allow userspace to set the clock under PVNico Boehr1-0/+3
When running under PV, the guest's TOD clock is under control of the ultravisor and the hypervisor isn't allowed to change it. Hence, don't allow userspace to change the guest's TOD clock by returning -EOPNOTSUPP. When userspace changes the guest's TOD clock, KVM updates its kvm.arch.epoch field and, in addition, the epoch field in all state descriptions of all VCPUs. But, under PV, the ultravisor will ignore the epoch field in the state description and simply overwrite it on next SIE exit with the actual guest epoch. This leads to KVM having an incorrect view of the guest's TOD clock: it has updated its internal kvm.arch.epoch field, but the ultravisor ignores the field in the state description. Whenever a guest is now waiting for a clock comparator, KVM will incorrectly calculate the time when the guest should wake up, possibly causing the guest to sleep for much longer than expected. With this change, kvm_s390_set_tod() will now take the kvm->lock to be able to call kvm_s390_pv_is_protected(). Since kvm_s390_set_tod_clock() also takes kvm->lock, use __kvm_s390_set_tod_clock() instead. The function kvm_s390_set_tod_clock is now unused, hence remove it. Update the documentation to indicate the TOD clock attr calls can now return -EOPNOTSUPP. Fixes: 0f3035047140 ("KVM: s390: protvirt: Do only reset registers that are accessible") Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com> Signed-off-by: Nico Boehr <nrb@linux.ibm.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> Link: https://lore.kernel.org/r/20221011160712.928239-2-nrb@linux.ibm.com Message-Id: <20221011160712.928239-2-nrb@linux.ibm.com> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
2022-03-09Merge branch kvm-arm64/misc-5.18 into kvmarm-master/nextMarc Zyngier1-1/+1
* kvm-arm64/misc-5.18: : . : Misc fixes for KVM/arm64 5.18: : : - Drop unused kvm parameter to kvm_psci_version() : : - Implement CONFIG_DEBUG_LIST at EL2 : : - Make CONFIG_ARM64_ERRATUM_2077057 default y : : - Only do the interrupt dance if we have exited because of an interrupt : : - Remove traces of 32bit ARM host support from the documentation : . Documentation: KVM: Update documentation to indicate KVM is arm64-only KVM: arm64: Only open the interrupt window on exit due to an interrupt KVM: arm64: Enable Cortex-A510 erratum 2077057 by default Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-03-09Documentation: KVM: Update documentation to indicate KVM is arm64-onlyOliver Upton1-1/+1
KVM support for 32-bit ARM hosts (KVM/arm) has been removed from the kernel since commit 541ad0150ca4 ("arm: Remove 32bit KVM host support"). There still exists some remnants of the old architecture in the KVM documentation. Remove all traces of 32-bit host support from the documentation. Note that AArch32 guests are still supported. Suggested-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Oliver Upton <oupton@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220308172856.2997250-1-oupton@google.com
2022-02-08KVM: arm64: Refuse to run VCPU if the PMU doesn't match the physical CPUAlexandru Elisei1-1/+5
Userspace can assign a PMU to a VCPU with the KVM_ARM_VCPU_PMU_V3_SET_PMU device ioctl. If the VCPU is scheduled on a physical CPU which has a different PMU, the perf events needed to emulate a guest PMU won't be scheduled in and the guest performance counters will stop counting. Treat it as an userspace error and refuse to run the VCPU in this situation. Suggested-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-7-alexandru.elisei@arm.com
2022-02-08KVM: arm64: Add KVM_ARM_VCPU_PMU_V3_SET_PMU attributeAlexandru Elisei1-0/+28
When KVM creates an event and there are more than one PMUs present on the system, perf_init_event() will go through the list of available PMUs and will choose the first one that can create the event. The order of the PMUs in this list depends on the probe order, which can change under various circumstances, for example if the order of the PMU nodes change in the DTB or if asynchronous driver probing is enabled on the kernel command line (with the driver_async_probe=armv8-pmu option). Another consequence of this approach is that on heteregeneous systems all virtual machines that KVM creates will use the same PMU. This might cause unexpected behaviour for userspace: when a VCPU is executing on the physical CPU that uses this default PMU, PMU events in the guest work correctly; but when the same VCPU executes on another CPU, PMU events in the guest will suddenly stop counting. Fortunately, perf core allows user to specify on which PMU to create an event by using the perf_event_attr->type field, which is used by perf_init_event() as an index in the radix tree of available PMUs. Add the KVM_ARM_VCPU_PMU_V3_CTRL(KVM_ARM_VCPU_PMU_V3_SET_PMU) VCPU attribute to allow userspace to specify the arm_pmu that KVM will use when creating events for that VCPU. KVM will make no attempt to run the VCPU on the physical CPUs that share the PMU, leaving it up to userspace to manage the VCPU threads' affinity accordingly. To ensure that KVM doesn't expose an asymmetric system to the guest, the PMU set for one VCPU will be used by all other VCPUs. Once a VCPU has run, the PMU cannot be changed in order to avoid changing the list of available events for a VCPU, or to change the semantics of existing events. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-6-alexandru.elisei@arm.com
2022-02-08KVM: arm64: Do not change the PMU event filter after a VCPU has runMarc Zyngier1-1/+1
Userspace can specify which events a guest is allowed to use with the KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be identified by a guest from reading the PMCEID{0,1}_EL0 registers. Changing the PMU event filter after a VCPU has run can cause reads of the registers performed before the filter is changed to return different values than reads performed with the new event filter in place. The architecture defines the two registers as read-only, and this behaviour contradicts that. Keep track when the first VCPU has run and deny changes to the PMU event filter to prevent this from happening. Signed-off-by: Marc Zyngier <maz@kernel.org> [ Alexandru E: Added commit message, updated ioctl documentation ] Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
2021-10-18selftests: KVM: Introduce system counter offset testOliver Upton1-14/+27
Introduce a KVM selftest to verify that userspace manipulation of the TSC (via the new vCPU attribute) results in the correct behavior within the guest. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Oliver Upton <oupton@google.com> Message-Id: <20210916181555.973085-6-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-10-18KVM: x86: Expose TSC offset controls to userspaceOliver Upton1-0/+57
To date, VMM-directed TSC synchronization and migration has been a bit messy. KVM has some baked-in heuristics around TSC writes to infer if the VMM is attempting to synchronize. This is problematic, as it depends on host userspace writing to the guest's TSC within 1 second of the last write. A much cleaner approach to configuring the guest's views of the TSC is to simply migrate the TSC offset for every vCPU. Offsets are idempotent, and thus not subject to change depending on when the VMM actually reads/writes values from/to KVM. The VMM can then read the TSC once with KVM_GET_CLOCK to capture a (realtime, host_tsc) pair at the instant when the guest is paused. Cc: David Matlack <dmatlack@google.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Oliver Upton <oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20210916181538.968978-8-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-30kvm: rename KVM_MAX_VCPU_ID to KVM_MAX_VCPU_IDSJuergen Gross2-2/+2
KVM_MAX_VCPU_ID is not specifying the highest allowed vcpu-id, but the number of allowed vcpu-ids. This has already led to confusion, so rename KVM_MAX_VCPU_ID to KVM_MAX_VCPU_IDS to make its semantics more clear Suggested-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20210913135745.13944-3-jgross@suse.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-04-13Merge branch 'kvm-arm64/vlpi-save-restore' into kvmarm-master/nextMarc Zyngier1-1/+1
Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-04-06docs: kvm: devices/arm-vgic-v3: enhance KVM_DEV_ARM_VGIC_CTRL_INIT docEric Auger1-1/+1
kvm_arch_vcpu_precreate() returns -EBUSY if the vgic is already initialized. So let's document that KVM_DEV_ARM_VGIC_CTRL_INIT must be called after all vcpu creations. Signed-off-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210405163941.510258-6-eric.auger@redhat.com
2021-03-24KVM: arm64: GICv4.1: Give a chance to save VLPI stateShenming Lu1-1/+1
Before GICv4.1, we don't have direct access to the VLPI state. So we simply let it fail early when encountering any VLPI in saving. But now we don't have to return -EACCES directly if on GICv4.1. Let’s change the hard code and give a chance to save the VLPI state (and preserve the UAPI). Signed-off-by: Shenming Lu <lushenming@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210322060158.1584-7-lushenming@huawei.com
2020-10-02KVM: arm64: Fix some documentation build warningsMauro Carvalho Chehab1-13/+13
As warned with make htmldocs: .../Documentation/virt/kvm/devices/vcpu.rst:70: WARNING: Malformed table. Text in column margin in table line 2. ======= ====================================================== -ENODEV: PMUv3 not supported or GIC not initialized -ENXIO: PMUv3 not properly configured or in-kernel irqchip not configured as required prior to calling this attribute -EBUSY: PMUv3 already initialized -EINVAL: Invalid filter range ======= ====================================================== The ':' character for two lines are above the size of the column. Besides that, other tables at the file doesn't use ':', so just drop them. While here, also fix this warning also introduced at the same patch: .../Documentation/virt/kvm/devices/vcpu.rst:88: WARNING: Block quote ends without a blank line; unexpected unindent. By marking the C code as a literal block. Fixes: 8be86a5eec04 ("KVM: arm64: Document PMU filtering API") Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Link: https://lore.kernel.org/r/b5385dd0213f1f070667925bf7a807bf5270ba78.1601616399.git.mchehab+huawei@kernel.org
2020-09-29KVM: arm64: Match PMU error code descriptions with error conditionsAlexandru Elisei1-4/+5
Update the description of the PMU KVM_{GET, SET}_DEVICE_ATTR error codes to be a better match for the code that returns them. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Link: https://lore.kernel.org/r/20200924123731.268177-3-alexandru.elisei@arm.com
2020-09-29KVM: arm64: Add undocumented return values for PMU device control groupAlexandru Elisei1-0/+2
KVM_ARM_VCPU_PMU_V3_IRQ returns -EFAULT if get_user() fails when reading the interrupt number from kvm_device_attr.addr. KVM_ARM_VCPU_PMU_V3_INIT returns the error value from kvm_vgic_set_owner(). kvm_arm_pmu_v3_init() checks that the vgic has been initialized and the interrupt number is valid, but kvm_vgic_set_owner() can still return the error code -EEXIST if another device has already claimed the interrupt. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Andrew Jones <drjones@redhat.com> Link: https://lore.kernel.org/r/20200924123731.268177-2-alexandru.elisei@arm.com
2020-09-29KVM: arm64: Document PMU filtering APIMarc Zyngier1-0/+46
Add a small blurb describing how the event filtering API gets used. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2020-04-21docs: fix broken references to text filesMauro Carvalho Chehab1-1/+1
Several references got broken due to txt to ReST conversion. Several of them can be automatically fixed with: scripts/documentation-file-ref-check --fix Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> # hwtracing/coresight/Kconfig Reviewed-by: Paul E. McKenney <paulmck@kernel.org> # memory-barrier.txt Acked-by: Alex Shi <alex.shi@linux.alibaba.com> # translations/zh_CN Acked-by: Federico Vaga <federico.vaga@vaga.pv.it> # translations/it_IT Acked-by: Marc Zyngier <maz@kernel.org> # kvm/arm64 Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/6f919ddb83a33b5f2a63b6b5f0575737bb2b36aa.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-02-27KVM: s390/interrupt: do not pin adapter interrupt pagesUlrich Weigand1-9/+2
The adapter interrupt page containing the indicator bits is currently pinned. That means that a guest with many devices can pin a lot of memory pages in the host. This also complicates the reference tracking which is needed for memory management handling of protected virtual machines. It might also have some strange side effects for madvise MADV_DONTNEED and other things. We can simply try to get the userspace page set the bits and free the page. By storing the userspace address in the irq routing entry instead of the guest address we can actually avoid many lookups and list walks so that this variant is very likely not slower. If userspace messes around with the memory slots the worst thing that can happen is that we write to some other memory within that process. As we get the the page with FOLL_WRITE this can also not be used to write to shared read-only pages. Signed-off-by: Ulrich Weigand <Ulrich.Weigand@de.ibm.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> [borntraeger@de.ibm.com: patch simplification] Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2020-02-12docs: kvm: convert devices/xive.txt to ReSTMauro Carvalho Chehab2-55/+98
- Use title markups; - adjust indentation and add blank lines as needed; - adjust tables to match ReST accepted formats; - mark code blocks as such. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12docs: kvm: convert devices/xics.txt to ReSTMauro Carvalho Chehab2-6/+23
- Use title markups; - adjust indentation and add blank lines as needed; - adjust tables to match ReST accepted formats; - use :field: markups. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12docs: kvm: convert devices/vm.txt to ReSTMauro Carvalho Chehab2-80/+127
- Use title markups; - adjust indentation and add blank lines as needed; - use :field: markups; - Use cross-references; - mark code blocks as such. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12docs: kvm: convert devices/vfio.txt to ReSTMauro Carvalho Chehab2-10/+16
- Use standard title markup; - adjust lists; - mark code blocks as such. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12docs: kvm: convert devices/vcpu.txt to ReSTMauro Carvalho Chehab3-76/+115
- Use title markups; - adjust indentation and add blank lines as needed; - adjust tables to match ReST accepted formats; - use :field: markups; - mark code blocks as such. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12docs: kvm: convert devices/s390_flic.txt to ReSTMauro Carvalho Chehab2-30/+41
- Use standard markup for document title; - Adjust indentation and add blank lines as needed; - use the notes markup; - mark code blocks as such. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12docs: kvm: convert devices/mpic.txt to ReSTMauro Carvalho Chehab2-3/+9
This document is almost in ReST format. The only thing needed is to mark a list as such and to add an extra whitespace. Yet, let's also use the standard document title markup, as it makes easier if anyone wants later to add sessions to it. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12docs: kvm: convert devices/arm-vgit.txt to ReSTMauro Carvalho Chehab2-30/+60
- Use title markups; - change indent to match ReST syntax; - use proper table markups; - use literal block markups. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12docs: kvm: devices/arm-vgit-v3.txt to ReSTMauro Carvalho Chehab2-46/+87
- Use title markups; - change indent to match ReST syntax; - use proper table markups; - use literal block markups. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12docs: kvm: devices/arm-vgic-its.txt to ReST formatMauro Carvalho Chehab2-39/+77
- Fix document title to match ReST format - Convert the table to be properly recognized - use proper markups for literal blocks - Some indentation fixes to match ReST While here, add an index for kvm devices. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-21Merge tag 'kvmarm-5.5' of ↵Paolo Bonzini1-0/+14
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm updates for Linux 5.5: - Allow non-ISV data aborts to be reported to userspace - Allow injection of data aborts from userspace - Expose stolen time to guests - GICv4 performance improvements - vgic ITS emulation fixes - Simplify FWB handling - Enable halt pool counters - Make the emulated timer PREEMPT_RT compliant Conflicts: include/uapi/linux/kvm.h
2019-10-22KVM: PPC: Book3S HV: XIVE: Allow userspace to set the # of VPsGreg Kurz2-2/+20
Add a new attribute to both XIVE and XICS-on-XIVE KVM devices so that userspace can tell how many interrupt servers it needs. If a VM needs less than the current default of KVM_MAX_VCPUS (2048), we can allocate less VPs in OPAL. Combined with a core stride (VSMT) that matches the number of guest threads per core, this may substantially increases the number of VMs that can run concurrently with an in-kernel XIVE device. Since the legacy XIVE KVM device is exposed to userspace through the XICS KVM API, a new attribute group is added to it for this purpose. While here, fix the syntax of the existing KVM_DEV_XICS_GRP_SOURCES in the XICS documentation. Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-10-21KVM: arm64: Document PV-time interfaceSteven Price1-0/+14
Introduce a paravirtualization interface for KVM/arm64 based on the "Arm Paravirtualized Time for Arm-Base Systems" specification DEN 0057A. This only adds the details about "Stolen Time" as the details of "Live Physical Time" have not been fully agreed. User space can specify a reserved area of memory for the guest and inform KVM to populate the memory with information on time that the host kernel has stolen from the guest. A hypercall interface is provided for the guest to interrogate the hypervisor's support for this interface and the location of the shared memory structures. Signed-off-by: Steven Price <steven.price@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2019-07-24Documentation: move Documentation/virtual to Documentation/virtChristoph Hellwig11-0/+1407
Renaming docs seems to be en vogue at the moment, so fix on of the grossly misnamed directories. We usually never use "virtual" as a shortcut for virtualization in the kernel, but always virt, as seen in the virt/ top-level directory. Fix up the documentation to match that. Fixes: ed16648eb5b8 ("Move kvm, uml, and lguest subdirectories under a common "virtual" directory, I.E:") Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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