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* KVM: add explicit barrier to kvm_vcpu_kickAndrew Jones2017-04-27
| | | | | | | | | | | | | | | | | | | | | | | | kvm_vcpu_kick() must issue a general memory barrier prior to reading vcpu->mode in order to ensure correctness of the mutual-exclusion memory barrier pattern used with vcpu->requests. While the cmpxchg called from kvm_vcpu_kick(): kvm_vcpu_kick kvm_arch_vcpu_should_kick kvm_vcpu_exiting_guest_mode cmpxchg implies general memory barriers before and after the operation, that implication is only valid when cmpxchg succeeds. We need an explicit barrier for when it fails, otherwise a VCPU thread on its entry path that reads zero for vcpu->requests does not exclude the possibility the requesting thread sees !IN_GUEST_MODE when it reads vcpu->mode. kvm_make_all_cpus_request already had a barrier, so we remove it, as now it would be redundant. Signed-off-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: perform a wake_up in kvm_make_all_cpus_requestRadim Krčmář2017-04-27
| | | | | | | | | | | | | | | | | | | | | | | | | | We want to have kvm_make_all_cpus_request() to be an optmized version of kvm_for_each_vcpu(i, vcpu, kvm) { kvm_make_request(vcpu, request); kvm_vcpu_kick(vcpu); } and kvm_vcpu_kick() wakes up the target vcpu. We know which requests do not need the wake up and use it to optimize the loop. Thanks to that, this patch doesn't change the behavior of current users (the all don't need the wake up) and only prepares for future where the wake up is going to be needed. I think that most requests do not need the wake up, so we would flip the bit then. Later on, kvm_make_request() will take care of kicking too, using this bit to make the decision whether to kick or not. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: mark requests that do not need a wakeupRadim Krčmář2017-04-27
| | | | | | | | | | | | | | | | | | | | | Some operations must ensure that the guest is not running with stale data, but if the guest is halted, then the update can wait until another event happens. kvm_make_all_requests() currently doesn't wake up, so we can mark all requests used with it. First 8 bits were arbitrarily reserved for request numbers. Most uses of requests have the request type as a constant, so a compiler will optimize the '&'. An alternative would be to have an inline function that would return whether the request needs a wake-up or not, but I like this one better even though it might produce worse assembly. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: remove #ifndef CONFIG_S390 around kvm_vcpu_wake_upRadim Krčmář2017-04-27
| | | | | | | | | | The #ifndef was protecting a missing halt_wakeup stat, but that is no longer necessary. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: always use kvm_make_request instead of set_bitRadim Krčmář2017-04-27
| | | | | | | Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: add kvm_{test,clear}_request to replace {test,clear}_bitRadim Krčmář2017-04-27
| | | | | | | | | | | | | | Users were expected to use kvm_check_request() for testing and clearing, but request have expanded their use since then and some users want to only test or do a faster clear. Make sure that requests are not directly accessed with bit operations. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* Merge tag 'kvm-s390-next-4.12-3' of ↵Paolo Bonzini2017-04-27
|\ | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD KVM: s390: MSA8 feature for guests - Detect all function codes for KMA and export the features for use in the cpu model
| * s390: kvm: Cpu model support for msa6, msa7 and msa8Jason J. Herne2017-04-26
| | | | | | | | | | | | | | | | | | msa6 and msa7 require no changes. msa8 adds kma instruction and feature area. Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * Merge branch 's390forkvm' of ↵Christian Borntraeger2017-04-26
| |\ | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux
| | * s390/cpacf: Introduce kma instructionJason J. Herne2017-04-26
| | | | | | | | | | | | | | | | | | | | | | | | Provide a kma instruction definition for use by callers of __cpacf_query. Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| | * s390/cpacf: query instructions use unique parameters for compatibility with KMAJason J. Herne2017-04-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | The new KMA instruction requires unique parameters. Update __cpacf_query to generate a compatible assembler instruction. Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com> Acked-by: Harald Freudenberger <freude@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | | KVM: x86: remove irq disablement around KVM_SET_CLOCK/KVM_GET_CLOCKMarcelo Tosatti2017-04-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The disablement of interrupts at KVM_SET_CLOCK/KVM_GET_CLOCK attempts to disable software suspend from causing "non atomic behaviour" of the operation: Add a helper function to compute the kernel time and convert nanoseconds back to CPU specific cycles. Note that these must not be called in preemptible context, as that would mean the kernel could enter software suspend state, which would cause non-atomic operation. However, assume the kernel can enter software suspend at the following 2 points: ktime_get_ts(&ts); 1. hypothetical_ktime_get_ts(&ts) monotonic_to_bootbased(&ts); 2. monotonic_to_bootbased() should be correct relative to a ktime_get_ts(&ts) performed after point 1 (that is after resuming from software suspend), hypothetical_ktime_get_ts() Therefore it is also correct for the ktime_get_ts(&ts) before point 1, which is ktime_get_ts(&ts) = hypothetical_ktime_get_ts(&ts) + time-to-execute-suspend-code Note CLOCK_MONOTONIC does not count during suspension. So remove the irq disablement, which causes the following warning on -RT kernels: With this reasoning, and the -RT bug that the irq disablement causes (because spin_lock is now a sleeping lock), remove the IRQ protection as it causes: [ 1064.668109] in_atomic(): 0, irqs_disabled(): 1, pid: 15296, name:m [ 1064.668110] INFO: lockdep is turned off. [ 1064.668110] irq event stamp: 0 [ 1064.668112] hardirqs last enabled at (0): [< (null)>] ) [ 1064.668116] hardirqs last disabled at (0): [] c0 [ 1064.668118] softirqs last enabled at (0): [] c0 [ 1064.668118] softirqs last disabled at (0): [< (null)>] ) [ 1064.668121] CPU: 13 PID: 15296 Comm: qemu-kvm Not tainted 3.10.0-1 [ 1064.668121] Hardware name: Dell Inc. PowerEdge R730/0H21J3, BIOS 5 [ 1064.668123] ffff8c1796b88000 00000000afe7344c ffff8c179abf3c68 f3 [ 1064.668125] ffff8c179abf3c90 ffffffff930ccb3d ffff8c1b992b3610 f0 [ 1064.668126] 00007ffc1a26fbc0 ffff8c179abf3cb0 ffffffff9375f694 f0 [ 1064.668126] Call Trace: [ 1064.668132] [] dump_stack+0x19/0x1b [ 1064.668135] [] __might_sleep+0x12d/0x1f0 [ 1064.668138] [] rt_spin_lock+0x24/0x60 [ 1064.668155] [] __get_kvmclock_ns+0x36/0x110 [k] [ 1064.668159] [] ? futex_wait_queue_me+0x103/0x10 [ 1064.668171] [] kvm_arch_vm_ioctl+0xa2/0xd70 [k] [ 1064.668173] [] ? futex_wait+0x1ac/0x2a0 v2: notice get_kvmclock_ns with the same problem (Pankaj). v3: remove useless helper function (Pankaj). Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | kvm: better MWAIT emulation for guestsMichael S. Tsirkin2017-04-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Guests that are heavy on futexes end up IPI'ing each other a lot. That can lead to significant slowdowns and latency increase for those guests when running within KVM. If only a single guest is needed on a host, we have a lot of spare host CPU time we can throw at the problem. Modern CPUs implement a feature called "MWAIT" which allows guests to wake up sleeping remote CPUs without an IPI - thus without an exit - at the expense of never going out of guest context. The decision whether this is something sensible to use should be up to the VM admin, so to user space. We can however allow MWAIT execution on systems that support it properly hardware wise. This patch adds a CAP to user space and a KVM cpuid leaf to indicate availability of native MWAIT execution. With that enabled, the worst a guest can do is waste as many cycles as a "jmp ." would do, so it's not a privilege problem. We consciously do *not* expose the feature in our CPUID bitmap, as most people will want to benefit from sleeping vCPUs to allow for over commit. Reported-by: "Gabriel L. Somlo" <gsomlo@gmail.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> [agraf: fix amd, change commit message] Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: x86: virtualize cpuid faultingKyle Huey2017-04-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Hardware support for faulting on the cpuid instruction is not required to emulate it, because cpuid triggers a VM exit anyways. KVM handles the relevant MSRs (MSR_PLATFORM_INFO and MSR_MISC_FEATURES_ENABLE) and upon a cpuid-induced VM exit checks the cpuid faulting state and the CPL. kvm_require_cpl is even kind enough to inject the GP fault for us. Signed-off-by: Kyle Huey <khuey@kylehuey.com> Reviewed-by: David Matlack <dmatlack@google.com> [Return "1" from kvm_emulate_cpuid, it's not void. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | Merge tag 'kvm-s390-next-4.12-2' of ↵Paolo Bonzini2017-04-21
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD KVM: s390: Guarded storage fixup and keyless subset mode - detect and use the keyless subset mode (guests without storage keys) - fix vSIE support for sdnxc - fix machine check data for guarded storage
| * | KVM: s390: Support keyless subset guest modeFarhan Ali2017-04-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the KSS facility is available on the machine, we also make it available for our KVM guests. The KSS facility bypasses storage key management as long as the guest does not issue a related instruction. When that happens, the control is returned to the host, which has to turn off KSS for a guest vcpu before retrying the instruction. Signed-off-by: Corey S. McQuay <csmcquay@linux.vnet.ibm.com> Signed-off-by: Farhan Ali <alifm@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | s390/sclp: Detect KSS facilityFarhan Ali2017-04-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's detect the keyless subset facility. Signed-off-by: Farhan Ali <alifm@linux.vnet.ibm.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
| * | KVM: s390: fix stale machine check data for guarded storageChristian Borntraeger2017-04-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When delivering a machine check the CPU state is "loaded", which means that some registers are already in the host registers. Before writing the register content into the machine check save area, we must make sure that we save the content of the registers into the data structures that are used for delivering the machine check. We already do the right thing for access, vector/floating point registers, let's do the same for guarded storage. Fixes: 4e0b1ab72b8a ("KVM: s390: gs support for kvm guests") Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
| * | KVM: s390: Fix sdnxo setting for nested guestsChristian Borntraeger2017-04-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the guest does not use the host register management, but it uses the sdnx area, we must fill in a proper sdnxo value (address of sdnx and the sdnxc). Reported-by: David Hildenbrand <david@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
* | | Merge branch 'kvm-ppc-next' of ↵Paolo Bonzini2017-04-21
|\ \ \ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD
| * | | KVM: PPC: Book3S PR: Do not fail emulation with mtspr/mfspr for unknown SPRsThomas Huth2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | According to the PowerISA 2.07, mtspr and mfspr should not always generate an illegal instruction exception when being used with an undefined SPR, but rather treat the instruction as a NOP or inject a privilege exception in some cases, too - depending on the SPR number. Also turn the printk here into a ratelimited print statement, so that the guest can not flood the dmesg log of the host by issueing lots of illegal mtspr/mfspr instruction here. Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: VFIO: Add in-kernel acceleration for VFIOAlexey Kardashevskiy2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This allows the host kernel to handle H_PUT_TCE, H_PUT_TCE_INDIRECT and H_STUFF_TCE requests targeted an IOMMU TCE table used for VFIO without passing them to user space which saves time on switching to user space and back. This adds H_PUT_TCE/H_PUT_TCE_INDIRECT/H_STUFF_TCE handlers to KVM. KVM tries to handle a TCE request in the real mode, if failed it passes the request to the virtual mode to complete the operation. If it a virtual mode handler fails, the request is passed to the user space; this is not expected to happen though. To avoid dealing with page use counters (which is tricky in real mode), this only accelerates SPAPR TCE IOMMU v2 clients which are required to pre-register the userspace memory. The very first TCE request will be handled in the VFIO SPAPR TCE driver anyway as the userspace view of the TCE table (iommu_table::it_userspace) is not allocated till the very first mapping happens and we cannot call vmalloc in real mode. If we fail to update a hardware IOMMU table unexpected reason, we just clear it and move on as there is nothing really we can do about it - for example, if we hot plug a VFIO device to a guest, existing TCE tables will be mirrored automatically to the hardware and there is no interface to report to the guest about possible failures. This adds new attribute - KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE - to the VFIO KVM device. It takes a VFIO group fd and SPAPR TCE table fd and associates a physical IOMMU table with the SPAPR TCE table (which is a guest view of the hardware IOMMU table). The iommu_table object is cached and referenced so we do not have to look up for it in real mode. This does not implement the UNSET counterpart as there is no use for it - once the acceleration is enabled, the existing userspace won't disable it unless a VFIO container is destroyed; this adds necessary cleanup to the KVM_DEV_VFIO_GROUP_DEL handler. This advertises the new KVM_CAP_SPAPR_TCE_VFIO capability to the user space. This adds real mode version of WARN_ON_ONCE() as the generic version causes problems with rcu_sched. Since we testing what vmalloc_to_phys() returns in the code, this also adds a check for already existing vmalloc_to_phys() call in kvmppc_rm_h_put_tce_indirect(). This finally makes use of vfio_external_user_iommu_id() which was introduced quite some time ago and was considered for removal. Tests show that this patch increases transmission speed from 220MB/s to 750..1020MB/s on 10Gb network (Chelsea CXGB3 10Gb ethernet card). Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Acked-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: iommu: Unify TCE checkingAlexey Kardashevskiy2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reworks helpers for checking TCE update parameters in way they can be used in KVM. This should cause no behavioral change. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Use preregistered memory API to access TCE listAlexey Kardashevskiy2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | VFIO on sPAPR already implements guest memory pre-registration when the entire guest RAM gets pinned. This can be used to translate the physical address of a guest page containing the TCE list from H_PUT_TCE_INDIRECT. This makes use of the pre-registrered memory API to access TCE list pages in order to avoid unnecessary locking on the KVM memory reverse map as we know that all of guest memory is pinned and we have a flat array mapping GPA to HPA which makes it simpler and quicker to index into that array (even with looking up the kernel page tables in vmalloc_to_phys) than it is to find the memslot, lock the rmap entry, look up the user page tables, and unlock the rmap entry. Note that the rmap pointer is initialized to NULL where declared (not in this patch). If a requested chunk of memory has not been preregistered, this will fall back to non-preregistered case and lock rmap. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Pass kvm* to kvmppc_find_table()Alexey Kardashevskiy2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The guest view TCE tables are per KVM anyway (not per VCPU) so pass kvm* there. This will be used in the following patches where we will be attaching VFIO containers to LIOBNs via ioctl() to KVM (rather than to VCPU). Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Enable IOMMU_API for KVM_BOOK3S_64 permanentlyAlexey Kardashevskiy2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It does not make much sense to have KVM in book3s-64 and not to have IOMMU bits for PCI pass through support as it costs little and allows VFIO to function on book3s KVM. Having IOMMU_API always enabled makes it unnecessary to have a lot of "#ifdef IOMMU_API" in arch/powerpc/kvm/book3s_64_vio*. With those ifdef's we could have only user space emulated devices accelerated (but not VFIO) which do not seem to be very useful. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Reserve KVM_CAP_SPAPR_TCE_VFIO capability numberAlexey Kardashevskiy2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds a capability number for in-kernel support for VFIO on SPAPR platform. The capability will tell the user space whether in-kernel handlers of H_PUT_TCE can handle VFIO-targeted requests or not. If not, the user space must not attempt allocating a TCE table in the host kernel via the KVM_CREATE_SPAPR_TCE KVM ioctl because in that case TCE requests will not be passed to the user space which is desired action in the situation like that. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | Merge remote-tracking branch 'remotes/powerpc/topic/ppc-kvm' into kvm-ppc-nextPaul Mackerras2017-04-19
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This merges in the commits in the topic/ppc-kvm branch of the powerpc tree to get the changes to arch/powerpc which subsequent patches will rely on. Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| | * | | powerpc/vfio_spapr_tce: Add reference counting to iommu_tableAlexey Kardashevskiy2017-03-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | So far iommu_table obejcts were only used in virtual mode and had a single owner. We are going to change this by implementing in-kernel acceleration of DMA mapping requests. The proposed acceleration will handle requests in real mode and KVM will keep references to tables. This adds a kref to iommu_table and defines new helpers to update it. This replaces iommu_free_table() with iommu_tce_table_put() and makes iommu_free_table() static. iommu_tce_table_get() is not used in this patch but it will be in the following patch. Since this touches prototypes, this also removes @node_name parameter as it has never been really useful on powernv and carrying it for the pseries platform code to iommu_free_table() seems to be quite useless as well. This should cause no behavioral change. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| | * | | powerpc/iommu/vfio_spapr_tce: Cleanup iommu_table disposalAlexey Kardashevskiy2017-03-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | At the moment iommu_table can be disposed by either calling iommu_table_free() directly or it_ops::free(); the only implementation of free() is in IODA2 - pnv_ioda2_table_free() - and it calls iommu_table_free() anyway. As we are going to have reference counting on tables, we need an unified way of disposing tables. This moves it_ops::free() call into iommu_free_table() and makes use of the latter. The free() callback now handles only platform-specific data. As from now on the iommu_free_table() calls it_ops->free(), we need to have it_ops initialized before calling iommu_free_table() so this moves this initialization in pnv_pci_ioda2_create_table(). This should cause no behavioral change. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| | * | | powerpc/powernv/iommu: Add real mode version of iommu_table_ops::exchange()Alexey Kardashevskiy2017-03-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In real mode, TCE tables are invalidated using special cache-inhibited store instructions which are not available in virtual mode This defines and implements exchange_rm() callback. This does not define set_rm/clear_rm/flush_rm callbacks as there is no user for those - exchange/exchange_rm are only to be used by KVM for VFIO. The exchange_rm callback is defined for IODA1/IODA2 powernv platforms. This replaces list_for_each_entry_rcu with its lockless version as from now on pnv_pci_ioda2_tce_invalidate() can be called in the real mode too. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| | * | | powerpc/mmu: Add real mode support for IOMMU preregistered memoryAlexey Kardashevskiy2017-03-27
| | | |/ | | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This makes mm_iommu_lookup() able to work in realmode by replacing list_for_each_entry_rcu() (which can do debug stuff which can fail in real mode) with list_for_each_entry_lockless(). This adds realmode version of mm_iommu_ua_to_hpa() which adds explicit vmalloc'd-to-linear address conversion. Unlike mm_iommu_ua_to_hpa(), mm_iommu_ua_to_hpa_rm() can fail. This changes mm_iommu_preregistered() to receive @mm as in real mode @current does not always have a correct pointer. This adds realmode version of mm_iommu_lookup() which receives @mm (for the same reason as for mm_iommu_preregistered()) and uses lockless version of list_for_each_entry_rcu(). Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| * | | KVM: PPC: Align the table size to system page sizeAlexey Kardashevskiy2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | At the moment the userspace can request a table smaller than a page size and this value will be stored as kvmppc_spapr_tce_table::size. However the actual allocated size will still be aligned to the system page size as alloc_page() is used there. This aligns the table size up to the system page size. It should not change the existing behaviour but when in-kernel TCE acceleration patchset reaches the upstream kernel, this will allow small TCE tables be accelerated as well: PCI IODA iommu_table allocator already aligns the size and, without this patch, an IOMMU group won't attach to LIOBN due to the mismatching table size. Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Book3S PR: Preserve storage control bitsAlexey Kardashevskiy2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PR KVM page fault handler performs eaddr to pte translation for a guest, however kvmppc_mmu_book3s_64_xlate() does not preserve WIMG bits (storage control) in the kvmppc_pte struct. If PR KVM is running as a second level guest under HV KVM, and PR KVM tries inserting HPT entry, this fails in HV KVM if it already has this mapping. This preserves WIMG bits between kvmppc_mmu_book3s_64_xlate() and kvmppc_mmu_map_page(). Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Book3S PR: Exit KVM on failed mappingAlexey Kardashevskiy2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | At the moment kvmppc_mmu_map_page() returns -1 if mmu_hash_ops.hpte_insert() fails for any reason so the page fault handler resumes the guest and it faults on the same address again. This adds distinction to kvmppc_mmu_map_page() to return -EIO if mmu_hash_ops.hpte_insert() failed for a reason other than full pteg. At the moment only pSeries_lpar_hpte_insert() returns -2 if plpar_pte_enter() failed with a code other than H_PTEG_FULL. Other mmu_hash_ops.hpte_insert() instances can only fail with -1 "full pteg". With this change, if PR KVM fails to update HPT, it can signal the userspace about this instead of returning to guest and having the very same page fault over and over again. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Book3S PR: Get rid of unused local variableAlexey Kardashevskiy2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | @is_mmio has never been used since introduction in commit 2f4cf5e42d13 ("Add book3s.c") from 2009. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: e500: Use kcalloc() in e500_mmu_host_init()Markus Elfring2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * A multiplication for the size determination of a memory allocation indicated that an array data structure should be processed. Thus use the corresponding function "kcalloc". This issue was detected by using the Coccinelle software. * Replace the specification of a data type by a pointer dereference to make the corresponding size determination a bit safer according to the Linux coding style convention. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Book3S HV: Use common error handling code in kvmppc_clr_passthru_irq()Markus Elfring2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a jump target so that a bit of exception handling can be better reused at the end of this function. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Add MMIO emulation for remaining floating-point instructionsPaul Mackerras2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For completeness, this adds emulation of the lfiwax and lfiwzx instructions. With this, all floating-point load and store instructions as of Power ISA V2.07 are emulated. Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Emulation for more integer loads and storesPaul Mackerras2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds emulation for the following integer loads and stores, thus enabling them to be used in a guest for accessing emulated MMIO locations. - lhaux - lwaux - lwzux - ldu - lwa - stdux - stwux - stdu - ldbrx - stdbrx Previously, most of these would cause an emulation failure exit to userspace, though ldu and lwa got treated incorrectly as ld, and stdu got treated incorrectly as std. This also tidies up some of the formatting and updates the comment listing instructions that still need to be implemented. With this, all integer loads and stores that are defined in the Power ISA v2.07 are emulated, except for those that are permitted to trap when used on cache-inhibited or write-through mappings (and which do in fact trap on POWER8), that is, lmw/stmw, lswi/stswi, lswx/stswx, lq/stq, and l[bhwdq]arx/st[bhwdq]cx. Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Add MMIO emulation for stdx (store doubleword indexed)Alexey Kardashevskiy2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds missing stdx emulation for emulated MMIO accesses by KVM guests. This allows the Mellanox mlx5_core driver from recent kernels to work when MMIO emulation is enforced by userspace. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Book3S: Add MMIO emulation for FP and VSX instructionsBin Lu2017-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch provides the MMIO load/store emulation for instructions of 'double & vector unsigned char & vector signed char & vector unsigned short & vector signed short & vector unsigned int & vector signed int & vector double '. The instructions that this adds emulation for are: - ldx, ldux, lwax, - lfs, lfsx, lfsu, lfsux, lfd, lfdx, lfdu, lfdux, - stfs, stfsx, stfsu, stfsux, stfd, stfdx, stfdu, stfdux, stfiwx, - lxsdx, lxsspx, lxsiwax, lxsiwzx, lxvd2x, lxvw4x, lxvdsx, - stxsdx, stxsspx, stxsiwx, stxvd2x, stxvw4x [paulus@ozlabs.org - some cleanups, fixes and rework, make it compile for Book E, fix build when PR KVM is built in] Signed-off-by: Bin Lu <lblulb@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
| * | | KVM: PPC: Provide functions for queueing up FP/VEC/VSX unavailable interruptsPaul Mackerras2017-04-19
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | This provides functions that can be used for generating interrupts indicating that a given functional unit (floating point, vector, or VSX) is unavailable. These functions will be used in instruction emulation code. Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
* | | Merge branch 'x86/process' of ↵Paolo Bonzini2017-04-21
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into HEAD Required for KVM support of the CPUID faulting feature. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | | x86/syscalls/32: Ignore arch_prctl for other architecturesArnd Bergmann2017-03-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sys_arch_prctl is only provided on x86, and there is no reason to add it elsewhere. However, including it on the 32-bit syscall table caused a warning for most configurations on non-x86: :1328:2: warning: #warning syscall arch_prctl not implemented [-Wcpp] This adds an exception to the syscall table checking script. Fixes: 79170fda313e ("x86/syscalls/32: Wire up arch_prctl on x86-32") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Kyle Huey <khuey@kylehuey.com> Link: http://lkml.kernel.org/r/20170323151904.706286-1-arnd@arndb.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | um/arch_prctl: Fix fallout from x86 arch_prctl() reworkKyle Huey2017-03-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The recent arch_prctl rework added a bracket instead of a comma. Fix it. Fixes: 17a6e1b8e8e8 ("x86/arch_prctl/64: Rename do_arch_prctl() to do_arch_prctl_64()") Signed-off-by: Kyle Huey <khuey@kylehuey.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: kbuild-all@01.org Link: http://lkml.kernel.org/r/20170320230535.11281-1-khuey@kylehuey.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | x86/arch_prctl: Add ARCH_[GET|SET]_CPUIDKyle Huey2017-03-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Intel supports faulting on the CPUID instruction beginning with Ivy Bridge. When enabled, the processor will fault on attempts to execute the CPUID instruction with CPL>0. Exposing this feature to userspace will allow a ptracer to trap and emulate the CPUID instruction. When supported, this feature is controlled by toggling bit 0 of MSR_MISC_FEATURES_ENABLES. It is documented in detail in Section 2.3.2 of https://bugzilla.kernel.org/attachment.cgi?id=243991 Implement a new pair of arch_prctls, available on both x86-32 and x86-64. ARCH_GET_CPUID: Returns the current CPUID state, either 0 if CPUID faulting is enabled (and thus the CPUID instruction is not available) or 1 if CPUID faulting is not enabled. ARCH_SET_CPUID: Set the CPUID state to the second argument. If cpuid_enabled is 0 CPUID faulting will be activated, otherwise it will be deactivated. Returns ENODEV if CPUID faulting is not supported on this system. The state of the CPUID faulting flag is propagated across forks, but reset upon exec. Signed-off-by: Kyle Huey <khuey@kylehuey.com> Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: linux-kselftest@vger.kernel.org Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Robert O'Callahan <robert@ocallahan.org> Cc: Richard Weinberger <richard@nod.at> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Len Brown <len.brown@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: user-mode-linux-devel@lists.sourceforge.net Cc: Jeff Dike <jdike@addtoit.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: user-mode-linux-user@lists.sourceforge.net Cc: David Matlack <dmatlack@google.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: linux-fsdevel@vger.kernel.org Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/20170320081628.18952-9-khuey@kylehuey.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | x86/cpufeature: Detect CPUID faulting supportKyle Huey2017-03-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Intel supports faulting on the CPUID instruction beginning with Ivy Bridge. When enabled, the processor will fault on attempts to execute the CPUID instruction with CPL>0. This will allow a ptracer to emulate the CPUID instruction. Bit 31 of MSR_PLATFORM_INFO advertises support for this feature. It is documented in detail in Section 2.3.2 of https://bugzilla.kernel.org/attachment.cgi?id=243991 Detect support for this feature and expose it as X86_FEATURE_CPUID_FAULT. Signed-off-by: Kyle Huey <khuey@kylehuey.com> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: linux-kselftest@vger.kernel.org Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Robert O'Callahan <robert@ocallahan.org> Cc: Richard Weinberger <richard@nod.at> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Len Brown <len.brown@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: user-mode-linux-devel@lists.sourceforge.net Cc: Jeff Dike <jdike@addtoit.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: user-mode-linux-user@lists.sourceforge.net Cc: David Matlack <dmatlack@google.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: linux-fsdevel@vger.kernel.org Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/20170320081628.18952-8-khuey@kylehuey.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | x86/syscalls/32: Wire up arch_prctl on x86-32Kyle Huey2017-03-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Hook up arch_prctl to call do_arch_prctl() on x86-32, and in 32 bit compat mode on x86-64. This allows to have arch_prctls that are not specific to 64 bits. On UML, simply stub out this syscall. Signed-off-by: Kyle Huey <khuey@kylehuey.com> Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: linux-kselftest@vger.kernel.org Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Robert O'Callahan <robert@ocallahan.org> Cc: Richard Weinberger <richard@nod.at> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Len Brown <len.brown@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: user-mode-linux-devel@lists.sourceforge.net Cc: Jeff Dike <jdike@addtoit.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: user-mode-linux-user@lists.sourceforge.net Cc: David Matlack <dmatlack@google.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: linux-fsdevel@vger.kernel.org Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/20170320081628.18952-7-khuey@kylehuey.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | x86/arch_prctl: Add do_arch_prctl_common()Kyle Huey2017-03-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add do_arch_prctl_common() to handle arch_prctls that are not specific to 64 bit mode. Call it from the syscall entry point, but not any of the other callsites in the kernel, which all want one of the existing 64 bit only arch_prctls. Signed-off-by: Kyle Huey <khuey@kylehuey.com> Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: linux-kselftest@vger.kernel.org Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Robert O'Callahan <robert@ocallahan.org> Cc: Richard Weinberger <richard@nod.at> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Len Brown <len.brown@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: user-mode-linux-devel@lists.sourceforge.net Cc: Jeff Dike <jdike@addtoit.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: user-mode-linux-user@lists.sourceforge.net Cc: David Matlack <dmatlack@google.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: linux-fsdevel@vger.kernel.org Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/20170320081628.18952-6-khuey@kylehuey.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>