- 04 6月, 2017 1 次提交
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由 Andrew Jones 提交于
Marc Zyngier suggested that we define the arch specific VCPU request base, rather than requiring each arch to remember to start from 8. That suggestion, along with Radim Krcmar's recent VCPU request flag addition, snowballed into defining something of an arch VCPU request defining API. No functional change. (Looks like x86 is running out of arch VCPU request bits. Maybe someday we'll need to extend to 64.) Signed-off-by: NAndrew Jones <drjones@redhat.com> Acked-by: NChristoffer Dall <cdall@linaro.org> Signed-off-by: NChristoffer Dall <cdall@linaro.org>
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- 27 4月, 2017 1 次提交
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由 Benjamin Herrenschmidt 提交于
This patch makes KVM capable of using the XIVE interrupt controller to provide the standard PAPR "XICS" style hypercalls. It is necessary for proper operations when the host uses XIVE natively. This has been lightly tested on an actual system, including PCI pass-through with a TG3 device. Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org> [mpe: Cleanup pr_xxx(), unsplit pr_xxx() strings, etc., fix build failures by adding KVM_XIVE which depends on KVM_XICS and XIVE, and adding empty stubs for the kvm_xive_xxx() routines, fixup subject, integrate fixes from Paul for building PR=y HV=n] Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 20 4月, 2017 3 次提交
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由 Alexey Kardashevskiy 提交于
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: NAlexey Kardashevskiy <aik@ozlabs.ru> Acked-by: NAlex Williamson <alex.williamson@redhat.com> Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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由 Alexey Kardashevskiy 提交于
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: NAlexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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由 Bin Lu 提交于
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: NBin Lu <lblulb@linux.vnet.ibm.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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- 07 4月, 2017 1 次提交
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由 Paolo Bonzini 提交于
Its value has never changed; we might as well make it part of the ABI instead of using the return value of KVM_CHECK_EXTENSION(KVM_CAP_COALESCED_MMIO). Because PPC does not always make MMIO available, the code has to be made dependent on CONFIG_KVM_MMIO rather than KVM_COALESCED_MMIO_PAGE_OFFSET. Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com> Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
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- 31 1月, 2017 7 次提交
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由 David Gibson 提交于
This adds a not yet working outline of the HPT resizing PAPR extension. Specifically it adds the necessary ioctl() functions, their basic steps, the work function which will handle preparation for the resize, and synchronization between these, the guest page fault path and guest HPT update path. The actual guts of the implementation isn't here yet, so for now the calls will always fail. Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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由 David Gibson 提交于
Currently the kvm_hpt_info structure stores the hashed page table's order, and also the number of HPTEs it contains and a mask for its size. The last two can be easily derived from the order, so remove them and just calculate them as necessary with a couple of helper inlines. Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au> Reviewed-by: NThomas Huth <thuth@redhat.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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由 David Gibson 提交于
Currently, the powerpc kvm_arch structure contains a number of variables tracking the state of the guest's hashed page table (HPT) in KVM HV. This patch gathers them all together into a single kvm_hpt_info substructure. This makes life more convenient for the upcoming HPT resizing implementation. Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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由 Paul Mackerras 提交于
With radix, the guest can do TLB invalidations itself using the tlbie (global) and tlbiel (local) TLB invalidation instructions. Linux guests use local TLB invalidations for translations that have only ever been accessed on one vcpu. However, that doesn't mean that the translations have only been accessed on one physical cpu (pcpu) since vcpus can move around from one pcpu to another. Thus a tlbiel might leave behind stale TLB entries on a pcpu where the vcpu previously ran, and if that task then moves back to that previous pcpu, it could see those stale TLB entries and thus access memory incorrectly. The usual symptom of this is random segfaults in userspace programs in the guest. To cope with this, we detect when a vcpu is about to start executing on a thread in a core that is a different core from the last time it executed. If that is the case, then we mark the core as needing a TLB flush and then send an interrupt to any thread in the core that is currently running a vcpu from the same guest. This will get those vcpus out of the guest, and the first one to re-enter the guest will do the TLB flush. The reason for interrupting the vcpus executing on the old core is to cope with the following scenario: CPU 0 CPU 1 CPU 4 (core 0) (core 0) (core 1) VCPU 0 runs task X VCPU 1 runs core 0 TLB gets entries from task X VCPU 0 moves to CPU 4 VCPU 0 runs task X Unmap pages of task X tlbiel (still VCPU 1) task X moves to VCPU 1 task X runs task X sees stale TLB entries That is, as soon as the VCPU starts executing on the new core, it could unmap and tlbiel some page table entries, and then the task could migrate to one of the VCPUs running on the old core and potentially see stale TLB entries. Since the TLB is shared between all the threads in a core, we only use the bit of kvm->arch.need_tlb_flush corresponding to the first thread in the core. To ensure that we don't have a window where we can miss a flush, this moves the clearing of the bit from before the actual flush to after it. This way, two threads might both do the flush, but we prevent the situation where one thread can enter the guest before the flush is finished. Signed-off-by: NPaul Mackerras <paulus@ozlabs.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Paul Mackerras 提交于
This adds code to branch around the parts that radix guests don't need - clearing and loading the SLB with the guest SLB contents, saving the guest SLB contents on exit, and restoring the host SLB contents. Since the host is now using radix, we need to save and restore the host value for the PID register. On hypervisor data/instruction storage interrupts, we don't do the guest HPT lookup on radix, but just save the guest physical address for the fault (from the ASDR register) in the vcpu struct. Signed-off-by: NPaul Mackerras <paulus@ozlabs.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Paul Mackerras 提交于
This adds a field in struct kvm_arch and an inline helper to indicate whether a guest is a radix guest or not, plus a new file to contain the radix MMU code, which currently contains just a translate function which knows how to traverse the guest page tables to translate an address. Signed-off-by: NPaul Mackerras <paulus@ozlabs.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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由 Paul Mackerras 提交于
This adds the implementation of the KVM_PPC_CONFIGURE_V3_MMU ioctl for HPT guests on POWER9. With this, we can return 1 for the KVM_CAP_PPC_MMU_HASH_V3 capability. Signed-off-by: NPaul Mackerras <paulus@ozlabs.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 28 11月, 2016 1 次提交
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由 Suraj Jitindar Singh 提交于
KVM_HALT_POLL_NS_DEFAULT is an arch specific constant which sets the default value of the halt_poll_ns kvm module parameter which determines the global maximum halt polling interval. The current value for powerpc is 500000 (500us) which means that any repetitive workload with a period of less than that can drive the cpu usage to 100% where it may have been mostly idle without halt polling. This presents the possibility of a large increase in power usage with a comparatively small performance benefit. Reduce the default to 10000 (10us) and a user can tune this themselves to set their affinity for halt polling based on the trade off between power and performance which they are willing to make. Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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- 24 11月, 2016 2 次提交
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由 Paul Mackerras 提交于
POWER9 adds new capabilities to the tlbie (TLB invalidate entry) and tlbiel (local tlbie) instructions. Both instructions get a set of new parameters (RIC, PRS and R) which appear as bits in the instruction word. The tlbiel instruction now has a second register operand, which contains a PID and/or LPID value if needed, and should otherwise contain 0. This adapts KVM-HV's usage of tlbie and tlbiel to work on POWER9 as well as older processors. Since we only handle HPT guests so far, we need RIC=0 PRS=0 R=0, which ends up with the same instruction word as on previous processors, so we don't need to conditionally execute different instructions depending on the processor. The local flush on first entry to a guest in book3s_hv_rmhandlers.S is a loop which depends on the number of TLB sets. Rather than using feature sections to set the number of iterations based on which CPU we're on, we now work out this number at VM creation time and store it in the kvm_arch struct. That will make it possible to get the number from the device tree in future, which will help with compatibility with future processors. Since mmu_partition_table_set_entry() does a global flush of the whole LPID, we don't need to do the TLB flush on first entry to the guest on each processor. Therefore we don't set all bits in the tlb_need_flush bitmap on VM startup on POWER9. Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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由 Paul Mackerras 提交于
This adds code to handle two new guest-accessible special-purpose registers on POWER9: TIDR (thread ID register) and PSSCR (processor stop status and control register). They are context-switched between host and guest, and the guest values can be read and set via the one_reg interface. The PSSCR contains some fields which are guest-accessible and some which are only accessible in hypervisor mode. We only allow the guest-accessible fields to be read or set by userspace. Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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- 21 11月, 2016 2 次提交
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由 Paul Mackerras 提交于
When switching from/to a guest that has a transaction in progress, we need to save/restore the checkpointed register state. Although XER is part of the CPU state that gets checkpointed, the code that does this saving and restoring doesn't save/restore XER. This fixes it by saving and restoring the XER. To allow userspace to read/write the checkpointed XER value, we also add a new ONE_REG specifier. The visible effect of this bug is that the guest may see its XER value being corrupted when it uses transactions. Fixes: e4e38121 ("KVM: PPC: Book3S HV: Add transactional memory support") Fixes: 0a8eccef ("KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit") Cc: stable@vger.kernel.org # v3.15+ Signed-off-by: NPaul Mackerras <paulus@ozlabs.org> Reviewed-by: NThomas Huth <thuth@redhat.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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由 Yongji Xie 提交于
This keeps a per vcpu cache for recently page faulted MMIO entries. On a page fault, if the entry exists in the cache, we can avoid some time-consuming paths, for example, looking up HPT, locking HPTE twice and searching mmio gfn from memslots, then directly call kvmppc_hv_emulate_mmio(). In current implenment, we limit the size of cache to four. We think it's enough to cover the high-frequency MMIO HPTEs in most case. For example, considering the case of using virtio device, for virtio legacy devices, one HPTE could handle notifications from up to 1024 (64K page / 64 byte Port IO register) devices, so one cache entry is enough; for virtio modern devices, we always need one HPTE to handle notification for each device because modern device would use a 8M MMIO register to notify host instead of Port IO register, typically the system's configuration should not exceed four virtio devices per vcpu, four cache entry is also enough in this case. Of course, if needed, we could also modify the macro to a module parameter in the future. Signed-off-by: NYongji Xie <xyjxie@linux.vnet.ibm.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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- 27 9月, 2016 1 次提交
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由 Paul Mackerras 提交于
POWER8 has one virtual timebase (VTB) register per subcore, not one per CPU thread. The HV KVM code currently treats VTB as a per-thread register, which can lead to spurious soft lockup messages from guests which use the VTB as the time source for the soft lockup detector. (CPUs before POWER8 did not have the VTB register.) For HV KVM, this fixes the problem by making only the primary thread in each virtual core save and restore the VTB value. With this, the VTB state becomes part of the kvmppc_vcore structure. This also means that "piggybacking" of multiple virtual cores onto one subcore is not possible on POWER8, because then the virtual cores would share a single VTB register. PR KVM emulates a VTB register, which is per-vcpu because PR KVM has no notion of CPU threads or SMT. For PR KVM we move the VTB state into the kvmppc_vcpu_book3s struct. Cc: stable@vger.kernel.org # v3.14+ Reported-by: NThomas Huth <thuth@redhat.com> Tested-by: NThomas Huth <thuth@redhat.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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- 12 9月, 2016 1 次提交
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由 Suresh Warrier 提交于
Add VCPU stat counters to track affinity for passthrough interrupts. pthru_all: Counts all passthrough interrupts whose IRQ mappings are in the kvmppc_passthru_irq_map structure. pthru_host: Counts all cached passthrough interrupts that were injected from the host through kvm_set_irq (i.e. not handled in real mode). pthru_bad_aff: Counts how many cached passthrough interrupts have bad affinity (receiving CPU is not running VCPU that is the target of the virtual interrupt in the guest). Signed-off-by: NSuresh Warrier <warrier@linux.vnet.ibm.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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- 09 9月, 2016 1 次提交
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由 Suresh Warrier 提交于
This patch introduces an IRQ mapping structure, the kvmppc_passthru_irqmap structure that is to be used to map the real hardware IRQ in the host with the virtual hardware IRQ (gsi) that is injected into a guest by KVM for passthrough adapters. Currently, we assume a separate IRQ mapping structure for each guest. Each kvmppc_passthru_irqmap has a mapping arrays, containing all defined real<->virtual IRQs. [paulus@ozlabs.org - removed irq_chip field from struct kvmppc_passthru_irqmap; changed parameter for kvmppc_get_passthru_irqmap from struct kvm_vcpu * to struct kvm *, removed small cached array.] Signed-off-by: NSuresh Warrier <warrier@linux.vnet.ibm.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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- 08 9月, 2016 5 次提交
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由 Suraj Jitindar Singh 提交于
vcpu stats are used to collect information about a vcpu which can be viewed in the debugfs. For example halt_attempted_poll and halt_successful_poll are used to keep track of the number of times the vcpu attempts to and successfully polls. These stats are currently not used on powerpc. Implement incrementation of the halt_attempted_poll and halt_successful_poll vcpu stats for powerpc. Since these stats are summed over all the vcpus for all running guests it doesn't matter which vcpu they are attributed to, thus we choose the current runner vcpu of the vcore. Also add new vcpu stats: halt_poll_success_ns, halt_poll_fail_ns and halt_wait_ns to be used to accumulate the total time spend polling successfully, polling unsuccessfully and waiting respectively, and halt_successful_wait to accumulate the number of times the vcpu waits. Given that halt_poll_success_ns, halt_poll_fail_ns and halt_wait_ns are expressed in nanoseconds it is necessary to represent these as 64-bit quantities, otherwise they would overflow after only about 4 seconds. Given that the total time spend either polling or waiting will be known and the number of times that each was done, it will be possible to determine the average poll and wait times. This will give the ability to tune the kvm module parameters based on the calculated average wait and poll times. Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com> Reviewed-by: NDavid Matlack <dmatlack@google.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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由 Suraj Jitindar Singh 提交于
vms and vcpus have statistics associated with them which can be viewed within the debugfs. Currently it is assumed within the vcpu_stat_get() and vm_stat_get() functions that all of these statistics are represented as u32s, however the next patch adds some u64 vcpu statistics. Change all vcpu statistics to u64 and modify vcpu_stat_get() accordingly. Since vcpu statistics are per vcpu, they will only be updated by a single vcpu at a time so this shouldn't present a problem on 32-bit machines which can't atomically increment 64-bit numbers. However vm statistics could potentially be updated by multiple vcpus from that vm at a time. To avoid the overhead of atomics make all vm statistics ulong such that they are 64-bit on 64-bit systems where they can be atomically incremented and are 32-bit on 32-bit systems which may not be able to atomically increment 64-bit numbers. Modify vm_stat_get() to expect ulongs. Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com> Reviewed-by: NDavid Matlack <dmatlack@google.com> Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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由 Suraj Jitindar Singh 提交于
This patch introduces new halt polling functionality into the kvm_hv kernel module. When a vcore is idle it will poll for some period of time before scheduling itself out. When all of the runnable vcpus on a vcore have ceded (and thus the vcore is idle) we schedule ourselves out to allow something else to run. In the event that we need to wake up very quickly (for example an interrupt arrives), we are required to wait until we get scheduled again. Implement halt polling so that when a vcore is idle, and before scheduling ourselves, we poll for vcpus in the runnable_threads list which have pending exceptions or which leave the ceded state. If we poll successfully then we can get back into the guest very quickly without ever scheduling ourselves, otherwise we schedule ourselves out as before. There exists generic halt_polling code in virt/kvm_main.c, however on powerpc the polling conditions are different to the generic case. It would be nice if we could just implement an arch specific kvm_check_block() function, but there is still other arch specific things which need to be done for kvm_hv (for example manipulating vcore states) which means that a separate implementation is the best option. Testing of this patch with a TCP round robin test between two guests with virtio network interfaces has found a decrease in round trip time of ~15us on average. A performance gain is only seen when going out of and back into the guest often and quickly, otherwise there is no net benefit from the polling. The polling interval is adjusted such that when we are often scheduled out for long periods of time it is reduced, and when we often poll successfully it is increased. The rate at which the polling interval increases or decreases, and the maximum polling interval, can be set through module parameters. Based on the implementation in the generic kvm module by Wanpeng Li and Paolo Bonzini, and on direction from Paul Mackerras. Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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由 Suraj Jitindar Singh 提交于
The struct kvmppc_vcore is a structure used to store various information about a virtual core for a kvm guest. The runnable_threads element of the struct provides a list of all of the currently runnable vcpus on the core (those in the KVMPPC_VCPU_RUNNABLE state). The previous implementation of this list was a linked_list. The next patch requires that the list be able to be iterated over without holding the vcore lock. Reimplement the runnable_threads list in the kvmppc_vcore struct as an array. Implement function to iterate over valid entries in the array and update access sites accordingly. Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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由 Suraj Jitindar Singh 提交于
The next commit will introduce a member to the kvmppc_vcore struct which references MAX_SMT_THREADS which is defined in kvm_book3s_asm.h, however this file isn't included in kvm_host.h directly. Thus compiling for certain platforms such as pmac32_defconfig and ppc64e_defconfig with KVM fails due to MAX_SMT_THREADS not being defined. Move the struct kvmppc_vcore definition to kvm_book3s.h which explicitly includes kvm_book3s_asm.h. Signed-off-by: NSuraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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- 19 8月, 2016 1 次提交
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由 Paul Mackerras 提交于
It doesn't make sense to create irqfds for a VM that doesn't have in-kernel interrupt controller emulation. There is an existing interface for architecture code to tell the irqfd code whether or not any interrupt controller has been initialized, called kvm_arch_intc_initialized(), so let's implement that for powerpc. Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
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- 13 5月, 2016 1 次提交
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由 Christian Borntraeger 提交于
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: NChristian 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: NPaolo Bonzini <pbonzini@redhat.com>
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- 12 5月, 2016 1 次提交
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由 Greg Kurz 提交于
The KVM_MAX_VCPUS define provides the maximum number of vCPUs per guest, and also the upper limit for vCPU ids. This is okay for all archs except PowerPC which can have higher ids, depending on the cpu/core/thread topology. In the worst case (single threaded guest, host with 8 threads per core), it limits the maximum number of vCPUS to KVM_MAX_VCPUS / 8. This patch separates the vCPU numbering from the total number of vCPUs, with the introduction of KVM_MAX_VCPU_ID, as the maximal valid value for vCPU ids plus one. The corresponding KVM_CAP_MAX_VCPU_ID allows userspace to validate vCPU ids before passing them to KVM_CREATE_VCPU. This patch only implements KVM_MAX_VCPU_ID with a specific value for PowerPC. Other archs continue to return KVM_MAX_VCPUS instead. Suggested-by: NRadim Krcmar <rkrcmar@redhat.com> Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com> Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 02 3月, 2016 2 次提交
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由 Alexey Kardashevskiy 提交于
This enables userspace view of TCE tables to start from non-zero offset on a bus. This will be used for huge DMA windows. This only changes the internal structure, the user interface needs to change in order to use an offset. Signed-off-by: NAlexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au> Signed-off-by: NPaul Mackerras <paulus@samba.org>
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由 Alexey Kardashevskiy 提交于
At the moment the kvmppc_spapr_tce_table struct can only describe 4GB windows and handle fixed size (4K) pages. Dynamic DMA windows support more so these limits need to be extended. This replaces window_size (in bytes, 4GB max) with page_shift (32bit) and size (64bit, in pages). This should cause no behavioural change as this is changing the internal structures only - the user interface still only allows one to create a 32-bit table with 4KiB pages at this stage. Signed-off-by: NAlexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au> Signed-off-by: NPaul Mackerras <paulus@samba.org>
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- 25 2月, 2016 1 次提交
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由 Marcelo Tosatti 提交于
The problem: On -rt, an emulated LAPIC timer instances has the following path: 1) hard interrupt 2) ksoftirqd is scheduled 3) ksoftirqd wakes up vcpu thread 4) vcpu thread is scheduled This extra context switch introduces unnecessary latency in the LAPIC path for a KVM guest. The solution: Allow waking up vcpu thread from hardirq context, thus avoiding the need for ksoftirqd to be scheduled. Normal waitqueues make use of spinlocks, which on -RT are sleepable locks. Therefore, waking up a waitqueue waiter involves locking a sleeping lock, which is not allowed from hard interrupt context. cyclictest command line: This patch reduces the average latency in my tests from 14us to 11us. Daniel writes: Paolo asked for numbers from kvm-unit-tests/tscdeadline_latency benchmark on mainline. The test was run 1000 times on tip/sched/core 4.4.0-rc8-01134-g0905f04e: ./x86-run x86/tscdeadline_latency.flat -cpu host with idle=poll. The test seems not to deliver really stable numbers though most of them are smaller. Paolo write: "Anything above ~10000 cycles means that the host went to C1 or lower---the number means more or less nothing in that case. The mean shows an improvement indeed." Before: min max mean std count 1000.000000 1000.000000 1000.000000 1000.000000 mean 5162.596000 2019270.084000 5824.491541 20681.645558 std 75.431231 622607.723969 89.575700 6492.272062 min 4466.000000 23928.000000 5537.926500 585.864966 25% 5163.000000 16132529.750000 5790.132275 16683.745433 50% 5175.000000 2281919.000000 5834.654000 23151.990026 75% 5190.000000 2382865.750000 5861.412950 24148.206168 max 5228.000000 4175158.000000 6254.827300 46481.048691 After min max mean std count 1000.000000 1000.00000 1000.000000 1000.000000 mean 5143.511000 2076886.10300 5813.312474 21207.357565 std 77.668322 610413.09583 86.541500 6331.915127 min 4427.000000 25103.00000 5529.756600 559.187707 25% 5148.000000 1691272.75000 5784.889825 17473.518244 50% 5160.000000 2308328.50000 5832.025000 23464.837068 75% 5172.000000 2393037.75000 5853.177675 24223.969976 max 5222.000000 3922458.00000 6186.720500 42520.379830 [Patch was originaly based on the swait implementation found in the -rt tree. Daniel ported it to mainline's version and gathered the benchmark numbers for tscdeadline_latency test.] Signed-off-by: NDaniel Wagner <daniel.wagner@bmw-carit.de> Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-rt-users@vger.kernel.org Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1455871601-27484-4-git-send-email-wagi@monom.orgSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 16 2月, 2016 1 次提交
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由 Alexey Kardashevskiy 提交于
At the moment only spapr_tce_tables updates are protected against races but not lookups. This fixes missing protection by using RCU for the list. As lookups also happen in real mode, this uses list_for_each_entry_lockless() (which is expected not to access any vmalloc'd memory). This converts release_spapr_tce_table() to a RCU scheduled handler. Signed-off-by: NAlexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au> Signed-off-by: NPaul Mackerras <paulus@samba.org>
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- 09 1月, 2016 1 次提交
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由 Paolo Bonzini 提交于
Since the numbers now overlap, it makes sense to enumerate them in asm/kvm_host.h rather than linux/kvm_host.h. Functions that refer to architecture-specific requests are also moved to arch/. Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 10 12月, 2015 1 次提交
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由 Thomas Huth 提交于
Only using 32 memslots for KVM on powerpc is way too low, you can nowadays hit this limit quite fast by adding a couple of PCI devices and/or pluggable memory DIMMs to the guest. x86 already increased the KVM_USER_MEM_SLOTS to 509, to satisfy 256 pluggable DIMM slots, 3 private slots and 253 slots for other things like PCI devices (i.e. resulting in 256 + 3 + 253 = 512 slots in total). We should do something similar for powerpc, and since we do not use private slots here, we can set the value to 512 directly. While we're at it, also remove the KVM_MEM_SLOTS_NUM definition from the powerpc-specific header since this gets defined in the generic kvm_host.h header anyway. Signed-off-by: NThomas Huth <thuth@redhat.com> Signed-off-by: NPaul Mackerras <paulus@samba.org>
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- 23 10月, 2015 1 次提交
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由 Christoffer Dall 提交于
Some times it is useful for architecture implementations of KVM to know when the VCPU thread is about to block or when it comes back from blocking (arm/arm64 needs to know this to properly implement timers, for example). Therefore provide a generic architecture callback function in line with what we do elsewhere for KVM generic-arch interactions. Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com> Signed-off-by: NChristoffer Dall <christoffer.dall@linaro.org>
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- 21 10月, 2015 1 次提交
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由 Paul Mackerras 提交于
This reverts commit 9678cdaa ("Use the POWER8 Micro Partition Prefetch Engine in KVM HV on POWER8") because the original commit had multiple, partly self-cancelling bugs, that could cause occasional memory corruption. In fact the logmpp instruction was incorrectly using register r0 as the source of the buffer address and operation code, and depending on what was in r0, it would either do nothing or corrupt the 64k page pointed to by r0. The logmpp instruction encoding and the operation code definitions could be corrected, but then there is the problem that there is no clearly defined way to know when the hardware has finished writing to the buffer. The original commit attempted to work around this by aborting the write-out before starting the prefetch, but this is ineffective in the case where the virtual core is now executing on a different physical core from the one where the write-out was initiated. These problems plus advice from the hardware designers not to use the function (since the measured performance improvement from using the feature was actually mostly negative), mean that reverting the code is the best option. Fixes: 9678cdaa ("Use the POWER8 Micro Partition Prefetch Engine in KVM HV on POWER8") Signed-off-by: NPaul Mackerras <paulus@samba.org> Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
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- 25 9月, 2015 1 次提交
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由 David Hildenbrand 提交于
We observed some performance degradation on s390x with dynamic halt polling. Until we can provide a proper fix, let's enable halt_poll_ns as default only for supported architectures. Architectures are now free to set their own halt_poll_ns default value. Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 16 9月, 2015 1 次提交
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由 Paolo Bonzini 提交于
This new statistic can help diagnosing VCPUs that, for any reason, trigger bad behavior of halt_poll_ns autotuning. For example, say halt_poll_ns = 480000, and wakeups are spaced exactly like 479us, 481us, 479us, 481us. Then KVM always fails polling and wastes 10+20+40+80+160+320+480 = 1110 microseconds out of every 479+481+479+481+479+481+479 = 3359 microseconds. The VCPU then is consuming about 30% more CPU than it would use without polling. This would show as an abnormally high number of attempted polling compared to the successful polls. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com< Reviewed-by: NDavid Matlack <dmatlack@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 03 9月, 2015 1 次提交
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由 Thomas Huth 提交于
The size of the Problem State Priority Boost Register is only 32 bits, but the kvm_vcpu_arch->pspb variable is declared as "ulong", ie. 64-bit. However, the assembler code accesses this variable with 32-bit accesses, and the KVM_REG_PPC_PSPB macro is defined with SIZE_U32, too, so that the current code is broken on big endian hosts: kvmppc_get_one_reg_hv() will only return zero for this register since it is using the wrong half of the pspb variable. Let's fix this problem by adjusting the size of the pspb field in the kvm_vcpu_arch structure. Signed-off-by: NThomas Huth <thuth@redhat.com> Signed-off-by: NPaul Mackerras <paulus@samba.org>
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