1. 14 7月, 2016 1 次提交
    • P
      x86/kvm: Audit and remove any unnecessary uses of module.h · 1767e931
      Paul Gortmaker 提交于
      Historically a lot of these existed because we did not have
      a distinction between what was modular code and what was providing
      support to modules via EXPORT_SYMBOL and friends.  That changed
      when we forked out support for the latter into the export.h file.
      
      This means we should be able to reduce the usage of module.h
      in code that is obj-y Makefile or bool Kconfig.  In the case of
      kvm where it is modular, we can extend that to also include files
      that are building basic support functionality but not related
      to loading or registering the final module; such files also have
      no need whatsoever for module.h
      
      The advantage in removing such instances is that module.h itself
      sources about 15 other headers; adding significantly to what we feed
      cpp, and it can obscure what headers we are effectively using.
      
      Since module.h was the source for init.h (for __init) and for
      export.h (for EXPORT_SYMBOL) we consider each instance for the
      presence of either and replace as needed.
      
      Several instances got replaced with moduleparam.h since that was
      really all that was required for those particular files.
      Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
      Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: kvm@vger.kernel.org
      Link: http://lkml.kernel.org/r/20160714001901.31603-8-paul.gortmaker@windriver.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      1767e931
  2. 27 6月, 2016 1 次提交
  3. 19 5月, 2016 4 次提交
  4. 05 4月, 2016 1 次提交
    • L
      kvm: x86: make lapic hrtimer pinned · 61abdbe0
      Luiz Capitulino 提交于
      When a vCPU runs on a nohz_full core, the hrtimer used by
      the lapic emulation code can be migrated to another core.
      When this happens, it's possible to observe milisecond
      latency when delivering timer IRQs to KVM guests.
      
      The huge latency is mainly due to the fact that
      apic_timer_fn() expects to run during a kvm exit. It
      sets KVM_REQ_PENDING_TIMER and let it be handled on kvm
      entry. However, if the timer fires on a different core,
      we have to wait until the next kvm exit for the guest
      to see KVM_REQ_PENDING_TIMER set.
      
      This problem became visible after commit 9642d18e. This
      commit changed the timer migration code to always attempt
      to migrate timers away from nohz_full cores. While it's
      discussable if this is correct/desirable (I don't think
      it is), it's clear that the lapic emulation code has
      a requirement on firing the hrtimer in the same core
      where it was started. This is achieved by making the
      hrtimer pinned.
      
      Lastly, note that KVM has code to migrate timers when a
      vCPU is scheduled to run in different core. However, this
      forced migration may fail. When this happens, we can have
      the same problem. If we want 100% correctness, we'll have
      to modify apic_timer_fn() to cause a kvm exit when it runs
      on a different core than the vCPU. Not sure if this is
      possible.
      
      Here's a reproducer for the issue being fixed:
      
       1. Set all cores but core0 to be nohz_full cores
       2. Start a guest with a single vCPU
       3. Trace apic_timer_fn() and kvm_inject_apic_timer_irqs()
      
      You'll see that apic_timer_fn() will run in core0 while
      kvm_inject_apic_timer_irqs() runs in a different core. If
      you get both on core0, try running a program that takes 100%
      of the CPU and pin it to core0 to force the vCPU out.
      Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
      Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      61abdbe0
  5. 03 3月, 2016 2 次提交
  6. 25 2月, 2016 1 次提交
    • M
      KVM: Use simple waitqueue for vcpu->wq · 8577370f
      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>
      8577370f
  7. 17 2月, 2016 1 次提交
  8. 09 2月, 2016 5 次提交
  9. 26 11月, 2015 3 次提交
    • A
      kvm/x86: Hyper-V synthetic interrupt controller · 5c919412
      Andrey Smetanin 提交于
      SynIC (synthetic interrupt controller) is a lapic extension,
      which is controlled via MSRs and maintains for each vCPU
       - 16 synthetic interrupt "lines" (SINT's); each can be configured to
         trigger a specific interrupt vector optionally with auto-EOI
         semantics
       - a message page in the guest memory with 16 256-byte per-SINT message
         slots
       - an event flag page in the guest memory with 16 2048-bit per-SINT
         event flag areas
      
      The host triggers a SINT whenever it delivers a new message to the
      corresponding slot or flips an event flag bit in the corresponding area.
      The guest informs the host that it can try delivering a message by
      explicitly asserting EOI in lapic or writing to End-Of-Message (EOM)
      MSR.
      
      The userspace (qemu) triggers interrupts and receives EOM notifications
      via irqfd with resampler; for that, a GSI is allocated for each
      configured SINT, and irq_routing api is extended to support GSI-SINT
      mapping.
      
      Changes v4:
      * added activation of SynIC by vcpu KVM_ENABLE_CAP
      * added per SynIC active flag
      * added deactivation of APICv upon SynIC activation
      
      Changes v3:
      * added KVM_CAP_HYPERV_SYNIC and KVM_IRQ_ROUTING_HV_SINT notes into
      docs
      
      Changes v2:
      * do not use posted interrupts for Hyper-V SynIC AutoEOI vectors
      * add Hyper-V SynIC vectors into EOI exit bitmap
      * Hyper-V SyniIC SINT msr write logic simplified
      Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
      Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
      Signed-off-by: NDenis V. Lunev <den@openvz.org>
      CC: Gleb Natapov <gleb@kernel.org>
      CC: Paolo Bonzini <pbonzini@redhat.com>
      CC: Roman Kagan <rkagan@virtuozzo.com>
      CC: Denis V. Lunev <den@openvz.org>
      CC: qemu-devel@nongnu.org
      Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      5c919412
    • A
      kvm/x86: per-vcpu apicv deactivation support · d62caabb
      Andrey Smetanin 提交于
      The decision on whether to use hardware APIC virtualization used to be
      taken globally, based on the availability of the feature in the CPU
      and the value of a module parameter.
      
      However, under certain circumstances we want to control it on per-vcpu
      basis.  In particular, when the userspace activates HyperV synthetic
      interrupt controller (SynIC), APICv has to be disabled as it's
      incompatible with SynIC auto-EOI behavior.
      
      To achieve that, introduce 'apicv_active' flag on struct
      kvm_vcpu_arch, and kvm_vcpu_deactivate_apicv() function to turn APICv
      off.  The flag is initialized based on the module parameter and CPU
      capability, and consulted whenever an APICv-specific action is
      performed.
      Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
      Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
      Signed-off-by: NDenis V. Lunev <den@openvz.org>
      CC: Gleb Natapov <gleb@kernel.org>
      CC: Paolo Bonzini <pbonzini@redhat.com>
      CC: Roman Kagan <rkagan@virtuozzo.com>
      CC: Denis V. Lunev <den@openvz.org>
      CC: qemu-devel@nongnu.org
      Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      d62caabb
    • A
      kvm/x86: split ioapic-handled and EOI exit bitmaps · 6308630b
      Andrey Smetanin 提交于
      The function to determine if the vector is handled by ioapic used to
      rely on the fact that only ioapic-handled vectors were set up to
      cause vmexits when virtual apic was in use.
      
      We're going to break this assumption when introducing Hyper-V
      synthetic interrupts: they may need to cause vmexits too.
      
      To achieve that, introduce a new bitmap dedicated specifically for
      ioapic-handled vectors, and populate EOI exit bitmap from it for now.
      Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
      Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
      Signed-off-by: NDenis V. Lunev <den@openvz.org>
      CC: Gleb Natapov <gleb@kernel.org>
      CC: Paolo Bonzini <pbonzini@redhat.com>
      CC: Roman Kagan <rkagan@virtuozzo.com>
      CC: Denis V. Lunev <den@openvz.org>
      CC: qemu-devel@nongnu.org
      Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      6308630b
  10. 10 11月, 2015 1 次提交
  11. 04 11月, 2015 1 次提交
  12. 14 10月, 2015 1 次提交
  13. 01 10月, 2015 8 次提交
  14. 11 8月, 2015 1 次提交
  15. 23 7月, 2015 2 次提交
  16. 06 7月, 2015 1 次提交
  17. 04 7月, 2015 3 次提交
  18. 16 6月, 2015 1 次提交
    • R
      KVM: x86: fix lapic.timer_mode on restore · b6ac0695
      Radim Krčmář 提交于
      lapic.timer_mode was not properly initialized after migration, which
      broke few useful things, like login, by making every sleep eternal.
      
      Fix this by calling apic_update_lvtt in kvm_apic_post_state_restore.
      
      There are other slowpaths that update lvtt, so this patch makes sure
      something similar doesn't happen again by calling apic_update_lvtt
      after every modification.
      
      Cc: stable@vger.kernel.org
      Fixes: f30ebc31 ("KVM: x86: optimize some accesses to LVTT and SPIV")
      Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
      b6ac0695
  19. 04 6月, 2015 2 次提交