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  1. 28 Nov, 2012 12 commits
  3. 14 Nov, 2012 3 commits
  5. 01 Nov, 2012 2 commits
    • Marcelo Tosatti's avatar
      Merge branch 'for-queue' of https://github.com/agraf/linux-2.6 into queue · f026399f
      Marcelo Tosatti authored 
      * 'for-queue' of https://github.com/agraf/linux-2.6:
  PPC: ePAPR: Convert hcall header to uapi (round 2)
  KVM: PPC: Book3S HV: Fix thinko in try_lock_hpte()
  KVM: PPC: Book3S HV: Allow DTL to be set to address 0, length 0
  KVM: PPC: Book3S HV: Fix accounting of stolen time
  KVM: PPC: Book3S HV: Run virtual core whenever any vcpus in it can run
  KVM: PPC: Book3S HV: Fixes for late-joining threads
  KVM: PPC: Book3s HV: Don't access runnable threads list without vcore lock
  KVM: PPC: Book3S HV: Fix some races in starting secondary threads
  KVM: PPC: Book3S HV: Allow KVM guests to stop secondary threads coming online
  PPC: ePAPR: Convert header to uapi
  KVM: PPC: Move mtspr/mfspr emulation into own functions
  KVM: Documentation: Fix reentry-to-be-consistent paragraph
  KVM: PPC: 44x: fix DCR read/write
      f026399f
    • Joerg Roedel's avatar
      KVM: SVM: update MAINTAINERS entry · 7de609c8
      Joerg Roedel authored 
      I have no access to my AMD email address anymore. Update
entry in MAINTAINERS to the new address.

Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
      7de609c8
  7. 31 Oct, 2012 2 commits
  9. 30 Oct, 2012 12 commits
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Fix thinko in try_lock_hpte() · 8b5869ad
      Paul Mackerras authored 
      This fixes an error in the inline asm in try_lock_hpte() where we
were erroneously using a register number as an immediate operand.
The bug only affects an error path, and in fact the code will still
work as long as the compiler chooses some register other than r0
for the "bits" variable.  Nevertheless it should still be fixed.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      8b5869ad
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Allow DTL to be set to address 0, length 0 · 9f8c8c78
      Paul Mackerras authored 
      Commit 55b665b0 ("KVM: PPC: Book3S HV: Provide a way for userspace
to get/set per-vCPU areas") includes a check on the length of the
dispatch trace log (DTL) to make sure the buffer is at least one entry
long.  This is appropriate when registering a buffer, but the
interface also allows for any existing buffer to be unregistered by
specifying a zero address.  In this case the length check is not
appropriate.  This makes the check conditional on the address being
non-zero.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      9f8c8c78
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Fix accounting of stolen time · c7b67670
      Paul Mackerras authored 
      Currently the code that accounts stolen time tends to overestimate the
stolen time, and will sometimes report more stolen time in a DTL
(dispatch trace log) entry than has elapsed since the last DTL entry.
This can cause guests to underflow the user or system time measured
for some tasks, leading to ridiculous CPU percentages and total runtimes
being reported by top and other utilities.

In addition, the current code was designed for the previous policy where
a vcore would only run when all the vcpus in it were runnable, and so
only counted stolen time on a per-vcore basis.  Now that a vcore can
run while some of the vcpus in it are doing other things in the kernel
(e.g. handling a page fault), we need to count the time when a vcpu task
is preempted while it is not running as part of a vcore as stolen also.

To do this, we bring back the BUSY_IN_HOST vcpu state and extend the
vcpu_load/put functions to count preemption time while the vcpu is
in that state.  Handling the transitions between the RUNNING and
BUSY_IN_HOST states requires checking and updating two variables
(accumulated time stolen and time last preempted), so we add a new
spinlock, vcpu->arch.tbacct_lock.  This protects both the per-vcpu
stolen/preempt-time variables, and the per-vcore variables while this
vcpu is running the vcore.

Finally, we now don't count time spent in userspace as stolen time.
The task could be executing in userspace on behalf of the vcpu, or
it could be preempted, or the vcpu could be genuinely stopped.  Since
we have no way of dividing up the time between these cases, we don't
count any of it as stolen.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      c7b67670
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Run virtual core whenever any vcpus in it can run · 8455d79e
      Paul Mackerras authored 
      Currently the Book3S HV code implements a policy on multi-threaded
processors (i.e. POWER7) that requires all of the active vcpus in a
virtual core to be ready to run before we run the virtual core.
However, that causes problems on reset, because reset stops all vcpus
except vcpu 0, and can also reduce throughput since all four threads
in a virtual core have to wait whenever any one of them hits a
hypervisor page fault.

This relaxes the policy, allowing the virtual core to run as soon as
any vcpu in it is runnable.  With this, the KVMPPC_VCPU_STOPPED state
and the KVMPPC_VCPU_BUSY_IN_HOST state have been combined into a single
KVMPPC_VCPU_NOTREADY state, since we no longer need to distinguish
between them.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      8455d79e
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Fixes for late-joining threads · 2f12f034
      Paul Mackerras authored 
      If a thread in a virtual core becomes runnable while other threads
in the same virtual core are already running in the guest, it is
possible for the latecomer to join the others on the core without
first pulling them all out of the guest.  Currently this only happens
rarely, when a vcpu is first started.  This fixes some bugs and
omissions in the code in this case.

First, we need to check for VPA updates for the latecomer and make
a DTL entry for it.  Secondly, if it comes along while the master
vcpu is doing a VPA update, we don't need to do anything since the
master will pick it up in kvmppc_run_core.  To handle this correctly
we introduce a new vcore state, VCORE_STARTING.  Thirdly, there is
a race because we currently clear the hardware thread's hwthread_req
before waiting to see it get to nap.  A latecomer thread could have
its hwthread_req cleared before it gets to test it, and therefore
never increment the nap_count, leading to messages about wait_for_nap
timeouts.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      2f12f034
    • Paul Mackerras's avatar
      KVM: PPC: Book3s HV: Don't access runnable threads list without vcore lock · 913d3ff9
      Paul Mackerras authored 
      There were a few places where we were traversing the list of runnable
threads in a virtual core, i.e. vc->runnable_threads, without holding
the vcore spinlock.  This extends the places where we hold the vcore
spinlock to cover everywhere that we traverse that list.

Since we possibly need to sleep inside kvmppc_book3s_hv_page_fault,
this moves the call of it from kvmppc_handle_exit out to
kvmppc_vcpu_run, where we don't hold the vcore lock.

In kvmppc_vcore_blocked, we don't actually need to check whether
all vcpus are ceded and don't have any pending exceptions, since the
caller has already done that.  The caller (kvmppc_run_vcpu) wasn't
actually checking for pending exceptions, so we add that.

The change of if to while in kvmppc_run_vcpu is to make sure that we
never call kvmppc_remove_runnable() when the vcore state is RUNNING or
EXITING.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      913d3ff9
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Fix some races in starting secondary threads · 7b444c67
      Paul Mackerras authored 
      Subsequent patches implementing in-kernel XICS emulation will make it
possible for IPIs to arrive at secondary threads at arbitrary times.
This fixes some races in how we start the secondary threads, which
if not fixed could lead to occasional crashes of the host kernel.

This makes sure that (a) we have grabbed all the secondary threads,
and verified that they are no longer in the kernel, before we start
any thread, (b) that the secondary thread loads its vcpu pointer
after clearing the IPI that woke it up (so we don't miss a wakeup),
and (c) that the secondary thread clears its vcpu pointer before
incrementing the nap count.  It also removes unnecessary setting
of the vcpu and vcore pointers in the paca in kvmppc_core_vcpu_load.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      7b444c67
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Allow KVM guests to stop secondary threads coming online · 512691d4
      Paul Mackerras authored 
      When a Book3S HV KVM guest is running, we need the host to be in
single-thread mode, that is, all of the cores (or at least all of
the cores where the KVM guest could run) to be running only one
active hardware thread.  This is because of the hardware restriction
in POWER processors that all of the hardware threads in the core
must be in the same logical partition.  Complying with this restriction
is much easier if, from the host kernel's point of view, only one
hardware thread is active.

This adds two hooks in the SMP hotplug code to allow the KVM code to
make sure that secondary threads (i.e. hardware threads other than
thread 0) cannot come online while any KVM guest exists.  The KVM
code still has to check that any core where it runs a guest has the
secondary threads offline, but having done that check it can now be
sure that they will not come online while the guest is running.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Acked-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      512691d4
    • Alexander Graf's avatar
      PPC: ePAPR: Convert header to uapi · c99ec973
      Alexander Graf authored 
      The new uapi framework splits kernel internal and user space exported
bits of header files more cleanly. Adjust the ePAPR header accordingly.
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      c99ec973
    • Alexander Graf's avatar
      KVM: PPC: Move mtspr/mfspr emulation into own functions · 388cf9ee
      Alexander Graf authored 
      The mtspr/mfspr emulation code became quite big over time. Move it
into its own function so things stay more readable.
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      388cf9ee
    • Alexander Graf's avatar
      KVM: Documentation: Fix reentry-to-be-consistent paragraph · 686de182
      Alexander Graf authored 
      All user space offloaded instruction emulation needs to reenter kvm
to produce consistent state again. Fix the section in the documentation
to mention all of them.
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
      686de182
    • Alexander Graf's avatar
      KVM: PPC: 44x: fix DCR read/write · e43a0287
      Alexander Graf authored 
      When remembering the direction of a DCR transaction, we should write
to the same variable that we interpret on later when doing vcpu_run
again.
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Cc: stable@vger.kernel.org
      e43a0287
  11. 29 Oct, 2012 4 commits
  13. 28 Oct, 2012 5 commits
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