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  1. 05 3月, 2008 33 次提交
  3. 04 3月, 2008 7 次提交
    • R
      freezer vs stopped or traced · 13b1c3d4
      由 Roland McGrath 提交于 
      This changes the "freezer" code used by suspend/hibernate in its treatment
of tasks in TASK_STOPPED (job control stop) and TASK_TRACED (ptrace) states.

As I understand it, the intent of the "freezer" is to hold all tasks
from doing anything significant.  For this purpose, TASK_STOPPED and
TASK_TRACED are "frozen enough".  It's possible the tasks might resume
from ptrace calls (if the tracer were unfrozen) or from signals
(including ones that could come via timer interrupts, etc).  But this
doesn't matter as long as they quickly block again while "freezing" is
in effect.  Some minor adjustments to the signal.c code make sure that
try_to_freeze() very shortly follows all wakeups from both kinds of
stop.  This lets the freezer code safely leave stopped tasks unmolested.

Changing this fixes the longstanding bug of seeing after resuming from
suspend/hibernate your shell report "[1] Stopped" and the like for all
your jobs stopped by ^Z et al, as if you had freshly fg'd and ^Z'd them.
It also removes from the freezer the arcane special case treatment for
ptrace'd tasks, which relied on intimate knowledge of ptrace internals.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      13b1c3d4
    • R
      x86: disable KVM for Voyager and friends · 1a4e3f89
      由 Randy Dunlap 提交于 
      Most classic Pentiums don't have hardware virtualization extension,
and building kvm with Voyager, Visual Workstation, or NUMAQ
generates spurious failures.
Signed-off-by: NAvi Kivity <avi@qumranet.com>
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
      1a4e3f89
    • A
      KVM: VMX: Avoid rearranging switched guest msrs while they are loaded · 33f9c505
      由 Avi Kivity 提交于 
      KVM tries to run as much as possible with the guest msrs loaded instead of
host msrs, since switching msrs is very expensive.  It also tries to minimize
the number of msrs switched according to the guest mode; for example,
MSR_LSTAR is needed only by long mode guests.  This optimization is done by
setup_msrs().

However, we must not change which msrs are switched while we are running with
guest msr state:

 - switch to guest msr state
 - call setup_msrs(), removing some msrs from the list
 - switch to host msr state, leaving a few guest msrs loaded

An easy way to trigger this is to kexec an x86_64 linux guest.  Early during
setup, the guest will switch EFER to not include SCE.  KVM will stop saving
MSR_LSTAR, and on the next msr switch it will leave the guest LSTAR loaded.
The next host syscall will end up in a random location in the kernel.

Fix by reloading the host msrs before changing the msr list.
Signed-off-by: NAvi Kivity <avi@qumranet.com>
      33f9c505
    • A
      KVM: MMU: Fix race when instantiating a shadow pte · f7d9c7b7
      由 Avi Kivity 提交于 
      For improved concurrency, the guest walk is performed concurrently with other
vcpus.  This means that we need to revalidate the guest ptes once we have
write-protected the guest page tables, at which point they can no longer be
modified.

The current code attempts to avoid this check if the shadow page table is not
new, on the assumption that if it has existed before, the guest could not have
modified the pte without the shadow lock.  However the assumption is incorrect,
as the racing vcpu could have modified the pte, then instantiated the shadow
page, before our vcpu regains control:

  vcpu0        vcpu1

  fault
  walk pte

               modify pte
               fault in same pagetable
               instantiate shadow page

  lookup shadow page
  conclude it is old
  instantiate spte based on stale guest pte

We could do something clever with generation counters, but a test run by
Marcelo suggests this is unnecessary and we can just do the revalidation
unconditionally.  The pte will be in the processor cache and the check can
be quite fast.
Signed-off-by: NAvi Kivity <avi@qumranet.com>
      f7d9c7b7
    • A
      KVM: Route irq 0 to vcpu 0 exclusively · 8c35f237
      由 Avi Kivity 提交于 
      Some Linux versions allow the timer interrupt to be processed by more than
one cpu, leading to hangs due to tsc instability.  Work around the issue
by only disaptching the interrupt to vcpu 0.

Problem analyzed (and patch tested) by Sheng Yang.
Signed-off-by: NAvi Kivity <avi@qumranet.com>
      8c35f237
    • A
      KVM: Avoid infinite-frequency local apic timer · 0b975a3c
      由 Avi Kivity 提交于 
      If the local apic initial count is zero, don't start a an hrtimer with infinite
frequency, locking up the host.
Signed-off-by: NAvi Kivity <avi@qumranet.com>
      0b975a3c
    • M
      KVM: make MMU_DEBUG compile again · 24993d53
      由 Marcelo Tosatti 提交于 
      the cr3 variable is now inside the vcpu->arch structure.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>
      24993d53