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  1. 03 8月, 2015 1 次提交
  3. 22 7月, 2015 2 次提交
    • H
      s390/kernel: lazy restore fpu registers · 9977e886
      由 Hendrik Brueckner 提交于 
      Improve the save and restore behavior of FPU register contents to use the
vector extension within the kernel.

The kernel does not use floating-point or vector registers and, therefore,
saving and restoring the FPU register contents are performed for handling
signals or switching processes only.  To prepare for using vector
instructions and vector registers within the kernel, enhance the save
behavior and implement a lazy restore at return to user space from a
system call or interrupt.

To implement the lazy restore, the save_fpu_regs() sets a CPU information
flag, CIF_FPU, to indicate that the FPU registers must be restored.
Saving and setting CIF_FPU is performed in an atomic fashion to be
interrupt-safe.  When the kernel wants to use the vector extension or
wants to change the FPU register state for a task during signal handling,
the save_fpu_regs() must be called first.  The CIF_FPU flag is also set at
process switch.  At return to user space, the FPU state is restored.  In
particular, the FPU state includes the floating-point or vector register
contents, as well as, vector-enablement and floating-point control.  The
FPU state restore and clearing CIF_FPU is also performed in an atomic
fashion.

For KVM, the restore of the FPU register state is performed when restoring
the general-purpose guest registers before the SIE instructions is started.
Because the path towards the SIE instruction is interruptible, the CIF_FPU
flag must be checked again right before going into SIE.  If set, the guest
registers must be reloaded again by re-entering the outer SIE loop.  This
is the same behavior as if the SIE critical section is interrupted.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      9977e886
    • H
      s390/kvm: validate the floating-point control before restoring it · 96b2d7a8
      由 Hendrik Brueckner 提交于 
      The kvm_arch_vcpu_load() does not validate whether the floating-point
control (FPC) is valid.  Further, the return code of the restore is not
checked too.  If the FPC is invalid, the restore fails and the host FPC
value might remain.  The correct behavior would be to clear the FPC if it
is not valid.  Hence, validate the FPC value and, optionally, reset the
value before restoring it.
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      96b2d7a8
  5. 23 6月, 2015 1 次提交
  7. 02 6月, 2015 2 次提交
  9. 28 5月, 2015 1 次提交
  11. 26 5月, 2015 2 次提交
  13. 13 5月, 2015 1 次提交
  15. 08 5月, 2015 9 次提交
  17. 07 5月, 2015 1 次提交
    • C
      KVM: provide irq_unsafe kvm_guest_{enter|exit} · 0097d12e
      由 Christian Borntraeger 提交于 
      Several kvm architectures disable interrupts before kvm_guest_enter.
kvm_guest_enter then uses local_irq_save/restore to disable interrupts
again or for the first time. Lets provide underscore versions of
kvm_guest_{enter|exit} that assume being called locked.
kvm_guest_enter now disables interrupts for the full function and
thus we can remove the check for preemptible.

This patch then adopts s390/kvm to use local_irq_disable/enable calls
which are slighty cheaper that local_irq_save/restore and call these
new functions.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      0097d12e
  19. 15 4月, 2015 1 次提交
  21. 08 4月, 2015 1 次提交
  23. 01 4月, 2015 6 次提交
  25. 31 3月, 2015 2 次提交
    • C
      KVM: s390: enable more features that need no hypervisor changes · a3ed8dae
      由 Christian Borntraeger 提交于 
      After some review about what these facilities do, the following
facilities will work under KVM and can, therefore, be reported
to the guest if the cpu model and the host cpu provide this bit.

There are plans underway to make the whole bit thing more readable,
but its not yet finished. So here are some last bit changes and
we enhance the KVM mask with:

9 The sense-running-status facility is installed in the
  z/Architecture architectural mode.
  ---> handled by SIE or KVM

10 The conditional-SSKE facility is installed in the
   z/Architecture architectural mode.
  ---> handled by SIE. KVM will retry SIE

13 The IPTE-range facility is installed in the
   z/Architecture architectural mode.
  ---> handled by SIE. KVM will retry SIE

36 The enhanced-monitor facility is installed in the
   z/Architecture architectural mode.
  ---> handled by SIE

47 The CMPSC-enhancement facility is installed in the
   z/Architecture architectural mode.
  ---> handled by SIE

48 The decimal-floating-point zoned-conversion facility
   is installed in the z/Architecture architectural mode.
  ---> handled by SIE

49 The execution-hint, load-and-trap, miscellaneous-
   instruction-extensions and processor-assist
  ---> handled by SIE

51 The local-TLB-clearing facility is installed in the
   z/Architecture architectural mode.
  ---> handled by SIE

52 The interlocked-access facility 2 is installed.
  ---> handled by SIE

53 The load/store-on-condition facility 2 and load-and-
   zero-rightmost-byte facility are installed in the
   z/Architecture architectural mode.
  ---> handled by SIE

57 The message-security-assist-extension-5 facility is
  installed in the z/Architecture architectural mode.
  ---> handled by SIE

66 The reset-reference-bits-multiple facility is installed
  in the z/Architecture architectural mode.
  ---> handled by SIE. KVM will retry SIE

80 The decimal-floating-point packed-conversion
   facility is installed in the z/Architecture architectural
   mode.
  ---> handled by SIE
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Tested-by: NMichael Mueller <mimu@linux.vnet.ibm.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
      a3ed8dae
    • D
      KVM: s390: store the breaking-event address on pgm interrupts · 2ba45968
      由 David Hildenbrand 提交于 
      If the PER-3 facility is installed, the breaking-event address is to be
stored in the low core.

There is no facility bit for PER-3 in stfl(e) and Linux always uses the
value at address 272 no matter if PER-3 is available or not.
We can't hide its existence from the guest. All program interrupts
injected via the SIE automatically store this information if the PER-3
facility is available in the hypervisor. Also the itdb contains the
address automatically.

As there is no switch to turn this mechanism off, let's simply make it
consistent and also store the breaking event address in case of manual
program interrupt injection.
Reviewed-by: NJens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
      2ba45968
  27. 27 3月, 2015 1 次提交
  29. 17 3月, 2015 9 次提交