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  1. Mar 27, 2014
  3. Mar 25, 2014
  5. Mar 24, 2014
  7. Mar 21, 2014
  9. Mar 20, 2014
    • James Hogan's avatar
      MIPS: KVM: Remove dead code in CP0 emulation · 36c95494
      James Hogan authored 
      

The code to check whether rd > MIPS_CP0_DESAVE is dead code, since
MIPS_CP0_DESAVE = 31 and rd is already masked with 0x1f. Remove it.

Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sanjay Lal <sanjayl@kymasys.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      36c95494
    • James Hogan's avatar
      MIPS: KVM: Consult HWREna before emulating RDHWR · 26f4f3b5
      James Hogan authored 
      

The ability to read hardware registers from userland with the RDHWR
instruction should depend upon the corresponding bit of the HWREna
register being set, otherwise a reserved instruction exception should be
generated.

However KVM's current emulation ignores the guest's HWREna and always
emulates RDHWR instructions even if the guest OS has disallowed them.

Therefore rework the RDHWR emulation code to check for privilege or the
corresponding bit in the guest HWREna bit. Also remove the #if 0 case
for the UserLocal register. I presume it was there for debug purposes
but it seems unnecessary now that the guest can control whether it
causes a guest exception.

Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sanjay Lal <sanjayl@kymasys.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      26f4f3b5
    • James Hogan's avatar
      MIPS: KVM: Pass reserved instruction exceptions to guest · 15505679
      James Hogan authored 
      

Previously a reserved instruction exception while in guest code would
cause a KVM internal error if kvm_mips_handle_ri() didn't recognise the
instruction (including a RDHWR from an unrecognised hardware register).

However the guest OS should really have the opportunity to catch the
exception so that it can take the appropriate actions such as sending a
SIGILL to the guest user process or emulating the instruction itself.

Therefore in these cases emulate a guest RI exception and only return
EMULATE_FAIL if that fails, being careful to revert the PC first in case
the exception occurred in a branch delay slot in which case the PC will
already point to the branch target.

Also turn the printk messages relating to these cases into kvm_debug
messages so that they aren't usually visible.

This allows crashme to run in the guest without killing the entire VM.

Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sanjay Lal <sanjayl@kymasys.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      15505679
    • James Hogan's avatar
      MIPS: KVM: asm/kvm_host.h: Clean up whitespace · 22027945
      James Hogan authored 
      

The whitespace in asm/kvm_host.h is quite inconsistent in places. Clean
up the whole file to use tabs more consistently.

When you use the --ignore-space-change argument to git diff this patch
only changes line wrapping in TLB_IS_GLOBAL and TLB_IS_VALID macros.

Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sanjay Lal <sanjayl@kymasys.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      22027945
  11. Mar 19, 2014
    • Cornelia Huck's avatar
      KVM: eventfd: Fix lock order inversion. · 684a0b71
      Cornelia Huck authored 
      

When registering a new irqfd, we call its ->poll method to collect any
event that might have previously been pending so that we can trigger it.
This is done under the kvm->irqfds.lock, which means the eventfd's ctx
lock is taken under it.

However, if we get a POLLHUP in irqfd_wakeup, we will be called with the
ctx lock held before getting the irqfds.lock to deactivate the irqfd,
causing lockdep to complain.

Calling the ->poll method does not really need the irqfds.lock, so let's
just move it after we've given up the irqfds.lock in kvm_irqfd_assign().

Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      684a0b71
  13. Mar 17, 2014
  15. Mar 14, 2014
  17. Mar 13, 2014
    • Gabriel L. Somlo's avatar
      kvm: x86: ignore ioapic polarity · 100943c5
      Gabriel L. Somlo authored 
      

Both QEMU and KVM have already accumulated a significant number of
optimizations based on the hard-coded assumption that ioapic polarity
will always use the ActiveHigh convention, where the logical and
physical states of level-triggered irq lines always match (i.e.,
active(asserted) == high == 1, inactive == low == 0). QEMU guests
are expected to follow directions given via ACPI and configure the
ioapic with polarity 0 (ActiveHigh). However, even when misbehaving
guests (e.g. OS X <= 10.9) set the ioapic polarity to 1 (ActiveLow),
QEMU will still use the ActiveHigh signaling convention when
interfacing with KVM.

This patch modifies KVM to completely ignore ioapic polarity as set by
the guest OS, enabling misbehaving guests to work alongside those which
comply with the ActiveHigh polarity specified by QEMU's ACPI tables.

Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarGabriel L. Somlo <somlo@cmu.edu>
[Move documentation to KVM_IRQ_LINE, add ia64. - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      100943c5
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Fix register usage when loading/saving VRSAVE · e724f080
      Paul Mackerras authored 
      Commit 595e4f7e

 ("KVM: PPC: Book3S HV: Use load/store_fp_state
functions in HV guest entry/exit") changed the register usage in
kvmppc_save_fp() and kvmppc_load_fp() but omitted changing the
instructions that load and save VRSAVE.  The result is that the
VRSAVE value was loaded from a constant address, and saved to a
location past the end of the vcpu struct, causing host kernel
memory corruption and various kinds of host kernel crashes.

This fixes the problem by using register r31, which contains the
vcpu pointer, instead of r3 and r4.

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      e724f080
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Remove bogus duplicate code · a5b0ccb0
      Paul Mackerras authored 
      Commit 7b490411

 ("KVM: PPC: Book3S HV: Add new state for
transactional memory") incorrectly added some duplicate code to the
guest exit path because I didn't manage to clean up after a rebase
correctly.  This removes the extraneous material.  The presence of
this extraneous code causes host crashes whenever a guest is run.

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      a5b0ccb0
  19. Mar 11, 2014
    • Paolo Bonzini's avatar
      KVM: svm: Allow the guest to run with dirty debug registers · facb0139
      Paolo Bonzini authored 
      

When not running in guest-debug mode (i.e. the guest controls the debug
registers, having to take an exit for each DR access is a waste of time.
If the guest gets into a state where each context switch causes DR to be
saved and restored, this can take away as much as 40% of the execution
time from the guest.

If the guest is running with vcpu->arch.db == vcpu->arch.eff_db, we
can let it write freely to the debug registers and reload them on the
next exit.  We still need to exit on the first access, so that the
KVM_DEBUGREG_WONT_EXIT flag is set in switch_db_regs; after that, further
accesses to the debug registers will not cause a vmexit.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      facb0139
    • Paolo Bonzini's avatar
      KVM: svm: set/clear all DR intercepts in one swoop · 5315c716
      Paolo Bonzini authored 
      

Unlike other intercepts, debug register intercepts will be modified
in hot paths if the guest OS is bad or otherwise gets tricked into
doing so.

Avoid calling recalc_intercepts 16 times for debug registers.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      5315c716
    • Paolo Bonzini's avatar
      KVM: nVMX: Allow nested guests to run with dirty debug registers · d16c293e
      Paolo Bonzini authored 
      

When preparing the VMCS02, the CPU-based execution controls is computed
by vmx_exec_control.  Turn off DR access exits there, too, if the
KVM_DEBUGREG_WONT_EXIT bit is set in switch_db_regs.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      d16c293e
    • Paolo Bonzini's avatar
      KVM: vmx: Allow the guest to run with dirty debug registers · 81908bf4
      Paolo Bonzini authored 
      

When not running in guest-debug mode (i.e. the guest controls the debug
registers, having to take an exit for each DR access is a waste of time.
If the guest gets into a state where each context switch causes DR to be
saved and restored, this can take away as much as 40% of the execution
time from the guest.

If the guest is running with vcpu->arch.db == vcpu->arch.eff_db, we
can let it write freely to the debug registers and reload them on the
next exit.  We still need to exit on the first access, so that the
KVM_DEBUGREG_WONT_EXIT flag is set in switch_db_regs; after that, further
accesses to the debug registers will not cause a vmexit.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      81908bf4
    • Paolo Bonzini's avatar
      KVM: x86: Allow the guest to run with dirty debug registers · c77fb5fe
      Paolo Bonzini authored 
      

When not running in guest-debug mode, the guest controls the debug
registers and having to take an exit for each DR access is a waste
of time.  If the guest gets into a state where each context switch
causes DR to be saved and restored, this can take away as much as 40%
of the execution time from the guest.

After this patch, VMX- and SVM-specific code can set a flag in
switch_db_regs, telling vcpu_enter_guest that on the next exit the debug
registers might be dirty and need to be reloaded (syncing will be taken
care of by a new callback in kvm_x86_ops).  This flag can be set on the
first access to a debug registers, so that multiple accesses to the
debug registers only cause one vmexit.

Note that since the guest will be able to read debug registers and
enable breakpoints in DR7, we need to ensure that they are synchronized
on entry to the guest---including DR6 that was not synced before.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      c77fb5fe
    • Paolo Bonzini's avatar
      KVM: x86: change vcpu->arch.switch_db_regs to a bit mask · 360b948d
      Paolo Bonzini authored 
      

The next patch will add another bit that we can test with the
same "if".

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      360b948d
    • Paolo Bonzini's avatar
      KVM: vmx: we do rely on loading DR7 on entry · c845f9c6
      Paolo Bonzini authored 
      

Currently, this works even if the bit is not in "min", because the bit is always
set in MSR_IA32_VMX_ENTRY_CTLS.  Mention it for the sake of documentation, and
to avoid surprises if we later switch to MSR_IA32_VMX_TRUE_ENTRY_CTLS.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      c845f9c6
    • Jan Kiszka's avatar
      KVM: x86: Remove return code from enable_irq/nmi_window · c9a7953f
      Jan Kiszka authored 
      

It's no longer possible to enter enable_irq_window in guest mode when
L1 intercepts external interrupts and we are entering L2. This is now
caught in vcpu_enter_guest. So we can remove the check from the VMX
version of enable_irq_window, thus the need to return an error code from
both enable_irq_window and enable_nmi_window.

Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      c9a7953f