Commit Graph

169 Commits

Author SHA1 Message Date
Paolo Bonzini f781951299 kvm: add halt_poll_ns module parameter
This patch introduces a new module parameter for the KVM module; when it
is present, KVM attempts a bit of polling on every HLT before scheduling
itself out via kvm_vcpu_block.

This parameter helps a lot for latency-bound workloads---in particular
I tested it with O_DSYNC writes with a battery-backed disk in the host.
In this case, writes are fast (because the data doesn't have to go all
the way to the platters) but they cannot be merged by either the host or
the guest.  KVM's performance here is usually around 30% of bare metal,
or 50% if you use cache=directsync or cache=writethrough (these
parameters avoid that the guest sends pointless flush requests, and
at the same time they are not slow because of the battery-backed cache).
The bad performance happens because on every halt the host CPU decides
to halt itself too.  When the interrupt comes, the vCPU thread is then
migrated to a new physical CPU, and in general the latency is horrible
because the vCPU thread has to be scheduled back in.

With this patch performance reaches 60-65% of bare metal and, more
important, 99% of what you get if you use idle=poll in the guest.  This
means that the tunable gets rid of this particular bottleneck, and more
work can be done to improve performance in the kernel or QEMU.

Of course there is some price to pay; every time an otherwise idle vCPUs
is interrupted by an interrupt, it will poll unnecessarily and thus
impose a little load on the host.  The above results were obtained with
a mostly random value of the parameter (500000), and the load was around
1.5-2.5% CPU usage on one of the host's core for each idle guest vCPU.

The patch also adds a new stat, /sys/kernel/debug/kvm/halt_successful_poll,
that can be used to tune the parameter.  It counts how many HLT
instructions received an interrupt during the polling period; each
successful poll avoids that Linux schedules the VCPU thread out and back
in, and may also avoid a likely trip to C1 and back for the physical CPU.

While the VM is idle, a Linux 4 VCPU VM halts around 10 times per second.
Of these halts, almost all are failed polls.  During the benchmark,
instead, basically all halts end within the polling period, except a more
or less constant stream of 50 per second coming from vCPUs that are not
running the benchmark.  The wasted time is thus very low.  Things may
be slightly different for Windows VMs, which have a ~10 ms timer tick.

The effect is also visible on Marcelo's recently-introduced latency
test for the TSC deadline timer.  Though of course a non-RT kernel has
awful latency bounds, the latency of the timer is around 8000-10000 clock
cycles compared to 20000-120000 without setting halt_poll_ns.  For the TSC
deadline timer, thus, the effect is both a smaller average latency and
a smaller variance.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-06 13:08:37 +01:00
Alexander Graf 8d0eff6385 KVM: PPC: Pass enum to kvmppc_get_last_inst
The kvmppc_get_last_inst function recently received a facelift that allowed
us to pass an enum of the type of instruction we want to read into it rather
than an unreadable boolean.

Unfortunately, not all callers ended up passing the enum. This wasn't really
an issue as "true" and "false" happen to match the two enum values we have,
but it's still hard to read.

Update all callers of kvmppc_get_last_inst() to follow the new calling
convention.

Signed-off-by: Alexander Graf <agraf@suse.de>
2014-09-22 10:11:36 +02:00
Madhavan Srinivasan 033aaa14af powerpc/kvm: common sw breakpoint instr across ppc
This patch extends the use of illegal instruction as software
breakpoint instruction across the ppc platform. Patch extends
booke program interrupt code to support software breakpoint.

Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
[agraf: Fix bookehv]
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-09-22 10:11:36 +02:00
Mihai Caraman d02d4d156e KVM: PPC: Remove the tasklet used by the hrtimer
Powerpc timer implementation is a copycat version of s390. Now that they removed
the tasklet with commit ea74c0ea1b follow this
optimization.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Bogdan Purcareata <bogdan.purcareata@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-09-22 10:11:34 +02:00
Bharat Bhushan 2f699a59f3 KVM: PPC: BOOKE: Emulate debug registers and exception
This patch emulates debug registers and debug exception
to support guest using debug resource. This enables running
gdb/kgdb etc in guest.

On BOOKE architecture we cannot share debug resources between QEMU and
guest because:
    When QEMU is using debug resources then debug exception must
    be always enabled. To achieve this we set MSR_DE and also set
    MSRP_DEP so guest cannot change MSR_DE.

    When emulating debug resource for guest we want guest
    to control MSR_DE (enable/disable debug interrupt on need).

    So above mentioned two configuration cannot be supported
    at the same time. So the result is that we cannot share
    debug resources between QEMU and Guest on BOOKE architecture.

In the current design QEMU gets priority over guest, this means that if
QEMU is using debug resources then guest cannot use them and if guest is
using debug resource then QEMU can overwrite them.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-09-22 10:11:33 +02:00
Mihai Caraman 8a41ea53b3 KVM: PPC: Make ONE_REG powerpc generic
Make ONE_REG generic for server and embedded architectures by moving
kvm_vcpu_ioctl_get_one_reg() and kvm_vcpu_ioctl_set_one_reg() functions
to powerpc layer.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-09-22 10:11:33 +02:00
Mihai Caraman 95d80a294b KVM: PPC: Book3e: Add AltiVec support
Add AltiVec support in KVM for Book3e. FPU support gracefully reuse host
infrastructure so follow the same approach for AltiVec.

Book3e specification defines shared interrupt numbers for SPE and AltiVec
units. Still SPE is present in e200/e500v2 cores while AltiVec is present in
e6500 core. So we can currently decide at compile-time which of the SPE or
AltiVec units to support exclusively by using CONFIG_SPE_POSSIBLE and
CONFIG_PPC_E500MC defines. As Alexander Graf suggested, keep SPE and AltiVec
exception handlers distinct to improve code readability.

Guests have the privilege to enable AltiVec, so we always need to support
AltiVec in KVM and implicitly in host to reflect interrupts and to save/restore
the unit context. KVM will be loaded on cores with AltiVec unit only if
CONFIG_ALTIVEC is defined. Use this define to guard KVM AltiVec logic.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-09-22 10:11:32 +02:00
Mihai Caraman 3efc7da61f KVM: PPC: Book3E: Increase FPU laziness
Increase FPU laziness by loading the guest state into the unit before entering
the guest instead of doing it on each vcpu schedule. Without this improvement
an interrupt may claim floating point corrupting guest state.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-09-22 10:11:32 +02:00
Bharat Bhushan 2c5096720f KVM: PPC: BOOKE: Add one reg interface for DBSR
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-09-22 10:11:30 +02:00
Bharat Bhushan 348ba71081 KVM: PPC: BOOKE: Guest and hardware visible debug registers are same
Guest visible debug register and hardware visible debug registers are
same, so ther is no need to have arch->shadow_dbg_reg, instead use
arch->dbg_reg.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-09-22 10:11:30 +02:00
Bharat Bhushan 2190991e7c KVM: PPC: BOOKE: Clear guest dbsr in userspace exit KVM_EXIT_DEBUG
Dbsr is not visible to userspace and we do not think any need to
expose this to userspace because:
  Userspace cannot inject debug interrupt to guest (as this
  does not know guest ability to handle debug interrupt), so
  userspace will always clear DBSR.
  Now if userspace has to always clear DBSR in KVM_EXIT_DEBUG
  handling then clearing dbsr in kernel looks simple as this
  avoid doing SET_SREGS/set_one_reg() to clear DBSR

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-09-22 10:11:30 +02:00
Bharat Bhushan 9fee7563cd KVM: PPC: BOOKE: allow debug interrupt at "debug level"
Debug interrupt can be either "critical level" or "debug level".
There are separate set of save/restore registers used for different level.
Example: DSRR0/DSRR1 are used for "debug level" and CSRR0/CSRR1
are used for critical level debug interrupt.

Using CPU_FTR_DEBUG_LVL_EXC to decide which interrupt level to be used.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-09-22 10:11:29 +02:00
Alexander Graf ce91ddc471 KVM: PPC: Remove DCR handling
DCR handling was only needed for 440 KVM. Since we removed it, we can also
remove handling of DCR accesses.

Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28 19:29:15 +02:00
Alexander Graf 8de12015ff KVM: PPC: Expose helper functions for data/inst faults
We're going to implement guest code interpretation in KVM for some rare
corner cases. This code needs to be able to inject data and instruction
faults into the guest when it encounters them.

Expose generic APIs to do this in a reasonably subarch agnostic fashion.

Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28 18:30:18 +02:00
Alexander Graf 7d15c06f1a KVM: PPC: Implement kvmppc_xlate for all targets
We have a nice API to find the translated GPAs of a GVA including protection
flags. So far we only use it on Book3S, but there's no reason the same shouldn't
be used on BookE as well.

Implement a kvmppc_xlate() version for BookE and clean it up to make it more
readable in general.

Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28 16:15:50 +02:00
Mihai Caraman f5250471b2 KVM: PPC: Bookehv: Get vcpu's last instruction for emulation
On book3e, KVM uses load external pid (lwepx) dedicated instruction to read
guest last instruction on the exit path. lwepx exceptions (DTLB_MISS, DSI
and LRAT), generated by loading a guest address, needs to be handled by KVM.
These exceptions are generated in a substituted guest translation context
(EPLC[EGS] = 1) from host context (MSR[GS] = 0).

Currently, KVM hooks only interrupts generated from guest context (MSR[GS] = 1),
doing minimal checks on the fast path to avoid host performance degradation.
lwepx exceptions originate from host state (MSR[GS] = 0) which implies
additional checks in DO_KVM macro (beside the current MSR[GS] = 1) by looking
at the Exception Syndrome Register (ESR[EPID]) and the External PID Load Context
Register (EPLC[EGS]). Doing this on each Data TLB miss exception is obvious
too intrusive for the host.

Read guest last instruction from kvmppc_load_last_inst() by searching for the
physical address and kmap it. This address the TODO for TLB eviction and
execute-but-not-read entries, and allow us to get rid of lwepx until we are
able to handle failures.

A simple stress benchmark shows a 1% sys performance degradation compared with
previous approach (lwepx without failure handling):

time for i in `seq 1 10000`; do /bin/echo > /dev/null; done

real    0m 8.85s
user    0m 4.34s
sys     0m 4.48s

vs

real    0m 8.84s
user    0m 4.36s
sys     0m 4.44s

A solution to use lwepx and to handle its exceptions in KVM would be to temporary
highjack the interrupt vector from host. This imposes additional synchronizations
for cores like FSL e6500 that shares host IVOR registers between hardware threads.
This optimized solution can be later developed on top of this patch.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28 15:23:14 +02:00
Mihai Caraman 51f047261e KVM: PPC: Allow kvmppc_get_last_inst() to fail
On book3e, guest last instruction is read on the exit path using load
external pid (lwepx) dedicated instruction. This load operation may fail
due to TLB eviction and execute-but-not-read entries.

This patch lay down the path for an alternative solution to read the guest
last instruction, by allowing kvmppc_get_lat_inst() function to fail.
Architecture specific implmentations of kvmppc_load_last_inst() may read
last guest instruction and instruct the emulation layer to re-execute the
guest in case of failure.

Make kvmppc_get_last_inst() definition common between architectures.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28 15:23:14 +02:00
Bharat Bhushan 34f754b99e kvm: ppc: Add SPRN_EPR get helper function
kvmppc_set_epr() is already defined in asm/kvm_ppc.h, So
rename and move get_epr helper function to same file.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
[agraf: remove duplicate return]
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28 15:23:13 +02:00
Bharat Bhushan c1b8a01bf9 kvm: ppc: booke: Use the shared struct helpers for SPRN_SPRG0-7
Use kvmppc_set_sprg[0-7]() and kvmppc_get_sprg[0-7]() helper
functions

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28 15:23:12 +02:00
Bharat Bhushan dc168549d9 kvm: ppc: booke: Add shared struct helpers of SPRN_ESR
Add and use kvmppc_set_esr() and kvmppc_get_esr() helper functions

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28 15:23:12 +02:00
Bharat Bhushan a5414d4b5e kvm: ppc: booke: Use the shared struct helpers of SPRN_DEAR
Uses kvmppc_set_dar() and kvmppc_get_dar() helper functions

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28 15:23:12 +02:00
Bharat Bhushan 31579eea69 kvm: ppc: booke: Use the shared struct helpers of SRR0 and SRR1
Use kvmppc_set_srr0/srr1() and kvmppc_get_srr0/srr1() helper functions

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28 15:23:11 +02:00
Paolo Bonzini b73117c493 Merge branch 'kvm-ppc-next' of git://github.com/agraf/linux-2.6 into kvm-queue
Conflicts:
	arch/powerpc/kvm/book3s_hv_rmhandlers.S
	arch/powerpc/kvm/booke.c
2014-01-29 18:29:01 +01:00
Scott Wood 6c85f52b10 kvm/ppc: IRQ disabling cleanup
Simplify the handling of lazy EE by going directly from fully-enabled
to hard-disabled.  This replaces the lazy_irq_pending() check
(including its misplaced kvm_guest_exit() call).

As suggested by Tiejun Chen, move the interrupt disabling into
kvmppc_prepare_to_enter() rather than have each caller do it.  Also
move the IRQ enabling on heavyweight exit into
kvmppc_prepare_to_enter().

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-27 16:00:55 +01:00
Tiejun Chen 9bd880a2c8 KVM: PPC: Book3E HV: call RECONCILE_IRQ_STATE to sync the software state
Rather than calling hard_irq_disable() when we're back in C code
we can just call RECONCILE_IRQ_STATE to soft disable IRQs while
we're already in hard disabled state.

This should be functionally equivalent to the code before, but
cleaner and faster.

Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
[agraf: fix comment, commit message]
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-09 10:15:10 +01:00
Bharat Bhushan 08c9a188d0 kvm: powerpc: use caching attributes as per linux pte
KVM uses same WIM tlb attributes as the corresponding qemu pte.
For this we now search the linux pte for the requested page and
get these cache caching/coherency attributes from pte.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Reviewed-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-09 10:15:08 +01:00
Paul Mackerras 99dae3bad2 KVM: PPC: Load/save FP/VMX/VSX state directly to/from vcpu struct
Now that we have the vcpu floating-point and vector state stored in
the same type of struct as the main kernel uses, we can load that
state directly from the vcpu struct instead of having extra copies
to/from the thread_struct.  Similarly, when the guest state needs to
be saved, we can have it saved it directly to the vcpu struct by
setting the current->thread.fp_save_area and current->thread.vr_save_area
pointers.  That also means that we don't need to back up and restore
userspace's FP/vector state.  This all makes the code simpler and
faster.

Note that it's not necessary to save or modify current->thread.fpexc_mode,
since nothing in KVM uses or is affected by its value.  Nor is it
necessary to touch used_vr or used_vsr.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-09 10:15:02 +01:00
Paul Mackerras efff191223 KVM: PPC: Store FP/VSX/VMX state in thread_fp/vr_state structures
This uses struct thread_fp_state and struct thread_vr_state to store
the floating-point, VMX/Altivec and VSX state, rather than flat arrays.
This makes transferring the state to/from the thread_struct simpler
and allows us to unify the get/set_one_reg implementations for the
VSX registers.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-09 10:15:00 +01:00
Scott Wood f5f972102d powerpc/kvm/booke: Fix build break due to stack frame size warning
Commit ce11e48b7f ("KVM: PPC: E500: Add
userspace debug stub support") added "struct thread_struct" to the
stack of kvmppc_vcpu_run().  thread_struct is 1152 bytes on my build,
compared to 48 bytes for the recently-introduced "struct debug_reg".
Use the latter instead.

This fixes the following error:

cc1: warnings being treated as errors
arch/powerpc/kvm/booke.c: In function 'kvmppc_vcpu_run':
arch/powerpc/kvm/booke.c:760:1: error: the frame size of 1424 bytes is larger than 1024 bytes
make[2]: *** [arch/powerpc/kvm/booke.o] Error 1
make[1]: *** [arch/powerpc/kvm] Error 2
make[1]: *** Waiting for unfinished jobs....

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-12-11 00:12:44 +01:00
Linus Torvalds f080480488 Here are the 3.13 KVM changes. There was a lot of work on the PPC
side: the HV and emulation flavors can now coexist in a single kernel
 is probably the most interesting change from a user point of view.
 On the x86 side there are nested virtualization improvements and a
 few bugfixes.  ARM got transparent huge page support, improved
 overcommit, and support for big endian guests.
 
 Finally, there is a new interface to connect KVM with VFIO.  This
 helps with devices that use NoSnoop PCI transactions, letting the
 driver in the guest execute WBINVD instructions.  This includes
 some nVidia cards on Windows, that fail to start without these
 patches and the corresponding userspace changes.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM changes from Paolo Bonzini:
 "Here are the 3.13 KVM changes.  There was a lot of work on the PPC
  side: the HV and emulation flavors can now coexist in a single kernel
  is probably the most interesting change from a user point of view.

  On the x86 side there are nested virtualization improvements and a few
  bugfixes.

  ARM got transparent huge page support, improved overcommit, and
  support for big endian guests.

  Finally, there is a new interface to connect KVM with VFIO.  This
  helps with devices that use NoSnoop PCI transactions, letting the
  driver in the guest execute WBINVD instructions.  This includes some
  nVidia cards on Windows, that fail to start without these patches and
  the corresponding userspace changes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (146 commits)
  kvm, vmx: Fix lazy FPU on nested guest
  arm/arm64: KVM: PSCI: propagate caller endianness to the incoming vcpu
  arm/arm64: KVM: MMIO support for BE guest
  kvm, cpuid: Fix sparse warning
  kvm: Delete prototype for non-existent function kvm_check_iopl
  kvm: Delete prototype for non-existent function complete_pio
  hung_task: add method to reset detector
  pvclock: detect watchdog reset at pvclock read
  kvm: optimize out smp_mb after srcu_read_unlock
  srcu: API for barrier after srcu read unlock
  KVM: remove vm mmap method
  KVM: IOMMU: hva align mapping page size
  KVM: x86: trace cpuid emulation when called from emulator
  KVM: emulator: cleanup decode_register_operand() a bit
  KVM: emulator: check rex prefix inside decode_register()
  KVM: x86: fix emulation of "movzbl %bpl, %eax"
  kvm_host: typo fix
  KVM: x86: emulate SAHF instruction
  MAINTAINERS: add tree for kvm.git
  Documentation/kvm: add a 00-INDEX file
  ...
2013-11-15 13:51:36 +09:00
Aneesh Kumar K.V cbbc58d4fd kvm: powerpc: book3s: Allow the HV and PR selection per virtual machine
This moves the kvmppc_ops callbacks to be a per VM entity. This
enables us to select HV and PR mode when creating a VM. We also
allow both kvm-hv and kvm-pr kernel module to be loaded. To
achieve this we move /dev/kvm ownership to kvm.ko module. Depending on
which KVM mode we select during VM creation we take a reference
count on respective module

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[agraf: fix coding style]
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17 18:42:36 +02:00
Aneesh Kumar K.V 5587027ce9 kvm: Add struct kvm arg to memslot APIs
We will use that in the later patch to find the kvm ops handler

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17 15:49:23 +02:00
Aneesh Kumar K.V dba291f2ce kvm: powerpc: booke: Move booke related tracepoints to separate header
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17 15:37:16 +02:00
Aneesh Kumar K.V 3a167beac0 kvm: powerpc: Add kvmppc_ops callback
This patch add a new callback kvmppc_ops. This will help us in enabling
both HV and PR KVM together in the same kernel. The actual change to
enable them together is done in the later patch in the series.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[agraf: squash in booke changes]
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17 15:24:26 +02:00
Bharat Bhushan ce11e48b7f KVM: PPC: E500: Add userspace debug stub support
This patch adds the debug stub support on booke/bookehv.
Now QEMU debug stub can use hw breakpoint, watchpoint and
software breakpoint to debug guest.

This is how we save/restore debug register context when switching
between guest, userspace and kernel user-process:

When QEMU is running
 -> thread->debug_reg == QEMU debug register context.
 -> Kernel will handle switching the debug register on context switch.
 -> no vcpu_load() called

QEMU makes ioctls (except RUN)
 -> This will call vcpu_load()
 -> should not change context.
 -> Some ioctls can change vcpu debug register, context saved in vcpu->debug_regs

QEMU Makes RUN ioctl
 -> Save thread->debug_reg on STACK
 -> Store thread->debug_reg == vcpu->debug_reg
 -> load thread->debug_reg
 -> RUN VCPU ( So thread points to vcpu context )

Context switch happens When VCPU running
 -> makes vcpu_load() should not load any context
 -> kernel loads the vcpu context as thread->debug_regs points to vcpu context.

On heavyweight_exit
 -> Load the context saved on stack in thread->debug_reg

Currently we do not support debug resource emulation to guest,
On debug exception, always exit to user space irrespective of
user space is expecting the debug exception or not. If this is
unexpected exception (breakpoint/watchpoint event not set by
userspace) then let us leave the action on user space. This
is similar to what it was before, only thing is that now we
have proper exit state available to user space.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17 14:49:40 +02:00
Bharat Bhushan 547465ef8b KVM: PPC: E500: Using "struct debug_reg"
For KVM also use the "struct debug_reg" defined in asm/processor.h

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17 14:49:39 +02:00
Bharat Bhushan b12c784123 KVM: PPC: E500: exit to user space on "ehpriv 1" instruction
"ehpriv 1" instruction is used for setting software breakpoints
by user space. This patch adds support to exit to user space
with "run->debug" have relevant information.

As this is the first point we are using run->debug, also defined
the run->debug structure.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17 14:49:39 +02:00
Paul Mackerras 8b75cbbe64 KVM: PPC: BookE: Add GET/SET_ONE_REG interface for VRSAVE
This makes the VRSAVE register value for a vcpu accessible through
the GET/SET_ONE_REG interface on Book E systems (in addition to the
existing GET/SET_SREGS interface), for consistency with Book 3S.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17 14:45:01 +02:00
Paul Mackerras de79f7b9f6 powerpc: Put FP/VSX and VR state into structures
This creates new 'thread_fp_state' and 'thread_vr_state' structures
to store FP/VSX state (including FPSCR) and Altivec/VSX state
(including VSCR), and uses them in the thread_struct.  In the
thread_fp_state, the FPRs and VSRs are represented as u64 rather
than double, since we rarely perform floating-point computations
on the values, and this will enable the structures to be used
in KVM code as well.  Similarly FPSCR is now a u64 rather than
a structure of two 32-bit values.

This takes the offsets out of the macros such as SAVE_32FPRS,
REST_32FPRS, etc.  This enables the same macros to be used for normal
and transactional state, enabling us to delete the transactional
versions of the macros.   This also removes the unused do_load_up_fpu
and do_load_up_altivec, which were in fact buggy since they didn't
create large enough stack frames to account for the fact that
load_up_fpu and load_up_altivec are not designed to be called from C
and assume that their caller's stack frame is an interrupt frame.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-11 17:26:49 +11:00
Scott Wood c09ec198eb kvm/ppc/booke: Don't call kvm_guest_enter twice
kvm_guest_enter() was already called by kvmppc_prepare_to_enter().
Don't call it again.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-07-11 00:58:49 +02:00
Scott Wood 5f1c248f52 kvm/ppc: Call trace_hardirqs_on before entry
Currently this is only being done on 64-bit.  Rather than just move it
out of the 64-bit ifdef, move it to kvm_lazy_ee_enable() so that it is
consistent with lazy ee state, and so that we don't track more host
code as interrupts-enabled than necessary.

Rename kvm_lazy_ee_enable() to kvm_fix_ee_before_entry() to reflect
that this function now has a role on 32-bit as well.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-07-11 00:51:28 +02:00
Linus Torvalds fe489bf450 KVM fixes for 3.11
On the x86 side, there are some optimizations and documentation updates.
 The big ARM/KVM change for 3.11, support for AArch64, will come through
 Catalin Marinas's tree.  s390 and PPC have misc cleanups and bugfixes.
 
 There is a conflict due to "s390/pgtable: fix ipte notify bit" having
 entered 3.10 through Martin Schwidefsky's s390 tree.  This pull request
 has additional changes on top, so this tree's version is the correct one.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:
 "On the x86 side, there are some optimizations and documentation
  updates.  The big ARM/KVM change for 3.11, support for AArch64, will
  come through Catalin Marinas's tree.  s390 and PPC have misc cleanups
  and bugfixes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (87 commits)
  KVM: PPC: Ignore PIR writes
  KVM: PPC: Book3S PR: Invalidate SLB entries properly
  KVM: PPC: Book3S PR: Allow guest to use 1TB segments
  KVM: PPC: Book3S PR: Don't keep scanning HPTEG after we find a match
  KVM: PPC: Book3S PR: Fix invalidation of SLB entry 0 on guest entry
  KVM: PPC: Book3S PR: Fix proto-VSID calculations
  KVM: PPC: Guard doorbell exception with CONFIG_PPC_DOORBELL
  KVM: Fix RTC interrupt coalescing tracking
  kvm: Add a tracepoint write_tsc_offset
  KVM: MMU: Inform users of mmio generation wraparound
  KVM: MMU: document fast invalidate all mmio sptes
  KVM: MMU: document fast invalidate all pages
  KVM: MMU: document fast page fault
  KVM: MMU: document mmio page fault
  KVM: MMU: document write_flooding_count
  KVM: MMU: document clear_spte_count
  KVM: MMU: drop kvm_mmu_zap_mmio_sptes
  KVM: MMU: init kvm generation close to mmio wrap-around value
  KVM: MMU: add tracepoint for check_mmio_spte
  KVM: MMU: fast invalidate all mmio sptes
  ...
2013-07-03 13:21:40 -07:00
Tiejun Chen 5f17ce8b95 KVM: PPC: Guard doorbell exception with CONFIG_PPC_DOORBELL
Availablity of the doorbell_exception function is guarded by
CONFIG_PPC_DOORBELL. Use the same define to guard our caller
of it.

Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
[agraf: improve patch description]
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-06-30 03:33:21 +02:00
Scott Wood f8941fbe20 kvm/ppc/booke: Delay kvmppc_lazy_ee_enable
kwmppc_lazy_ee_enable() should be called as late as possible,
or else we get things like WARN_ON(preemptible()) in enable_kernel_fp()
in configurations where preemptible() works.

Note that book3s_pr already waits until just before __kvmppc_vcpu_run
to call kvmppc_lazy_ee_enable().

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-19 12:15:13 +02:00
Scott Wood 7c11c0ccc7 kvm/ppc/booke64: Fix lazy ee handling in kvmppc_handle_exit()
EE is hard-disabled on entry to kvmppc_handle_exit(), so call
hard_irq_disable() so that PACA_IRQ_HARD_DIS is set, and soft_enabled
is unset.

Without this, we get warnings such as arch/powerpc/kernel/time.c:300,
and sometimes host kernel hangs.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-06-11 11:11:00 +03:00
Scott Wood f1e89028f0 kvm/ppc/booke: Hold srcu lock when calling gfn functions
KVM core expects arch code to acquire the srcu lock when calling
gfn_to_memslot and similar functions.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-06-11 11:10:59 +03:00
Scott Wood eb1e4f43e0 kvm/ppc/mpic: add KVM_CAP_IRQ_MPIC
Enabling this capability connects the vcpu to the designated in-kernel
MPIC.  Using explicit connections between vcpus and irqchips allows
for flexibility, but the main benefit at the moment is that it
simplifies the code -- KVM doesn't need vm-global state to remember
which MPIC object is associated with this vm, and it doesn't need to
care about ordering between irqchip creation and vcpu creation.

Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: add stub functions for kvmppc_mpic_{dis,}connect_vcpu]
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-26 20:27:24 +02:00
Scott Wood 5df554ad5b kvm/ppc/mpic: in-kernel MPIC emulation
Hook the MPIC code up to the KVM interfaces, add locking, etc.

Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: add stub function for kvmppc_mpic_set_epr, non-booke, 64bit]
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-26 20:27:23 +02:00
Mihai Caraman 35b299e279 KVM: PPC: Book3E: Refactor ONE_REG ioctl implementation
Refactor Book3E ONE_REG ioctl implementation to use kvmppc_get_one_reg/
kvmppc_set_one_reg delegation interface introduced by Book3S. This is
necessary for MMU SPRs which are platform specifics.

Get rid of useless case braces in the process.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-26 20:27:05 +02:00
Bharat Bhushan 9b4f530807 booke: exit to user space if emulator request
This allows the exit to user space if emulator request by returning
EMULATE_EXIT_USER. This will be used in subsequent patches in list

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-26 20:27:04 +02:00