When reading and writing SPRs, every SPR emulation piece had to read
or write the respective GPR the value was read from or stored in itself.

This approach is pretty prone to failure. What if we accidentally
implement mfspr emulation where we just do "break" and nothing else?
Suddenly we would get a random value in the return register - which is
always a bad idea.

So let's consolidate the generic code paths and only give the core
specific SPR handling code readily made variables to read/write from/to.

Functionally, this patch doesn't change anything, but it increases the
readability of the code and makes is less prone to bugs.
Signed-off-by: NAlexander Graf <agraf@suse.de>

Instructions on PPC are pretty similarly encoded. So instead of
every instruction emulation code decoding the instruction fields
itself, we can move that code to more generic places and rely on
the compiler to optimize the unused bits away.

This has 2 advantages. It makes the code smaller and it makes the
code less error prone, as the instruction fields are always
available, so accidental misusage is reduced.

Functionally, this patch doesn't change anything.
Signed-off-by: NAlexander Graf <agraf@suse.de>

Stbux writes the address it's operating on to the register specified in ra,
not into the data source register.
Signed-off-by: NAlexander Graf <agraf@suse.de>

Time for which the hrtimer is started for decrementer emulation is calculated
using tb_ticks_per_usec. While hrtimer uses the clockevent for DEC
reprogramming (if needed) and which calculate timebase ticks using the
multiplier and shifter mechanism implemented within clockevent layer.

It was observed that this conversion (timebase->time->timebase) are not
correct because the mechanism are not consistent.
In our setup it adds 2% jitter.

With this patch clockevent multiplier and shifter mechanism are used when
starting hrtimer for decrementer emulation. Now the jitter is < 0.5%.
Signed-off-by: NBharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

There are 4 conditional trapping instructions: tw, twi, td, tdi. The
ones with an i take an immediate comparison, the others compare two
registers. All of them arrive in the emulator when the condition to
trap was successfully fulfilled.

Unfortunately, we were only implementing the i versions so far, so
let's also add support for the other two.

This fixes kernel booting with recents book3s_32 guest kernels.
Reported-by: NJörg Sommer <joerg@alea.gnuu.de>
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

When emulating updating load/store instructions (lwzu, stwu, ...) we need to
write the effective address of the load/store into a register.

Currently, we write the physical address in there, which is very wrong. So
instead let's save off where the virtual fault was on MMIO and use that
information as value to put into the register.

While at it, also move the XOP variants of the above instructions to the new
scheme of using the already known vaddr instead of calculating it themselves.
Reported-by: NJörg Sommer <joerg@alea.gnuu.de>
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Decrementers are now properly driven by TCR/TSR, and the guest
has full read/write access to these registers.

The decrementer keeps ticking (and setting the TSR bit) regardless of
whether the interrupts are enabled with TCR.

The decrementer stops at zero, rather than going negative.

Decrementers (and FITs, once implemented) are delivered as
level-triggered interrupts -- dequeued when the TSR bit is cleared, not
on delivery.
Signed-off-by: NLiu Yu <yu.liu@freescale.com>
[scottwood@freescale.com: significant changes]
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

This allows additional registers to be accessed by the guest
in PR-mode KVM without trapping.

SPRG4-7 are readable from userspace.  On booke, KVM will sync
these registers when it enters the guest, so that accesses from
guest userspace will work.  The guest kernel, OTOH, must consistently
use either the real registers or the shared area between exits.  This
also applies to the already-paravirted SPRG3.

On non-booke, it's not clear to what extent SPRG4-7 are supported
(they're not architected for book3s, but exist on at least some classic
chips).  They are copied in the get/set regs ioctls, but I do not see any
non-booke emulation.  I also do not see any syncing with real registers
(in PR-mode) including the user-readable SPRG3.  This patch should not
make that situation any worse.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

As per specification the decrementer interrupt not happen when DEC is written
with 0. Also when DEC is zero, no decrementer running. So we should not start
hrtimer for decrementer when DEC = 0.
Signed-off-by: NBharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

kvmppc_emulate_dec() uses dec_nsec of type unsigned long and does below calculation:

        dec_nsec = vcpu->arch.dec;
        dec_nsec *= 1000;
This will truncate if DEC value "vcpu->arch.dec" is greater than 0xffff_ffff/1000.
For example : For tb_ticks_per_usec = 4a, we can not set decrementer more than ~58ms.
Signed-off-by: NBharat Bhushan <bharat.bhushan@freescale.com>
Acked-by: NLiu Yu <yu.liu@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

The exit type setting for mfspr/mtspr is moved from 44x to toplevel SPR
emulation.  This enables it on e500, and makes sure that all SPRs
are covered.

Exit accounting for tlbwe and tlbsx is added to e500.
Signed-off-by: NStuart Yoder <stuart.yoder@freescale.com>
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

When in kernel mode there are 4 additional registers available that are
simple data storage. Instead of exiting to the hypervisor to read and
write those, we can just share them with the guest using the page.

This patch converts all users of the current field to the shared page.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

The SRR0 and SRR1 registers contain cached values of the PC and MSR
respectively. They get written to by the hypervisor when an interrupt
occurs or directly by the kernel. They are also used to tell the rfi(d)
instruction where to jump to.

Because it only gets touched on defined events that, it's very simple to
share with the guest. Hypervisor and guest both have full r/w access.

This patch converts all users of the current field to the shared page.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

When instruction fetch failed, the inline function hook automatically
detects that and starts the internal guest memory load function. So
whenever we access kvmppc_get_last_inst(), we're sure the result is sane.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Upstream recently added a new name for PPC64: Book3S_64.

So instead of using CONFIG_PPC64 we should use CONFIG_PPC_BOOK3S consotently.
That makes understanding the code easier (I hope).
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

We already have some inline fuctions we use to access vcpu or svcpu structs,
depending on whether we're on booke or book3s. Since we just put a few more
registers into the svcpu, we also need to make sure the respective callbacks
are available and get used.

So this patch moves direct use of the now in the svcpu struct fields to
inline function calls. While at it, it also moves the definition of those
inline function calls to respective header files for booke and book3s,
greatly improving readability.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

We get MMIOs with the weirdest instructions. But every time we do,
we need to improve our emulator to implement them.

So let's do that - this time it's lbzux and lhax's round.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Emulation of an instruction can have different outcomes. It can succeed,
fail, require MMIO, do funky BookE stuff - or it can just realize something's
odd and will be fixed the next time around.

Exactly that is what EMULATE_AGAIN means. Using that flag we can now tell
the caller that nothing happened, but we still want to go back to the
guest and see what happens next time we come around.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

The guest I was trying to get to run uses the LHA and LHAU instructions.
Those instructions basically do a load, but also sign extend the result.

Since we need to fill our registers by hand when doing MMIO, we also need
to sign extend manually.

This patch implements sign extended MMIO and the LHA(U) instructions.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Old method prematurely sets ESR and DEAR.
Move this part after we decide to inject interrupt,
which is more like hardware behave.
Signed-off-by: NLiu Yu <yu.liu@freescale.com>
Acked-by: NHollis Blanchard <hollis@penguinppc.org>
Acked-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

When we get a program interrupt in guest kernel mode, we try to emulate the
instruction.

If that doesn't fail, we report to the user and try again - at the exact same
instruction pointer. So if the guest kernel really does trigger an invalid
instruction, we loop forever.

So let's better go and forward program exceptions to the guest when we don't
know the instruction we're supposed to emulate.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Book3S needs some flags in SRR1 to get to know details about an interrupt.

One such example is the trap instruction. It tells the guest kernel that
a program interrupt is due to a trap using a bit in SRR1.

This patch implements above behavior, making WARN_ON behave like WARN_ON.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

To fetch the last instruction we were interrupted on, we enable DR in early
exit code, where we are still in a very transitional phase between guest
and host state.

Most of the time this seemed to work, but another CPU can easily flush our
TLB and HTAB which makes us go in the Linux page fault handler which totally
breaks because we still use the guest's SLB entries.

To work around that, let's introduce a second KVM guest mode that defines
that whenever we get a trap, we don't call the Linux handler or go into
the KVM exit code, but just jump over the faulting instruction.

That way a potentially bad lwz doesn't trigger any faults and we can later
on interpret the invalid instruction we fetched as "fetch didn't work".
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

All code in PPC KVM currently accesses gprs in the vcpu struct directly.

While there's nothing wrong with that wrt the current way gprs are stored
and loaded, it doesn't suffice for the PACA acceleration that will follow
in this patchset.

So let's just create little wrapper inline functions that we call whenever
a GPR needs to be read from or written to. The compiled code shouldn't really
change at all for now.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAvi Kivity <avi@redhat.com>

We treated the DEC interrupt like an edge based one. This is not true for
Book3s. The DEC keeps firing until mtdec is issued again and thus clears
the interrupt line.

So let's implement this logic in KVM too. This patch moves the line clearing
from the firing of the interrupt to the mtdec emulation.

This makes PPC64 guests work without AGGRESSIVE_DEC defined.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Acked-by: NAcked-by: Hollis Blanchard <hollis@penguinppc.org>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Following S390's good example we should use hrtimers for the decrementer too!
This patch converts the timer from the old mechanism to hrtimers.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Little opcodes behave differently on desktop and embedded PowerPC cores.
In order to reflect those differences, let's add some #ifdef code to emulate.c.

We could probably also handle them in the core specific emulation files, but I
would prefer to reuse as much code as possible.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

We support setting the DEC to a certain value right now. Doing that basically
triggers the CPU local timer.

But there's also an mfdec command that enabled the OS to read the decrementor.

This is required at least by all desktop and server PowerPC Linux kernels. It
can't really hurt to allow embedded ones to do it as well though.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

[avi: make it build]
[avi: fold trace-arch.h into trace.h]

CC: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Latest kernel started to use these two registers.
Signed-off-by: NLiu Yu <yu.liu@freescale.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Signed-off-by: NLiu Yu <yu.liu@freescale.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Signed-off-by: NHollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Existing KVM statistics are either just counters (kvm_stat) reported for
KVM generally or trace based aproaches like kvm_trace.
For KVM on powerpc we had the need to track the timings of the different exit
types. While this could be achieved parsing data created with a kvm_trace
extension this adds too much overhead (at least on embedded PowerPC) slowing
down the workloads we wanted to measure.

Therefore this patch adds a in-kernel exit timing statistic to the powerpc kvm
code. These statistic is available per vm&vcpu under the kvm debugfs directory.
As this statistic is low, but still some overhead it can be enabled via a
.config entry and should be off by default.

Since this patch touched all powerpc kvm_stat code anyway this code is now
merged and simplified together with the exit timing statistic code (still
working with exit timing disabled in .config).
Signed-off-by: NChristian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: NHollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

set ESR[PTR] when emulating a guest trap. This allows Linux guests to
properly handle WARN_ON() (i.e. detect that it's a non-fatal trap).

Also remove debugging printk in trap emulation.
Signed-off-by: NHollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

However, some of these fields could be split into separate per-core structures
in the future.
Signed-off-by: NHollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Cores provide 3 emulation hooks, implemented for example in the new
4xx_emulate.c:
kvmppc_core_emulate_op
kvmppc_core_emulate_mtspr
kvmppc_core_emulate_mfspr

Strictly speaking the last two aren't necessary, but provide for more
informative error reporting ("unknown SPR").

Long term I'd like to have instruction decoding autogenerated from tables of
opcodes, and that way we could aggregate universal, Book E, and core-specific
instructions more easily and without redundant switch statements.
Signed-off-by: NHollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

This is used in a couple places in KVM, but isn't KVM-specific.

However, this patch doesn't modify other in-kernel emulation code:
- xmon uses a direct copy of ppc_opc.c from binutils
- emulate_instruction() doesn't need it because it can use a series
  of mask tests.
Signed-off-by: NHollis Blanchard <hollisb@us.ibm.com>
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAvi Kivity <avi@redhat.com>

This introduces a set of core-provided hooks. For 440, some of these are
implemented by booke.c, with the rest in (the new) 44x.c.

Note that these hooks are link-time, not run-time. Since it is not possible to
build a single kernel for both e500 and 440 (for example), using function
pointers would only add overhead.
Signed-off-by: NHollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>