Today we handle split real mode by mapping both instruction and data faults
into a special virtual address space that only exists during the split mode
phase.

This is good enough to catch 32bit Linux guests that use split real mode for
copy_from/to_user. In this case we're always prefixed with 0xc0000000 for our
instruction pointer and can map the user space process freely below there.

However, that approach fails when we're running KVM inside of KVM. Here the 1st
level last_inst reader may well be in the same virtual page as a 2nd level
interrupt handler.

It also fails when running Mac OS X guests. Here we have a 4G/4G split, so a
kernel copy_from/to_user implementation can easily overlap with user space
addresses.

The architecturally correct way to fix this would be to implement an instruction
interpreter in KVM that kicks in whenever we go into split real mode. This
interpreter however would not receive a great amount of testing and be a lot of
bloat for a reasonably isolated corner case.

So I went back to the drawing board and tried to come up with a way to make
split real mode work with a single flat address space. And then I realized that
we could get away with the same trick that makes it work for Linux:

Whenever we see an instruction address during split real mode that may collide,
we just move it higher up the virtual address space to a place that hopefully
does not collide (keep your fingers crossed!).

That approach does work surprisingly well. I am able to successfully run
Mac OS X guests with KVM and QEMU (no split real mode hacks like MOL) when I
apply a tiny timing probe hack to QEMU. I'd say this is a win over even more
broken split real mode :).
Signed-off-by: NAlexander Graf <agraf@suse.de>

When a page lookup failed because we're not allowed to write to the page, we
should not overwrite that value with another lookup on the second PTEG which
will return "page not found". Instead, we should just tell the caller that we
had a permission problem.

This fixes Mac OS X guests looping endlessly in page lookup code for me.
Signed-off-by: NAlexander Graf <agraf@suse.de>

When we have a page that we're not allowed to write to, xlate() will already
tell us -EPERM on lookup of that page. With the code as is we change it into
a "page missing" error which a guest may get confused about. Instead, just
tell the caller about the -EPERM directly.

This fixes Mac OS X guests when run with DCBZ32 emulation.
Signed-off-by: NAlexander Graf <agraf@suse.de>

When building KVM with a lot of vcores (NR_CPUS is big), we can potentially
get out of the ld immediate range for dereferences inside that struct.

Move the array to the end of our kvm_arch struct. This fixes compilation
issues with NR_CPUS=2048 for me.
Signed-off-by: NAlexander Graf <agraf@suse.de>

For FSL e6500 core the kernel uses power management SPR register (PWRMGTCR0)
to enable idle power down for cores and devices by setting up the idle count
period at boot time. With the host already controlling the power management
configuration the guest could simply benefit from it, so emulate guest request
as a general store.
Signed-off-by: NMihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Now that we've fixed all the issues that HV KVM code had on little endian
hosts, we can enable it in the kernel configuration for users to play with.
Signed-off-by: NAlexander Graf <agraf@suse.de>

For code that doesn't live in modules we can just branch to the real function
names, giving us compatibility with ABIv1 and ABIv2.

Do this for the compiled-in code of HV KVM.
Signed-off-by: NAlexander Graf <agraf@suse.de>

On the exit path from the guest we check what type of interrupt we received
if we received one. This means we're doing hardware access to the XICS interrupt
controller.

However, when running on a little endian system, this access is byte reversed.

So let's make sure to swizzle the bytes back again and virtually make XICS
accesses big endian.
Signed-off-by: NAlexander Graf <agraf@suse.de>

Some data structures are always stored in big endian. Among those are the LPPACA
fields as well as the shadow slb. These structures might be shared with a
hypervisor.

So whenever we access those fields, make sure we do so in big endian byte order.
Signed-off-by: NAlexander Graf <agraf@suse.de>

There are a few shared data structures between the host and the guest. Most
of them get registered through the VPA interface.

These data structures are defined to always be in big endian byte order, so
let's make sure we always access them in big endian.
Signed-off-by: NAlexander Graf <agraf@suse.de>

When running on an LE host all data structures are kept in little endian
byte order. However, the HTAB still needs to be maintained in big endian.

So every time we access any HTAB we need to make sure we do so in the right
byte order. Fix up all accesses to manually byte swap.
Signed-off-by: NAlexander Graf <agraf@suse.de>

From assembly code we might not only have to explicitly BE access 64bit values,
but sometimes also 32bit ones. Add helpers that allow for easy use of lwzx/stwx
in their respective byte-reverse or native form.
Signed-off-by: NAlexander Graf <agraf@suse.de>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Tlb search operation used for victim hint relies on the default tlb set by the
host. When hardware tablewalk support is enabled in the host, the default tlb is
TLB1 which leads KVM to evict the bolted entry. Set and restore the default tlb
when searching for victim hint.
Signed-off-by: NMihai Caraman <mihai.caraman@freescale.com>
Reviewed-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

This adds support for the H_SET_MODE hcall.  This hcall is a
multiplexer that has several functions, some of which are called
rarely, and some which are potentially called very frequently.
Here we add support for the functions that set the debug registers
CIABR (Completed Instruction Address Breakpoint Register) and
DAWR/DAWRX (Data Address Watchpoint Register and eXtension),
since they could be updated by the guest as often as every context
switch.

This also adds a kvmppc_power8_compatible() function to test to see
if a guest is compatible with POWER8 or not.  The CIABR and DAWR/X
only exist on POWER8.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

This adds code to check that when the KVM_CAP_PPC_ENABLE_HCALL
capability is used to enable or disable in-kernel handling of an
hcall, that the hcall is actually implemented by the kernel.
If not an EINVAL error is returned.

This also checks the default-enabled list of hcalls and prints a
warning if any hcall there is not actually implemented.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

This provides a way for userspace controls which sPAPR hcalls get
handled in the kernel.  Each hcall can be individually enabled or
disabled for in-kernel handling, except for H_RTAS.  The exception
for H_RTAS is because userspace can already control whether
individual RTAS functions are handled in-kernel or not via the
KVM_PPC_RTAS_DEFINE_TOKEN ioctl, and because the numeric value for
H_RTAS is out of the normal sequence of hcall numbers.

Hcalls are enabled or disabled using the KVM_ENABLE_CAP ioctl for the
KVM_CAP_PPC_ENABLE_HCALL capability on the file descriptor for the VM.
The args field of the struct kvm_enable_cap specifies the hcall number
in args[0] and the enable/disable flag in args[1]; 0 means disable
in-kernel handling (so that the hcall will always cause an exit to
userspace) and 1 means enable.  Enabling or disabling in-kernel
handling of an hcall is effective across the whole VM.

The ability for KVM_ENABLE_CAP to be used on a VM file descriptor
on PowerPC is new, added by this commit.  The KVM_CAP_ENABLE_CAP_VM
capability advertises that this ability exists.

When a VM is created, an initial set of hcalls are enabled for
in-kernel handling.  The set that is enabled is the set that have
an in-kernel implementation at this point.  Any new hcall
implementations from this point onwards should not be added to the
default set without a good reason.

No distinction is made between real-mode and virtual-mode hcall
implementations; the one setting controls them both.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

On vcpu schedule, the condition checked for tlb pollution is too loose.
The tlb entries of a vcpu become polluted (vs stale) only when a different
vcpu within the same logical partition runs in-between. Optimize the tlb
invalidation condition keeping last_vcpu per logical partition id.

With the new invalidation condition, a guest shows 4% performance improvement
on P5020DS while running a memory stress application with the cpu oversubscribed,
the other guest running a cpu intensive workload.

Guest - old invalidation condition
  real 3.89
  user 3.87
  sys 0.01

Guest - enhanced invalidation condition
  real 3.75
  user 3.73
  sys 0.01

Host
  real 3.70
  user 1.85
  sys 0.00

The memory stress application accesses 4KB pages backed by 75% of available
TLB0 entries:

char foo[ENTRIES][4096] __attribute__ ((aligned (4096)));

int main()
{
	char bar;
	int i, j;

	for (i = 0; i < ITERATIONS; i++)
        	for (j = 0; j < ENTRIES; j++)
            		bar = foo[j][0];

	return 0;
}
Signed-off-by: NMihai Caraman <mihai.caraman@freescale.com>
Reviewed-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

While sending sparse with endian checks over the code base, it triggered at
some places that were missing casts or had wrong types. Fix them up.
Signed-off-by: NAlexander Graf <agraf@suse.de>

We switched to ABIv2 on Little Endian systems now which gets rid of the
dotted function names. Branch to the actual functions when we see such
a system.
Signed-off-by: NAlexander Graf <agraf@suse.de>

Both kvmppc_hv_entry_trampoline and kvmppc_entry_trampoline are
assembly functions that are exported to modules and also require
a valid r2.

As such we need to use _GLOBAL_TOC so we provide a global entry
point that establishes the TOC (r2).
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

To establish addressability quickly, ABIv2 requires the target
address of the function being called to be in r12.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

If we're running PR KVM in HV mode, we may get hypervisor doorbell interrupts.
Handle those the same way we treat normal doorbells.
Signed-off-by: NAlexander Graf <agraf@suse.de>

Some compilers complain about uninitialized variables in the compute_tlbie_rb
function. When you follow the code path you'll realize that we'll never get
to that point, but the compiler isn't all that smart.

So just default to 4k page sizes for everything, making the compiler happy
and the code slightly easier to read.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Acked-by: NPaul Mackerras <paulus@samba.org>

When we're using PR KVM we must not allow the CPU to take interrupts
in virtual mode, as the SLB does not contain host kernel mappings
when running inside the guest context.

To make sure we get good performance for non-KVM tasks but still
properly functioning PR KVM, let's just disable AIL whenever a vcpu
is scheduled in.

This is fundamentally different from how we deal with AIL on pSeries
type machines where we disable AIL for the whole machine as soon as
a single KVM VM is up.

The reason for that is easy - on pSeries we do not have control over
per-cpu configuration of AIL. We also don't want to mess with CPU hotplug
races and AIL configuration, so setting it per CPU is easier and more
flexible.

This patch fixes running PR KVM on POWER8 bare metal for me.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Acked-by: NPaul Mackerras <paulus@samba.org>

Writing to IC is not allowed in the privileged mode.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

virtual time base register is a per VM, per cpu register that needs
to be saved and restored on vm exit and entry. Writing to VTB is not
allowed in the privileged mode.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[agraf: fix compile error]
Signed-off-by: NAlexander Graf <agraf@suse.de>

We use time base for PURR and SPURR emulation with PR KVM since we
are emulating a single threaded core. When using time base
we need to make sure that we don't accumulate time spent in the host
in PURR and SPURR value.

Also we don't need to emulate mtspr because both the registers are
hypervisor resource.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

A struct member variable is set to the same value more than once

This was found using a static code analysis program called cppcheck.
Signed-off-by: NRickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

It's impossible to fall into the error handling of the TLB index after
being masked by (KVM_MIPS_GUEST_TLB_SIZE - 1). Remove the dead code.
Reported-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Reviewed-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The commpage is allocated using kzalloc(), so there's no need of cleaning
the memory of the kvm_mips_commpage struct and its internal mips_coproc.
Reviewed-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Since all the files are in arch/mips/kvm/, there's no need of the prefixes
"kvm_" and "kvm_mips_".
Reviewed-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The keyword volatile for idx in the TLB functions is unnecessary.
Reviewed-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

No logic changes inside.
Reviewed-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Replace printks with kvm_[err|info|debug].
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Reviewed-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

No logic changes inside.
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Reviewed-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Merge tag 'kvms390-20140626' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

Fix sie.h header related problems introduced during the 3.16 development
cycle.

Fix bad x86 regression introduced during merge window.

We import the CPL via SS.DPL since ae9fedc7. However, we fail to
export it this way so far. This caused spurious guest crashes, e.g. of
Linux when accessing the vmport from guest user space which triggered
register saving/restoring to/from host user space.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

sie.h was missing in arch/s390/include/uapi/asm/Kbuild and therefore missed
the "make headers_check" target.
If added it reveals that also arch/s390/include/asm/sigp.h would become uapi.
This is something we certainly do not want. So remove that dependency as well.

The header file was merged with ceae283b "KVM: s390: add sie exit
reasons tables", therefore we never had a kernel release with this commit and
can still change anything.
Acked-by: NAlexander Yarygin <yarygin@linux.vnet.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

VMX instructions use 32-bit operands in 32-bit mode, and 64-bit operands in
64-bit mode.  The current implementation is broken since it does not use the
register operands correctly, and always uses 64-bit for reads and writes.
Moreover, write to memory in vmwrite only considers long-mode, so it ignores
cs.l. This patch fixes this behavior.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>