Based on original patch from Jeng-fang (Nick) Wang

When standby memory is specified for a guest Linux, but no virtual memory has
been allocated on the Qemu host backing that guest, the guest memory detection
process encounters a memory access exception which is not thrown from the KVM
handle_tprot() instruction-handler function. The access exception comes from
sie64a returning EFAULT, which then passes an addressing exception to the guest.
Unfortunately this does not the proper PSW fixup (nullifying vs.
suppressing) so the guest will get a fault for the wrong address.

Let's just intercept the tprot instruction all the time to do the right thing
and not go the page fault handler path for standby memory. tprot is only used
by Linux during startup so some exits should be ok.
Without this patch, standby memory cannot be used with KVM.
Signed-off-by: NNick Wang <jfwang@us.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Tested-by: NMatthew Rosato <mjrosato@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This patch removes the start of a VCPU when delivering a RESTART interrupt.
Interrupt delivery is called from kvm_arch_vcpu_ioctl_run. So the VCPU is
already considered started - no need to call kvm_s390_vcpu_start. This function
will early exit anyway.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This patch fixes a minor bug when updating the guest debug settings.
We should check the given debug flags, not the already set ones.
Doesn't do any harm but too many (for now unused) flags could be set internally
without error.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>

We have all the logic to inject interrupts available in
kvm_s390_inject_vcpu(), so let's use it instead of
injecting irqs manually to the list in sigp code.

SIGP stop is special because we have to check the
action_flags before injecting the interrupt. As
the action_flags are not available in kvm_s390_inject_vcpu()
we leave the code for the stop order code untouched for now.
Signed-off-by: NJens Freimann <jfrei@linux.vnet.ibm.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

The TPROT instruction can be used to check the accessability of storage
for any kind of logical addresses. So far, our handler only supported
real addresses. This patch now also enables support for addresses that
have to be translated via DAT first. And while we're at it, change the
code to use the common KVM function gfn_to_hva_prot() to check for the
validity and writability of the memory page.
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

This patch adds a function for translating logical guest addresses into
physical guest addresses without touching the memory at the given location.
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

This patch splits the SIE state guest prefix at offset 4
into a prefix bit field. Additionally it provides the
access functions:

 - kvm_s390_get_prefix()
 - kvm_s390_set_prefix()

to access the prefix per vcpu.
Signed-off-by: NMichael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>

The patch adds functionality to retrieve the IBC configuration
by means of function sclp_get_ibc().
Signed-off-by: NMichael Mueller <mimu@linux.vnet.ibm.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>

If the sigp interpretation facility is installed, most SIGP EXTERNAL CALL
operations will be interpreted instead of intercepted. A partial execution
interception will occurr at the sending cpu only if the target cpu is in the
wait state ("W" bit in the cpuflags set). Instruction interception will only
happen in error cases (e.g. cpu addr invalid).

As a sending cpu might set the external call interrupt pending flags at the
target cpu at every point in time, we can't handle this kind of interrupt using
our kvm interrupt injection mechanism. The injection will be done automatically
by the SIE when preparing the start of the target cpu.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
CC: Thomas Huth <thuth@linux.vnet.ibm.com>
[Adopt external call injection to check for sigp interpretion]
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

The current trace definition doesn't work very well with the perf tool.
Perf shows a "insn_to_mnemonic not found" message. Let's handle the
decoding completely in a parseable format.
Signed-off-by: NAlexander Yarygin <yarygin@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This patch adds a new decoder of SIE intercepted instructions.

The decoder implemented as a macro and potentially can be used in
both kernelspace and userspace.

Note that this simplified instruction decoder is only intended to be
used with the subset of instructions that may cause a SIE intercept.
Signed-off-by: NAlexander Yarygin <yarygin@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Use the symbolic translation tables from sie.h for decoding diag, sigp
and sie exit codes.
Signed-off-by: NAlexander Yarygin <yarygin@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This patch defines tables of reasons for exiting from SIE mode
in a new sie.h header file. Tables contain SIE intercepted codes,
intercepted instructions and program interruptions codes.
Signed-off-by: NAlexander Yarygin <yarygin@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Use the new helper function kvm_arch_fault_in_page() for faulting-in
the guest pages and only inject addressing errors when we've really
hit a bad address (and return other error codes to userspace instead).
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Rework the function kvm_arch_fault_in_sync() to become a proper helper
function for faulting-in a guest page. Now it takes the guest address as
a parameter and does not ignore the possible error code from gmap_fault()
anymore (which could cause undetected error conditions before).
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

If the new PSW for program interrupts is invalid, the VM ends up
in an endless loop of specification exceptions. Since there is not
much left we can do in this case, we should better drop to userspace
instead so that the crash can be reported to the user.
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

As a program status word is also invalid (and thus generates an
specification exception) if the instruction address is not even,
we should test this in is_valid_psw(), too. This patch also exports
the function so that it becomes available for other parts of the
S390 KVM code as well.
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Use the mm semaphore to serialize multiple invocations of s390_enable_skey.
The second CPU faulting on a storage key operation needs to wait for the
completion of the page table update. Taking the mm semaphore writable
has the positive side-effect that it prevents any host faults from
taking place which does have implications on keys vs PGSTE.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

The external interrupt interception can only occur in rare cases, e.g.
when the PSW of the interrupt handler has a bad value. The old handler
for this interception simply ignored these events (except for increasing
the exit_external_interrupt counter), but for proper operation we either
have to inject the interrupts manually or we should drop to userspace in
case of errors.
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Add an interface to inject clock comparator and CPU timer interrupts
into the guest. This is needed for handling the external interrupt
interception.
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

When copy_from_user() fails, this code returns the number of bytes
remaining instead of a negative error code.  The positive number is
returned to the user but otherwise it is harmless.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This patch enables the IBS facility when a single VCPU is running.
The facility is dynamically turned on/off as soon as other VCPUs
enter/leave the stopped state.

When this facility is operating, some instructions can be executed
faster for single-cpu guests.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NDominik Dingel <dingel@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This patch introduces two new functions to set/clear the CPUSTAT_STOPPED bit and
makes use of it at all applicable places. These functions prepare the additional
execution of code when starting/stopping a vcpu.

The CPUSTAT_STOPPED bit should not be touched outside of these functions.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

TEST BLOCK is also subject to the low-address protection, so we need
to check the destination address in our handler.
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Add a check for low-address protection to the PFMF handler and
convert real-addresses to absolute if necessary, as it is defined
in the Principles of Operations specification.
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

The s390 architecture has a special protection mechanism that can
be used to prevent write access to the vital data in the low-core
memory area. This patch adds a new helper function that can be used
to check for such write accesses and in case of protection, it also
sets up the exception data accordingly.
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

When the guest executes the MVPG instruction with DAT disabled,
and the source or destination page is not mapped in the host,
the so-called partial execution interception occurs. We need to
handle this event by setting up a mapping for the corresponding
user pages.
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Factor out the new function handle_itdb(), which copies the ITDB into
guest lowcore to fully handle a TX abort.
Signed-off-by: NMichael Mueller <mimu@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

The generically assembled low core labels already contain the
address for the TDB.
Signed-off-by: NMichael Mueller <mimu@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

On hard exits (abort, sigkill) we have have some kvm_s390_interrupt_info
structures hanging around. Delete those on exit to avoid memory leaks.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
CC: stable@vger.kernel.org
Reviewed-by: NThomas Huth <thuth@linux.vnet.ibm.com>

When a guest is single-stepped, we want to disable timer interrupts. Otherwise,
the guest will continuously execute the external interrupt handler and make
debugging of code where timer interrupts are enabled almost impossible.

The delivery of timer interrupts can be enforced in such sections by setting a
breakpoint and continuing execution.

In order to disable timer interrupts, they are disabled in the control register
of the guest just before SIE entry and are suppressed in the interrupt
check/delivery methods.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This patch moves the checks for enabled timer (clock-comparator) interrupts and pending
timer interrupts into own functions, making the code better readable and easier to
maintain.

The method kvm_cpu_has_pending_timer is filled with life.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This patch adds support to debug the guest using the PER facility on s390.
Single-stepping, hardware breakpoints and hardware watchpoints are supported. In
order to use the PER facility of the guest without it noticing it, the control
registers of the guest have to be patched and access to them has to be
intercepted(stctl, stctg, lctl, lctlg).

All PER program interrupts have to be intercepted and only the relevant PER
interrupts for the guest have to be given back. Special care has to be taken
about repeated exits on the same hardware breakpoint. The intervention of the
host in the guests PER configuration is not fully transparent. PER instruction
nullification can not be used by the guest and too many storage alteration
events may be reported to the guest (if it is activated for special address
ranges only) when the host concurrently debugging it.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This patch adds the structs to the kernel headers needed to pass information
from/to userspace in order to debug a guest on s390 with hardware support.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Introduce the methods to emulate the stctl and stctg instruction. Added tracing
code.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

When a program interrupt was to be delivered until now, no program interrupt
parameters were stored in the low-core of the target vcpu.

This patch enables the delivery of those program interrupt parameters, takes
care of concurrent PER events which can be injected in addition to any program
interrupt and uses the correct instruction length code (depending on the
interception code) for the injection of program interrupts.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Whenever a program interrupt is intercepted, some parameters are stored in the
sie control block. These parameters have to be extracted in order to be
reinjected correctly. This patch also takes care of intercepted PER events which
can occurr in addition to any program interrupt.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

This patch adds fields which are currently missing but needed for the correct
injection of interrupts.

This is based on a patch by David Hildenbrand
Signed-off-by: NJens Freimann <jfrei@linux.vnet.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

per_perc_atmid is currently a two-byte field that combines two
fields, the PER code and the PER Addressing-and-Translation-Mode
Identification (ATMID)

Let's make them accessible indepently and also rename per_cause to
per_code.
Signed-off-by: NJens Freimann <jfrei@linux.vnet.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

According to the Principles of Operation, at offset 0xA3
in the lowcore we have the "Architectural-Mode identification",
not an "access identification".
Signed-off-by: NJens Freimann <jfrei@linux.vnet.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>