For now, we only have an interface to query and configure facilities
indicated via STFL(E). However, we also have features indicated via
SCLP, that have to be indicated to the guest by user space and usually
require KVM support.
This patch allows user space to query and configure available cpu features
for the guest.
Please note that disabling a feature doesn't necessarily mean that it is
completely disabled (e.g. ESOP is mostly handled by the SIE). We will try
our best to disable it.
Most features (e.g. SCLP) can't directly be forwarded, as most of them need
in addition to hardware support, support in KVM. As we later on want to
turn these features in KVM explicitly on/off (to simulate different
behavior), we have to filter all features provided by the hardware and
make them configurable.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
We have a table of mnemonic names for intercepted program
interruptions, let's print readable name of the interruption in the
kvm_s390_intercept_prog trace event.
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Store hypervisor information is a valid instruction not only in
supervisor state but also in problem state, i.e. the guest's
userspace. Its execution is not only computational and memory
intensive, but also has to get hold of the ipte lock to write to the
guest's memory.
This lock is not intended to be held often and long, especially not
from the untrusted guest userspace. Therefore we apply rate limiting
of sthyi executions per VM.
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Acked-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Store Hypervisor Information is an emulated z/VM instruction that
provides a guest with basic information about the layers it is running
on. This includes information about the cpu configuration of both the
machine and the lpar, as well as their names, machine model and
machine type. This information enables an application to determine the
maximum capacity of CPs and IFLs available to software.
The instruction is available whenever the facility bit 74 is set,
otherwise executing it results in an operation exception.
It is important to check the validity flags in the sections before
using data from any structure member. It is not guaranteed that all
members will be valid on all machines / machine configurations.
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit introduces code that handles operation exception
interceptions. With this handler we can emulate instructions by using
illegal opcodes.
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Some wakeups should not be considered a sucessful poll. For example on
s390 I/O interrupts are usually floating, which means that _ALL_ CPUs
would be considered runnable - letting all vCPUs poll all the time for
transactional like workload, even if one vCPU would be enough.
This can result in huge CPU usage for large guests.
This patch lets architectures provide a way to qualify wakeups if they
should be considered a good/bad wakeups in regard to polls.
For s390 the implementation will fence of halt polling for anything but
known good, single vCPU events. The s390 implementation for floating
interrupts does a wakeup for one vCPU, but the interrupt will be delivered
by whatever CPU checks first for a pending interrupt. We prefer the
woken up CPU by marking the poll of this CPU as "good" poll.
This code will also mark several other wakeup reasons like IPI or
expired timers as "good". This will of course also mark some events as
not sucessful. As KVM on z runs always as a 2nd level hypervisor,
we prefer to not poll, unless we are really sure, though.
This patch successfully limits the CPU usage for cases like uperf 1byte
transactional ping pong workload or wakeup heavy workload like OLTP
while still providing a proper speedup.
This also introduced a new vcpu stat "halt_poll_no_tuning" that marks
wakeups that are considered not good for polling.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Radim Krčmář <rkrcmar@redhat.com> (for an earlier version)
Cc: David Matlack <dmatlack@google.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
[Rename config symbol. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When a guest is initializing, KVM provides facility bits that can be
successfully used by the guest. It's done by applying
kvm_s390_fac_list_mask mask on host facility bits stored by the STFLE
instruction. Facility bits can be one of two kinds: it's either a
hypervisor managed bit or non-hypervisor managed.
The hardware provides information which bits need special handling.
Let's automatically passthrough to guests new facility bits, that
don't require hypervisor support.
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Eric Farman <farman@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Some facility bits are in a range that is defined to be "ok for guests
without any necessary hypervisor changes". Enable those bits.
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Some hardware variants will round the ibc value up/down themselves,
others will report a validity intercept. Let's always round it up/down.
This patch will also make sure that the ibc is set to 0 in case we don't
have ibc support (lowest_ibc == 0).
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
We only have one cpuid for all VCPUs, so let's directly use the one in the
cpu model. Also always store it directly as u64, no need for struct cpuid.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
If we don't have SIGP SENSE RUNNING STATUS enabled for the guest, let's
not enable interpretation so we can correctly report an invalid order.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Only enable PFMF interpretation if the necessary facility (EDAT1) is
available, otherwise the pfmf handler in priv.c will inject an exception
Reviewed-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
While we can not fully fence of the Nonquiescing Key-Setting facility,
we should as try our best to hide it.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
We should never inject an exception after we manually rewound the PSW
(to retry the ESSA instruction in this case). This will mess up the PSW.
So this never worked and therefore never really triggered.
Looking at the details, we don't even have to perform any validity checks.
1. Bits 52-63 of an entry are stored as 0 by the hardware.
2. We are dealing with absolute addresses but only check for the prefix
starting at address 0. This isn't correct and doesn't make much sense,
cpus could still zap the prefix of other cpus. But as prefix pages
cannot be swapped out without a notifier being called for the affected
VCPU, a zap can never remove a protected prefix.
Reviewed-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Introduce a FLIC operation for clearing I/O interrupts for a subchannel.
Rationale: According to the platform specification, pending I/O
interruption requests have to be revoked in certain situations. For
instance, according to the Principles of Operation (page 17-27), a
subchannel put into the installed parameters initialized state is in the
same state as after an I/O system reset (just parameters possibly changed).
This implies that any I/O interrupts for that subchannel are no longer
pending (as I/O system resets clear I/O interrupts). Therefore, we need an
interface to clear pending I/O interrupts.
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
HAS_ATTR is useful for determining the supported attributes; let's
implement it.
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Pull s390 updates from Martin Schwidefsky:
- Add the CPU id for the new z13s machine
- Add a s390 specific XOR template for RAID-5 checksumming based on the
XC instruction. Remove all other alternatives, XC is always faster
- The merge of our four different stack tracers into a single one
- Tidy up the code related to page tables, several large inline
functions are now out-of-line. Bloat-o-meter reports ~11K text size
reduction
- A binary interface for the priviledged CLP instruction to retrieve
the hardware view of the installed PCI functions
- Improvements for the dasd format code
- Bug fixes and cleanups
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (31 commits)
s390/pci: enforce fmb page boundary rule
s390: fix floating pointer register corruption (again)
s390/cpumf: add missing lpp magic initialization
s390: Fix misspellings in comments
s390/mm: split arch/s390/mm/pgtable.c
s390/mm: uninline pmdp_xxx functions from pgtable.h
s390/mm: uninline ptep_xxx functions from pgtable.h
s390/pci: add ioctl interface for CLP
s390: Use pr_warn instead of pr_warning
s390/dasd: remove casts to dasd_*_private
s390/dasd: Refactor dasd format functions
s390/dasd: Simplify code in format logic
s390/dasd: Improve dasd format code
s390/percpu: remove this_cpu_cmpxchg_double_4
s390/cpumf: Improve guest detection heuristics
s390/fault: merge report_user_fault implementations
s390/dis: use correct escape sequence for '%' character
s390/kvm: simplify set_guest_storage_key
s390/oprofile: add z13/z13s model numbers
s390: add z13s model number to z13 elf platform
...
but lots of architecture-specific changes.
* ARM:
- VHE support so that we can run the kernel at EL2 on ARMv8.1 systems
- PMU support for guests
- 32bit world switch rewritten in C
- various optimizations to the vgic save/restore code.
* PPC:
- enabled KVM-VFIO integration ("VFIO device")
- optimizations to speed up IPIs between vcpus
- in-kernel handling of IOMMU hypercalls
- support for dynamic DMA windows (DDW).
* s390:
- provide the floating point registers via sync regs;
- separated instruction vs. data accesses
- dirty log improvements for huge guests
- bugfixes and documentation improvements.
* x86:
- Hyper-V VMBus hypercall userspace exit
- alternative implementation of lowest-priority interrupts using vector
hashing (for better VT-d posted interrupt support)
- fixed guest debugging with nested virtualizations
- improved interrupt tracking in the in-kernel IOAPIC
- generic infrastructure for tracking writes to guest memory---currently
its only use is to speedup the legacy shadow paging (pre-EPT) case, but
in the future it will be used for virtual GPUs as well
- much cleanup (LAPIC, kvmclock, MMU, PIT), including ubsan fixes.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"One of the largest releases for KVM... Hardly any generic
changes, but lots of architecture-specific updates.
ARM:
- VHE support so that we can run the kernel at EL2 on ARMv8.1 systems
- PMU support for guests
- 32bit world switch rewritten in C
- various optimizations to the vgic save/restore code.
PPC:
- enabled KVM-VFIO integration ("VFIO device")
- optimizations to speed up IPIs between vcpus
- in-kernel handling of IOMMU hypercalls
- support for dynamic DMA windows (DDW).
s390:
- provide the floating point registers via sync regs;
- separated instruction vs. data accesses
- dirty log improvements for huge guests
- bugfixes and documentation improvements.
x86:
- Hyper-V VMBus hypercall userspace exit
- alternative implementation of lowest-priority interrupts using
vector hashing (for better VT-d posted interrupt support)
- fixed guest debugging with nested virtualizations
- improved interrupt tracking in the in-kernel IOAPIC
- generic infrastructure for tracking writes to guest
memory - currently its only use is to speedup the legacy shadow
paging (pre-EPT) case, but in the future it will be used for
virtual GPUs as well
- much cleanup (LAPIC, kvmclock, MMU, PIT), including ubsan fixes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (217 commits)
KVM: x86: remove eager_fpu field of struct kvm_vcpu_arch
KVM: x86: disable MPX if host did not enable MPX XSAVE features
arm64: KVM: vgic-v3: Only wipe LRs on vcpu exit
arm64: KVM: vgic-v3: Reset LRs at boot time
arm64: KVM: vgic-v3: Do not save an LR known to be empty
arm64: KVM: vgic-v3: Save maintenance interrupt state only if required
arm64: KVM: vgic-v3: Avoid accessing ICH registers
KVM: arm/arm64: vgic-v2: Make GICD_SGIR quicker to hit
KVM: arm/arm64: vgic-v2: Only wipe LRs on vcpu exit
KVM: arm/arm64: vgic-v2: Reset LRs at boot time
KVM: arm/arm64: vgic-v2: Do not save an LR known to be empty
KVM: arm/arm64: vgic-v2: Move GICH_ELRSR saving to its own function
KVM: arm/arm64: vgic-v2: Save maintenance interrupt state only if required
KVM: arm/arm64: vgic-v2: Avoid accessing GICH registers
KVM: s390: allocate only one DMA page per VM
KVM: s390: enable STFLE interpretation only if enabled for the guest
KVM: s390: wake up when the VCPU cpu timer expires
KVM: s390: step the VCPU timer while in enabled wait
KVM: s390: protect VCPU cpu timer with a seqcount
KVM: s390: step VCPU cpu timer during kvm_run ioctl
...
Pull scheduler updates from Ingo Molnar:
"The main changes in this cycle are:
- Make schedstats a runtime tunable (disabled by default) and
optimize it via static keys.
As most distributions enable CONFIG_SCHEDSTATS=y due to its
instrumentation value, this is a nice performance enhancement.
(Mel Gorman)
- Implement 'simple waitqueues' (swait): these are just pure
waitqueues without any of the more complex features of full-blown
waitqueues (callbacks, wake flags, wake keys, etc.). Simple
waitqueues have less memory overhead and are faster.
Use simple waitqueues in the RCU code (in 4 different places) and
for handling KVM vCPU wakeups.
(Peter Zijlstra, Daniel Wagner, Thomas Gleixner, Paul Gortmaker,
Marcelo Tosatti)
- sched/numa enhancements (Rik van Riel)
- NOHZ performance enhancements (Rik van Riel)
- Various sched/deadline enhancements (Steven Rostedt)
- Various fixes (Peter Zijlstra)
- ... and a number of other fixes, cleanups and smaller enhancements"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (29 commits)
sched/cputime: Fix steal_account_process_tick() to always return jiffies
sched/deadline: Remove dl_new from struct sched_dl_entity
Revert "kbuild: Add option to turn incompatible pointer check into error"
sched/deadline: Remove superfluous call to switched_to_dl()
sched/debug: Fix preempt_disable_ip recording for preempt_disable()
sched, time: Switch VIRT_CPU_ACCOUNTING_GEN to jiffy granularity
time, acct: Drop irq save & restore from __acct_update_integrals()
acct, time: Change indentation in __acct_update_integrals()
sched, time: Remove non-power-of-two divides from __acct_update_integrals()
sched/rt: Kick RT bandwidth timer immediately on start up
sched/debug: Add deadline scheduler bandwidth ratio to /proc/sched_debug
sched/debug: Move sched_domain_sysctl to debug.c
sched/debug: Move the /sys/kernel/debug/sched_features file setup into debug.c
sched/rt: Fix PI handling vs. sched_setscheduler()
sched/core: Remove duplicated sched_group_set_shares() prototype
sched/fair: Consolidate nohz CPU load update code
sched/fair: Avoid using decay_load_missed() with a negative value
sched/deadline: Always calculate end of period on sched_yield()
sched/cgroup: Fix cgroup entity load tracking tear-down
rcu: Use simple wait queues where possible in rcutree
...
The pgtable.c file is quite big, before it grows any larger split it
into pgtable.c, pgalloc.c and gmap.c. In addition move the gmap related
header definitions into the new gmap.h header and all of the pgste
helpers from pgtable.h to pgtable.c.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The code in the various ptep_xxx functions has grown quite large,
consolidate them to four out-of-line functions:
ptep_xchg_direct to exchange a pte with another with immediate flushing
ptep_xchg_lazy to exchange a pte with another in a batched update
ptep_modify_prot_start to begin a protection flags update
ptep_modify_prot_commit to commit a protection flags update
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
We can fit the 2k for the STFLE interpretation and the crypto
control block into one DMA page. As we now only have to allocate
one DMA page, we can clean up the code a bit.
As a nice side effect, this also fixes a problem with crycbd alignment in
case special allocation debug options are enabled, debugged by Sascha
Silbe.
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Not setting the facility list designation disables STFLE interpretation,
this is what we want if the guest was told to not have it.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
When the VCPU cpu timer expires, we have to wake up just like when the ckc
triggers. For now, setting up a cpu timer in the guest and going into
enabled wait will never lead to a wakeup. This patch fixes this problem.
Just as for the ckc, we have to take care of waking up too early. We
have to recalculate the sleep time and go back to sleep.
Please note that the timer callback calls kvm_s390_get_cpu_timer() from
interrupt context. As the timer is canceled when leaving handle_wait(),
and we don't do any VCPU cpu timer writes/updates in that function, we can
be sure that we will never try to read the VCPU cpu timer from the same cpu
that is currentyl updating the timer (deadlock).
Reported-by: Sascha Silbe <silbe@linux.vnet.ibm.com>
Tested-by: Sascha Silbe <silbe@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
The cpu timer is a mean to measure task execution time. We want
to account everything for a VCPU for which it is responsible. Therefore,
if the VCPU wants to sleep, it shall be accounted for it.
We can easily get this done by not disabling cpu timer accounting when
scheduled out while sleeping because of enabled wait.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
For now, only the owning VCPU thread (that has loaded the VCPU) can get a
consistent cpu timer value when calculating the delta. However, other
threads might also be interested in a more recent, consistent value. Of
special interest will be the timer callback of a VCPU that executes without
having the VCPU loaded and could run in parallel with the VCPU thread.
The cpu timer has a nice property: it is only updated by the owning VCPU
thread. And speaking about accounting, a consistent value can only be
calculated by looking at cputm_start and the cpu timer itself in
one shot, otherwise the result might be wrong.
As we only have one writing thread at a time (owning VCPU thread), we can
use a seqcount instead of a seqlock and retry if the VCPU refreshed its
cpu timer. This avoids any heavy locking and only introduces a counter
update/check plus a handful of smp_wmb().
The owning VCPU thread should never have to retry on reads, and also for
other threads this might be a very rare scenario.
Please note that we have to use the raw_* variants for locking the seqcount
as lockdep will produce false warnings otherwise. The rq->lock held during
vcpu_load/put is also acquired from hardirq context. Lockdep cannot know
that we avoid potential deadlocks by disabling preemption and thereby
disable concurrent write locking attempts (via vcpu_put/load).
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Architecturally we should only provide steal time if we are scheduled
away, and not if the host interprets a guest exit. We have to step
the guest CPU timer in these cases.
In the first shot, we will step the VCPU timer only during the kvm_run
ioctl. Therefore all time spent e.g. in interception handlers or on irq
delivery will be accounted for that VCPU.
We have to take care of a few special cases:
- Other VCPUs can test for pending irqs. We can only report a consistent
value for the VCPU thread itself when adding the delta.
- We have to take care of STP sync, therefore we have to extend
kvm_clock_sync() and disable preemption accordingly
- During any call to disable/enable/start/stop we could get premeempted
and therefore get start/stop calls. Therefore we have to make sure we
don't get into an inconsistent state.
Whenever a VCPU is scheduled out, sleeping, in user space or just about
to enter the SIE, the guest cpu timer isn't stepped.
Please note that all primitives are prepared to be called from both
environments (cpu timer accounting enabled or not), although not completely
used in this patch yet (e.g. kvm_s390_set_cpu_timer() will never be called
while cpu timer accounting is enabled).
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
We want to manually step the cpu timer in certain scenarios in the future.
Let's abstract any access to the cpu timer, so we can hide the complexity
internally.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
By storing the cpu id, we have a way to verify if the current cpu is
owning a VCPU.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
With MACHINE_HAS_VX, we convert the floating point registers from the
vector registeres when storing the status. For other VCPUs, these are
stored to vcpu->run->s.regs.vrs, but we are using current->thread.fpu.vxrs,
which resolves to the currently loaded VCPU.
So kvm_s390_store_status_unloaded() currently writes the wrong floating
point registers (converted from the vector registers) when called from
another VCPU on a z13.
This is only the case for old user space not handling SIGP STORE STATUS and
SIGP STOP AND STORE STATUS, but relying on the kernel implementation. All
other calls come from the loaded VCPU via kvm_s390_store_status().
Fixes: 9abc2a08a7 (KVM: s390: fix memory overwrites when vx is disabled)
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The problem:
On -rt, an emulated LAPIC timer instances has the following path:
1) hard interrupt
2) ksoftirqd is scheduled
3) ksoftirqd wakes up vcpu thread
4) vcpu thread is scheduled
This extra context switch introduces unnecessary latency in the
LAPIC path for a KVM guest.
The solution:
Allow waking up vcpu thread from hardirq context,
thus avoiding the need for ksoftirqd to be scheduled.
Normal waitqueues make use of spinlocks, which on -RT
are sleepable locks. Therefore, waking up a waitqueue
waiter involves locking a sleeping lock, which
is not allowed from hard interrupt context.
cyclictest command line:
This patch reduces the average latency in my tests from 14us to 11us.
Daniel writes:
Paolo asked for numbers from kvm-unit-tests/tscdeadline_latency
benchmark on mainline. The test was run 1000 times on
tip/sched/core 4.4.0-rc8-01134-g0905f04:
./x86-run x86/tscdeadline_latency.flat -cpu host
with idle=poll.
The test seems not to deliver really stable numbers though most of
them are smaller. Paolo write:
"Anything above ~10000 cycles means that the host went to C1 or
lower---the number means more or less nothing in that case.
The mean shows an improvement indeed."
Before:
min max mean std
count 1000.000000 1000.000000 1000.000000 1000.000000
mean 5162.596000 2019270.084000 5824.491541 20681.645558
std 75.431231 622607.723969 89.575700 6492.272062
min 4466.000000 23928.000000 5537.926500 585.864966
25% 5163.000000 1613252.750000 5790.132275 16683.745433
50% 5175.000000 2281919.000000 5834.654000 23151.990026
75% 5190.000000 2382865.750000 5861.412950 24148.206168
max 5228.000000 4175158.000000 6254.827300 46481.048691
After
min max mean std
count 1000.000000 1000.00000 1000.000000 1000.000000
mean 5143.511000 2076886.10300 5813.312474 21207.357565
std 77.668322 610413.09583 86.541500 6331.915127
min 4427.000000 25103.00000 5529.756600 559.187707
25% 5148.000000 1691272.75000 5784.889825 17473.518244
50% 5160.000000 2308328.50000 5832.025000 23464.837068
75% 5172.000000 2393037.75000 5853.177675 24223.969976
max 5222.000000 3922458.00000 6186.720500 42520.379830
[Patch was originaly based on the swait implementation found in the -rt
tree. Daniel ported it to mainline's version and gathered the
benchmark numbers for tscdeadline_latency test.]
Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-rt-users@vger.kernel.org
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1455871601-27484-4-git-send-email-wagi@monom.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
A KVM_GET_DIRTY_LOG ioctl might take a long time.
This can result in fatal signals seemingly being ignored.
Lets bail out during the dirty bit sync, if a fatal signal
is pending.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Dirty log query can take a long time for huge guests.
Holding the mmap_sem for very long times can cause some unwanted
latencies.
Turns out that we do not need to hold the mmap semaphore.
We hold the slots_lock for gfn->hva translation and walk the page
tables with that address, so no need to look at the VMAs. KVM also
holds a reference to the mm, which should prevent other things
going away. During the walk we take the necessary ptl locks.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
On instruction-fetch exceptions, we have to forward the PSW by any
valid ilc and correctly use that ilc when injecting the irq. Injection
will already take care of rewinding the PSW if we injected a nullifying
program irq, so we don't need special handling prior to injection.
Until now, autodetection would have guessed an ilc of 0.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
On SIE faults, the ilc cannot be detected automatically, as the icptcode
is 0. The ilc indicated in the program irq will always be 0. Therefore we
have to manually specify the ilc in order to tell the guest which ilen was
used when forwarding the PSW.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Program irq injection during program irq intercepts is the last candidates
that injects nullifying irqs and relies on delivery to do the right thing.
As we should not rely on the icptcode during any delivery (because that
value will not be migrated), let's add a flag, telling prog IRQ delivery
to not rewind the PSW in case of nullifying prog IRQs.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
__extract_prog_irq() is used only once for getting the program check data
in one place. Let's combine it with an injection function to avoid a memset
and to prevent misuse on injection by simplifying the interface to only
have the VCPU as parameter.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Let's use our fresh new function read_guest_instr() to access
guest storage via the correct addressing schema.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
When an instruction is to be fetched, special handling applies to
secondary-space mode and access-register mode. The instruction is to be
fetched from primary space.
We can easily support this by selecting the right asce for translation.
Access registers will never be used during translation, so don't
include them in the interface. As we only want to read from the current
PSW address for now, let's also hide that detail.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
We will need special handling when fetching instructions, so let's
introduce new guest access modes GACC_FETCH and GACC_STORE instead
of a write flag. An additional patch will then introduce GACC_IFETCH.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
We have to migrate the program irq ilc and someday we will have to
specify the ilc without KVM trying to autodetect the value.
Let's reuse one of the spare fields in our program irq that should
always be set to 0 by user space. Because we also want to make use
of 0 ilcs ("not available"), we need a validity indicator.
If no valid ilc is given, we try to autodetect the ilc via the current
icptcode and icptstatus + parameter and store the valid ilc in the
irq structure.
This has a nice effect: QEMU's making use of KVM_S390_IRQ /
KVM_S390_SET_IRQ_STATE / KVM_S390_GET_IRQ_STATE for migration will
directly migrate the ilc without any changes.
Please note that we use bit 0 as validity and bit 1,2 for the ilc, so
by applying the ilc mask we directly get the ilen which is usually what
we work with.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
We have some confusion about ilc vs. ilen in our current code. So let's
correctly use the term ilen when dealing with (ilc << 1).
Program irq injection didn't take care of the correct ilc in case of
irqs triggered by EXECUTE functions, let's provide one function
kvm_s390_get_ilen() to take care of all that.
Also, manually specifying in intercept handlers the size of the
instruction (and sometimes overwriting that value for EXECUTE internally)
doesn't make too much sense. So also provide the functions:
- kvm_s390_retry_instr to retry the currently intercepted instruction
- kvm_s390_rewind_psw to rewind the PSW without internal overwrites
- kvm_s390_forward_psw to forward the PSW
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
As we already store the floating point registers in the vector save area
in floating point register format when we don't have MACHINE_HAS_VX, we can
directly expose them to user space using a new sync flag.
The floating point registers will be valid when KVM_SYNC_FPRS is set. The
fpc will also be valid when KVM_SYNC_FPRS is set.
Either KVM_SYNC_FPRS or KVM_SYNC_VRS will be enabled, never both.
Let's also change two positions where we access vrs, making the code easier
to read and one comment superfluous.
Suggested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
If we have MACHINE_HAS_VX, the floating point registers are stored
in the vector register format, event if the guest isn't enabled for vector
registers. So we can allow KVM_SYNC_VRS as soon as MACHINE_HAS_VX is
available.
This can in return be used by user space to support floating point
registers via struct kvm_run when the machine has vector registers.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Pull s390 updates from Martin Schwidefsky:
"An optimization for irq-restore, the SSM instruction is quite a bit
slower than an if-statement and a STOSM.
The copy_file_range system all is added.
Cleanup for PCI and CIO.
And a couple of bug fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/cio: update measurement characteristics
s390/cio: ensure consistent measurement state
s390/cio: fix measurement characteristics memleak
s390/zcrypt: Fix cryptographic device id in kernel messages
s390/pci: remove iomap sanity checks
s390/pci: set error state for unusable functions
s390/pci: fix bar check
s390/pci: resize iomap
s390/pci: improve ZPCI_* macros
s390/pci: provide ZPCI_ADDR macro
s390/pci: adjust IOMAP_MAX_ENTRIES
s390/numa: move numa_init_late() from device to arch_initcall
s390: remove all usages of PSW_ADDR_INSN
s390: remove all usages of PSW_ADDR_AMODE
s390: wire up copy_file_range syscall
s390: remove superfluous memblock_alloc() return value checks
s390/numa: allocate memory with correct alignment
s390/irqflags: optimize irq restore
s390/mm: use TASK_MAX_SIZE where applicable
The kernel now always uses vector registers when available, however KVM
has special logic if support is really enabled for a guest. If support
is disabled, guest_fpregs.fregs will only contain memory for the fpu.
The kernel, however, will store vector registers into that area,
resulting in crazy memory overwrites.
Simply extending that area is not enough, because the format of the
registers also changes. We would have to do additional conversions, making
the code even more complex. Therefore let's directly use one place for
the vector/fpu registers + fpc (in kvm_run). We just have to convert the
data properly when accessing it. This makes current code much easier.
Please note that vector/fpu registers are now always stored to
vcpu->run->s.regs.vrs. Although this data is visible to QEMU and
used for migration, we only guarantee valid values to user space when
KVM_SYNC_VRS is set. As that is only the case when we have vector
register support, we are on the safe side.
Fixes: b5510d9b68 ("s390/fpu: always enable the vector facility if it is available")
Cc: stable@vger.kernel.org # v4.4 d9a3a09af5 s390/kvm: remove dependency on struct save_area definition
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
[adopt to d9a3a09af5]
The KVM-VFIO device is used by the QEMU VFIO device. It is used to
record the list of in-use VFIO groups so that KVM can manipulate
them.
While we don't need this on s390 currently, let's try to be like
everyone else.
Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
fprs is never freed, therefore resulting in a memory leak if
kvm_vcpu_init() fails or the vcpu is destroyed.
Fixes: 9977e886cb ("s390/kernel: lazy restore fpu registers")
Cc: stable@vger.kernel.org # v4.3+
Reported-by: Eric Farman <farman@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Eric Farman <farman@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Yet another leftover from the 31 bit era. The usual operation
"y = x & PSW_ADDR_INSN" with the PSW_ADDR_INSN mask is a nop for
CONFIG_64BIT.
Therefore remove all usages and hope the code is a bit less confusing.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Pull s390 updates from Martin Schwidefsky:
"Among the traditional bug fixes and cleanups are some improvements:
- A tool to generated the facility lists, generating the bit fields
by hand has been a source of bugs in the past
- The spinlock loop is reordered to avoid bursts of hypervisor calls
- Add support for the open-for-business interface to the service
element
- The get_cpu call is added to the vdso
- A set of tracepoints is defined for the common I/O layer
- The deprecated sclp_cpi module is removed
- Update default configuration"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (56 commits)
s390/sclp: fix possible control register corruption
s390: fix normalization bug in exception table sorting
s390/configs: update default configurations
s390/vdso: optimize getcpu system call
s390: drop smp_mb in vdso_init
s390: rename struct _lowcore to struct lowcore
s390/mem_detect: use unsigned longs
s390/ptrace: get rid of long longs in psw_bits
s390/sysinfo: add missing SYSIB 1.2.2 multithreading fields
s390: get rid of CONFIG_SCHED_MC and CONFIG_SCHED_BOOK
s390/Kconfig: remove pointless 64 bit dependencies
s390/dasd: fix failfast for disconnected devices
s390/con3270: testing return kzalloc retval
s390/hmcdrv: constify hmcdrv_ftp_ops structs
s390/cio: add NULL test
s390/cio: Change I/O instructions from inline to normal functions
s390/cio: Introduce common I/O layer tracepoints
s390/cio: Consolidate inline assemblies and related data definitions
s390/cio: Fix incorrect xsch opcode specification
s390/cio: Remove unused inline assemblies
...
Finally get rid of the leading underscore. I tried this already two or
three years ago, however Michael Holzheu objected since this would
break the crash utility (again).
However Michael integrated support for the new name into the crash
utility back then, so it doesn't break if the name will be changed
now. So finally get rid of the ever confusing leading underscore.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This patch adds runtime instrumentation support for KVM guest. We need to
setup a save area for the runtime instrumentation-controls control block(RICCB)
and implement the necessary interfaces to live migrate the guest settings.
We setup the sie control block in a way, that the runtime
instrumentation instructions of a guest are handled by hardware.
We also add a capability KVM_CAP_S390_RI to make this feature opt-in as
it needs migration support.
Signed-off-by: Fan Zhang <zhangfan@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
smp_mb on vcpu destroy isn't paired with anything, violating pairing
rules, and seems to be useless.
Drop it.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <1452010811-25486-1-git-send-email-mst@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Verify that the guest maximum storage address is below the MHA (maximum
host address) value allowed on the host.
Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Guenther Hutzl <hutzl@linux.vnet.ibm.com>
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
[adopt to match recent limit,size changes]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
While the userspace interface requests the maximum size the gmap code
expects to get a maximum address.
This error resulted in bigger page tables than necessary for some guest
sizes, e.g. a 2GB guest used 3 levels instead of 2.
At the same time we introduce KVM_S390_NO_MEM_LIMIT, which allows in a
bright future that a guest spans the complete 64 bit address space.
We also switch to TASK_MAX_SIZE for the initial memory size, this is a
cosmetic change as the previous size also resulted in a 4 level pagetable
creation.
Reported-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
The s390dbf and trace events provide a debugfs interface.
If kptr_restrict is active, we should not expose kernel
pointers. We can fence the debugfs output by using %pK
instead of %p.
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Replace two memcpy with proper assignment.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
rc already contains -ENOMEM, no need to assign it twice.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
This evaluates always to 'true'.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
If we don't have support for virtualization (SIE), e.g. when running under
a hypervisor not supporting execution of the SIE instruction, we should
immediately abort loading the kvm module, as the SIE instruction cannot
be enabled dynamically.
Currently, the SIE instructions fails with an exception on a non-SIE
host, resulting in the guest making no progress, instead of failing hard.
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
sca_add_vpcu is not called for ucontrol guests. We must also not
apply the sca checking for sca_can_add_vcpu as ucontrol guests
do not have to follow the sca limits.
As common code already checks that id < KVM_MAX_VCPUS all other
data structures are safe as well.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Now that we already have kvm and the VCPU id set for the VCPU, we can
convert sda_add_vcpu to look much more like sda_del_vcpu.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Let's always set and clear the sda when enabling/disabling a VCPU.
Dealing with sda being set to something else makes no sense anymore
as we enable a VCPU in the SCA now after it has been registered at
the VM.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
If something goes wrong in kvm_arch_vcpu_create, the VCPU has already
been added to the sca but will never be removed. Trying to create VCPUs
with duplicate ids (e.g. after a failed attempt) is problematic.
Also, when creating multiple VCPUs in parallel, we could theoretically
forget to set the correct SCA when the switch to ESCA happens just
before the VCPU is registered.
Let's add the VCPU to the SCA in kvm_arch_vcpu_postcreate, where we can
be sure that no duplicate VCPU with the same id is around and the VCPU
has already been registered at the VM. We also have to make sure to update
ECB at that point.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Having no sca can never happen, even when something goes wrong when
switching to ESCA. Otherwise we would have a serious bug.
Let's remove this superfluous check.
Acked-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
If CPUSTAT_ECALL_PEND isn't set, we can't have an external call pending,
so we can directly avoid taking the lock.
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This patch allows s390 to have more than 64 VCPUs for a guest (up to
248 for memory usage considerations), if supported by the underlaying
hardware (sclp.has_esca).
Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This patch adds code that performs transparent switch to Extended
SCA on addition of 65th VCPU in a VM. Disposal of ESCA is added too.
The entier ESCA functionality, however, is still not enabled.
The enablement will be provided in a separate patch.
This patch also uses read/write lock protection of SCA and its subfields for
possible disposal at the BSCA-to-ESCA transition. While only Basic SCA needs such
a protection (for the swap), any SCA access is now guarded.
Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This patch updates the routines (sca_*) to provide transparent access
to and manipulation on the data for both Basic and Extended SCA in use.
The kvm.arch.sca is generalized to (void *) to handle BSCA/ESCA cases.
Also the kvm.arch.use_esca flag is provided.
The actual functionality is kept the same.
Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This patch adds new structures and updates some existing ones to
provide the base for Extended SCA functionality.
The old sca_* structures were renamed to bsca_* to keep things uniform.
The access to fields of SIGP controls were turned into bitfields instead
of hardcoded bitmasks.
Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This patch provides SCA-aware helpers to create/delete a VCPU.
This is to prepare for upcoming introduction of Extended SCA support.
Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This patch generalizes access to the SIGP controls, which is a part of SCA.
This is to prepare for upcoming introduction of Extended SCA support.
Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This patch generalizes access to the IPTE controls, which is a part of SCA.
This is to prepare for upcoming introduction of Extended SCA support.
Signed-off-by: Eugene (jno) Dvurechenski <jno@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Let's rewrite this function to better reflect how we actually handle
exit_code. By dropping out early we can save a few cycles. This
especially speeds up sie exits caused by host irqs.
Also, let's move the special -EOPNOTSUPP for intercepts to
the place where it belongs and convert it to -EREMOTE.
Reviewed-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Let's reuse the new common function for VPCU lookup by id.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
[split out the new function into a separate patch]
Replace the offsets based on the struct area_area with the offset
constants from asm-offsets.c based on the struct _lowcore.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
For now, VCPUs were always created sequentially with incrementing
VCPU ids. Therefore, the index in the VCPUs array matched the id.
As sequential creation might change with cpu hotplug, let's use
the correct lookup function to find a VCPU by id, not array index.
Let's also use kvm_lookup_vcpu() for validation of the sending VCPU
on external call injection.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org # db27a7a KVM: Provide function for VCPU lookup by id
Commit 383d0b0501 ("KVM: s390: handle pending local interrupts via
bitmap") introduced a possible memory overwrite from user space.
User space could pass an invalid emergency signal code (sending VCPU)
and therefore exceed the bitmap. Let's take care of this case and
check that the id is in the valid range.
Reviewed-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # v3.19+ db27a7a KVM: Provide function for VCPU lookup by id
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
The pfmf intercept handler should check if the EDAT 1 facility
is installed in the guest, not if it is installed in the host.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
We should never allow to enable/disable any facilities for the guest
when other VCPUs were already created.
kvm_arch_vcpu_(load|put) relies on SIMD not changing during runtime.
If somebody would create and run VCPUs and then decides to enable
SIMD, undefined behaviour could be possible (e.g. vector save area
not being set up).
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org # 4.1+
handling.
PPC: Mostly bug fixes.
ARM: No big features, but many small fixes and prerequisites including:
- a number of fixes for the arch-timer
- introducing proper level-triggered semantics for the arch-timers
- a series of patches to synchronously halt a guest (prerequisite for
IRQ forwarding)
- some tracepoint improvements
- a tweak for the EL2 panic handlers
- some more VGIC cleanups getting rid of redundant state
x86: quite a few changes:
- support for VT-d posted interrupts (i.e. PCI devices can inject
interrupts directly into vCPUs). This introduces a new component (in
virt/lib/) that connects VFIO and KVM together. The same infrastructure
will be used for ARM interrupt forwarding as well.
- more Hyper-V features, though the main one Hyper-V synthetic interrupt
controller will have to wait for 4.5. These will let KVM expose Hyper-V
devices.
- nested virtualization now supports VPID (same as PCID but for vCPUs)
which makes it quite a bit faster
- for future hardware that supports NVDIMM, there is support for clflushopt,
clwb, pcommit
- support for "split irqchip", i.e. LAPIC in kernel + IOAPIC/PIC/PIT in
userspace, which reduces the attack surface of the hypervisor
- obligatory smattering of SMM fixes
- on the guest side, stable scheduler clock support was rewritten to not
require help from the hypervisor.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"First batch of KVM changes for 4.4.
s390:
A bunch of fixes and optimizations for interrupt and time handling.
PPC:
Mostly bug fixes.
ARM:
No big features, but many small fixes and prerequisites including:
- a number of fixes for the arch-timer
- introducing proper level-triggered semantics for the arch-timers
- a series of patches to synchronously halt a guest (prerequisite
for IRQ forwarding)
- some tracepoint improvements
- a tweak for the EL2 panic handlers
- some more VGIC cleanups getting rid of redundant state
x86:
Quite a few changes:
- support for VT-d posted interrupts (i.e. PCI devices can inject
interrupts directly into vCPUs). This introduces a new
component (in virt/lib/) that connects VFIO and KVM together.
The same infrastructure will be used for ARM interrupt
forwarding as well.
- more Hyper-V features, though the main one Hyper-V synthetic
interrupt controller will have to wait for 4.5. These will let
KVM expose Hyper-V devices.
- nested virtualization now supports VPID (same as PCID but for
vCPUs) which makes it quite a bit faster
- for future hardware that supports NVDIMM, there is support for
clflushopt, clwb, pcommit
- support for "split irqchip", i.e. LAPIC in kernel +
IOAPIC/PIC/PIT in userspace, which reduces the attack surface of
the hypervisor
- obligatory smattering of SMM fixes
- on the guest side, stable scheduler clock support was rewritten
to not require help from the hypervisor"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (123 commits)
KVM: VMX: Fix commit which broke PML
KVM: x86: obey KVM_X86_QUIRK_CD_NW_CLEARED in kvm_set_cr0()
KVM: x86: allow RSM from 64-bit mode
KVM: VMX: fix SMEP and SMAP without EPT
KVM: x86: move kvm_set_irq_inatomic to legacy device assignment
KVM: device assignment: remove pointless #ifdefs
KVM: x86: merge kvm_arch_set_irq with kvm_set_msi_inatomic
KVM: x86: zero apic_arb_prio on reset
drivers/hv: share Hyper-V SynIC constants with userspace
KVM: x86: handle SMBASE as physical address in RSM
KVM: x86: add read_phys to x86_emulate_ops
KVM: x86: removing unused variable
KVM: don't pointlessly leave KVM_COMPAT=y in non-KVM configs
KVM: arm/arm64: Merge vgic_set_lr() and vgic_sync_lr_elrsr()
KVM: arm/arm64: Clean up vgic_retire_lr() and surroundings
KVM: arm/arm64: Optimize away redundant LR tracking
KVM: s390: use simple switch statement as multiplexer
KVM: s390: drop useless newline in debugging data
KVM: s390: SCA must not cross page boundaries
KVM: arm: Do not indent the arguments of DECLARE_BITMAP
...
We currently do some magic shifting (by exploiting that exit codes
are always a multiple of 4) and a table lookup to jump into the
exit handlers. This causes some calculations and checks, just to
do an potentially expensive function call.
Changing that to a switch statement gives the compiler the chance
to inline and dynamically decide between jump tables or inline
compare and branches. In addition it makes the code more readable.
bloat-o-meter gives me a small reduction in code size:
add/remove: 0/7 grow/shrink: 1/1 up/down: 986/-1334 (-348)
function old new delta
kvm_handle_sie_intercept 72 1058 +986
handle_prog 704 696 -8
handle_noop 54 - -54
handle_partial_execution 60 - -60
intercept_funcs 120 - -120
handle_instruction 198 - -198
handle_validity 210 - -210
handle_stop 316 - -316
handle_external_interrupt 368 - -368
Right now my gcc does conditional branches instead of jump tables.
The inlining seems to give us enough cycles as some micro-benchmarking
shows minimal improvements, but still in noise.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
the s390 debug feature does not need newlines. In fact it will
result in empty lines. Get rid of 4 leftovers.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
We seemed to have missed a few corner cases in commit f6c137ff00
("KVM: s390: randomize sca address").
The SCA has a maximum size of 2112 bytes. By setting the sca_offset to
some unlucky numbers, we exceed the page.
0x7c0 (1984) -> Fits exactly
0x7d0 (2000) -> 16 bytes out
0x7e0 (2016) -> 32 bytes out
0x7f0 (2032) -> 48 bytes out
One VCPU entry is 32 bytes long.
For the last two cases, we actually write data to the other page.
1. The address of the VCPU.
2. Injection/delivery/clearing of SIGP externall calls via SIGP IF.
Especially the 2. happens regularly. So this could produce two problems:
1. The guest losing/getting external calls.
2. Random memory overwrites in the host.
So this problem happens on every 127 + 128 created VM with 64 VCPUs.
Cc: stable@vger.kernel.org # v3.15+
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
If the kernel detects that the s390 hardware supports the vector
facility, it is enabled by default at an early stage. To force
it off, use the novx kernel parameter. Note that there is a small
time window, where the vector facility is enabled before it is
forced to be off.
With enabling the vector facility by default, the FPU save and
restore functions can be improved. They do not longer require
to manage expensive control register updates to enable or disable
the vector enablement control for particular processes.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Let's factor this out and always use get_tod_clock_fast() when
reading the guest TOD.
STORE CLOCK FAST does not do serialization and, therefore, might
result in some fuzziness between different processors in a way
that subsequent calls on different CPUs might have time stamps that
are earlier. This semantics is fine though for all KVM use cases.
To make it obvious that the new function has STORE CLOCK FAST
semantics we name it kvm_s390_get_tod_clock_fast.
With this patch, we only have a handful of places were we
have to care about STP sync (using preempt_disable() logic).
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Let's move that whole logic into one function. We now always use unsigned
values when calculating the epoch (to avoid over/underflow defined).
Also, we always have to get all VCPUs out of SIE before doing the update
to avoid running differing VCPUs with different TODs.
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Nobody except early.c makes use of store_tod_clock() to handle the
cc. So if we would get a cc != 0, we would be in more trouble.
Let's replace all users with get_tod_clock(). Returning a cc
on an ioctl sounded strange either way.
We can now also easily move the get_tod_clock() call into the
preempt_disable() section. This is in fact necessary to make the
STP sync work as expected. Otherwise the host TOD could change
and we would end up with a wrong epoch calculation.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
PER events can always co-exist with other program interrupts.
For now, we always overwrite all program interrupt parameters when
injecting any type of program interrupt.
Let's handle that correctly by only overwriting the relevant portion of
the program interrupt parameters. Therefore we can now inject PER events
and ordinary program interrupts concurrently, resulting in no loss of
program interrupts. This will especially by helpful when manually detecting
PER events later - as both types might be triggered during one SIE exit.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
The main reason to keep program injection in kernel separated until now
was that we were able to do some checking, if really only the owning
thread injects program interrupts (via waitqueue_active(li->wq)).
This BUG_ON was never triggered and the chances of really hitting it, if
another thread injected a program irq to another vcpu, were very small.
Let's drop this check and turn kvm_s390_inject_program_int() and
kvm_s390_inject_prog_irq() into simple inline functions that makes use of
kvm_s390_inject_vcpu().
__must_check can be dropped as they are implicitely given by
kvm_s390_inject_vcpu(), to avoid ugly long function prototypes.
Reviewed-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Let's get rid of the local variable and exit directly if we found
any pending interrupt. This is not only faster, but also better
readable.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
We can remove that double check.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
No need to separate pending and floating irqs when setting interception
requests. Let's do it for all equally.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
We don't care about program event recording irqs (synchronous
program irqs) but asynchronous irqs when checking for disabled
wait. Machine checks were missing.
Let's directly switch to the functions we have for that purpose
instead of testing once again for magic bits.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
the float int structure is no longer used in __inject_vm.
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
The offending commit accidentally replaces an atomic_clear with an
atomic_or instead of an atomic_andnot in kvm_s390_vcpu_request_handled.
The symptom is that kvm guests on s390 hang on startup.
This patch simply replaces the incorrect atomic_or with atomic_andnot
Fixes: 805de8f43c (atomic: Replace atomic_{set,clear}_mask() usage)
Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This new statistic can help diagnosing VCPUs that, for any reason,
trigger bad behavior of halt_poll_ns autotuning.
For example, say halt_poll_ns = 480000, and wakeups are spaced exactly
like 479us, 481us, 479us, 481us. Then KVM always fails polling and wastes
10+20+40+80+160+320+480 = 1110 microseconds out of every
479+481+479+481+479+481+479 = 3359 microseconds. The VCPU then
is consuming about 30% more CPU than it would use without
polling. This would show as an abnormally high number of
attempted polling compared to the successful polls.
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com<
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull locking and atomic updates from Ingo Molnar:
"Main changes in this cycle are:
- Extend atomic primitives with coherent logic op primitives
(atomic_{or,and,xor}()) and deprecate the old partial APIs
(atomic_{set,clear}_mask())
The old ops were incoherent with incompatible signatures across
architectures and with incomplete support. Now every architecture
supports the primitives consistently (by Peter Zijlstra)
- Generic support for 'relaxed atomics':
- _acquire/release/relaxed() flavours of xchg(), cmpxchg() and {add,sub}_return()
- atomic_read_acquire()
- atomic_set_release()
This came out of porting qwrlock code to arm64 (by Will Deacon)
- Clean up the fragile static_key APIs that were causing repeat bugs,
by introducing a new one:
DEFINE_STATIC_KEY_TRUE(name);
DEFINE_STATIC_KEY_FALSE(name);
which define a key of different types with an initial true/false
value.
Then allow:
static_branch_likely()
static_branch_unlikely()
to take a key of either type and emit the right instruction for the
case. To be able to know the 'type' of the static key we encode it
in the jump entry (by Peter Zijlstra)
- Static key self-tests (by Jason Baron)
- qrwlock optimizations (by Waiman Long)
- small futex enhancements (by Davidlohr Bueso)
- ... and misc other changes"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (63 commits)
jump_label/x86: Work around asm build bug on older/backported GCCs
locking, ARM, atomics: Define our SMP atomics in terms of _relaxed() operations
locking, include/llist: Use linux/atomic.h instead of asm/cmpxchg.h
locking/qrwlock: Make use of _{acquire|release|relaxed}() atomics
locking/qrwlock: Implement queue_write_unlock() using smp_store_release()
locking/lockref: Remove homebrew cmpxchg64_relaxed() macro definition
locking, asm-generic: Add _{relaxed|acquire|release}() variants for 'atomic_long_t'
locking, asm-generic: Rework atomic-long.h to avoid bulk code duplication
locking/atomics: Add _{acquire|release|relaxed}() variants of some atomic operations
locking, compiler.h: Cast away attributes in the WRITE_ONCE() magic
locking/static_keys: Make verify_keys() static
jump label, locking/static_keys: Update docs
locking/static_keys: Provide a selftest
jump_label: Provide a self-test
s390/uaccess, locking/static_keys: employ static_branch_likely()
x86, tsc, locking/static_keys: Employ static_branch_likely()
locking/static_keys: Add selftest
locking/static_keys: Add a new static_key interface
locking/static_keys: Rework update logic
locking/static_keys: Add static_key_{en,dis}able() helpers
...
