The following conditions can cause cpu_has_work(env) to become true:

- env->queued_work_first: run_on_cpu is already kicking the VCPU

- env->stop = 1: pause_all_vcpus is already kicking the VCPU

- env->stopped = 0: resume_all_vcpus is already kicking the VCPU

- vm_running = 1: vm_start is calling resume_all_vcpus

- env->halted = 0: see previous patch

- qemu_cpu_has_work(env): when it becomes true, board code should set
  env->halted = 0 too.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

Sometimes vcpus are stopped directly without going through ->stop = 1.
Exit the VCPU execution loop in this case as well.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

We have qemu_cpu_self and qemu_thread_self. The latter is retrieving the
current thread, the former is checking for equality (using CPUState). We
also have qemu_thread_equal which is only used like qemu_cpu_self.

This refactors the interfaces, creating qemu_cpu_is_self and
qemu_thread_is_self as well ass qemu_thread_get_self.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Mixing up TCG bits with KVM already led to problems around eflags
emulation on x86. Moreover, quite some code that TCG requires on cpu
enty/exit is useless for KVM. So dispatch between tcg_cpu_exec and
kvm_cpu_exec as early as possible.

The core logic of cpu_halted from cpu_exec is added to
kvm_arch_process_irqchip_events. Moving away from cpu_exec makes
exception_index meaningless for KVM, we can simply pass the exit reason
directly (only "EXCP_DEBUG vs. rest" is relevant).
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

To prepare splitting up KVM and TCG CPU entry/exit, move the debug
exception into cpus.c and invoke cpu_handle_debug_exception on return
from qemu_cpu_exec.

This also allows to clean up the debug request signaling: We can assign
the job of informing main-loop to qemu_system_debug_request and stop the
calling cpu directly in cpu_handle_debug_exception. That means a debug
stop will now only be signaled via debug_requested and not additionally
via vmstop_requested.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Instead of fiddling with debug_requested and vmstop_requested directly,
introduce qemu_system_debug_request and turn qemu_system_vmstop_request
into a public interface. This aligns those services with exiting ones in
vl.c.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Define and use dedicated constants for vm_stop reasons, they actually
have nothing to do with the EXCP_* defines used so far. At this chance,
specify more detailed reasons so that VM state change handlers can
evaluate them.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

No functional changes.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Avoid duplicate use of the function name cpu_has_work, it's confusing,
also their scope. Refactor cpu_has_work to cpu_thread_is_idle and do the
same with any_cpu_has_work.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Pure interface cosmetics: Ensure that only kvm core services (as
declared in kvm.h) start with "kvm_". Prepend "qemu_" to those that
violate this rule in cpus.c. Also rename the corresponding tcg functions
for the sake of consistency.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Introduce qemu_cpu_kick_self to send SIG_IPI to the calling VCPU
context. First user will be kvm.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Currently, we only configure and process MCE-related SIGBUS events if
CONFIG_IOTHREAD is enabled. The groundwork is laid, we just need to
factor out the required handler registration and system configuration.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
CC: Huang Ying <ying.huang@intel.com>
CC: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
CC: Jin Dongming <jin.dongming@np.css.fujitsu.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Found by Stefan Hajnoczi: There is a race in kvm_cpu_exec between
checking for exit_request on vcpu entry and timer signals arriving
before KVM starts to catch them. Plug it by blocking both timer related
signals also on !CONFIG_IOTHREAD and process those via signalfd.

As this fix depends on real signalfd support (otherwise the timer
signals only kick the compat helper thread, and the main thread hangs),
we need to detect the invalid constellation and abort configure.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
CC: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Will be required for SIGBUS handling. For obvious reasons, this will
remain a nop on Windows hosts.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Move qemu_kvm_eat_signals around and call it also when the IO-thread is
not used. Do not yet process SIGBUS, will be armed in a separate step.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

We do not use the timeout, so drop its logic. As we always poll our
signals, we do not need to drop the global lock. Removing those calls
allows some further simplifications. Also fix the error processing of
sigpending at this chance.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Block SIG_IPI, unblock it during KVM_RUN, just like in io-thread mode.
It's unused so far, but this infrastructure will be required for
self-IPIs and to process SIGBUS plus, in KVM mode, SIGIO and SIGALRM. As
Windows doesn't support signal services, we need to provide a stub for
the init function.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Move {tcg,kvm}_init_ipi and block_io_signals to avoid prototypes, rename
the former two to clarify that they deal with more than SIG_IPI. No
functional changes - except for the tiny fixup of strerror usage.

The forward declaration of sigbus_handler is just temporarily, it will
be moved in a succeeding patch. dummy_signal is moved into the !_WIN32
block as we will soon need it also for !CONFIG_IOTHREAD.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Provide arch-independent kvm_on_sigbus* stubs to remove the #ifdef'ery
from cpus.c. This patch also fixes --disable-kvm build by providing the
missing kvm_on_sigbus_vcpu kvm-stub.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Acked-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Do not ignore errors of kvm_init_vcpu, they are fatal.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Except for timer events, we currently do not leave the loop over all
VCPUs if an IO event was filed. That may cause unexpected IO latencies
under !CONFIG_IOTHREAD in SMP scenarios. Fix it by setting the global
exit_request which breaks the loop.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

If some I/O operation ends up calling qemu_system_reset_request in VCPU
context, we record this and inform the io-thread, but we do not
terminate the VCPU loop. This can lead to fairly unexpected behavior if
the triggering reset operation is supposed to work synchronously.

Fix this for TCG (when run in deterministic I/O mode) by setting the
VCPU on stop and issuing a cpu_exit. KVM requires some more work on its
VCPU loop.

[ ported from qemu-kvm ]
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

If we call qemu_cpu_kick more than once before the target was able to
process the signal, pthread_kill will fail, and qemu will abort. Prevent
this by avoiding the redundant signal.

This logic can be found in qemu-kvm as well.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

The imbalance in the hold time of qemu_global_mutex only exists in TCG
mode. In contrast to TCG VCPUs, KVM drops the global lock during guest
execution. We already avoid touching the fairness lock from the
IO-thread in KVM mode, so also stop using it from the VCPU threads.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Flush all requests once we have stopped all
cpus and devices.
Make sure disk is in consistent state.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Tested-by: NJason Wang <jasowang@redhat.com>
Acked-by: NMarcelo Tosatti <mtosatti@redhat.com>

fprintf_function uses format checking with GCC_FMT_ATTR.

Format errors were fixed in
* target-i386/helper.c
* target-mips/translate.c
* target-ppc/translate.c

Cc: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

Port qemu-kvm's

commit 4b62fff1101a7ad77553147717a8bd3bf79df7ef
Author: Huang Ying <ying.huang@intel.com>
Date:   Mon Sep 21 10:43:25 2009 +0800

    MCE: Relay UCR MCE to guest

    UCR (uncorrected recovery) MCE is supported in recent Intel CPUs,
    where some hardware error such as some memory error can be reported
    without PCC (processor context corrupted). To recover from such MCE,
    the corresponding memory will be unmapped, and all processes accessing
    the memory will be killed via SIGBUS.

    For KVM, if QEMU/KVM is killed, all guest processes will be killed
    too. So we relay SIGBUS from host OS to guest system via a UCR MCE
    injection. Then guest OS can isolate corresponding memory and kill
    necessary guest processes only. SIGBUS sent to main thread (not VCPU
    threads) will be broadcast to all VCPU threads as UCR MCE.

aliguori: fix build
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Block SIGALRM, SIGIO and consume them via signalfd.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Guest debugging is currently broken under CONFIG_IOTHREAD. The reason is
inconsistent or even lacking signaling the debug events from the source
VCPU to the main loop and the gdbstub.

This patch addresses the issue by pushing this signaling into a
CPUDebugExcpHandler: cpu_debug_handler is registered as first handler,
thus will be executed last after potential breakpoint emulation
handlers. It sets informs the gdbstub about the debug event source,
requests a debug exit of the main loop and stops the current VCPU. This
mechanism works both for TCG and KVM, with and without IO-thread.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

These functions are also used for kvm under !CONFIG_IOTHREAD, having
'tcg' in their name is just misleading.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

When checking for I/O events in the tcg CPU loop, make sure that we
call qemu_wait_io_event_common for all CPUs, not only the current one.
Otherwise pause_all_vcpus may lock up or run_on_cpu requests may starve.

Rename qemu_wait_io_event to qemu_tcg_wait_io_event at this chance and
purge its argument list as it has no use for it.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

If a cpu_exit request is pending, ensure that we leave the CPU loop
quickly. For this purpose, keep the global exit_request pending until
we are about to leave tcg_cpu_exec. Also, immediately break out of the
SMP loop if the request is set, do not run till the end of the chain.
This preserves the VCPU scheduling order in SMP mode.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

All signals will thus be routed through the IO thread.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>