KVM: selftests: Remove redundant newlines

TEST_* functions append their own newline. Remove newlines from
TEST_* callsites to avoid extra newlines in output.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20231206170241.82801-8-ajones@ventanamicro.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

KVM: selftests: Fix build of rseq test

The KVM rseq test is failing to build in -next due to a commit merged
from the tip tree which adds a wrapper for sys_getcpu() to the rseq
kselftests, conflicting with the wrapper already included in the KVM
selftest:

rseq_test.c:48:13: error: conflicting types for 'sys_getcpu'
48 | static void sys_getcpu(unsigned *cpu)
| ^~~~~~~~~~
In file included from rseq_test.c:23:
../rseq/rseq.c:82:12: note: previous definition of 'sys_getcpu' was here
82 | static int sys_getcpu(unsigned *cpu, unsigned *node)
| ^~~~~~~~~~

Fix this by removing the local wrapper and moving the result check up to
the caller.

Fixes: 99babd04b250 ("selftests/rseq: Implement rseq numa node id field selftest")
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/r/20230106-fix-kvm-rseq-build-v1-1-b704d9831d02@kernel.org

KVM: selftests: move common startup logic to kvm_util.c

Consolidate common startup logic in one place by implementing a single
setup function with __attribute((constructor)) for all selftests within
kvm_util.c.

This allows moving logic like:
/* Tell stdout not to buffer its content */
setbuf(stdout, NULL);
to a single file for all selftests.

This will also allow any required setup at entry in future to be done in
common main function.

Link: https://lore.kernel.org/lkml/Ywa9T+jKUpaHLu%2Fl@google.com
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Reviewed-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Link: https://lore.kernel.org/r/20221115213845.3348210-2-vannapurve@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

KVM: selftests: Automatically do init_ucall() for non-barebones VMs

Do init_ucall() automatically during VM creation to kill two (three?)
birds with one stone.

First, initializing ucall immediately after VM creations allows forcing
aarch64's MMIO ucall address to immediately follow memslot0. This is
still somewhat fragile as tests could clobber the MMIO address with a
new memslot, but it's safe-ish since tests have to be conversative when
accounting for memslot0. And this can be hardened in the future by
creating a read-only memslot for the MMIO page (KVM ARM exits with MMIO
if the guest writes to a read-only memslot). Add a TODO to document that
selftests can and should use a memslot for the ucall MMIO (doing so
requires yet more rework because tests assumes thay can use all memslots
except memslot0).

Second, initializing ucall for all VMs prepares for making ucall
initialization meaningful on all architectures. aarch64 is currently the
only arch that needs to do any setup, but that will change in the future
by switching to a pool-based implementation (instead of the current
stack-based approach).

Lastly, defining the ucall MMIO address from common code will simplify
switching all architectures (except s390) to a common MMIO-based ucall
implementation (if there's ever sufficient motivation to do so).

Cc: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Tested-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006003409.649993-4-seanjc@google.com

selftests: kvm: Fix a compile error in selftests/kvm/rseq_test.c

The following warning appears when executing:
make -C tools/testing/selftests/kvm

rseq_test.c: In function ‘main’:
rseq_test.c:237:33: warning: implicit declaration of function ‘gettid’; did you mean ‘getgid’? [-Wimplicit-function-declaration]
(void *)(unsigned long)gettid());
^~~~~~
getgid
/usr/bin/ld: /tmp/ccr5mMko.o: in function `main':
../kvm/tools/testing/selftests/kvm/rseq_test.c:237: undefined reference to `gettid'
collect2: error: ld returned 1 exit status
make: *** [../lib.mk:173: ../kvm/tools/testing/selftests/kvm/rseq_test] Error 1

Use the more compatible syscall(SYS_gettid) instead of gettid() to fix it.
More subsequent reuse may cause it to be wrapped in a lib file.

Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
Message-Id: <20220802071240.84626-1-cloudliang@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Use getcpu() instead of sched_getcpu() in rseq_test

sched_getcpu() is glibc dependent and it can simply return the CPU
ID from the registered rseq information, as Florian Weimer pointed.
In this case, it's pointless to compare the return value from
sched_getcpu() and that fetched from the registered rseq information.

Fix the issue by replacing sched_getcpu() with getcpu(), as Florian
suggested. The comments are modified accordingly by replacing
"sched_getcpu()" with "getcpu()".

Reported-by: Yihuang Yu <yihyu@redhat.com>
Suggested-by: Florian Weimer <fweimer@redhat.com>
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Message-Id: <20220810104114.6838-3-gshan@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Make rseq compatible with glibc-2.35

The rseq information is registered by TLS, starting from glibc-2.35.
In this case, the test always fails due to syscall(__NR_rseq). For
example, on RHEL9.1 where upstream glibc-2.35 features are enabled
on downstream glibc-2.34, the test fails like below.

# ./rseq_test
==== Test Assertion Failure ====
rseq_test.c:60: !r
pid=112043 tid=112043 errno=22 - Invalid argument
1 0x0000000000401973: main at rseq_test.c:226
2 0x0000ffff84b6c79b: ?? ??:0
3 0x0000ffff84b6c86b: ?? ??:0
4 0x0000000000401b6f: _start at ??:?
rseq failed, errno = 22 (Invalid argument)
# rpm -aq | grep glibc-2
glibc-2.34-39.el9.aarch64

Fix the issue by using "../rseq/rseq.c" to fetch the rseq information,
registred by TLS if it exists. Otherwise, we're going to register our
own rseq information as before.

Reported-by: Yihuang Yu <yihyu@redhat.com>
Suggested-by: Florian Weimer <fweimer@redhat.com>
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Message-Id: <20220810104114.6838-2-gshan@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Add TEST_REQUIRE macros to reduce skipping copy+paste

Add TEST_REQUIRE() and __TEST_REQUIRE() to replace the myriad open coded
instances of selftests exiting with KSFT_SKIP after printing an
informational message. In addition to reducing the amount of boilerplate
code in selftests, the UPPERCASE macro names make it easier to visually
identify a test's requirements.

Convert usage that erroneously uses something other than print_skip()
and/or "exits" with '0' or some other non-KSFT_SKIP value.

Intentionally drop a kvm_vm_free() in aarch64/debug-exceptions.c as part
of the conversion. All memory and file descriptors are freed on process
exit, so the explicit free is superfluous.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Purge vm+vcpu_id == vcpu silliness

Take a vCPU directly instead of a VM+vcpu pair in all vCPU-scoped helpers
and ioctls.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Convert rseq_test away from VCPU_ID

Convert rseq_test to use vm_create_with_one_vcpu() and pass around a
'struct kvm_vcpu' object instead of using a global VCPU_ID.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Fix target thread to be migrated in rseq_test

In rseq_test, there are two threads, which are vCPU thread and migration
worker separately. Unfortunately, the test has the wrong PID passed to
sched_setaffinity() in the migration worker. It forces migration on the
migration worker because zeroed PID represents the calling thread, which
is the migration worker itself. It means the vCPU thread is never enforced
to migration and it can migrate at any time, which eventually leads to
failure as the following logs show.

host# uname -r
5.19.0-rc6-gavin+
host# # cat /proc/cpuinfo | grep processor | tail -n 1
processor : 223
host# pwd
/home/gavin/sandbox/linux.main/tools/testing/selftests/kvm
host# for i in `seq 1 100`; do \
echo "--------> $i"; ./rseq_test; done
--------> 1
--------> 2
--------> 3
--------> 4
--------> 5
--------> 6
==== Test Assertion Failure ====
rseq_test.c:265: rseq_cpu == cpu
pid=3925 tid=3925 errno=4 - Interrupted system call
1 0x0000000000401963: main at rseq_test.c:265 (discriminator 2)
2 0x0000ffffb044affb: ?? ??:0
3 0x0000ffffb044b0c7: ?? ??:0
4 0x0000000000401a6f: _start at ??:?
rseq CPU = 4, sched CPU = 27

Fix the issue by passing correct parameter, TID of the vCPU thread, to
sched_setaffinity() in the migration worker.

Fixes: 61e52f1630f5 ("KVM: selftests: Add a test for KVM_RUN+rseq to detect task migration bugs")
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Message-Id: <20220719020830.3479482-1-gshan@redhat.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Ensure all migrations are performed when test is affined

Rework the CPU selection in the migration worker to ensure the specified
number of migrations are performed when the test iteslf is affined to a
subset of CPUs. The existing logic skips iterations if the target CPU is
not in the original set of possible CPUs, which causes the test to fail
if too many iterations are skipped.

==== Test Assertion Failure ====
rseq_test.c:228: i > (NR_TASK_MIGRATIONS / 2)
pid=10127 tid=10127 errno=4 - Interrupted system call
1 0x00000000004018e5: main at rseq_test.c:227
2 0x00007fcc8fc66bf6: ?? ??:0
3 0x0000000000401959: _start at ??:?
Only performed 4 KVM_RUNs, task stalled too much?

Calculate the min/max possible CPUs as a cheap "best effort" to avoid
high runtimes when the test is affined to a small percentage of CPUs.
Alternatively, a list or xarray of the possible CPUs could be used, but
even in a horrendously inefficient setup, such optimizations are not
needed because the runtime is completely dominated by the cost of
migrating the task, and the absolute runtime is well under a minute in
even truly absurd setups, e.g. running on a subset of vCPUs in a VM that
is heavily overcommited (16 vCPUs per pCPU).

Fixes: 61e52f1630f5 ("KVM: selftests: Add a test for KVM_RUN+rseq to detect task migration bugs")
Reported-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210929234112.1862848-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

selftests: KVM: Call ucall_init when setting up in rseq_test

While x86 does not require any additional setup to use the ucall
infrastructure, arm64 needs to set up the MMIO address used to signal a
ucall to userspace. rseq_test does not initialize the MMIO address,
resulting in the test spinning indefinitely.

Fix the issue by calling ucall_init() during setup.

Fixes: 61e52f1630f5 ("KVM: selftests: Add a test for KVM_RUN+rseq to detect task migration bugs")
Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20210923220033.4172362-1-oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Add a test for KVM_RUN+rseq to detect task migration bugs

Add a test to verify an rseq's CPU ID is updated correctly if the task is
migrated while the kernel is handling KVM_RUN. This is a regression test
for a bug introduced by commit 72c3c0fe54a3 ("x86/kvm: Use generic xfer
to guest work function"), where TIF_NOTIFY_RESUME would be cleared by KVM
without updating rseq, leading to a stale CPU ID and other badness.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Message-Id: <20210901203030.1292304-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>