KVM: selftests: Add option to rseq test to override /dev/cpu_dma_latency

Add a "-l <latency>" param to the rseq test so that the user can override
/dev/cpu_dma_latency, as described by the test's su

KVM: selftests: Add option to rseq test to override /dev/cpu_dma_latency

Add a "-l <latency>" param to the rseq test so that the user can override
/dev/cpu_dma_latency, as described by the test's suggested workaround for
not being able to complete enough migrations.

cpu_dma_latency is not a normal file, even as far as procfs files go.
Writes to cpu_dma_latency only persist so long as the file is open, e.g.
so that the kernel automatically reverts back to a power-optimized state
once the sensitive workload completes. Provide the necessary functionality
instead of effectively forcing the user to write a non-obvious wrapper.

Cc: Dongsheng Zhang <[email protected]>
Cc: Zide Chen <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

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KVM: selftests: Allow skipping the KVM_RUN sanity check in rseq_test

The rseq test's migration worker delays 1-10 us, assuming that one KVM_RUN
iteration only takes a few microseconds. But if the C

KVM: selftests: Allow skipping the KVM_RUN sanity check in rseq_test

The rseq test's migration worker delays 1-10 us, assuming that one KVM_RUN
iteration only takes a few microseconds. But if the CPU low power wakeup
latency is large enough, for example, hundreds or even thousands of
microseconds for deep C-state exit latencies on x86 server CPUs, it may
happen that the target CPU is unable to wakeup and run the vCPU before the
migration worker starts to migrate the vCPU thread to the _next_ CPU.

If the system workload is light, most CPUs could be at a certain low
power state, which may result in less successful migrations and fail the
migration/KVM_RUN ratio sanity check. But this is not supposed to be
deemed a test failure.

Add a command line option to skip the sanity check, along with a comment
and a verbose assert message to try to help the user resolve the potential
source of failures without having to resort to disabling the check.

Co-developed-by: Dongsheng Zhang <[email protected]>
Signed-off-by: Dongsheng Zhang <[email protected]>
Signed-off-by: Zide Chen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[sean: massage changelog]
Signed-off-by: Sean Christopherson <[email protected]>

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Revert "kvm: selftests: move base kvm_util.h declarations to kvm_util_base.h"

Effectively revert the movement of code from kvm_util.h => kvm_util_base.h,
as the TL;DR of the justification for the mo

Revert "kvm: selftests: move base kvm_util.h declarations to kvm_util_base.h"

Effectively revert the movement of code from kvm_util.h => kvm_util_base.h,
as the TL;DR of the justification for the move was to avoid #idefs and/or
circular dependencies between what ended up being ucall_common.h and what
was (and now again, is), kvm_util.h.

But avoiding #ifdef and circular includes is trivial: don't do that. The
cost of removing kvm_util_base.h is a few extra includes of ucall_common.h,
but that cost is practically nothing. On the other hand, having a "base"
version of a header that is really just the header itself is confusing,
and makes it weird/hard to choose names for headers that actually are
"base" headers, e.g. to hold core KVM selftests typedefs.

For all intents and purposes, this reverts commit
7d9a662ed9f0403e7b94940dceb81552b8edb931.

Reviewed-by: Ackerley Tng <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sean Christopherson <[email protected]>

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KVM: selftests: Define _GNU_SOURCE for all selftests code

Define _GNU_SOURCE is the base CFLAGS instead of relying on selftests to
manually #define _GNU_SOURCE, which is repetitive and error prone.

KVM: selftests: Define _GNU_SOURCE for all selftests code

Define _GNU_SOURCE is the base CFLAGS instead of relying on selftests to
manually #define _GNU_SOURCE, which is repetitive and error prone. E.g.
kselftest_harness.h requires _GNU_SOURCE for asprintf(), but if a selftest
includes kvm_test_harness.h after stdio.h, the include guards result in
the effective version of stdio.h consumed by kvm_test_harness.h not
defining asprintf():

In file included from x86_64/fix_hypercall_test.c:12:
In file included from include/kvm_test_harness.h:11:
../kselftest_harness.h:1169:2: error: call to undeclared function
'asprintf'; ISO C99 and later do not support implicit function declarations
[-Wimplicit-function-declaration]
1169 | asprintf(&test_name, "%s%s%s.%s", f->name,
| ^

When including the rseq selftest's "library" code, #undef _GNU_SOURCE so
that rseq.c controls whether or not it wants to build with _GNU_SOURCE.

Reported-by: Muhammad Usama Anjum <[email protected]>
Acked-by: Claudio Imbrenda <[email protected]>
Acked-by: Oliver Upton <[email protected]>
Acked-by: Anup Patel <[email protected]>
Reviewed-by: Muhammad Usama Anjum <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sean Christopherson <[email protected]>

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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@ven

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 <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sean Christopherson <[email protected]>

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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, conflicti

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 <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Mathieu Desnoyers <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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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: 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%[email protected]
Suggested-by: Sean Christopherson <[email protected]>
Reviewed-by: Andrew Jones <[email protected]>
Reviewed-by: Peter Gonda <[email protected]>
Signed-off-by: Vishal Annapurve <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sean Christopherson <[email protected]>

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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

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 <[email protected]>
Reviewed-by: Andrew Jones <[email protected]>
Tested-by: Peter Gonda <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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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:

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 <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

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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 poin

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 <[email protected]>
Suggested-by: Florian Weimer <[email protected]>
Suggested-by: Mathieu Desnoyers <[email protected]>
Suggested-by: Sean Christopherson <[email protected]>
Signed-off-by: Gavin Shan <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

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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,

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 <[email protected]>
Suggested-by: Florian Weimer <[email protected]>
Suggested-by: Mathieu Desnoyers <[email protected]>
Suggested-by: Paolo Bonzini <[email protected]>
Signed-off-by: Gavin Shan <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

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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 pa

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 <[email protected]>
Signed-off-by: Gavin Shan <[email protected]>
Reviewed-by: Oliver Upton <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Andrew Jones <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

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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 pri

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 <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

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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 <[email protected]>
Signe

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 <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

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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: S

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 <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

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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 ite

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 <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

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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

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 <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

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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. Th

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 <[email protected]>
Acked-by: Mathieu Desnoyers <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

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