Introduce a KVM selftest to verify that userspace manipulation of the
TSC (via the new vCPU attribute) results in the correct behavior within
the guest.
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NOliver Upton <oupton@google.com>
Message-Id: <20210916181555.973085-6-oupton@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

vCPU file descriptors are abstracted away from test code in KVM
selftests, meaning that tests cannot directly access a vCPU's device
attributes. Add helpers that tests can use to get at vCPU device
attributes.
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NOliver Upton <oupton@google.com>
Message-Id: <20210916181555.973085-5-oupton@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The KVM_CREATE_DEVICE and KVM_{GET,SET}_DEVICE_ATTR ioctls are defined
to return a value of zero on success. As such, tighten the assertions in
the helper functions to only pass if the return code is zero.
Suggested-by: NAndrew Jones <drjones@redhat.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NOliver Upton <oupton@google.com>
Message-Id: <20210916181555.973085-4-oupton@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Add a selftest for the new KVM clock UAPI that was introduced. Ensure
that the KVM clock is consistent between userspace and the guest, and
that the difference in realtime will only ever cause the KVM clock to
advance forward.

Cc: Andrew Jones <drjones@redhat.com>
Signed-off-by: NOliver Upton <oupton@google.com>
Message-Id: <20210916181555.973085-3-oupton@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The kvm_vm_free() statement here is currently dead code, since the loop
in front of it can only be left with the "goto done" that jumps right
after the kvm_vm_free(). Fix it by swapping the locations of the "done"
label and the kvm_vm_free().
Signed-off-by: NThomas Huth <thuth@redhat.com>
Message-Id: <20210826074928.240942-1-thuth@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

There is a spelling mistake in an error message. Fix it.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Message-Id: <20210826120752.12633-1-colin.king@canonical.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

KVM_MAX_VCPU_ID is not specifying the highest allowed vcpu-id, but the
number of allowed vcpu-ids. This has already led to confusion, so
rename KVM_MAX_VCPU_ID to KVM_MAX_VCPU_IDS to make its semantics more
clear
Suggested-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210913135745.13944-3-jgross@suse.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

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: 61e52f16 ("KVM: selftests: Add a test for KVM_RUN+rseq to detect task migration bugs")
Reported-by: NDongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210929234112.1862848-1-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

There is no need to clobber a register that is only being read from.
Oops. Drop the XMM register from the clobbers list.
Signed-off-by: NOliver Upton <oupton@google.com>
Message-Id: <20210927223621.50178-1-oupton@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Compiling the KVM selftests with clang emits the following warning:

>> include/x86_64/processor.h:297:25: error: variable 'xmm0' is uninitialized when used here [-Werror,-Wuninitialized]
>>                return (unsigned long)xmm0;

where xmm0 is accessed via an uninitialized register variable.

Indeed, this is a misuse of register variables, which really should only
be used for specifying register constraints on variables passed to
inline assembly. Rather than attempting to read xmm registers via
register variables, just explicitly perform the movq from the desired
xmm register.

Fixes: 783e9e51 ("kvm: selftests: add API testing infrastructure")
Signed-off-by: NOliver Upton <oupton@google.com>
Message-Id: <20210924005147.1122357-1-oupton@google.com>
Reviewed-by: NRicardo Koller <ricarkol@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

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: 61e52f16 ("KVM: selftests: Add a test for KVM_RUN+rseq to detect task migration bugs")
Signed-off-by: NOliver Upton <oupton@google.com>
Message-Id: <20210923220033.4172362-1-oupton@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Test that if:

* L1 disables virtual interrupt masking, and INTR intercept.

* L1 setups a virtual interrupt to be injected to L2 and enters L2 with
  interrupts disabled, thus the virtual interrupt is pending.

* Now an external interrupt arrives in L1 and since
  L1 doesn't intercept it, it should be delivered to L2 when
  it enables interrupts.

  to do this L0 (abuses) V_IRQ to setup an
  interrupt window, and returns to L2.

* L2 enables interrupts.
  This should trigger the interrupt window,
  injection of the external interrupt and delivery
  of the virtual interrupt that can now be done.

* Test that now L2 gets those interrupts.

This is the test that demonstrates the issue that was
fixed in the previous patch.
Signed-off-by: NMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210914154825.104886-3-mlevitsk@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The calculation to get the per-slot dirty bitmap was incorrect leading
to a buffer overrun. Fix it by splitting out the dirty bitmap into a
separate bitmap per slot.

Fixes: 609e6202 ("KVM: selftests: Support multiple slots in dirty_log_perf_test")
Signed-off-by: NDavid Matlack <dmatlack@google.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Message-Id: <20210917173657.44011-4-dmatlack@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

All selftests that support the backing_src option were printing their
own description of the flag and then calling backing_src_help() to dump
the list of available backing sources. Consolidate the flag printing in
backing_src_help() to align indentation, reduce duplicated strings, and
improve consistency across tests.

Note: Passing "-s" to backing_src_help is unnecessary since every test
uses the same flag. However I decided to keep it for code readability
at the call sites.

While here this opportunistically fixes the incorrectly interleaved
printing -x help message and list of backing source types in
dirty_log_perf_test.

Fixes: 609e6202 ("KVM: selftests: Support multiple slots in dirty_log_perf_test")
Reviewed-by: NBen Gardon <bgardon@google.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NDavid Matlack <dmatlack@google.com>
Message-Id: <20210917173657.44011-3-dmatlack@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Every other KVM selftest uses -s for the backing_src, so switch
demand_paging_test to match.
Reviewed-by: NBen Gardon <bgardon@google.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NDavid Matlack <dmatlack@google.com>
Message-Id: <20210917173657.44011-2-dmatlack@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The SMC64 calling convention passes a function identifier in w0 and its
parameters in x1-x17. Given this, there are two deviations in the
SMC64 call performed by the steal_time test: the function identifier is
assigned to a 64 bit register and the parameter is only 32 bits wide.

Align the call with the SMCCC by using a 32 bit register to handle the
function identifier and increasing the parameter width to 64 bits.
Suggested-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NOliver Upton <oupton@google.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Message-Id: <20210921171121.2148982-3-oupton@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The logical not operator applies only to the left hand side of a bitwise
operator. As such, the check for POLLIN not being set in revents wrong.
Fix it by adding parentheses around the bitwise expression.

Fixes: 4f72180e ("KVM: selftests: Add demand paging content to the demand paging test")
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NOliver Upton <oupton@google.com>
Message-Id: <20210921171121.2148982-2-oupton@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

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 72c3c0fe ("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: NSean Christopherson <seanjc@google.com>
Acked-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Message-Id: <20210901203030.1292304-5-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Should not use comparison of unsigned expressions < 0.
Signed-off-by: NXiang wangx <wangxiang@cdjrlc.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Minimal selftest which implements a small BPF policy program to the
connect(2) hook which rejects TCP connection requests to port 60123
with EPERM. This is being attached to a non-root cgroup v2 path. The
test asserts that this works under cgroup v2-only and under a mixed
cgroup v1/v2 environment where net_classid is set in the former case.

Before fix:

  # ./test_progs -t cgroup_v1v2
  test_cgroup_v1v2:PASS:server_fd 0 nsec
  test_cgroup_v1v2:PASS:client_fd 0 nsec
  test_cgroup_v1v2:PASS:cgroup_fd 0 nsec
  test_cgroup_v1v2:PASS:server_fd 0 nsec
  run_test:PASS:skel_open 0 nsec
  run_test:PASS:prog_attach 0 nsec
  test_cgroup_v1v2:PASS:cgroup-v2-only 0 nsec
  run_test:PASS:skel_open 0 nsec
  run_test:PASS:prog_attach 0 nsec
  run_test:PASS:join_classid 0 nsec
  (network_helpers.c:219: errno: None) Unexpected success to connect to server
  test_cgroup_v1v2:FAIL:cgroup-v1v2 unexpected error: -1 (errno 0)
  #27 cgroup_v1v2:FAIL
  Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED

After fix:

  # ./test_progs -t cgroup_v1v2
  #27 cgroup_v1v2:OK
  Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210913230759.2313-3-daniel@iogearbox.net

Minimal set of helpers for net_cls classid cgroupv1 management in order
to set an id, join from a process, initiate setup and teardown. cgroupv2
helpers are left as-is, but reused where possible.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210913230759.2313-2-daniel@iogearbox.net

The basic TM vs syscall test code hard codes an sc instruction for the
system call, which fails to cover scv even when the userspace libc has
support for it.

Duplicate the tests with hard coded scv variants so both are tested
when possible.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
[mpe: Fix build on old toolchains by using .long for scv]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210903125707.1601269-2-npiggin@gmail.com

If altname deletion of the short alternative name fails, the error
message printed is: "Failed to add short alternative name".
This is obviously a typo, as we are testing altname deletion.

Fix this using a proper error message.

Fixes: f95e6c9c ("selftest: net: add alternative names test")
Signed-off-by: NAndrea Claudi <aclaudi@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The original test for adding and removing eprobes used synthetic events
and retrieved the filename from the open system call at the end of the
system call. This would allow it to always be loaded into the page tables
when accessed.

Masami suggested that the test was too complex for just testing add and
remove, so it was changed to test just adding and removing an event probe
on top of the start of the open system call event. Now it is possible that
the filename will not be loaded into memory at the time the eprobe is
triggered, and will result in "(fault)" being displayed in the event. This
causes the test to fail.

Account for "(fault)" also being one of the values of the filename field
of the event probe.

Link: https://lkml.kernel.org/r/20210907230429.5783d519@rorschach.local.home

Fixes: 079db707 ("selftests/ftrace: Add test case to test adding and removing of event probe")
Acked-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Commit 54402986 ("selftests/memfd: add tests for F_SEAL_FUTURE_WRITE
seal") added an unused variable to mfd_assert_reopen_fd().

Delete the unused variable.

Link: https://lkml.kernel.org/r/20210702045509.1517643-1-gthelen@google.com
Fixes: 54402986 ("selftests/memfd: add tests for F_SEAL_FUTURE_WRITE seal")
Signed-off-by: NGreg Thelen <gthelen@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Rename bitmap_alloc() to bitmap_zalloc() in tools to follow the bitmap API
in the kernel.

No functional changes intended.

Link: https://lkml.kernel.org/r/20210814211713.180533-14-yury.norov@gmail.comSigned-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NYury Norov <yury.norov@gmail.com>
Suggested-by: NYury Norov <yury.norov@gmail.com>
Acked-by: NYury Norov <yury.norov@gmail.com>
Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NJiri Olsa <jolsa@redhat.com>
Cc: Alexander Lobakin <alobakin@pm.me>
Cc: Alexey Klimov <aklimov@redhat.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This commit adds a simple user space tests for DAMON.  The tests are using
kselftest framework.

Link: https://lkml.kernel.org/r/20210716081449.22187-13-sj38.park@gmail.comSigned-off-by: NSeongJae Park <sjpark@amazon.de>
Reviewed-by: NMarkus Boehme <markubo@amazon.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Fernand Sieber <sieberf@amazon.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

struct pt_regs is not exported to userspace on all archs. arm64 and s390
export "user_pt_regs" instead, which causes build failure at the moment:

  progs/test_task_pt_regs.c:8:16: error: variable has incomplete type 'struct pt_regs'
  struct pt_regs current_regs = {};

Instead of using pt_regs from ptrace.h, use the larger kernel struct
from vmlinux.h directly. Since the test runner task_pt_regs.c does not
have access to the kernel struct definition, copy it into a char array.

Fixes: 576d47bb ("bpf: selftests: Add bpf_task_pt_regs() selftest")
Suggested-by: NAndrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Tested-by: NIlya Leoshkevich <iii@linux.ibm.com>
Acked-by: NIlya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/bpf/20210906163635.302307-1-jean-philippe@linaro.org

Modify the test to check that enslaving a bond slave with a XDP program
is now allowed.

Extend attach test to exercise the program unwinding in bond_xdp_set and
add a new test for loading XDP program on doubly nested bond device to
verify that static key incr/decr is correct.
Signed-off-by: NJussi Maki <joamaki@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Set 'MSG_EOR' in one of message sent, check that 'MSG_EOR'
is visible in corresponding message at receiver.
Signed-off-by: NArseny Krasnov <arseny.krasnov@kaspersky.com>
Reviewed-by: NStefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20210903123321.3273866-1-arseny.krasnov@kaspersky.comSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>

Since merged pages are copied every time they need to be modified, the
write access time is different between shared and non-shared pages.  Add
ksm_cow_time() function which evaluates latency of these COW breaks.
First, 4000 pages are allocated and the time, required to modify 1 byte in
every other page, is measured.  After this, the pages are merged into 2000
pairs and in each pair, 1 page is modified (i.e.  they are decoupled) to
detect COW breaks.  The time needed to break COW of merged pages is then
compared with performance of non-shared pages.

The test is run as follows: ./ksm_tests -C
The output:
	Total size:    15 MiB

	Not merged pages:
	Total time:     0.002185489 s
	Average speed:  3202.945 MiB/s

	Merged pages:
	Total time:     0.004386872 s
	Average speed:  1595.670 MiB/s

Link: https://lkml.kernel.org/r/1d03ee0d1b341959d4b61672c6401d498bff5652.1629386192.git.zhansayabagdaulet@gmail.comSigned-off-by: NZhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
Reviewed-by: NTyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: NPavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "add KSM performance tests", v3.

Extend KSM self tests with a performance benchmark.  These tests are not
part of regular regression testing, as they are mainly intended to be used
by developers making changes to the memory management subsystem.

This patch (of 2):

Add ksm_merge_time() function to determine speed and time needed for
merging.  The total spent time is shown in seconds while speed is in
MiB/s.  User must specify the size of duplicated memory area (in MiB)
before running the test.

The test is run as follows: ./ksm_tests -P -s 100
The output:
	Total size:    100 MiB
	Total time:    0.201106786 s
	Average speed:  497.248 MiB/s

Link: https://lkml.kernel.org/r/cover.1629386192.git.zhansayabagdaulet@gmail.com
Link: https://lkml.kernel.org/r/318b946ac80cc9205c89d0962048378f7ce0705b.1629386192.git.zhansayabagdaulet@gmail.comSigned-off-by: NZhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
Reviewed-by: NTyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: NPavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add check_ksm_numa_merge() function to test that pages in different NUMA
nodes are being handled properly.  First, two duplicate pages are
allocated in two separate NUMA nodes using the libnuma library.  Since
there is one unique page in each node, with merge_across_nodes = 0, there
won't be any shared pages.  If merge_across_nodes is set to 1, the pages
will be treated as usual duplicate pages and will be merged.  If NUMA
config is not enabled or the number of NUMA nodes is less than two, then
the test is skipped.  The test is run as follows: ./ksm_tests -N

Link: https://lkml.kernel.org/r/071c17b5b04ebb0dfeba137acc495e5dd9d2a719.1626252248.git.zhansayabagdaulet@gmail.comSigned-off-by: NZhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
Reviewed-by: NPavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: NTyler Hicks <tyhicks@linux.microsoft.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add check_ksm_zero_page_merge() function to test that empty pages are
being handled properly.  For this, several zero pages are allocated and
merged using madvise.  If use_zero_pages is enabled, the pages must be
shared with the special kernel zero pages; otherwise, they are merged as
usual duplicate pages.  The test is run as follows: ./ksm_tests -Z

Link: https://lkml.kernel.org/r/6d0caab00d4bdccf5e3791cb95cf6dfd5eb85e45.1626252248.git.zhansayabagdaulet@gmail.comSigned-off-by: NZhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
Reviewed-by: NPavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: NTyler Hicks <tyhicks@linux.microsoft.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add check_ksm_unmerge() function to verify that KSM is properly unmerging
shared pages.  For this, two duplicate pages are merged first and then
their contents are modified.  Since they are not identical anymore, the
pages must be unmerged and the number of merged pages has to be 0.  The
test is run as follows: ./ksm_tests -U

Link: https://lkml.kernel.org/r/c0f55420440d704d5b094275b4365aa1b2ad46b5.1626252248.git.zhansayabagdaulet@gmail.comSigned-off-by: NZhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
Reviewed-by: NPavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: NTyler Hicks <tyhicks@linux.microsoft.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "add KSM selftests".

Introduce selftests to validate the functionality of KSM.  The tests are
run on private anonymous pages.  Since some KSM tunables are modified,
their starting values are saved and restored after testing.  At the start,
run is set to 2 to ensure that only test pages will be merged (we assume
that no applications make madvise syscalls in the background).  If KSM
config not enabled, all tests will be skipped.

This patch (of 4):

Add check_ksm_merge() function to check the basic merging feature of KSM.
First, some number of identical pages are allocated and the MADV_MERGEABLE
advice is given to merge these pages.  Then, pages_shared and
pages_sharing values are compared with the expected numbers using
assert_ksm_pages_count() function.  The number of pages can be changed
using -p option.

Link: https://lkml.kernel.org/r/cover.1626252248.git.zhansayabagdaulet@gmail.com
Link: https://lkml.kernel.org/r/90287685c13300972ea84de93d1f3f900373f9fe.1626252248.git.zhansayabagdaulet@gmail.comSigned-off-by: NZhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
Reviewed-by: NPavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: NTyler Hicks <tyhicks@linux.microsoft.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When userfaultfd copy-ioctl fails since the PTE already exists, an -EEXIST
error is returned and the faulting thread is not woken.  The current
userfaultfd test does not wake the faulting thread in such case.  The
assumption is presumably that another thread set the PTE through copy/wp
ioctl and would wake the faulting thread or that alternatively the fault
handler would realize there is no need to "must_wait" and continue.  This
is not necessarily true.

There is an assumption that the "must_wait" tests in handle_userfault()
are sufficient to provide definitive answer whether the offending PTE is
populated or not.  However, userfaultfd_must_wait() test is lockless.
Consequently, concurrent calls to ptep_modify_prot_start(), for instance,
can clear the PTE and can cause userfaultfd_must_wait() to wrongly assume
it is not populated and a wait is needed.

There are therefore 3 options:
(1) Change the tests to wake on copy failure.
(2) Wake faulting thread unconditionally on zero/copy ioctls before
    returning -EEXIST.
(3) Change the userfaultfd_must_wait() to hold locks.

This patch took the first approach, but the others are valid solutions
with different tradeoffs.

Link: https://lkml.kernel.org/r/20210808020724.1022515-4-namit@vmware.comSigned-off-by: NNadav Amit <namit@vmware.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

flush_kernel_dcache_page is a rather confusing interface that implements a
subset of flush_dcache_page by not being able to properly handle page
cache mapped pages.

The only callers left are in the exec code as all other previous callers
were incorrect as they could have dealt with page cache pages.  Replace
the calls to flush_kernel_dcache_page with calls to flush_dcache_page,
which for all architectures does either exactly the same thing, can
contains one or more of the following:

 1) an optimization to defer the cache flush for page cache pages not
    mapped into userspace
 2) additional flushing for mapped page cache pages if cache aliases
    are possible

Link: https://lkml.kernel.org/r/20210712060928.4161649-7-hch@lst.deSigned-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: NIra Weiny <ira.weiny@intel.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a spelling mistake in an error message. Fix it.

Link: https://lkml.kernel.org/r/20210826121217.12885-1-colin.king@canonical.comSigned-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are several test cases in the vm directory are still using exit 0
when they need to be skipped.  Use the kselftest framework to skip code
instead so it can help us to distinguish the return status.

Criterion to filter out what should be fixed in vm directory:
  grep -r "exit 0" -B1 | grep -i skip

This change might cause some false-positives if people are running these
test scripts directly and only checking their return codes, which will
change from 0 to 4.  However I think the impact should be small as most of
our scripts here are already using this skip code.  And there will be no
such issue if running them with the kselftest framework.

Link: https://lkml.kernel.org/r/20210823073433.37653-1-po-hsu.lin@canonical.comSigned-off-by: NPo-Hsu Lin <po-hsu.lin@canonical.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>