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Increase 'maxnode' when using 'get_mempolicy' syscall in guest_memfd
mmap and NUMA policy tests to fix a failure on one Intel GNR platform.
On a CXL-capable platform, the memory affinity of CXL memory regions may
not be covered by the SRAT. Since each CXL memory region is enumerated
via a CFMWS table, at early boot the kernel parses all CFMWS tables to
detect all CXL memory regions and assigns a 'faked' NUMA node for each
of them, starting from the highest NUMA node ID enumerated via the SRAT.
This increases the 'nr_node_ids'. E.g., on the aforementioned Intel GNR
platform which has 4 NUMA nodes and 18 CFMWS tables, it increases to 22.
This results in the 'get_mempolicy' syscall failure on that platform,
because currently 'maxnode' is hard-coded to 8 but the 'get_mempolicy'
syscall requires the 'maxnode' to be not smaller than the 'nr_node_ids'.
Increase the 'maxnode' to the number of bits of 'nodemask', which is
'unsigned long', to fix this.
This may not cover all systems. Perhaps a better way is to always set
the 'nodemask' and 'maxnode' based on the actual maximum NUMA node ID on
the system, but for now just do the simple way.
Reported-by: Yi Lai <yi1.lai@intel.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=221014
Closes: https://lore.kernel.org/all/bug-221014-28872@https.bugzilla.kernel.org%2F
Signed-off-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Yuan Yao <yaoyuan@linux.alibaba.com>
Link: https://patch.msgid.link/20260302205158.178058-1-kai.huang@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add tests for NUMA memory policy binding and NUMA aware allocation in
guest_memfd. This extends the existing selftests by adding proper
validation for:
- KVM GMEM set_policy and get_policy() vm_ops functionality using
mbind() and get_mempolicy()
- NUMA policy application before and after memory allocation
Run the NUMA mbind() test with and without INIT_SHARED, as KVM should allow
doing mbind(), madvise(), etc. on guest-private memory, e.g. so that
userspace can set NUMA policy for CoCo VMs.
Run the NUMA allocation test only for INIT_SHARED, i.e. if the host can't
fault-in memory (via direct access, madvise(), etc.) as move_pages()
returns -ENOENT if the page hasn't been faulted in (walks the host page
tables to find the associated folio)
[sean: don't skip entire test when running on non-NUMA system, test mbind()
with private memory, provide more info in assert messages]
Signed-off-by: Shivank Garg <shivankg@amd.com>
Tested-by: Ashish Kalra <ashish.kalra@amd.com>
Link: https://lore.kernel.org/r/20251016172853.52451-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Expand the guest_memfd negative testcases for overflow and MAP_PRIVATE to
verify that reads to inaccessible memory also get a SIGBUS.
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Lisa Wang <wyihan@google.com>
Tested-by: Lisa Wang <wyihan@google.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-14-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add a guest_memfd testcase to verify that faulting in private memory gets
a SIGBUS. For now, test only the case where memory is private by default
since KVM doesn't yet support in-place conversion.
Deliberately run the CoW test with and without INIT_SHARED set as KVM
should disallow MAP_PRIVATE regardless of whether the memory itself is
private from a CoCo perspective.
Cc: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-13-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Extract the guest_memfd test's SIGBUS handling functionality into a common
TEST_EXPECT_SIGBUS() macro in anticipation of adding more SIGBUS testcases.
Eating a SIGBUS isn't terrible difficult, but it requires a non-trivial
amount of boilerplate code, and using a macro allows selftests to print
out the exact action that failed to generate a SIGBUS without the developer
needing to remember to add a useful error message.
Explicitly mark the SIGBUS handler as "used", as gcc-14 at least likes to
discard the function before linking.
Opportunistically use TEST_FAIL(...) instead of TEST_ASSERT(false, ...),
and fix the write path of the guest_memfd test to use the local "val"
instead of hardcoding the literal value a second time.
Suggested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Lisa Wang <wyihan@google.com>
Tested-by: Lisa Wang <wyihan@google.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Move the guest_memfd Copy-on-Write (CoW) testcase to its own function to
better separate positive testcases from negative testcases.
No functional change intended.
Suggested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-11-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add and use wrappers for mmap() and munmap() that assert success to reduce
a significant amount of boilerplate code, to ensure all tests assert on
failure, and to provide consistent error messages on failure.
No functional change intended.
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-10-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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If a VM type supports KVM_CAP_GUEST_MEMFD_MMAP, the guest_memfd test will
run all test cases with GUEST_MEMFD_FLAG_MMAP set. This leaves the code
path for creating a non-mmap()-able guest_memfd on a VM that supports
mappable guest memfds untested.
Refactor the test to run the main test suite with a given set of flags.
Then, for VM types that support the mappable capability, invoke the test
suite twice: once with no flags, and once with GUEST_MEMFD_FLAG_MMAP
set.
This ensures both creation paths are properly exercised on capable VMs.
Run test_guest_memfd_flags() only once per VM type since it depends only
on the set of valid/supported flags, i.e. iterating over an arbitrary set
of flags is both unnecessary and wrong.
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
[sean: use double-underscores for the inner helper]
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Refactor the guest_memfd selftest to improve test isolation by creating a
a new guest_memfd for each testcase. Currently, the test reuses a single
guest_memfd instance for all testcases, and thus creates dependencies
between tests, e.g. not truncating folios from the guest_memfd instance
at the end of a test could lead to unexpected results (see the PUNCH_HOLE
purging that needs to done by in-flight the NUMA testcases[1]).
Invoke each test via a macro wrapper to create and close a guest_memfd
to cut down on the boilerplate copy+paste needed to create a test.
Link: https://lore.kernel.org/all/20250827175247.83322-10-shivankg@amd.com
Reported-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Use a global variable to track the host page size in the guest_memfd test
so that the information doesn't need to be constantly passed around. The
state is purely a reflection of the underlying system, i.e. can't be set
by the test and is constant for a given invocation of the test, and thus
explicitly passing the host page size to individual testcases adds no
value, e.g. doesn't allow testing different combinations.
Making page_size a global will simplify an upcoming change to create a new
guest_memfd instance per testcase.
No functional change intended.
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add a guest_memfd flag to allow userspace to state that the underlying
memory should be configured to be initialized as shared, and reject user
page faults if the guest_memfd instance's memory isn't shared. Because
KVM doesn't yet support in-place private<=>shared conversions, all
guest_memfd memory effectively follows the initial state.
Alternatively, KVM could deduce the initial state based on MMAP, which for
all intents and purposes is what KVM currently does. However, implicitly
deriving the default state based on MMAP will result in a messy ABI when
support for in-place conversions is added.
For x86 CoCo VMs, which don't yet support MMAP, memory is currently private
by default (otherwise the memory would be unusable). If MMAP implies
memory is shared by default, then the default state for CoCo VMs will vary
based on MMAP, and from userspace's perspective, will change when in-place
conversion support is added. I.e. to maintain guest<=>host ABI, userspace
would need to immediately convert all memory from shared=>private, which
is both ugly and inefficient. The inefficiency could be avoided by adding
a flag to state that memory is _private_ by default, irrespective of MMAP,
but that would lead to an equally messy and hard to document ABI.
Bite the bullet and immediately add a flag to control the default state so
that the effective behavior is explicit and straightforward.
Fixes: 3d3a04fad25a ("KVM: Allow and advertise support for host mmap() on guest_memfd files")
Cc: David Hildenbrand <david@redhat.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Rework the not-yet-released KVM_CAP_GUEST_MEMFD_MMAP into a more generic
KVM_CAP_GUEST_MEMFD_FLAGS capability so that adding new flags doesn't
require a new capability, and so that developers aren't tempted to bundle
multiple flags into a single capability.
Note, kvm_vm_ioctl_check_extension_generic() can only return a 32-bit
value, but that limitation can be easily circumvented by adding e.g.
KVM_CAP_GUEST_MEMFD_FLAGS2 in the unlikely event guest_memfd supports more
than 32 flags.
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20251003232606.4070510-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add a guest_memfd testcase to verify that a vCPU can fault-in guest_memfd
memory that supports mmap(), but that is not currently mapped into host
userspace and/or has a userspace address (in the memslot) that points at
something other than the target guest_memfd range. Mapping guest_memfd
memory into the guest is supposed to operate completely independently from
any userspace mappings.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20250729225455.670324-25-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Expand the guest_memfd selftests to comprehensively test host userspace
mmap functionality for guest_memfd-backed memory when supported by the
VM type.
Introduce new test cases to verify the following:
* Successful mmap operations: Ensure that MAP_SHARED mappings succeed
when guest_memfd mmap is enabled.
* Data integrity: Validate that data written to the mmap'd region is
correctly persistent and readable.
* fallocate interaction: Test that fallocate(FALLOC_FL_PUNCH_HOLE)
correctly zeros out mapped pages.
* Out-of-bounds access: Verify that accessing memory beyond the
guest_memfd's size correctly triggers a SIGBUS signal.
* Unsupported mmap: Confirm that mmap attempts fail as expected when
guest_memfd mmap support is not enabled for the specific guest_memfd
instance or VM type.
* Flag validity: Introduce test_vm_type_gmem_flag_validity() to
systematically test that only allowed guest_memfd creation flags are
accepted for different VM types (e.g., GUEST_MEMFD_FLAG_MMAP for
default VMs, no flags for CoCo VMs).
The existing tests for guest_memfd creation (multiple instances, invalid
sizes), file read/write, file size, and invalid punch hole operations
are integrated into the new test_with_type() framework to allow testing
across different VM types.
Cc: James Houghton <jthoughton@google.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Shivank Garg <shivankg@amd.com>
Co-developed-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20250729225455.670324-24-seanjc@google.com>
[Fix default vm_types to use BIT() - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Update the guest_memfd_test selftest to use getpagesize() instead of
hardcoded 4KB page size values.
Using hardcoded page sizes can cause test failures on architectures or
systems configured with larger page sizes, such as arm64 with 64KB
pages. By dynamically querying the system's page size, the test becomes
more portable and robust across different environments.
Additionally, build the guest_memfd_test selftest for arm64.
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Shivank Garg <shivankg@amd.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Suggested-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20250729225455.670324-23-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The loop in test_create_guest_memfd_invalid() that is supposed to test
that nothing is accepted as a valid flag to KVM_CREATE_GUEST_MEMFD was
initializing `flag` as 0 instead of BIT(0). This caused the loop to
immediately exit instead of iterating over BIT(0), BIT(1), ... .
Fixes: 8a89efd43423 ("KVM: selftests: Add basic selftest for guest_memfd()")
Signed-off-by: Patrick Roy <roypat@amazon.co.uk>
Reviewed-by: James Gowans <jgowans@amazon.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20241024095956.3668818-1-roypat@amazon.co.uk
Signed-off-by: Sean Christopherson <seanjc@google.com>
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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 <ackerleytng@google.com>
Link: https://lore.kernel.org/r/20240314232637.2538648-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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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 <usama.anjum@collabora.com>
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Acked-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20240423190308.2883084-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Explicitly close() guest_memfd files in various guest_memfd and
private_mem_conversions tests, there's no reason to keep the files open
until the test exits.
Fixes: 8a89efd43423 ("KVM: selftests: Add basic selftest for guest_memfd()")
Fixes: 43f623f350ce ("KVM: selftests: Add x86-only selftest for private memory conversions")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Link: https://lore.kernel.org/r/20240227015716.27284-1-dongli.zhang@oracle.com
[sean: massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
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MEM_REGION_SLOT and MEM_REGION_GPA are not really needed in
test_invalid_memory_region_flags; the VM never runs and there are no
other slots, so it is okay to use slot 0 and place it at address
zero. This fixes compilation on architectures that do not
define them.
Fixes: 5d74316466f4 ("KVM: selftests: Add a memory region subtest to validate invalid flags")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add a subtest to set_memory_region_test to verify that KVM rejects invalid
flags and combinations with -EINVAL. KVM might or might not fail with
EINVAL anyways, but we can at least try.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20231031002049.3915752-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add a selftest to verify the basic functionality of guest_memfd():
+ file descriptor created with the guest_memfd() ioctl does not allow
read/write/mmap operations
+ file size and block size as returned from fstat are as expected
+ fallocate on the fd checks that offset/length on
fallocate(FALLOC_FL_PUNCH_HOLE) should be page aligned
+ invalid inputs (misaligned size, invalid flags) are rejected
+ file size and inode are unique (the innocuous-sounding
anon_inode_getfile() backs all files with a single inode...)
Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Co-developed-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Co-developed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20231027182217.3615211-35-seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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