KVM: selftests: Verify stats fd is usable after VM fd has been closed

Verify that VM and vCPU binary stats files are usable even after userspace
has put its last direct reference to the VM. This is a regression test
for a UAF bug where KVM didn't gift the stats files a reference to the VM.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230711230131.648752-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Verify stats fd can be dup()'d and read

Expand the binary stats test to verify that a stats fd can be dup()'d
and read, to (very) roughly simulate userspace passing around the file.
Adding the dup() test is primarily an intermediate step towards verifying
that userspace can read VM/vCPU stats before _and_ after userspace closes
its copy of the VM fd; the dup() test itself is only mildly interesting.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230711230131.648752-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Verify userspace can create "redundant" binary stats files

Verify that KVM doesn't artificially limit KVM_GET_STATS_FD to a single
file per VM/vCPU. There's no known use case for getting multiple stats
fds, but it should work, and more importantly creating multiple files will
make it easier to test that KVM correct manages VM refcounts for stats
files.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230711230131.648752-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Explicitly free vcpus array in binary stats test

Explicitly free the all-encompassing vcpus array in the binary stats test
so that the test is consistent with respect to freeing all dynamically
allocated resources (versus letting them be freed on exit).

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230711230131.648752-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Clean up stats fd in common stats_test() helper

Move the stats fd cleanup code into stats_test() and drop the
superfluous vm_stats_test() and vcpu_stats_test() helpers in order to
decouple creation of the stats file from consuming/testing the file
(deduping code is a bonus). This will make it easier to test various
edge cases related to stats, e.g. that userspace can dup() a stats fd,
that userspace can have multiple stats files for a singleVM/vCPU, etc.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230711230131.648752-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Use pread() to read binary stats header

Use pread() with an explicit offset when reading the header and the header
name for a binary stats fd so that the common helper and the binary stats
test don't subtly rely on the file effectively being untouched, e.g. to
allow multiple reads of the header, name, etc.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230711230131.648752-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Stop assuming stats are contiguous in kvm_binary_stats_test

Remove the assumption from kvm_binary_stats_test that all stats are
laid out contiguously in memory. The current stats in KVM are
contiguously laid out in memory, but that may change in the future and
the ABI specifically allows holes in the stats data (since each stat
exposes its own offset).

While here drop the check that each stats' offset is less than
size_data, as that is now always true by construction.

Link: https://lore.kernel.org/kvm/20221208193857.4090582-9-dmatlack@google.com/
Fixes: 0b45d58738cd ("KVM: selftests: Add selftest for KVM statistics data binary interface")
Signed-off-by: Jing Zhang <jingzhangos@google.com>
[dmatlack: Re-worded the commit message.]
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20230117222707.3949974-1-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

KVM: selftests: Use TAP interface in the kvm_binary_stats_test

The kvm_binary_stats_test test currently does not have any output (unless
one of the TEST_ASSERT statement fails), so it's hard to say for a user
how far it did proceed already. Thus let's make this a little bit more
user-friendly and include some TAP output via the kselftest.h interface.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Message-Id: <20221004093131.40392-2-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Use TAP interface in the kvm_binary_stats_test

The kvm_binary_stats_test test currently does not have any output (unless
one of the TEST_ASSERT statement fails), so it's hard to say for a user
how far it did proceed already. Thus let's make this a little bit more
user-friendly and include some TAP output via the kselftest.h interface.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Message-Id: <20221004093131.40392-2-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

selftests: KVM: Add exponent check for boolean stats

The only sensible exponent for a boolean stat is 0. Add a test assertion
requiring all boolean statistics to have an exponent of 0.

Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Message-Id: <20220719143134.3246798-4-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

selftests: KVM: Provide descriptive assertions in kvm_binary_stats_test

As it turns out, tests sometimes fail. When that is the case, packing
the test assertion with as much relevant information helps track down
the problem more quickly.

Sharpen up the stat descriptor assertions in kvm_binary_stats_test to
more precisely describe the reason for the test assertion and which
stat is to blame.

Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Message-Id: <20220719143134.3246798-3-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

selftests: KVM: Check stat name before other fields

In order to provide more useful test assertions that describe the broken
stats descriptor, perform sanity check on the stat name before any other
descriptor field. While at it, avoid dereferencing the name field if the
sanity check fails as it is more likely to contain garbage.

Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Message-Id: <20220719143134.3246798-2-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Read binary stat data in lib

Move the code to read the binary stats data to the KVM selftests
library. It will be re-used by other tests to check KVM behavior.

Also opportunistically remove an unnecessary calculation with
"size_data" in stats_test.

Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20220613212523.3436117-6-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Clean up coding style in binary stats test

Fix a variety of code style violations and/or inconsistencies in the
binary stats test. The 80 char limit is a soft limit and can and should
be ignored/violated if doing so improves the overall code readability.

Specifically, provide consistent indentation and don't split expressions
at arbitrary points just to honor the 80 char limit.

Opportunistically expand/add comments to call out the more subtle aspects
of the code.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20220613212523.3436117-5-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Read binary stats desc in lib

Move the code to read the binary stats descriptors to the KVM selftests
library. It will be re-used by other tests to check KVM behavior.

No functional change intended.

Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20220613212523.3436117-4-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Read binary stats header in lib

Move the code to read the binary stats header to the KVM selftests
library. It will be re-used by other tests to check KVM behavior.

No functional change intended.

Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20220613212523.3436117-3-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Remove dynamic memory allocation for stats header

There's no need to allocate dynamic memory for the stats header since
its size is known at compile time.

Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20220613212523.3436117-2-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: kvm_binary_stats_test: Fix index expressions

kvm_binary_stats_test accepts two arguments, the number of vms
and number of vcpus. If these inputs are not equal then the
test would likely crash for one reason or another due to using
miscalculated indices for the vcpus array. Fix the index
expressions by swapping the use of i and j.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Message-Id: <20220614081041.2571511-1-drjones@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: Add kvm_has_cap() to provide syntactic sugar

Add kvm_has_cap() to wrap kvm_check_cap() and return a bool for the use
cases where the caller only wants check if a capability is supported,
i.e. doesn't care about the value beyond whether or not it's non-zero.
The "check" terminology is somewhat ambiguous as the non-boolean return
suggests that '0' might mean "success", i.e. suggests that the ioctl uses
the 0/-errno pattern. Provide a wrapper instead of trying to find a new
name for the raw helper; the "check" terminology is derived from the name
of the ioctl, so using e.g. "get" isn't a clear win.

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

KVM: selftests: Return an 'unsigned int' from kvm_check_cap()

Return an 'unsigned int' instead of a signed 'int' from kvm_check_cap(),
to make it more obvious that kvm_check_cap() can never return a negative
value due to its assertion that the return is ">= 0".

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 kvm_binary_stats_test away from vCPU IDs

Track vCPUs by their 'struct kvm_vcpu' object in kvm_binary_stats_test,
not by their ID. The per-vCPU helpers will soon take a vCPU instead of a
VM+vcpu_id pair.

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

KVM: selftests: Rename vm_vcpu_add* helpers to better show relationships

Rename vm_vcpu_add() to __vm_vcpu_add(), and vm_vcpu_add_default() to
vm_vcpu_add() to show the relationship between the newly minted
vm_vcpu_add() and __vm_vcpu_add().

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

KVM: selftests: Rename vm_create() => vm_create_barebones(), drop param

Rename vm_create() to vm_create_barebones() and drop the @phys_pages
param. Pass '0' for the number of pages even though some callers pass
'DEFAULT_GUEST_PHY_PAGES', as the intent behind creating truly barebones
VMs is purely to create a VM, i.e. there aren't vCPUs, there's no guest
code loaded, etc..., and so there is nothing that will ever need or
consume guest memory.

Freeing up the name vm_create() will allow using the name for an inner
helper to the other VM creators, which need a "full" VM.

Opportunisticaly rewrite the function comment for addr_gpa2alias() to
focus on what the _function_ does, not what its _sole caller_ does.

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

KVM: sefltests: Use vm_ioctl() and __vm_ioctl() helpers

Use the recently introduced VM-specific ioctl() helpers instead of open
coding calls to ioctl() just to pretty print the ioctl name. Keep a few
open coded assertions that provide additional info.

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

KVM: sefltests: Use vcpu_ioctl() and __vcpu_ioctl() helpers

Use the recently introduced vCPU-specific ioctl() helpers instead of
open coding calls to ioctl() just to pretty print the ioctl name.

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

KVM: selftests: Drop @mode from common vm_create() helper

Drop @mode from vm_create() and have it use VM_MODE_DEFAULT. Add and use
an inner helper, __vm_create(), to service the handful of tests that want
something other than VM_MODE_DEFAULT.

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

KVM: selftests: Always open VM file descriptors with O_RDWR

Drop the @perm param from vm_create() and always open VM file descriptors
with O_RDWR. There's no legitimate use case for other permissions, and
if a selftest wants to do oddball negative testing it can open code the
necessary bits instead of forcing a bunch of tests to provide useless
information.

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

KVM: selftests: Add checks for histogram stats bucket_size field

The bucket_size field should be non-zero for linear histogram stats and
should be zero for other stats types.

Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Message-Id: <20210802165633.1866976-4-jingzhangos@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

KVM: selftests: Add selftest for KVM statistics data binary interface

Add selftest to check KVM stats descriptors validity.

Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Tested-by: Fuad Tabba <tabba@google.com> #arm64
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Message-Id: <20210618222709.1858088-7-jingzhangos@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>