Commit Graph

6 Commits

Author SHA1 Message Date
Kirill A. Shutemov
dfd7a1569e selftests/x86/lam: Add test cases for LAM vs thread creation
LAM enabling is only allowed when the process has single thread.
LAM mode is inherited into child thread.

Trying to enable LAM after spawning a thread has to fail.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20230312112612.31869-18-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:41 -07:00
Weihong Zhang
34821473de selftests/x86/lam: Add ARCH_FORCE_TAGGED_SVA test cases for linear-address masking
By default do not allow to enable both LAM and use SVA in the same
process.
The new ARCH_FORCE_TAGGED_SVA arch_prctl() overrides the limitation.

Add new test cases for the new arch_prctl:
Before using ARCH_FORCE_TAGGED_SVA, should not allow to enable LAM/SVA
coexisting. the test cases should be negative.

The test depands on idxd driver and iommu. before test, need add
"intel_iommu=on,sm_on" in kernel command line and insmod idxd driver.

Signed-off-by: Weihong Zhang <weihong.zhang@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20230312112612.31869-17-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:40 -07:00
Weihong Zhang
833c12ce0f selftests/x86/lam: Add inherit test cases for linear-address masking
LAM is enabled per-thread and gets inherited on fork(2)/clone(2). exec()
reverts LAM status to the default disabled state.

There are two test scenarios:

 - Fork test cases:

   These cases were used to test the inheritance of LAM for per-thread,
   Child process generated by fork() should inherit LAM feature from
   parent process, Child process can get the LAM mode same as parent
   process.

 - Execve test cases:

   Processes generated by execve() are different from processes
   generated by fork(), these processes revert LAM status to disabled
   status.

Signed-off-by: Weihong Zhang <weihong.zhang@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20230312112612.31869-16-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:40 -07:00
Weihong Zhang
72fd6d738c selftests/x86/lam: Add io_uring test cases for linear-address masking
LAM should be supported in kernel thread, using io_uring to verify LAM feature.
The test cases implement read a file through io_uring, the test cases choose an
iovec array as receiving buffer, which used to receive data, according to LAM
mode, set metadata in high bits of these buffer.

io_uring can deal with these buffers that pointed to pointers with the metadata
in high bits.

Signed-off-by: Weihong Zhang <weihong.zhang@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20230312112612.31869-15-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:40 -07:00
Weihong Zhang
e67876962e selftests/x86/lam: Add mmap and SYSCALL test cases for linear-address masking
Add mmap and SYSCALL test cases.

SYSCALL test cases:

 - LAM supports set metadata in high bits 62:57 (LAM_U57) of a user pointer, pass
   the pointer to SYSCALL, SYSCALL can dereference the pointer and return correct
   result.

 - Disable LAM, pass a pointer with metadata in high bits to SYSCALL,
   SYSCALL returns -1 (EFAULT).

MMAP test cases:

 - Enable LAM_U57, MMAP with low address (below bits 47), set metadata
   in high bits of the address, dereference the address should be
   allowed.

 - Enable LAM_U57, MMAP with high address (above bits 47), set metadata
   in high bits of the address, dereference the address should be
   allowed.

Signed-off-by: Weihong Zhang <weihong.zhang@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20230312112612.31869-14-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:40 -07:00
Weihong Zhang
3de9745c12 selftests/x86/lam: Add malloc and tag-bits test cases for linear-address masking
LAM is supported only in 64-bit mode and applies only addresses used for data
accesses. In 64-bit mode, linear address have 64 bits. LAM is applied to 64-bit
linear address and allow software to use high bits for metadata.
LAM supports configurations that differ regarding which pointer bits are masked
and can be used for metadata.

LAM includes following mode:

 - LAM_U57, pointer bits in positions 62:57 are masked (LAM width 6),
   allows bits 62:57 of a user pointer to be used as metadata.

There are some arch_prctls:
ARCH_ENABLE_TAGGED_ADDR: enable LAM mode, mask high bits of a user pointer.
ARCH_GET_UNTAG_MASK: get current untagged mask.
ARCH_GET_MAX_TAG_BITS: the maximum tag bits user can request. zero if LAM
is not supported.

The LAM mode is for pre-process, a process has only one chance to set LAM mode.
But there is no API to disable LAM mode. So all of test cases are run under
child process.

Functions of this test:

MALLOC

 - LAM_U57 masks bits 57:62 of a user pointer. Process on user space
   can dereference such pointers.

 - Disable LAM, dereference a pointer with metadata above 48 bit or 57 bit
   lead to trigger SIGSEGV.

TAG_BITS

 - Max tag bits of LAM_U57 is 6.

Signed-off-by: Weihong Zhang <weihong.zhang@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20230312112612.31869-13-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:40 -07:00