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| author | Chang S. Bae <chang.seok.bae@intel.com> | 2021-10-21 15:55:16 -0700 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-10-26 10:18:09 +0200 |
| commit | c351101678ce54492b6e09810ec02efc0df036a9 (patch) | |
| tree | a57a31309b7c38cc2bea01e91b5ed2c297410b3c /drivers/fpga/fpga-mgr.c | |
| parent | e61d6310a0f80cb986fd2076d432760b3619fb6d (diff) | |
x86/cpufeatures: Add eXtended Feature Disabling (XFD) feature bit
Intel's eXtended Feature Disable (XFD) feature is an extension of the XSAVE
architecture. XFD allows the kernel to enable a feature state in XCR0 and
to receive a #NM trap when a task uses instructions accessing that state.
This is going to be used to postpone the allocation of a larger XSTATE
buffer for a task to the point where it is actually using a related
instruction after the permission to use that facility has been granted.
XFD is not used by the kernel, but only applied to userspace. This is a
matter of policy as the kernel knows how a fpstate is reallocated and the
XFD state.
The compacted XSAVE format is adjustable for dynamic features. Make XFD
depend on XSAVES.
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211021225527.10184-13-chang.seok.bae@intel.com
Diffstat (limited to 'drivers/fpga/fpga-mgr.c')
0 files changed, 0 insertions, 0 deletions