x86/pkeys: Don't check if PKRU is zero before writing it
authorSebastian Andrzej Siewior <bigeasy@linutronix.de>
Wed, 3 Apr 2019 16:41:43 +0000 (18:41 +0200)
committerBorislav Petkov <bp@suse.de>
Thu, 11 Apr 2019 13:41:05 +0000 (15:41 +0200)
commit0556cbdc2fbcb3068e5b924a8b3d5386ae0dd27d
tree56e3d3c4b173b86c92e6d0f7174a57e37fada17a
parent577ff465f5a6a5a0866d75a033844810baca20a0
x86/pkeys: Don't check if PKRU is zero before writing it

write_pkru() checks if the current value is the same as the expected
value. So instead of just checking if the current and new value is zero
(and skip the write in such a case) we can benefit from that.

Remove the zero check of PKRU, __write_pkru() provides such a check now.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: kvm ML <kvm@vger.kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190403164156.19645-15-bigeasy@linutronix.de
arch/x86/mm/pkeys.c