| Date | Tue, 22 Jun 2021 18:08:11 +0200 | From | Borislav Petkov <> | Subject | Re: [patch V3 51/66] x86/fpu: Dont restore PKRU in fpregs_restore_userspace() |
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On Fri, Jun 18, 2021 at 04:19:14PM +0200, Thomas Gleixner wrote: > switch_to(), flush_thread() write the task's PKRU value eagerly so the PKRU > value of current is always valid in the hardware. > > That means there is no point in restoring PKRU on exit to user or when > reactivating the task's FPU registers in the signal frame setup path. > > This allows to remove all the xstate buffer updates with PKRU values once > the PKRU state is stored in thread struct while a task is scheduled out. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > V3: Restore supervisor state too. (Yu-Cheng) > --- > arch/x86/include/asm/fpu/internal.h | 16 +++++++++++++++- > arch/x86/include/asm/fpu/xstate.h | 19 +++++++++++++++++++ > arch/x86/kernel/fpu/core.c | 2 +- > 3 files changed, 35 insertions(+), 2 deletions(-)
Reviewed-by: Borislav Petkov <bp@suse.de>
-- Regards/Gruss, Boris.
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