Commit 8bf26758 authored by Chang S. Bae's avatar Chang S. Bae Committed by Borislav Petkov
Browse files

x86/fpu: Add XFD state to fpstate 



Add storage for XFD register state to struct fpstate. This will be used to
store the XFD MSR state. This will be used for switching the XFD MSR when
FPU content is restored.

Add a per-CPU variable to cache the current MSR value so the MSR has only
to be written when the values are different.

Signed-off-by: default avatarChang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarChang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211021225527.10184-15-chang.seok.bae@intel.com
parent dae1bd58

arch/x86/include/asm/fpu/types.h

+3 −0
Original line number Diff line number Diff line
@@ -322,6 +322,9 @@ struct fpstate { 
	/* @user_xfeatures:	xfeatures valid in UABI buffers */

	u64			user_xfeatures;



	/* @xfd:		xfeatures disabled to trap userspace use. */

	u64			xfd;



	/* @is_valloc:		Indicator for dynamically allocated state */

	unsigned int		is_valloc	: 1;

arch/x86/kernel/fpu/core.c

+2 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 


#ifdef CONFIG_X86_64

DEFINE_STATIC_KEY_FALSE(__fpu_state_size_dynamic);

DEFINE_PER_CPU(u64, xfd_state);

#endif



/* The FPU state configuration data for kernel and user space */
@@ -409,6 +410,7 @@ static void __fpstate_reset(struct fpstate *fpstate) 
	fpstate->user_size	= fpu_user_cfg.default_size;

	fpstate->xfeatures	= fpu_kernel_cfg.default_features;

	fpstate->user_xfeatures	= fpu_user_cfg.default_features;

	fpstate->xfd		= init_fpstate.xfd;

}



void fpstate_reset(struct fpu *fpu)

arch/x86/kernel/fpu/xstate.h

+4 −0
Original line number Diff line number Diff line
@@ -5,6 +5,10 @@ 
#include <asm/cpufeature.h>

#include <asm/fpu/xstate.h>



#ifdef CONFIG_X86_64

DECLARE_PER_CPU(u64, xfd_state);

#endif



static inline void xstate_init_xcomp_bv(struct xregs_state *xsave, u64 mask)

{

	/*