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x86/fpu: Use fpstate in __copy_xstate_to_uabi_buf() 

With dynamically enabled features the copy function must know the features
and the size which is valid for the task. Retrieve them from fpstate.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211013145323.181495492@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-10-13 16:55:54 +02:00 committed by Borislav Petkov
parent ad6ede407a
commit 3ac8d75778
3 changed files with 11 additions and 10 deletions
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8
arch/x86/kernel/fpu/core.c
View File

@ -187,15 +187,15 @@ EXPORT_SYMBOL_GPL(fpu_swap_kvm_fpu);
void fpu_copy_fpstate_to_kvm_uabi(struct fpu *fpu, void *buf,
unsigned int size, u32 pkru)
{
union fpregs_state *kstate = &fpu->fpstate->regs;
struct fpstate *kstate = fpu->fpstate;
union fpregs_state *ustate = buf;
struct membuf mb = { .p = buf, .left = size };
if (cpu_feature_enabled(X86_FEATURE_XSAVE)) {
__copy_xstate_to_uabi_buf(mb, &kstate->xsave, pkru,
XSTATE_COPY_XSAVE);
__copy_xstate_to_uabi_buf(mb, kstate, pkru, XSTATE_COPY_XSAVE);
} else {
memcpy(&ustate->fxsave, &kstate->fxsave, sizeof(ustate->fxsave));
memcpy(&ustate->fxsave, &kstate->regs.fxsave,
sizeof(ustate->fxsave));
/* Make it restorable on a XSAVE enabled host */
ustate->xsave.header.xfeatures = XFEATURE_MASK_FPSSE;
}

11
arch/x86/kernel/fpu/xstate.c
View File

@ -969,7 +969,7 @@ static void copy_feature(bool from_xstate, struct membuf *to, void *xstate,
/**
* __copy_xstate_to_uabi_buf - Copy kernel saved xstate to a UABI buffer
* @to: membuf descriptor
* @xsave: The xsave from which to copy
* @fpstate: The fpstate buffer from which to copy
* @pkru_val: The PKRU value to store in the PKRU component
* @copy_mode: The requested copy mode
*
@ -979,11 +979,12 @@ static void copy_feature(bool from_xstate, struct membuf *to, void *xstate,
*
* It supports partial copy but @to.pos always starts from zero.
*/
void __copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate,
u32 pkru_val, enum xstate_copy_mode copy_mode)
{
const unsigned int off_mxcsr = offsetof(struct fxregs_state, mxcsr);
struct xregs_state *xinit = &init_fpstate.regs.xsave;
struct xregs_state *xsave = &fpstate->regs.xsave;
struct xstate_header header;
unsigned int zerofrom;
u64 mask;
@ -1003,7 +1004,7 @@ void __copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
break;
case XSTATE_COPY_XSAVE:
header.xfeatures &= xfeatures_mask_uabi();
header.xfeatures &= fpstate->user_xfeatures;
break;
}
@ -1046,7 +1047,7 @@ void __copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
* but there is no state to copy from in the compacted
* init_fpstate. The gap tracking will zero these states.
*/
mask = xfeatures_mask_uabi();
mask = fpstate->user_xfeatures;
for_each_extended_xfeature(i, mask) {
/*
@ -1097,7 +1098,7 @@ out:
void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk,
enum xstate_copy_mode copy_mode)
{
__copy_xstate_to_uabi_buf(to, &tsk->thread.fpu.fpstate->regs.xsave,
__copy_xstate_to_uabi_buf(to, tsk->thread.fpu.fpstate,
tsk->thread.pkru, copy_mode);
}

2
arch/x86/kernel/fpu/xstate.h
View File

@ -15,7 +15,7 @@ static inline void xstate_init_xcomp_bv(struct xregs_state *xsave, u64 mask)
xsave->header.xcomp_bv = mask | XCOMP_BV_COMPACTED_FORMAT;
}
extern void __copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
extern void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate,
u32 pkru_val, enum xstate_copy_mode copy_mode);
extern void fpu__init_cpu_xstate(void);