20f0afd1fb
A PASID is allocated for an "mm" the first time any thread binds to an SVA-capable device and is freed from the "mm" when the SVA is unbound by the last thread. It's possible for the "mm" to have different PASID values in different binding/unbinding SVA cycles. The mm's PASID (non-zero for valid PASID or 0 for invalid PASID) is propagated to a per-thread PASID MSR for all threads within the mm through IPI, context switch, or inherited. This is done to ensure that a running thread has the right PASID in the MSR matching the mm's PASID. [ bp: s/SVM/SVA/g; massage. ] Suggested-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/1600187413-163670-10-git-send-email-fenghua.yu@intel.com
78 lines
2.1 KiB
C
78 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 1994 Linus Torvalds
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*
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* Pentium III FXSR, SSE support
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* General FPU state handling cleanups
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* Gareth Hughes <gareth@valinux.com>, May 2000
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* x86-64 work by Andi Kleen 2002
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*/
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#ifndef _ASM_X86_FPU_API_H
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#define _ASM_X86_FPU_API_H
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#include <linux/bottom_half.h>
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/*
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* Use kernel_fpu_begin/end() if you intend to use FPU in kernel context. It
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* disables preemption so be careful if you intend to use it for long periods
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* of time.
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* If you intend to use the FPU in softirq you need to check first with
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* irq_fpu_usable() if it is possible.
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*/
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extern void kernel_fpu_begin(void);
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extern void kernel_fpu_end(void);
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extern bool irq_fpu_usable(void);
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extern void fpregs_mark_activate(void);
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/*
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* Use fpregs_lock() while editing CPU's FPU registers or fpu->state.
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* A context switch will (and softirq might) save CPU's FPU registers to
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* fpu->state and set TIF_NEED_FPU_LOAD leaving CPU's FPU registers in
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* a random state.
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*/
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static inline void fpregs_lock(void)
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{
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preempt_disable();
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local_bh_disable();
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}
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static inline void fpregs_unlock(void)
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{
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local_bh_enable();
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preempt_enable();
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}
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#ifdef CONFIG_X86_DEBUG_FPU
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extern void fpregs_assert_state_consistent(void);
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#else
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static inline void fpregs_assert_state_consistent(void) { }
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#endif
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/*
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* Load the task FPU state before returning to userspace.
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*/
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extern void switch_fpu_return(void);
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/*
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* Query the presence of one or more xfeatures. Works on any legacy CPU as well.
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*
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* If 'feature_name' is set then put a human-readable description of
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* the feature there as well - this can be used to print error (or success)
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* messages.
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*/
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extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name);
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/*
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* Tasks that are not using SVA have mm->pasid set to zero to note that they
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* will not have the valid bit set in MSR_IA32_PASID while they are running.
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*/
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#define PASID_DISABLED 0
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#ifdef CONFIG_IOMMU_SUPPORT
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/* Update current's PASID MSR/state by mm's PASID. */
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void update_pasid(void);
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#else
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static inline void update_pasid(void) { }
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#endif
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#endif /* _ASM_X86_FPU_API_H */
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