1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_SPECCTRL_H_
3#define _ASM_X86_SPECCTRL_H_
4
5#include <linux/thread_info.h>
6#include <asm/nospec-branch.h>
7#include <asm/msr.h>
8
9/*
10 * On VMENTER we must preserve whatever view of the SPEC_CTRL MSR
11 * the guest has, while on VMEXIT we restore the host view. This
12 * would be easier if SPEC_CTRL were architecturally maskable or
13 * shadowable for guests but this is not (currently) the case.
14 * Takes the guest view of SPEC_CTRL MSR as a parameter and also
15 * the guest's version of VIRT_SPEC_CTRL, if emulated.
16 */
17extern void x86_virt_spec_ctrl(u64 guest_virt_spec_ctrl, bool guest);
18
19/**
20 * x86_spec_ctrl_set_guest - Set speculation control registers for the guest
21 * @guest_spec_ctrl: The guest content of MSR_SPEC_CTRL
22 * @guest_virt_spec_ctrl: The guest controlled bits of MSR_VIRT_SPEC_CTRL
23 * (may get translated to MSR_AMD64_LS_CFG bits)
24 *
25 * Avoids writing to the MSR if the content/bits are the same
26 */
27static inline
28void x86_spec_ctrl_set_guest(u64 guest_virt_spec_ctrl)
29{
30 x86_virt_spec_ctrl(guest_virt_spec_ctrl, guest: true);
31}
32
33/**
34 * x86_spec_ctrl_restore_host - Restore host speculation control registers
35 * @guest_spec_ctrl: The guest content of MSR_SPEC_CTRL
36 * @guest_virt_spec_ctrl: The guest controlled bits of MSR_VIRT_SPEC_CTRL
37 * (may get translated to MSR_AMD64_LS_CFG bits)
38 *
39 * Avoids writing to the MSR if the content/bits are the same
40 */
41static inline
42void x86_spec_ctrl_restore_host(u64 guest_virt_spec_ctrl)
43{
44 x86_virt_spec_ctrl(guest_virt_spec_ctrl, guest: false);
45}
46
47/* AMD specific Speculative Store Bypass MSR data */
48extern u64 x86_amd_ls_cfg_base;
49extern u64 x86_amd_ls_cfg_ssbd_mask;
50
51static inline u64 ssbd_tif_to_spec_ctrl(u64 tifn)
52{
53 BUILD_BUG_ON(TIF_SSBD < SPEC_CTRL_SSBD_SHIFT);
54 return (tifn & _TIF_SSBD) >> (TIF_SSBD - SPEC_CTRL_SSBD_SHIFT);
55}
56
57static inline u64 stibp_tif_to_spec_ctrl(u64 tifn)
58{
59 BUILD_BUG_ON(TIF_SPEC_IB < SPEC_CTRL_STIBP_SHIFT);
60 return (tifn & _TIF_SPEC_IB) >> (TIF_SPEC_IB - SPEC_CTRL_STIBP_SHIFT);
61}
62
63static inline unsigned long ssbd_spec_ctrl_to_tif(u64 spec_ctrl)
64{
65 BUILD_BUG_ON(TIF_SSBD < SPEC_CTRL_SSBD_SHIFT);
66 return (spec_ctrl & SPEC_CTRL_SSBD) << (TIF_SSBD - SPEC_CTRL_SSBD_SHIFT);
67}
68
69static inline unsigned long stibp_spec_ctrl_to_tif(u64 spec_ctrl)
70{
71 BUILD_BUG_ON(TIF_SPEC_IB < SPEC_CTRL_STIBP_SHIFT);
72 return (spec_ctrl & SPEC_CTRL_STIBP) << (TIF_SPEC_IB - SPEC_CTRL_STIBP_SHIFT);
73}
74
75static inline u64 ssbd_tif_to_amd_ls_cfg(u64 tifn)
76{
77 return (tifn & _TIF_SSBD) ? x86_amd_ls_cfg_ssbd_mask : 0ULL;
78}
79
80/*
81 * This can be used in noinstr functions & should only be called in bare
82 * metal context.
83 */
84static __always_inline void __update_spec_ctrl(u64 val)
85{
86 __this_cpu_write(x86_spec_ctrl_current, val);
87 native_wrmsrl(MSR_IA32_SPEC_CTRL, val);
88}
89
90#ifdef CONFIG_SMP
91extern void speculative_store_bypass_ht_init(void);
92#else
93static inline void speculative_store_bypass_ht_init(void) { }
94#endif
95
96extern void speculation_ctrl_update(unsigned long tif);
97extern void speculation_ctrl_update_current(void);
98
99extern bool itlb_multihit_kvm_mitigation;
100
101#endif
102

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source code of linux/arch/x86/include/asm/spec-ctrl.h