xref: /openbmc/linux/arch/x86/include/asm/spec-ctrl.h (revision bd3d394e)
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 
8 /*
9  * On VMENTER we must preserve whatever view of the SPEC_CTRL MSR
10  * the guest has, while on VMEXIT we restore the host view. This
11  * would be easier if SPEC_CTRL were architecturally maskable or
12  * shadowable for guests but this is not (currently) the case.
13  * Takes the guest view of SPEC_CTRL MSR as a parameter and also
14  * the guest's version of VIRT_SPEC_CTRL, if emulated.
15  */
16 extern void x86_virt_spec_ctrl(u64 guest_virt_spec_ctrl, bool guest);
17 
18 /**
19  * x86_spec_ctrl_set_guest - Set speculation control registers for the guest
20  * @guest_spec_ctrl:		The guest content of MSR_SPEC_CTRL
21  * @guest_virt_spec_ctrl:	The guest controlled bits of MSR_VIRT_SPEC_CTRL
22  *				(may get translated to MSR_AMD64_LS_CFG bits)
23  *
24  * Avoids writing to the MSR if the content/bits are the same
25  */
26 static inline
x86_spec_ctrl_set_guest(u64 guest_virt_spec_ctrl)27 void x86_spec_ctrl_set_guest(u64 guest_virt_spec_ctrl)
28 {
29 	x86_virt_spec_ctrl(guest_virt_spec_ctrl, true);
30 }
31 
32 /**
33  * x86_spec_ctrl_restore_host - Restore host speculation control registers
34  * @guest_spec_ctrl:		The guest content of MSR_SPEC_CTRL
35  * @guest_virt_spec_ctrl:	The guest controlled bits of MSR_VIRT_SPEC_CTRL
36  *				(may get translated to MSR_AMD64_LS_CFG bits)
37  *
38  * Avoids writing to the MSR if the content/bits are the same
39  */
40 static inline
x86_spec_ctrl_restore_host(u64 guest_virt_spec_ctrl)41 void x86_spec_ctrl_restore_host(u64 guest_virt_spec_ctrl)
42 {
43 	x86_virt_spec_ctrl(guest_virt_spec_ctrl, false);
44 }
45 
46 /* AMD specific Speculative Store Bypass MSR data */
47 extern u64 x86_amd_ls_cfg_base;
48 extern u64 x86_amd_ls_cfg_ssbd_mask;
49 
ssbd_tif_to_spec_ctrl(u64 tifn)50 static inline u64 ssbd_tif_to_spec_ctrl(u64 tifn)
51 {
52 	BUILD_BUG_ON(TIF_SSBD < SPEC_CTRL_SSBD_SHIFT);
53 	return (tifn & _TIF_SSBD) >> (TIF_SSBD - SPEC_CTRL_SSBD_SHIFT);
54 }
55 
stibp_tif_to_spec_ctrl(u64 tifn)56 static inline u64 stibp_tif_to_spec_ctrl(u64 tifn)
57 {
58 	BUILD_BUG_ON(TIF_SPEC_IB < SPEC_CTRL_STIBP_SHIFT);
59 	return (tifn & _TIF_SPEC_IB) >> (TIF_SPEC_IB - SPEC_CTRL_STIBP_SHIFT);
60 }
61 
ssbd_spec_ctrl_to_tif(u64 spec_ctrl)62 static inline unsigned long ssbd_spec_ctrl_to_tif(u64 spec_ctrl)
63 {
64 	BUILD_BUG_ON(TIF_SSBD < SPEC_CTRL_SSBD_SHIFT);
65 	return (spec_ctrl & SPEC_CTRL_SSBD) << (TIF_SSBD - SPEC_CTRL_SSBD_SHIFT);
66 }
67 
stibp_spec_ctrl_to_tif(u64 spec_ctrl)68 static inline unsigned long stibp_spec_ctrl_to_tif(u64 spec_ctrl)
69 {
70 	BUILD_BUG_ON(TIF_SPEC_IB < SPEC_CTRL_STIBP_SHIFT);
71 	return (spec_ctrl & SPEC_CTRL_STIBP) << (TIF_SPEC_IB - SPEC_CTRL_STIBP_SHIFT);
72 }
73 
ssbd_tif_to_amd_ls_cfg(u64 tifn)74 static inline u64 ssbd_tif_to_amd_ls_cfg(u64 tifn)
75 {
76 	return (tifn & _TIF_SSBD) ? x86_amd_ls_cfg_ssbd_mask : 0ULL;
77 }
78 
79 #ifdef CONFIG_SMP
80 extern void speculative_store_bypass_ht_init(void);
81 #else
speculative_store_bypass_ht_init(void)82 static inline void speculative_store_bypass_ht_init(void) { }
83 #endif
84 
85 extern void speculation_ctrl_update(unsigned long tif);
86 extern void speculation_ctrl_update_current(void);
87 
88 #endif
89