diff options
Diffstat (limited to 'arch/x86/include/asm/nospec-branch.h')
| -rw-r--r-- | arch/x86/include/asm/nospec-branch.h | 16 |
1 files changed, 5 insertions, 11 deletions
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 640c11b25913..2757c79754e1 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -172,16 +172,7 @@ enum spectre_v2_mitigation { SPECTRE_V2_IBRS, }; -/* - * The Intel specification for the SPEC_CTRL MSR requires that we - * preserve any already set reserved bits at boot time (e.g. for - * future additions that this kernel is not currently aware of). - * We then set any additional mitigation bits that we want - * ourselves and always use this as the base for SPEC_CTRL. - * We also use this when handling guest entry/exit as below. - */ extern void x86_spec_ctrl_set(u64); -extern u64 x86_spec_ctrl_get_default(void); /* The Speculative Store Bypass disable variants */ enum ssb_mitigation { @@ -232,6 +223,9 @@ static inline void indirect_branch_prediction_barrier(void) alternative_msr_write(MSR_IA32_PRED_CMD, val, X86_FEATURE_USE_IBPB); } +/* The Intel SPEC CTRL MSR base value cache */ +extern u64 x86_spec_ctrl_base; + /* * With retpoline, we must use IBRS to restrict branch prediction * before calling into firmware. @@ -240,7 +234,7 @@ static inline void indirect_branch_prediction_barrier(void) */ #define firmware_restrict_branch_speculation_start() \ do { \ - u64 val = x86_spec_ctrl_get_default() | SPEC_CTRL_IBRS; \ + u64 val = x86_spec_ctrl_base | SPEC_CTRL_IBRS; \ \ preempt_disable(); \ alternative_msr_write(MSR_IA32_SPEC_CTRL, val, \ @@ -249,7 +243,7 @@ do { \ #define firmware_restrict_branch_speculation_end() \ do { \ - u64 val = x86_spec_ctrl_get_default(); \ + u64 val = x86_spec_ctrl_base; \ \ alternative_msr_write(MSR_IA32_SPEC_CTRL, val, \ X86_FEATURE_USE_IBRS_FW); \ |