diff options
| author | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2018-04-25 22:04:23 -0400 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-05-03 13:55:49 +0200 |
| commit | 1115a859f33276fe8afb31c60cf9d8e657872558 (patch) | |
| tree | ec85ff6ac7ff25b03c8893f47a691b610f13db11 /arch/x86 | |
| parent | 772439717dbf703b39990be58d8d4e3e4ad0598a (diff) | |
x86/bugs: Whitelist allowed SPEC_CTRL MSR values
Intel and AMD SPEC_CTRL (0x48) MSR semantics may differ in the
future (or in fact use different MSRs for the same functionality).
As such a run-time mechanism is required to whitelist the appropriate MSR
values.
[ tglx: Made the variable __ro_after_init ]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 17edf5bdc361..d809d398675a 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -35,6 +35,12 @@ static void __init ssb_select_mitigation(void); */ static u64 __ro_after_init x86_spec_ctrl_base; +/* + * The vendor and possibly platform specific bits which can be modified in + * x86_spec_ctrl_base. + */ +static u64 __ro_after_init x86_spec_ctrl_mask = ~SPEC_CTRL_IBRS; + void __init check_bugs(void) { identify_boot_cpu(); @@ -117,7 +123,7 @@ static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE; void x86_spec_ctrl_set(u64 val) { - if (val & ~(SPEC_CTRL_IBRS | SPEC_CTRL_RDS)) + if (val & x86_spec_ctrl_mask) WARN_ONCE(1, "SPEC_CTRL MSR value 0x%16llx is unknown.\n", val); else wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base | val); @@ -459,6 +465,7 @@ static enum ssb_mitigation_cmd __init __ssb_select_mitigation(void) switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_INTEL: x86_spec_ctrl_base |= SPEC_CTRL_RDS; + x86_spec_ctrl_mask &= ~SPEC_CTRL_RDS; x86_spec_ctrl_set(SPEC_CTRL_RDS); break; case X86_VENDOR_AMD: @@ -482,7 +489,7 @@ static void ssb_select_mitigation() void x86_spec_ctrl_setup_ap(void) { if (boot_cpu_has(X86_FEATURE_IBRS)) - x86_spec_ctrl_set(x86_spec_ctrl_base & (SPEC_CTRL_IBRS | SPEC_CTRL_RDS)); + x86_spec_ctrl_set(x86_spec_ctrl_base & ~x86_spec_ctrl_mask); } #ifdef CONFIG_SYSFS |