diff options
| author | Andre Przywara | 2019-05-03 15:27:48 +0100 |
|---|---|---|
| committer | Marc Zyngier | 2019-07-05 13:56:27 +0100 |
| commit | c118bbb52743df70e6297671606c1c08edc659fe (patch) | |
| tree | 3058edcfc6f08fa7b68f9e5ff037c9dc219255a6 /arch/arm64/kernel | |
| parent | 80f393a23be68e2f8a0f74258d6155438c200bbd (diff) | |
arm64: KVM: Propagate full Spectre v2 workaround state to KVM guests
Recent commits added the explicit notion of "workaround not required" to
the state of the Spectre v2 (aka. BP_HARDENING) workaround, where we
just had "needed" and "unknown" before.
Export this knowledge to the rest of the kernel and enhance the existing
kvm_arm_harden_branch_predictor() to report this new state as well.
Export this new state to guests when they use KVM's firmware interface
emulation.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/cpu_errata.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index ca11ff7bf55e..1e43ba5c79b7 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -554,6 +554,17 @@ cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused) static bool __hardenbp_enab = true; static bool __spectrev2_safe = true; +int get_spectre_v2_workaround_state(void) +{ + if (__spectrev2_safe) + return ARM64_BP_HARDEN_NOT_REQUIRED; + + if (!__hardenbp_enab) + return ARM64_BP_HARDEN_UNKNOWN; + + return ARM64_BP_HARDEN_WA_NEEDED; +} + /* * List of CPUs that do not need any Spectre-v2 mitigation at all. */ @@ -854,13 +865,15 @@ ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf) { - if (__spectrev2_safe) + switch (get_spectre_v2_workaround_state()) { + case ARM64_BP_HARDEN_NOT_REQUIRED: return sprintf(buf, "Not affected\n"); - - if (__hardenbp_enab) + case ARM64_BP_HARDEN_WA_NEEDED: return sprintf(buf, "Mitigation: Branch predictor hardening\n"); - - return sprintf(buf, "Vulnerable\n"); + case ARM64_BP_HARDEN_UNKNOWN: + default: + return sprintf(buf, "Vulnerable\n"); + } } ssize_t cpu_show_spec_store_bypass(struct device *dev, |