diff options
| author | Marc Zyngier <marc.zyngier@arm.com> | 2018-02-06 17:56:14 +0000 |
|---|---|---|
| committer | Alex Shi <alex.shi@linaro.org> | 2018-02-26 15:44:50 +0800 |
| commit | 6933d23688bd9fa670bc33ecc52842ad47dea3bb (patch) | |
| tree | 214dd0c26f0adc1e65fd217f7fd58196accbeaf6 | |
| parent | 87331ae36398077c604e7f6b08006242793f40a0 (diff) | |
arm64: KVM: Report SMCCC_ARCH_WORKAROUND_1 BP hardening support
commit 6167ec5c9145 upstream.
A new feature of SMCCC 1.1 is that it offers firmware-based CPU
workarounds. In particular, SMCCC_ARCH_WORKAROUND_1 provides
BP hardening for CVE-2017-5715.
If the host has some mitigation for this issue, report that
we deal with it using SMCCC_ARCH_WORKAROUND_1, as we apply the
host workaround on every guest exit.
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Alex Shi <alex.shi@linaro.org>
Conflicts:
no sve support in arch/arm64/include/asm/kvm_host.h
mv changes from virt/kvm/arm/psci.c to arch/arm/kvm/psci.c
using cpus_have_cap instead of cpus_have_const_cap
| -rw-r--r-- | arch/arm/include/asm/kvm_host.h | 6 | ||||
| -rw-r--r-- | arch/arm/kvm/psci.c | 9 | ||||
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 6 | ||||
| -rw-r--r-- | include/linux/arm-smccc.h | 5 |
4 files changed, 25 insertions, 1 deletions
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index d5423ab15ed5..9fe1043e72d2 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -318,4 +318,10 @@ static inline int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu, return -ENXIO; } +static inline bool kvm_arm_harden_branch_predictor(void) +{ + /* No way to detect it yet, pretend it is not there. */ + return false; +} + #endif /* __ARM_KVM_HOST_H__ */ diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c index 396eb5d1fa8e..a8256380042a 100644 --- a/arch/arm/kvm/psci.c +++ b/arch/arm/kvm/psci.c @@ -404,13 +404,20 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) { u32 func_id = smccc_get_function(vcpu); u32 val = PSCI_RET_NOT_SUPPORTED; + u32 feature; switch (func_id) { case ARM_SMCCC_VERSION_FUNC_ID: val = ARM_SMCCC_VERSION_1_1; break; case ARM_SMCCC_ARCH_FEATURES_FUNC_ID: - /* Nothing supported yet */ + feature = smccc_get_arg1(vcpu); + switch(feature) { + case ARM_SMCCC_ARCH_WORKAROUND_1: + if (kvm_arm_harden_branch_predictor()) + val = 0; + break; + } break; default: return kvm_psci_call(vcpu); diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index e5050388e062..7f5244a059c3 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -393,4 +393,10 @@ static inline void __cpu_init_stage2(void) "PARange is %d bits, unsupported configuration!", parange); } + +static inline bool kvm_arm_harden_branch_predictor(void) +{ + return cpus_have_cap(ARM64_HARDEN_BRANCH_PREDICTOR); +} + #endif /* __ARM64_KVM_HOST_H__ */ diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index dc68aa5a7261..e1ef944ef1da 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -73,6 +73,11 @@ ARM_SMCCC_SMC_32, \ 0, 1) +#define ARM_SMCCC_ARCH_WORKAROUND_1 \ + ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + 0, 0x8000) + #ifndef __ASSEMBLY__ #include <linux/linkage.h> |