From 55e3748e8902ff641e334226bdcb432f9a5d78d3 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 29 May 2018 13:11:16 +0100 Subject: arm64: KVM: Add ARCH_WORKAROUND_2 support for guests In order to offer ARCH_WORKAROUND_2 support to guests, we need a bit of infrastructure. Let's add a flag indicating whether or not the guest uses SSBD mitigation. Depending on the state of this flag, allow KVM to disable ARCH_WORKAROUND_2 before entering the guest, and enable it when exiting it. Reviewed-by: Christoffer Dall Reviewed-by: Mark Rutland Signed-off-by: Marc Zyngier Signed-off-by: Catalin Marinas --- virt/kvm/arm/arm.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'virt/kvm') diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index a4c1b76240df..2d9b4795edb2 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -1490,6 +1490,10 @@ static int init_hyp_mode(void) } } + err = hyp_map_aux_data(); + if (err) + kvm_err("Cannot map host auxilary data: %d\n", err); + return 0; out_err: -- cgit v1.2.3 From 5d81f7dc9bca4f4963092433e27b508cbe524a32 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 29 May 2018 13:11:18 +0100 Subject: arm64: KVM: Add ARCH_WORKAROUND_2 discovery through ARCH_FEATURES_FUNC_ID Now that all our infrastructure is in place, let's expose the availability of ARCH_WORKAROUND_2 to guests. We take this opportunity to tidy up a couple of SMCCC constants. Acked-by: Christoffer Dall Reviewed-by: Mark Rutland Signed-off-by: Marc Zyngier Signed-off-by: Catalin Marinas --- arch/arm/include/asm/kvm_host.h | 12 ++++++++++++ arch/arm64/include/asm/kvm_host.h | 23 +++++++++++++++++++++++ arch/arm64/kvm/reset.c | 4 ++++ virt/kvm/arm/psci.c | 18 ++++++++++++++++-- 4 files changed, 55 insertions(+), 2 deletions(-) (limited to 'virt/kvm') diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index c7c28c885a19..7001fb871429 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -315,6 +315,18 @@ static inline bool kvm_arm_harden_branch_predictor(void) return false; } +#define KVM_SSBD_UNKNOWN -1 +#define KVM_SSBD_FORCE_DISABLE 0 +#define KVM_SSBD_KERNEL 1 +#define KVM_SSBD_FORCE_ENABLE 2 +#define KVM_SSBD_MITIGATED 3 + +static inline int kvm_arm_have_ssbd(void) +{ + /* No way to detect it yet, pretend it is not there. */ + return KVM_SSBD_UNKNOWN; +} + static inline void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) {} static inline void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) {} diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 9bef3f69bdcd..95d8a0e15b5f 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -455,6 +455,29 @@ static inline bool kvm_arm_harden_branch_predictor(void) return cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR); } +#define KVM_SSBD_UNKNOWN -1 +#define KVM_SSBD_FORCE_DISABLE 0 +#define KVM_SSBD_KERNEL 1 +#define KVM_SSBD_FORCE_ENABLE 2 +#define KVM_SSBD_MITIGATED 3 + +static inline int kvm_arm_have_ssbd(void) +{ + switch (arm64_get_ssbd_state()) { + case ARM64_SSBD_FORCE_DISABLE: + return KVM_SSBD_FORCE_DISABLE; + case ARM64_SSBD_KERNEL: + return KVM_SSBD_KERNEL; + case ARM64_SSBD_FORCE_ENABLE: + return KVM_SSBD_FORCE_ENABLE; + case ARM64_SSBD_MITIGATED: + return KVM_SSBD_MITIGATED; + case ARM64_SSBD_UNKNOWN: + default: + return KVM_SSBD_UNKNOWN; + } +} + void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu); void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu); diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index 3256b9228e75..a74311beda35 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -122,6 +122,10 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) /* Reset PMU */ kvm_pmu_vcpu_reset(vcpu); + /* Default workaround setup is enabled (if supported) */ + if (kvm_arm_have_ssbd() == KVM_SSBD_KERNEL) + vcpu->arch.workaround_flags |= VCPU_WORKAROUND_2_FLAG; + /* Reset timer */ return kvm_timer_vcpu_reset(vcpu); } diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c index c4762bef13c6..c95ab4c5a475 100644 --- a/virt/kvm/arm/psci.c +++ b/virt/kvm/arm/psci.c @@ -405,7 +405,7 @@ static int kvm_psci_call(struct kvm_vcpu *vcpu) int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) { u32 func_id = smccc_get_function(vcpu); - u32 val = PSCI_RET_NOT_SUPPORTED; + u32 val = SMCCC_RET_NOT_SUPPORTED; u32 feature; switch (func_id) { @@ -417,7 +417,21 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) switch(feature) { case ARM_SMCCC_ARCH_WORKAROUND_1: if (kvm_arm_harden_branch_predictor()) - val = 0; + val = SMCCC_RET_SUCCESS; + break; + case ARM_SMCCC_ARCH_WORKAROUND_2: + switch (kvm_arm_have_ssbd()) { + case KVM_SSBD_FORCE_DISABLE: + case KVM_SSBD_UNKNOWN: + break; + case KVM_SSBD_KERNEL: + val = SMCCC_RET_SUCCESS; + break; + case KVM_SSBD_FORCE_ENABLE: + case KVM_SSBD_MITIGATED: + val = SMCCC_RET_NOT_REQUIRED; + break; + } break; } break; -- cgit v1.2.3