d4647f0a2a
The Spectre-v2 mitigation code is pretty unwieldy and hard to maintain. This is largely due to it being written hastily, without much clue as to how things would pan out, and also because it ends up mixing policy and state in such a way that it is very difficult to figure out what's going on. Rewrite the Spectre-v2 mitigation so that it clearly separates state from policy and follows a more structured approach to handling the mitigation. Signed-off-by: Will Deacon <will@kernel.org>
72 lines
1.5 KiB
C
72 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2019 Arm Ltd.
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#include <linux/arm-smccc.h>
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#include <linux/kvm_host.h>
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#include <asm/kvm_emulate.h>
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#include <kvm/arm_hypercalls.h>
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#include <kvm/arm_psci.h>
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int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
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{
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u32 func_id = smccc_get_function(vcpu);
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long val = SMCCC_RET_NOT_SUPPORTED;
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u32 feature;
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gpa_t gpa;
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switch (func_id) {
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case ARM_SMCCC_VERSION_FUNC_ID:
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val = ARM_SMCCC_VERSION_1_1;
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break;
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case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
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feature = smccc_get_arg1(vcpu);
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switch (feature) {
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case ARM_SMCCC_ARCH_WORKAROUND_1:
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switch (arm64_get_spectre_v2_state()) {
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case SPECTRE_VULNERABLE:
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break;
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case SPECTRE_MITIGATED:
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val = SMCCC_RET_SUCCESS;
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break;
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case SPECTRE_UNAFFECTED:
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val = SMCCC_RET_NOT_REQUIRED;
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break;
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}
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break;
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case ARM_SMCCC_ARCH_WORKAROUND_2:
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switch (kvm_arm_have_ssbd()) {
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case KVM_SSBD_FORCE_DISABLE:
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case KVM_SSBD_UNKNOWN:
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break;
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case KVM_SSBD_KERNEL:
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val = SMCCC_RET_SUCCESS;
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break;
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case KVM_SSBD_FORCE_ENABLE:
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case KVM_SSBD_MITIGATED:
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val = SMCCC_RET_NOT_REQUIRED;
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break;
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}
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break;
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case ARM_SMCCC_HV_PV_TIME_FEATURES:
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val = SMCCC_RET_SUCCESS;
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break;
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}
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break;
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case ARM_SMCCC_HV_PV_TIME_FEATURES:
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val = kvm_hypercall_pv_features(vcpu);
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break;
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case ARM_SMCCC_HV_PV_TIME_ST:
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gpa = kvm_init_stolen_time(vcpu);
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if (gpa != GPA_INVALID)
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val = gpa;
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break;
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default:
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return kvm_psci_call(vcpu);
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}
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smccc_set_retval(vcpu, val, 0, 0, 0);
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return 1;
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}
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