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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2019 Arm Ltd.
#include <linux/arm-smccc.h>
#include <linux/kvm_host.h>
#include <asm/kvm_emulate.h>
#include <kvm/arm_hypercalls.h>
#include <kvm/arm_psci.h>
static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val)
{
struct system_time_snapshot systime_snapshot;
u64 cycles = ~0UL;
u32 feature;
/*
* system time and counter value must captured at the same
* time to keep consistency and precision.
*/
ktime_get_snapshot(&systime_snapshot);
/*
* This is only valid if the current clocksource is the
* architected counter, as this is the only one the guest
* can see.
*/
if (systime_snapshot.cs_id != CSID_ARM_ARCH_COUNTER)
return;
/*
* The guest selects one of the two reference counters
* (virtual or physical) with the first argument of the SMCCC
* call. In case the identifier is not supported, error out.
*/
feature = smccc_get_arg1(vcpu);
switch (feature) {
case KVM_PTP_VIRT_COUNTER:
cycles = systime_snapshot.cycles - vcpu_read_sys_reg(vcpu, CNTVOFF_EL2);
break;
case KVM_PTP_PHYS_COUNTER:
cycles = systime_snapshot.cycles;
break;
default:
return;
}
/*
* This relies on the top bit of val[0] never being set for
* valid values of system time, because that is *really* far
* in the future (about 292 years from 1970, and at that stage
* nobody will give a damn about it).
*/
val[0] = upper_32_bits(systime_snapshot.real);
val[1] = lower_32_bits(systime_snapshot.real);
val[2] = upper_32_bits(cycles);
val[3] = lower_32_bits(cycles);
}
int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
{
u32 func_id = smccc_get_function(vcpu);
u64 val[4] = {SMCCC_RET_NOT_SUPPORTED};
u32 feature;
gpa_t gpa;
switch (func_id) {
case ARM_SMCCC_VERSION_FUNC_ID:
val[0] = ARM_SMCCC_VERSION_1_1;
break;
case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
feature = smccc_get_arg1(vcpu);
switch (feature) {
case ARM_SMCCC_ARCH_WORKAROUND_1:
switch (arm64_get_spectre_v2_state()) {
case SPECTRE_VULNERABLE:
break;
case SPECTRE_MITIGATED:
val[0] = SMCCC_RET_SUCCESS;
break;
case SPECTRE_UNAFFECTED:
val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
break;
}
break;
case ARM_SMCCC_ARCH_WORKAROUND_2:
switch (arm64_get_spectre_v4_state()) {
case SPECTRE_VULNERABLE:
break;
case SPECTRE_MITIGATED:
/*
* SSBS everywhere: Indicate no firmware
* support, as the SSBS support will be
* indicated to the guest and the default is
* safe.
*
* Otherwise, expose a permanent mitigation
* to the guest, and hide SSBS so that the
* guest stays protected.
*/
if (cpus_have_final_cap(ARM64_SSBS))
break;
fallthrough;
case SPECTRE_UNAFFECTED:
val[0] = SMCCC_RET_NOT_REQUIRED;
break;
}
break;
case ARM_SMCCC_ARCH_WORKAROUND_3:
switch (arm64_get_spectre_bhb_state()) {
case SPECTRE_VULNERABLE:
break;
case SPECTRE_MITIGATED:
val[0] = SMCCC_RET_SUCCESS;
break;
case SPECTRE_UNAFFECTED:
val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
break;
}
break;
case ARM_SMCCC_HV_PV_TIME_FEATURES:
val[0] = SMCCC_RET_SUCCESS;
break;
}
break;
case ARM_SMCCC_HV_PV_TIME_FEATURES:
val[0] = kvm_hypercall_pv_features(vcpu);
break;
case ARM_SMCCC_HV_PV_TIME_ST:
gpa = kvm_init_stolen_time(vcpu);
if (gpa != GPA_INVALID)
val[0] = gpa;
break;
case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
val[0] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0;
val[1] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1;
val[2] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2;
val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3;
break;
case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
val[0] = BIT(ARM_SMCCC_KVM_FUNC_FEATURES);
val[0] |= BIT(ARM_SMCCC_KVM_FUNC_PTP);
break;
case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
kvm_ptp_get_time(vcpu, val);
break;
case ARM_SMCCC_TRNG_VERSION:
case ARM_SMCCC_TRNG_FEATURES:
case ARM_SMCCC_TRNG_GET_UUID:
case ARM_SMCCC_TRNG_RND32:
case ARM_SMCCC_TRNG_RND64:
return kvm_trng_call(vcpu);
default:
return kvm_psci_call(vcpu);
}
smccc_set_retval(vcpu, val[0], val[1], val[2], val[3]);
return 1;
}
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