[PATCH v19 2/7] KVM: arm64: Advertise KVM UID to guests via SMCCC

Marc Zyngier
2021-03-30T14:55:32Z

From: Will Deacon <will@kernel.org>

We can advertise ourselves to guests as KVM and provide a basic features
bitmap for discoverability of future hypervisor services.

Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201209060932.212364-3-jianyong.wu@arm.com
---
arch/arm64/kvm/hypercalls.c | 27 ++++++++++++++++++---------
1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index ead21b98b620..78d32c34d49c 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -12,13 +12,13 @@
int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
{
u32 func_id = smccc_get_function(vcpu);
- long val = SMCCC_RET_NOT_SUPPORTED;
+ u64 val[4] = {SMCCC_RET_NOT_SUPPORTED};
u32 feature;
gpa_t gpa;

switch (func_id) {
case ARM_SMCCC_VERSION_FUNC_ID:
- val = ARM_SMCCC_VERSION_1_1;
+ val[0] = ARM_SMCCC_VERSION_1_1;
break;
case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
feature = smccc_get_arg1(vcpu);
@@ -28,10 +28,10 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
case SPECTRE_VULNERABLE:
break;
case SPECTRE_MITIGATED:
- val = SMCCC_RET_SUCCESS;
+ val[0] = SMCCC_RET_SUCCESS;
break;
case SPECTRE_UNAFFECTED:
- val = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
+ val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
break;
}
break;
@@ -54,22 +54,31 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
break;
fallthrough;
case SPECTRE_UNAFFECTED:
- val = SMCCC_RET_NOT_REQUIRED;
+ val[0] = SMCCC_RET_NOT_REQUIRED;
break;
}
break;
case ARM_SMCCC_HV_PV_TIME_FEATURES:
- val = SMCCC_RET_SUCCESS;
+ val[0] = SMCCC_RET_SUCCESS;
break;
}
break;
case ARM_SMCCC_HV_PV_TIME_FEATURES:
- val = kvm_hypercall_pv_features(vcpu);
+ 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 = gpa;
+ 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);
break;
case ARM_SMCCC_TRNG_VERSION:
case ARM_SMCCC_TRNG_FEATURES:
@@ -81,6 +90,6 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
return kvm_psci_call(vcpu);
}

- smccc_set_retval(vcpu, val, 0, 0, 0);
+ smccc_set_retval(vcpu, val[0], val[1], val[2], val[3]);
return 1;
}
--
2.29.2