[PATCH 3/8] KVM: arm64: Hoist SVE check into KVM_ARM_VCPU_INIT ioctl handler

Oliver Upton
2023-09-20T19:50:56Z

Test that the system supports SVE before ever getting to
kvm_reset_vcpu().

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
arch/arm64/kvm/arm.c | 3 +++
arch/arm64/kvm/reset.c | 14 +++-----------
2 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index c6cb7e40315f..9415a760fcda 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1200,6 +1200,9 @@ static unsigned long system_supported_vcpu_features(void)
if (!kvm_arm_support_pmu_v3())
clear_bit(KVM_ARM_VCPU_PMU_V3, &features);

+ if (!system_supports_sve())
+ clear_bit(KVM_ARM_VCPU_SVE, &features);
+
return features;
}

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 5b5c74cb901d..3cb08d35b8e0 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -73,11 +73,8 @@ int __init kvm_arm_init_sve(void)
return 0;
}

-static int kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
+static void kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
{
- if (!system_supports_sve())
- return -EINVAL;
-
vcpu->arch.sve_max_vl = kvm_sve_max_vl;

/*
@@ -86,8 +83,6 @@ static int kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
* kvm_arm_vcpu_finalize(), which freezes the configuration.
*/
vcpu_set_flag(vcpu, GUEST_HAS_SVE);
-
- return 0;
}

/*
@@ -231,11 +226,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
}

if (!kvm_arm_vcpu_sve_finalized(vcpu)) {
- if (test_bit(KVM_ARM_VCPU_SVE, vcpu->arch.features)) {
- ret = kvm_vcpu_enable_sve(vcpu);
- if (ret)
- goto out;
- }
+ if (test_bit(KVM_ARM_VCPU_SVE, vcpu->arch.features))
+ kvm_vcpu_enable_sve(vcpu);
} else {
kvm_vcpu_reset_sve(vcpu);
}
--
2.42.0.515.g380fc7ccd1-goog