This patch enables the Scalable Vector Extension for the guest when
the host supports it.
This requires use of the new KVM_ARM_VCPU_FINALIZE ioctl before the
vcpu is runnable, so a new hook kvm_cpu__configure_features() is
added to provide an appropriate place to do this work.
Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
---
Changes since v3:
* Drop command-line options and simply default SVE to on where
supported.
---
arm/aarch32/include/kvm/kvm-cpu-arch.h | 4 ++++
arm/aarch64/include/kvm/kvm-cpu-arch.h | 1 +
arm/aarch64/kvm-cpu.c | 18 ++++++++++++++++++
arm/kvm-cpu.c | 3 +++
4 files changed, 26 insertions(+)
diff --git a/arm/aarch32/include/kvm/kvm-cpu-arch.h b/arm/aarch32/include/kvm/kvm-cpu-arch.h
index 01983f0..780e0e2 100644
--- a/arm/aarch32/include/kvm/kvm-cpu-arch.h
+++ b/arm/aarch32/include/kvm/kvm-cpu-arch.h
@@ -15,5 +15,9 @@
static inline void kvm_cpu__select_features(struct kvm *kvm,
struct kvm_vcpu_init *init) { }
+static inline int kvm_cpu__configure_features(struct kvm_cpu *vcpu)
+{
+ return 0;
+}
#endif /* KVM__KVM_CPU_ARCH_H */
diff --git a/arm/aarch64/include/kvm/kvm-cpu-arch.h b/arm/aarch64/include/kvm/kvm-cpu-arch.h
index e6875fc..8dfb82e 100644
--- a/arm/aarch64/include/kvm/kvm-cpu-arch.h
+++ b/arm/aarch64/include/kvm/kvm-cpu-arch.h
@@ -18,5 +18,6 @@
#define ARM_CPU_CTRL_SCTLR_EL1 0
void kvm_cpu__select_features(struct kvm *kvm, struct kvm_vcpu_init *init);
+int kvm_cpu__configure_features(struct kvm_cpu *vcpu);
#endif /* KVM__KVM_CPU_ARCH_H */
diff --git a/arm/aarch64/kvm-cpu.c b/arm/aarch64/kvm-cpu.c
index 8c29a21..9f3e858 100644
--- a/arm/aarch64/kvm-cpu.c
+++ b/arm/aarch64/kvm-cpu.c
@@ -136,6 +136,24 @@ void kvm_cpu__select_features(struct kvm *kvm, struct kvm_vcpu_init *init)
init->features[0] |= 1UL << KVM_ARM_VCPU_PTRAUTH_ADDRESS;
init->features[0] |= 1UL << KVM_ARM_VCPU_PTRAUTH_GENERIC;
}
+
+ /* Enable SVE if available */
+ if (kvm__supports_extension(kvm, KVM_CAP_ARM_SVE))
+ init->features[0] |= 1UL << KVM_ARM_VCPU_SVE;
+}
+
+int kvm_cpu__configure_features(struct kvm_cpu *vcpu)
+{
+ if (kvm__supports_extension(vcpu->kvm, KVM_CAP_ARM_SVE)) {
+ int feature = KVM_ARM_VCPU_SVE;
+
+ if (ioctl(vcpu->vcpu_fd, KVM_ARM_VCPU_FINALIZE, &feature)) {
+ pr_err("KVM_ARM_VCPU_FINALIZE: %s", strerror(errno));
+ return -1;
+ }
+ }
+
+ return 0;
}
void kvm_cpu__reset_vcpu(struct kvm_cpu *vcpu)
diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
index 1652f6f..554414f 100644
--- a/arm/kvm-cpu.c
+++ b/arm/kvm-cpu.c
@@ -124,6 +124,9 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
vcpu->cpu_compatible = target->compatible;
vcpu->is_running = true;
+ if (kvm_cpu__configure_features(vcpu))
+ die("Unable to configure requested vcpu features");
+
return vcpu;
}
--
2.1.4
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