[PATCH v1 20/24] LoongArch: KVM: Implement handle fpu exception

From: Tianrui Zhao
Date: Mon Feb 13 2023 - 21:57:48 EST


Implement handle fpu exception, using kvm_own_fpu to enable fpu for
guest.

Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
---
arch/loongarch/kvm/exit.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)

diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
index 30e64ba72..89c90faa1 100644
--- a/arch/loongarch/kvm/exit.c
+++ b/arch/loongarch/kvm/exit.c
@@ -625,3 +625,30 @@ static int _kvm_handle_read_fault(struct kvm_vcpu *vcpu)
{
return _kvm_handle_mmu_fault(vcpu, false);
}
+
+/**
+ * _kvm_handle_fpu_disabled() - Guest used fpu however it is disabled at host
+ * @vcpu: Virtual CPU context.
+ *
+ * Handle when the guest attempts to use fpu which hasn't been allowed
+ * by the root context.
+ */
+static int _kvm_handle_fpu_disabled(struct kvm_vcpu *vcpu)
+{
+ struct kvm_run *run = vcpu->run;
+
+ /*
+ * If guest FPU not present, the FPU operation should have been
+ * treated as a reserved instruction!
+ * If FPU already in use, we shouldn't get this at all.
+ */
+ if (WARN_ON(!_kvm_guest_has_fpu(&vcpu->arch) ||
+ vcpu->arch.aux_inuse & KVM_LARCH_FPU)) {
+ kvm_err("%s internal error\n", __func__);
+ run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+ return RESUME_HOST;
+ }
+
+ kvm_own_fpu(vcpu);
+ return RESUME_GUEST;
+}
--
2.31.1