[PATCH v1 06/24] LoongArch: KVM: Implement fpu related operations for vcpu

From: Tianrui Zhao
Date: Mon Feb 13 2023 - 21:58:07 EST


Implement loongarch fpu related interface for vcpu, such as get fpu, set
fpu, own fpu and lose fpu, etc.

Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
---
arch/loongarch/kvm/vcpu.c | 70 +++++++++++++++++++++++++++++++++++++++
1 file changed, 70 insertions(+)

diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index dd803f26d..ed569508f 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -501,6 +501,76 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
return r;
}

+int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+ int i = 0;
+
+ /* no need vcpu_load and vcpu_put */
+ fpu->fcsr = vcpu->arch.fpu.fcsr;
+ fpu->fcc = vcpu->arch.fpu.fcc;
+ for (i = 0; i < NUM_FPU_REGS; i++)
+ memcpy(&fpu->fpr[i], &vcpu->arch.fpu.fpr[i], FPU_REG_WIDTH / 64);
+
+ return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+ int i = 0;
+
+ /* no need vcpu_load and vcpu_put */
+ vcpu->arch.fpu.fcsr = fpu->fcsr;
+ vcpu->arch.fpu.fcc = fpu->fcc;
+ for (i = 0; i < NUM_FPU_REGS; i++)
+ memcpy(&vcpu->arch.fpu.fpr[i], &fpu->fpr[i], FPU_REG_WIDTH / 64);
+
+ return 0;
+}
+
+/* Enable FPU for guest and restore context */
+void kvm_own_fpu(struct kvm_vcpu *vcpu)
+{
+ unsigned long sr;
+
+ preempt_disable();
+
+ sr = kvm_read_hw_gcsr(LOONGARCH_CSR_EUEN);
+
+ /*
+ * Enable FPU for guest
+ * We set FR and FRE according to guest context
+ */
+ set_csr_euen(CSR_EUEN_FPEN);
+
+ /* If guest FPU state not active, restore it now */
+ if (!(vcpu->arch.aux_inuse & KVM_LARCH_FPU)) {
+ kvm_restore_fpu(&vcpu->arch.fpu);
+ vcpu->arch.aux_inuse |= KVM_LARCH_FPU;
+ trace_kvm_aux(vcpu, KVM_TRACE_AUX_RESTORE, KVM_TRACE_AUX_FPU);
+ } else {
+ trace_kvm_aux(vcpu, KVM_TRACE_AUX_ENABLE, KVM_TRACE_AUX_FPU);
+ }
+
+ preempt_enable();
+}
+
+/* Save and disable FPU */
+void kvm_lose_fpu(struct kvm_vcpu *vcpu)
+{
+ preempt_disable();
+
+ if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
+ kvm_save_fpu(&vcpu->arch.fpu);
+ vcpu->arch.aux_inuse &= ~KVM_LARCH_FPU;
+ trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_FPU);
+
+ /* Disable FPU */
+ clear_csr_euen(CSR_EUEN_FPEN);
+ }
+
+ preempt_enable();
+}
+
int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
{
return 0;
--
2.31.1