From:   Tianrui Zhao <zhaotianrui@loongson.cn>
To:     Paolo Bonzini <pbonzini@redhat.com>
Cc:     Huacai Chen <chenhuacai@kernel.org>,
        WANG Xuerui <kernel@xen0n.name>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        loongarch@lists.linux.dev, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
        Mark Brown <broonie@kernel.org>,
        Alex Deucher <alexander.deucher@amd.com>,
        Oliver Upton <oliver.upton@linux.dev>, maobibo@loongson.cn
Subject: [PATCH v2 11/29] LoongArch: KVM: Implement fpu related operations for vcpu
Date:   Mon, 20 Feb 2023 14:57:17 +0800
Message-Id: <20230220065735.1282809-12-zhaotianrui@loongson.cn>
In-Reply-To: <20230220065735.1282809-1-zhaotianrui@loongson.cn>
References: <20230220065735.1282809-1-zhaotianrui@loongson.cn>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@loongson.cn>
---
 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 2ad9d126e..5c7216607 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -434,6 +434,76 @@ 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