MIPS: KVM: Wire up FPU capability

Now that the code is in place for KVM to support FPU in MIPS KVM guests,
wire up the new KVM_CAP_MIPS_FPU capability.

For backwards compatibility, the capability must be explicitly enabled
in order to detect or make use of the FPU from the guest.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-api@vger.kernel.org
Cc: linux-doc@vger.kernel.org

1 files changed, 37 insertions, 0 deletions

diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 5e41afe15ae8..7f86cb73d05d 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -797,6 +797,30 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
+static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
+				     struct kvm_enable_cap *cap)
+{
+	int r = 0;
+
+	if (!kvm_vm_ioctl_check_extension(vcpu->kvm, cap->cap))
+		return -EINVAL;
+	if (cap->flags)
+		return -EINVAL;
+	if (cap->args[0])
+		return -EINVAL;
+
+	switch (cap->cap) {
+	case KVM_CAP_MIPS_FPU:
+		vcpu->arch.fpu_enabled = true;
+		break;
+	default:
+		r = -EINVAL;
+		break;
+	}
+
+	return r;
+}
+
 long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl,
 			 unsigned long arg)
 {
@@ -854,6 +878,15 @@ long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl,
 			r = kvm_vcpu_ioctl_interrupt(vcpu, &irq);
 			break;
 		}
+	case KVM_ENABLE_CAP: {
+		struct kvm_enable_cap cap;
+
+		r = -EFAULT;
+		if (copy_from_user(&cap, argp, sizeof(cap)))
+			goto out;
+		r = kvm_vcpu_ioctl_enable_cap(vcpu, &cap);
+		break;
+	}
 	default:
 		r = -ENOIOCTLCMD;
 	}
@@ -962,11 +995,15 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 
 	switch (ext) {
 	case KVM_CAP_ONE_REG:
+	case KVM_CAP_ENABLE_CAP:
 		r = 1;
 		break;
 	case KVM_CAP_COALESCED_MMIO:
 		r = KVM_COALESCED_MMIO_PAGE_OFFSET;
 		break;
+	case KVM_CAP_MIPS_FPU:
+		r = !!cpu_has_fpu;
+		break;
 	default:
 		r = 0;
 		break;