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MIPS: KVM: Wire up FPU capability

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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
This commit is contained in:
James Hogan 2014-12-08 23:07:56 +00:00
parent 379245cdf1
commit 5fafd8748b
3 changed files with 51 additions and 0 deletions
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13
Documentation/virtual/kvm/api.txt
View file

@ -3312,6 +3312,19 @@ Parameters: none
This capability enables the in-kernel irqchip for s390. Please refer to
"4.24 KVM_CREATE_IRQCHIP" for details.
6.9 KVM_CAP_MIPS_FPU
Architectures: mips
Target: vcpu
Parameters: args[0] is reserved for future use (should be 0).
This capability allows the use of the host Floating Point Unit by the guest. It
allows the Config1.FP bit to be set to enable the FPU in the guest. Once this is
done the KVM_REG_MIPS_FPR_* and KVM_REG_MIPS_FCR_* registers can be accessed
(depending on the current guest FPU register mode), and the Status.FR,
Config5.FRE bits are accessible via the KVM API and also from the guest,
depending on them being supported by the FPU.
7. Capabilities that can be enabled on VMs
------------------------------------------

37
arch/mips/kvm/mips.c
View file

@ -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;

1
include/uapi/linux/kvm.h
View file

@ -802,6 +802,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_S390_MEM_OP 108
#define KVM_CAP_S390_USER_STSI 109
#define KVM_CAP_S390_SKEYS 110
#define KVM_CAP_MIPS_FPU 111
#ifdef KVM_CAP_IRQ_ROUTING