[PATCH 15/20] MIPS: KVM: Wire up FPU capability
From: James Hogan <hidden>
Date: 2015-03-11 14:44:51
Also in:
kvm, linux-mips
Subsystem:
documentation, kernel virtual machine (kvm), kernel virtual machine for mips (kvm/mips), mips, the rest · Maintainers:
Jonathan Corbet, Paolo Bonzini, Huacai Chen, Thomas Bogendoerfer, Linus Torvalds
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 <redacted> Cc: Paolo Bonzini <redacted> Cc: Ralf Baechle <ralf-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org> Cc: Gleb Natapov <redacted> Cc: Jonathan Corbet <redacted> Cc: linux-mips-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org Cc: kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org --- Documentation/virtual/kvm/api.txt | 13 +++++++++++++ arch/mips/kvm/mips.c | 37 +++++++++++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 1 + 3 files changed, 51 insertions(+)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 8ba55b9c903e..44623688d566 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt@@ -3208,6 +3208,19 @@ 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 ------------------------------------------
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 5e41afe15ae8..6cdb2a1cd8ec 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 (cap->flags) + return -EINVAL; + if (cap->args[0]) + return -EINVAL; + + switch (cap->cap) { + case KVM_CAP_MIPS_FPU: + if (!cpu_has_fpu) + return -EINVAL; + 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;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 805570650062..98f6e5c653ff 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h@@ -760,6 +760,7 @@ struct kvm_ppc_smmu_info { #define KVM_CAP_PPC_ENABLE_HCALL 104 #define KVM_CAP_CHECK_EXTENSION_VM 105 #define KVM_CAP_S390_USER_SIGP 106 +#define KVM_CAP_MIPS_FPU 107 #ifdef KVM_CAP_IRQ_ROUTING
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2.0.5