[13/21] KVM: Add support for enabling capabilities per-vcpu

Commit Message

Alexander Graf March 24, 2010, 8:48 p.m. UTC

None

Patch

diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt
index d170cb4..3da2240 100644
--- a/Documentation/kvm/api.txt
+++ b/Documentation/kvm/api.txt
@@ -749,6 +749,41 @@  Writes debug registers into the vcpu.
 See KVM_GET_DEBUGREGS for the data structure. The flags field is unused
 yet and must be cleared on entry.
 
+4.34 KVM_ENABLE_CAP
+
+Capability: KVM_CAP_ENABLE_CAP
+Architectures: ppc
+Type: vcpu ioctl
+Parameters: struct kvm_enable_cap (in)
+Returns: 0 on success; -1 on error
+
+Not all extensions are enabled by default. Using this ioctl the application
+can enable an extension, making it available to the guest.
+
+On systems that do not support this ioctl, it always fails. On systems that
+do support it, it only works for extensions that are supported for enablement.
+
+To check if a capability can be enabled, the KVM_CHECK_EXTENSION ioctl should
+be used.
+
+struct kvm_enable_cap {
+       /* in */
+       __u32 cap;
+
+The capability that is supposed to get enabled.
+
+       __u32 flags;
+
+A bitfield indicating future enhancements. Has to be 0 for now.
+
+       __u64 args[4];
+
+Arguments for enabling a feature. If a feature needs initial values to
+function properly, this is the place to put them.
+
+       __u8  pad[64];
+};
+
 
 5. The kvm_run structure
 
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index af873d9..2092157 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -149,6 +149,7 @@  int kvm_dev_ioctl_check_extension(long ext)
 	case KVM_CAP_PPC_SEGSTATE:
 	case KVM_CAP_PPC_PAIRED_SINGLES:
 	case KVM_CAP_PPC_UNSET_IRQ:
+	case KVM_CAP_ENABLE_CAP:
 		r = 1;
 		break;
 	case KVM_CAP_COALESCED_MMIO:
@@ -464,6 +465,23 @@  int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, struct kvm_interrupt *irq)
 	return 0;
 }
 
+static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
+				     struct kvm_enable_cap *cap)
+{
+	int r;
+
+	if (cap->flags)
+		return -EINVAL;
+
+	switch (cap->cap) {
+	default:
+		r = -EINVAL;
+		break;
+	}
+
+	return r;
+}
+
 int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
                                     struct kvm_mp_state *mp_state)
 {
@@ -492,6 +510,15 @@  long kvm_arch_vcpu_ioctl(struct file *filp,
 		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 = -EINVAL;
 	}
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index c36d093..d9e920e 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -400,6 +400,15 @@  struct kvm_ioeventfd {
 	__u8  pad[36];
 };
 
+/* for KVM_ENABLE_CAP */
+struct kvm_enable_cap {
+	/* in */
+	__u32 cap;
+	__u32 flags;
+	__u64 args[4];
+	__u8  pad[64];
+};
+
 #define KVMIO 0xAE
 
 /*
@@ -508,6 +517,7 @@  struct kvm_ioeventfd {
 #endif
 #define KVM_CAP_X86_ROBUST_SINGLESTEP 51
 #define KVM_CAP_PPC_UNSET_IRQ 53
+#define KVM_CAP_ENABLE_CAP 54
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -697,6 +707,8 @@  struct kvm_clock_data {
 /* Available with KVM_CAP_DEBUGREGS */
 #define KVM_GET_DEBUGREGS         _IOR(KVMIO,  0xa1, struct kvm_debugregs)
 #define KVM_SET_DEBUGREGS         _IOW(KVMIO,  0xa2, struct kvm_debugregs)
+/* No need for CAP, because then it just always fails */
+#define KVM_ENABLE_CAP            _IOW(KVMIO,  0xa3, struct kvm_enable_cap)
 
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)