Allow vendor modules to provide their own attributes on /dev/kvm.
To avoid proliferation of vendor ops, implement KVM_HAS_DEVICE_ATTR
and KVM_GET_DEVICE_ATTR in terms of the same function. You're not
supposed to use KVM_GET_DEVICE_ATTR to do complicated computations,
especially on /dev/kvm.
Reviewed-by: Michael Roth <michael.roth@xxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/include/asm/kvm-x86-ops.h | 1 +
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/x86.c | 43 ++++++++++++++++++++----------
3 files changed, 31 insertions(+), 14 deletions(-)
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 378ed944b849..ac8b7614e79d 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -122,6 +122,7 @@ KVM_X86_OP(enter_smm)
KVM_X86_OP(leave_smm)
KVM_X86_OP(enable_smi_window)
#endif
+KVM_X86_OP_OPTIONAL(dev_get_attr)
KVM_X86_OP_OPTIONAL(mem_enc_ioctl)
KVM_X86_OP_OPTIONAL(mem_enc_register_region)
KVM_X86_OP_OPTIONAL(mem_enc_unregister_region)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index aaf5a25ea7ed..651ce10cc152 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1770,6 +1770,7 @@ struct kvm_x86_ops {
void (*enable_smi_window)(struct kvm_vcpu *vcpu);
#endif
+ int (*dev_get_attr)(u64 attr, u64 *val);
int (*mem_enc_ioctl)(struct kvm *kvm, void __user *argp);
int (*mem_enc_register_region)(struct kvm *kvm, struct kvm_enc_region *argp);
int (*mem_enc_unregister_region)(struct kvm *kvm, struct kvm_enc_region *argp);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 14c969782d73..a12af5042d82 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4791,34 +4791,49 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
return r;
}
-static int kvm_x86_dev_get_attr(struct kvm_device_attr *attr)
+static int __kvm_x86_dev_get_attr(struct kvm_device_attr *attr, u64 *val)
{
- u64 __user *uaddr = u64_to_user_ptr(attr->addr);
+ int r;
if (attr->group)
return -ENXIO;
switch (attr->attr) {
case KVM_X86_XCOMP_GUEST_SUPP:
- if (put_user(kvm_caps.supported_xcr0, uaddr))
- return -EFAULT;
- return 0;
+ r = 0;
+ *val = kvm_caps.supported_xcr0;
+ break;
default:
- return -ENXIO;
+ r = -ENXIO;
+ if (kvm_x86_ops.dev_get_attr)
+ r = static_call(kvm_x86_dev_get_attr)(attr->attr, val);
+ break;
}
+
+ return r;
+}
+
+static int kvm_x86_dev_get_attr(struct kvm_device_attr *attr)
+{
+ u64 __user *uaddr = u64_to_user_ptr(attr->addr);
+ int r;
+ u64 val;
+
+ r = __kvm_x86_dev_get_attr(attr, &val);
+ if (r < 0)
+ return r;
+
+ if (put_user(val, uaddr))
+ return -EFAULT;
+
+ return 0;
}
static int kvm_x86_dev_has_attr(struct kvm_device_attr *attr)
{
- if (attr->group)
- return -ENXIO;
+ u64 val;
- switch (attr->attr) {
- case KVM_X86_XCOMP_GUEST_SUPP:
- return 0;
- default:
- return -ENXIO;
- }
+ return __kvm_x86_dev_get_attr(attr, &val);
}
long kvm_arch_dev_ioctl(struct file *filp,
--
2.39.1
