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KVM: introduce new vendor op for KVM_GET_DEVICE_ATTR

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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@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Message-ID: <20240404121327.3107131-5-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2024-04-04 08:13:14 -04:00
parent 8d2aec3b2d
commit 546d714b08
3 changed files with 26 additions and 14 deletions
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1
arch/x86/include/asm/kvm-x86-ops.h
View File

@ -121,6 +121,7 @@ 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)

1
arch/x86/include/asm/kvm_host.h
View File

@ -1778,6 +1778,7 @@ struct kvm_x86_ops {
void (*enable_smi_window)(struct kvm_vcpu *vcpu);
#endif
int (*dev_get_attr)(u32 group, 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);

38
arch/x86/kvm/x86.c
View File

@ -4842,34 +4842,44 @@ 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);
if (attr->group)
if (attr->group) {
if (kvm_x86_ops.dev_get_attr)
return static_call(kvm_x86_dev_get_attr)(attr->group, attr->attr, val);
return -ENXIO;
}
switch (attr->attr) {
case KVM_X86_XCOMP_GUEST_SUPP:
if (put_user(kvm_caps.supported_xcr0, uaddr))
return -EFAULT;
*val = kvm_caps.supported_xcr0;
return 0;
default:
return -ENXIO;
}
}
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,