Commit 546d714b authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: introduce new vendor op for KVM_GET_DEVICE_ATTR 



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: default avatarMichael Roth <michael.roth@amd.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarIsaku Yamahata <isaku.yamahata@intel.com>
Message-ID: <20240404121327.3107131-5-pbonzini@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 8d2aec3b

arch/x86/include/asm/kvm-x86-ops.h

+1 −0
Original line number Diff line number Diff line
@@ -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)

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

arch/x86/kvm/x86.c

+24 −14
Original line number Diff line number Diff line
@@ -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_has_attr(struct kvm_device_attr *attr)

static int kvm_x86_dev_get_attr(struct kvm_device_attr *attr)

{

	if (attr->group)

		return -ENXIO;

	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;



	switch (attr->attr) {

	case KVM_X86_XCOMP_GUEST_SUPP:

	return 0;

	default:

		return -ENXIO;

}



static int kvm_x86_dev_has_attr(struct kvm_device_attr *attr)

{

	u64 val;



	return __kvm_x86_dev_get_attr(attr, &val);

}



long kvm_arch_dev_ioctl(struct file *filp,