Hi,
On 18/06/2019 16:23, Volodymyr Babchuk wrote:
Julien Grall writes:
On 6/18/19 3:30 PM, Volodymyr Babchuk wrote:
Julien Grall writes:
On 18/06/2019 12:19, Volodymyr Babchuk wrote:
Hi Julien,
Hi,
Julien Grall writes:
> + > +=item B<optee> > + > +Allow a guest to use OP-TEE. Note that a virtualization-aware OP-TEE > +is required for this. If this option is selected, guest will be able
OOI, what happen if OP-TEE does not support virtualization. Will Xen forbid to use it?
Yes, Xen will get an error from OP-TEE during domain construction. This will lead to domain creation failure.
This is a bit odd. It means we have no way to know in advance whether OP-TEE will be able to create a client.
Yes. There can be at least two reasons for this:
- OP-TEE is built without virtualization support at all
- OP-TEE have no resources for a new guest
In other word, when the mediator is built in Xen, all existing setup with OP-TEE (and no-virtualization) will fail.
Right. If user provides DTB with 'optee' node, but OP-TEE is build without virtualization support, Dom0 will not be created. This can be fixed by adding new capability flag into OP-TEE, that tells Xen about virtualization support. For some reason I missed this when I implemented VM support in OP-TEE :(
My expectation is Xen should be able to know whether the mediator can be used.
I need to implement additional capability flag in the OP-TEE. This is not so hard, but it will be available only in the next release. For now, we can document this limitation somewhere.
Is OP-TEE already released with virtualization? If not, when will it be?
Yes, OP-TEE 3.5.0 was released on 26 April 2019 and it includes virtualization support.
Ok. Please try to solve this problem for the next release.
For now, I think there are a way to workaround the lack of a feature flag. In the detection of OP-TEE, you can try to create a client. If it fails, then it means OP-TEE does not support virtualization.
This is assuming that OP-TEE will fail gracefully.
Cheers,