Re: [Xen-devel] [PATCH v2 00/25] arm/altp2m: Introducing altp2m to ARM.

[Tamas K Lengyel <tamas.k.lengyel@xxxxxxxxx>]

On Thu, Aug 4, 2016 at 5:13 AM, George Dunlap <george.dunlap@xxxxxxxxxx> wrote:
> On 03/08/16 19:21, Tamas K Lengyel wrote:
>>> Although the behavior is very different compare to what x86 does. By default
>>> the guest will be able to play with altp2m.
>>
>> Personally my life would be a lot easier on x86 too if the default XSM
>> behavior was external-use only for altp2m.
>
> I'm a patch that allows altp2m to be exposed only to external tools
> sounds like something that would be a useful improvement.
>

Alright, to do this what I would actually prefer is extending the
current altp2m setup to distinguish between the various use-cases.
Right now it's an all or nothing (ie. exposed to both in-guest and
external tools) if we flip the altp2m_supported boolean in the
hvm_function_table, triggered by specifying altp2m=1 in the domain
config. What we would need is a way to specify that the intended mode
is external-only. With being able to specify this we could do the XSM
check with XSM_PRIV when the mode is external-only. If the mode is to
enable access to in-guest tools as well then we would do the check as
it is right now (XSM_TARGET). What are your thoughts on that route?

Tamas

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel