Re: [Xen-devel] Runtime services support for Xen on ARM

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 10.11.15 at 13:26, <stefano.stabellini@xxxxxxxxxxxxx> wrote:
> CC'ing xen-devel and Jan
> 
> On Tue, 10 Nov 2015, Shannon Zhao wrote:
>> Hi Stefano,
>> 
>> I'm working on adding Runtime services support at Xen side. Most of work
>> is adding the ARM part in xen/common/efi/runtime.c.
>> 
>> There is one problem which block me. That is how to implement
>> efi_rs_enter() and efi_rs_leave() for ARM, since I think current
>> implementation is x86 specific and won't work on ARM. Also the rtc_lock.
>> 
>> Could you give some suggestion? Thanks!
> 
> efi_rs_enter() and efi_rs_leave() look very PV x86 specific. It is
> possible that we don't actually need to do anything at all on ARM, aside
> from refactoring the code. Jan?

Whether you need to do much on ARM I don't know; doing
nothing doesn't seem to be among the options though, as at the
very least you need to acquire/release efi_rs_lock. The fact that
the code will need refactoring has been well known since the time
it got made common.

> Similarly we don't have an rtc_lock spinlock today and it is not
> actually needed, but for the sake of keeping the common code common, I
> would just introduce rtc_lock on ARM too.

I think this would better be hidden behind an arch abstraction,
doing nothing on ARM.

Jan


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