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Re: [Xen-devel] [PATCH RFC 0/N] xen: arm: rework early bring up



On Wed, 2013-09-18 at 20:22 +0100, Ian Campbell wrote:
> On Wed, 2013-09-18 at 18:33 +0100, Julien Grall wrote:
> > On 09/17/2013 02:37 AM, Ian Campbell wrote:
> > > Hi,
> > > 
> > > The following reworks early bring up on ARM to use a separate set of
> > > boot pagetables. This simplifies things by avoiding the need to bring up
> > > all CPUs in lock step, which in turn allows us to do secondary CPU
> > > bringup in C code.
> > > 
> > > Unfortunately the main bulk of this change is a single large patch which
> > > is hard to decompose any further since it is basically pulling on the
> > > thread and then knitting a new jumper from it.
> > > 
> > > With these changes Xen now absolutely requires that the bootloader calls
> > > the hypervisor in HYP mode, the previous workarounds have been removed.
> > > For use on models a bootwrapper is now required. See 
> > >         git://xenbits.xen.org/people/ianc/boot-wrapper.git xen-arm32
> > >         git://xenbits.xen.org/people/ianc/boot-wrapper-aarch64.git 
> > > xen-arm64
> > > 
> > > I have implemented support for CPU bringup on the fastmodel vexpress
> > > platforms (v7and v8) here, I suppose it should work OK on a real
> > > vexpress too but I've not tried it.
> > 
> > I have just tried the patch series on the versatile express and it
> > doesn't work. I'm using the u-boot from Andre and all the cpus already
> > boot in hyp mode (checked without this patch series).
> 
> :-(
> 
> The code should essentially the same as the old kick cpus, but
> reimplemented in C. The only difference I can spot is that the C version
> is kicking a single CPU at a time while the ASM version is kicking
> everyone at once. Does using send_SGI_allbutself instead work as a hack?
> 
> Perhaps our idea of the CPUID is wrong or something? Your patches to
> fixup the logical CPU id stuff might help?

You don't happen to still have your vexpress in A7 mode do you?

Ian.


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