Re: [Xen-devel] [PATCH 31/45] xen: arm: guest context switching.

[Tim Deegan <tim@xxxxxxx>]

At 14:50 +0000 on 14 Feb (1360853419), Ian Campbell wrote:
> On Thu, 2013-02-14 at 14:43 +0000, Tim Deegan wrote:
> > At 15:56 +0000 on 23 Jan (1358956597), Ian Campbell wrote:
> > > One side effect of this is that we now save the full 64-bit
> > > TTBR[0,1] even on a 32-bit hypervisor. This is needed anyway to
> > > support LPAE guests (although this patch doesn't implement anything
> > > other than the context switch).
> > > 
> > > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> > > ---
> > >  xen/arch/arm/domain.c        |  113 
> > > +++++++++++++++++++++++++-----------------
> > >  xen/arch/arm/traps.c         |   14 +++---
> > >  xen/include/asm-arm/cpregs.h |   21 +++++++-
> > >  xen/include/asm-arm/domain.h |   29 ++++++++---
> > >  4 files changed, 115 insertions(+), 62 deletions(-)
> > > 
> > > diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> > > index 077521e..0323552 100644
> > > --- a/xen/arch/arm/domain.c
> > > +++ b/xen/arch/arm/domain.c
> > > @@ -41,55 +41,67 @@ void idle_loop(void)
> > >  static void ctxt_switch_from(struct vcpu *p)
> > >  {
> > >      /* CP 15 */
> > > -    p->arch.csselr = READ_CP32(CSSELR);
> > > +    p->arch.csselr = READ_SYSREG(CSSELR_EL1);
> > >  
> > >      /* Control Registers */
> > > -    p->arch.actlr = READ_CP32(ACTLR);
> > > -    p->arch.sctlr = READ_CP32(SCTLR);
> > > -    p->arch.cpacr = READ_CP32(CPACR);
> > > +    p->arch.actlr = READ_SYSREG(ACTLR_EL1);
> > > +    p->arch.sctlr = READ_SYSREG(SCTLR_EL1);
> > > +    p->arch.cpacr = READ_SYSREG(CPACR_EL1);
> > >  
> > > -    p->arch.contextidr = READ_CP32(CONTEXTIDR);
> > > -    p->arch.tpidrurw = READ_CP32(TPIDRURW);
> > > -    p->arch.tpidruro = READ_CP32(TPIDRURO);
> > > -    p->arch.tpidrprw = READ_CP32(TPIDRPRW);
> > > +    p->arch.contextidr = READ_SYSREG(CONTEXTIDR_EL1);
> > > +    p->arch.tpidrurw = READ_SYSREG(TPIDR_EL0); /* XXX names */
> > 
> > XXX names indeed. :)
> 
> Do you think:
>         s/tpidrurw/tpidr_el0/
>         s/tpidrprw/tpidr_el1/
>         s/tpidruro/tpidrro_el0/
>         
> would be an improvement? They are all pretty aweful but the consistent
> answer would be to use the aarch64 names.

Yes, I think so - it matches how these registers are handled everywhere
else.  With just that change you can keep my ack on the patch.

Cheers,

Tim.

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