Re: [Xen-devel] [PATCH v2 4/4] Revert "xen: arm: force guest memory accesses to cacheable when MMU is disabled"

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Tue, 2014-02-04 at 15:37 +0000, Julien Grall wrote:
> On 02/04/2014 02:22 PM, Ian Campbell wrote:
> > This reverts commit 89eb02c2204a0b42a0aa169f107bc346a3fef802.
> > 
> > This approach has a short coming in that it breaks when a guest enables its
> > MMU (SCTLR.M, disabling HCR.DC) without enabling caches (SCTLR.C) first/at 
> > the
> > same time. It turns out that FreeBSD does this.
> > 
> > This has now been fixed (yet) another way (third time is the charm!) so 
> > remove
> > this support. The original commit contained some fixes which are still
> > relevant even with the revert of the bulk of the patch:
> >  - Correction to HSR_SYSREG_CRN_MASK
> >  - Rename of HSR_SYSCTL macros to avoid naming clash
> >  - Definition of some additional cp reg specifications
> > 
> > Since these are still useful they are not reverted.
> > 
> > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> 
> Except the spurious line toward the end of the patch:

Seems it was spuriously removed by the original, so this was just
reverting that, But I think it is correct to keep it out so I have done
so.

> Acked-by: Julien Grall <julien.grall@xxxxxxxxxx>

Thanks.

> 
> > diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> > index b8f2e82..ec51d1b 100644
> > --- a/xen/arch/arm/traps.c
> > +++ b/xen/arch/arm/traps.c
> 
> [..]
> 
> >      default:
> >          printk("%s %d, %d, c%d, c%d, %d %s x%d @ 0x%"PRIregister"\n",
> >                 sysreg.read ? "mrs" : "msr",
> > @@ -1635,6 +1477,7 @@ done:
> >      if (first) unmap_domain_page(first);
> >  }
> >  
> > +
> 
> Spurious change?
> 
> >  static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
> >                                        union hsr hsr)
> 
> 



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