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

[Julien Grall <julien.grall@linaro.org>]

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@citrix.com>

Except the spurious line toward the end of the patch:

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

> 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)


-- 
Julien Grall