Re: [Xen-devel] [PATCH 02/19] xen: arm: add missing break

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Ian,

On 31/03/2015 11:07, Ian Campbell wrote:
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
>
> xen: arm: Fix handling of ICC_{SGI1R,SGI0R,ASGI1R}_EL1
>
> Having injected an undefined instruction we don't want to also advance
> pc. So return.
>
> THe ICC_{SGI0R,ASGI1R}_EL1 case was previously missing a break, so
> would have fallen through to the default case and injected a second
> undef, corrupting SPSR_EL1 and ELR_EL1 for the guest.
>
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Reviewed-by: Julien Grall <julien.grall@xxxxxxxxxx>

Regards,

> ---
>   xen/arch/arm/traps.c |    4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index 69b9513..99ceaea 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -1908,7 +1908,7 @@ static void do_sysreg(struct cpu_user_regs *regs,
>           {
>               dprintk(XENLOG_WARNING,
>                       "failed emulation of sysreg ICC_SGI1R_EL1 access\n");
> -            inject_undef64_exception(regs, hsr.len);
> +            return inject_undef64_exception(regs, hsr.len);
>           }
>           break;
>       case HSR_SYSREG_ICC_SGI0R_EL1:
> @@ -1916,7 +1916,7 @@ static void do_sysreg(struct cpu_user_regs *regs,
>           /* TBD: Implement to support secure grp0/1 SGI forwarding */
>           dprintk(XENLOG_WARNING,
>                   "Emulation of sysreg ICC_SGI0R_EL1/ASGI1R_EL1 not 
> supported\n");
> -        inject_undef64_exception(regs, hsr.len);
> +        return inject_undef64_exception(regs, hsr.len);
>       default:
>           {
>               const struct hsr_sysreg sysreg = hsr.sysreg;
--
Julien Grall

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