Re: [Qemu-devel] [PATCH v2 3/9] target-i386: Ensure bit 10 on DR7 is never cleared

[Richard Henderson <rth@twiddle.net>]

On 10/16/2015 06:23 AM, Eduardo Habkost wrote:
> Bit 10 of DR7 is documented as always set to 1, so ensure that's
> always the case.
>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>   target-i386/bpt_helper.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/target-i386/bpt_helper.c b/target-i386/bpt_helper.c
> index 23ce828..493deba 100644
> --- a/target-i386/bpt_helper.c
> +++ b/target-i386/bpt_helper.c
> @@ -113,6 +113,8 @@ void cpu_x86_update_dr7(CPUX86State *env, uint32_t new_dr7)
>               hw_breakpoint_insert(env, i);
>           }
>       }
> +
> +    env->dr[7] |= DR7_FIXED_1;

Better to do this to new_dr7, above the xor test with old_dr7, so that we still 
pass the xor test.


r~