On 2020-06-26 15:46, Andrew Cooper wrote:
> On 26/06/2020 15:26, Jan Beulich wrote:
>> On 26.06.2020 15:59, Ross Lagerwall wrote:
>>> On 2020-06-26 13:24, Andrew Cooper wrote:
>>>> @@ -56,18 +57,48 @@ int arch_livepatch_safety_check(void)
>>>> return -EBUSY;
>>>> }
>>>>
>>>> -int arch_livepatch_quiesce(void)
>>>> +int noinline arch_livepatch_quiesce(void)
>>>> {
>>>> + /* If Shadow Stacks are in use, disable CR4.CET so we can modify
>>>> CR0.WP. */
>>>> + if ( cpu_has_xen_shstk )
>>> Should this be:
>>> if ( IS_ENABLED(CONFIG_XEN_SHSTK) && cpu_has_xen_shstk )
>>>
>>> to match arch_livepatch_revive?
>> While it may look a little asymmetric, I think it's preferable
>> to is IS_ENABLED() only where really needed, i.e. here it
>> guarding code that otherwise may not build.
>
> The reason for the asymmetry is because of the asm() block, which needs
> compiling out when we detect that we don't have a compatible assembler.
>
In that case,
Reviewed-by: Ross Lagerwall <ross.lagerw...@citrix.com>
Thanks
