Re: [RFC 09/13] iommu/smmuv3: Get prepared for nested stage support

From: Auger Eric
Date: Fri Aug 31 2018 - 10:11:47 EST

Hi Jean-Philippe,

On 08/31/2018 03:20 PM, Jean-Philippe Brucker wrote:
> On 23/08/18 13:17, Eric Auger wrote:
>> if (ste->s1_cfg) {
>> - BUG_ON(ste_live);
> Scary! :) The current code assumes that it can make modifications to the
> STE in any order and enable translation after a sync. So far I haven't
> been able to find anything that violates this rule in the spec: "If
> software modifies the structure while it is valid, it must not allow the
> structure to enter an invalid intermediate state." So maybe it's fine,
> though to be safe I would have started with disabling the STE
> (;a=commitdiff;h=936e49f923e101c061269eadd5fa43fef819d2e9)

Yep this works with my setup but I was waiting for such kind of comments
to turn this prototype into something more "production level" ;-) Did
you send anything upstream, related to this branch?


> Thanks,
> Jean