Re: [PATCH v7 01/15] swiotlb: Refactor swiotlb init functions

Tom Lendacky
2021-05-27T14:41:16Z

On 5/27/21 8:02 AM, Christoph Hellwig wrote:
> On Wed, May 19, 2021 at 11:50:07AM -0700, Florian Fainelli wrote:
>> You convert this call site with swiotlb_init_io_tlb_mem() which did not
>> do the set_memory_decrypted()+memset(). Is this okay or should
>> swiotlb_init_io_tlb_mem() add an additional argument to do this
>> conditionally?
>
> The zeroing is useful and was missing before. I think having a clean
> state here is the right thing.
>
> Not sure about the set_memory_decrypted, swiotlb_update_mem_attributes
> kinda suggests it is too early to set the memory decrupted.
>
> Adding Tom who should now about all this.

The reason for adding swiotlb_update_mem_attributes() was because having
the call to set_memory_decrypted() in swiotlb_init_with_tbl() triggered a
BUG_ON() related to interrupts not being enabled yet during boot. So that
call had to be delayed until interrupts were enabled.

Thanks,
Tom

>