lkml.org 
[lkml]   [2022]   [May]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v5 3/3] x86/tdx: Add Quote generation support
From


On 5/3/22 3:24 PM, Dave Hansen wrote:
> On 5/2/22 18:27, Kirill A. Shutemov wrote:
>>> Again, Dave and Andi already commented you should use vmap() to avoid breaking
>>> up the direct-mapping. Please use vmap() instead.
>>>
>>> https://lore.kernel.org/all/ce0feeec-a949-35f8-3010-b0d69acbbc2e@linux.intel.com/
>>>
>>> Will review the rest later.
>> I would rather convert it to use DMA API for memory allocation. It will
>> tap into swiotlb buffer that already converted and there's no need to
>> touch direct mapping. Both allocation and freeing such memory is cheaper
>> because of that.
>
> Sathya, I don't quite understand why you are so forcefully declining to
> incorporate review feedback on this point. I gave very specific
> feedback about the kind of mapping you need and that you should avoid
> fragmenting the direct map if at all possible.
>
> Why is this code still fragmenting the direct map?

I have already implemented it and testing it now.

In this discussion, we are comparing the use of DMA API for memory
allocation vs vmap/sharing it in driver itself.

--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer

\
 
 \ /
  Last update: 2022-05-04 00:29    [W:0.190 / U:0.840 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site