Messages in this thread | | | Date | Wed, 9 Dec 2020 13:54:42 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v8] swiotlb: Adjust SWIOTBL bounce buffer size for SEV guests. |
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On Wed, Dec 09, 2020 at 12:29:07PM +0000, Ashish Kalra wrote: > As i mentioned in the main comments above, this cannot be called in > mem_encrypt_init() as that breaks reserve_crashkernel() which depends > on SWIOTLB buffer size
Please elaborate how does it break.
> and is called before mem_encrypt_init(), therefore, it needs to be > called from setup_atch() before reserve_crashkernel().
I know you have your requirements what needs to be called when like all the other vendors who want to run stuff early in a particular order but our boot init order is a single fragile mess. So this better be done right!
Also,
[ 0.016630] software IO TLB: swiotlb_adjust: [ 0.017005] reserve_crashkernel: [ 0.050523] software IO TLB: swiotlb_init:
this looks strange - we're doing a swiotlb size adjust before init.
It probably makes sense as in: adjust the size before the SWIOTLB is initialized so that it uses the correct size but this better be spelled out.
> I believe that other memory encryption architectures such as s390 are > also looking for something similar to be available.
Until you have something more palpable than belief, "let the others extend it when they really need it." as I already mentioned.
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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