Messages in this thread | | | Subject | Re: [PATCH v15 06/12] swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing | From | Nathan Chancellor <> | Date | Tue, 6 Jul 2021 12:14:16 -0700 |
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Hi Will and Robin,
On 7/6/2021 10:06 AM, Will Deacon wrote: > On Tue, Jul 06, 2021 at 04:39:11PM +0100, Robin Murphy wrote: >> On 2021-07-06 15:05, Christoph Hellwig wrote: >>> On Tue, Jul 06, 2021 at 03:01:04PM +0100, Robin Murphy wrote: >>>> FWIW I was pondering the question of whether to do something along those >>>> lines or just scrap the default assignment entirely, so since I hadn't got >>>> round to saying that I've gone ahead and hacked up the alternative >>>> (similarly untested) for comparison :) >>>> >>>> TBH I'm still not sure which one I prefer... >>> >>> Claire did implement something like your suggestion originally, but >>> I don't really like it as it doesn't scale for adding multiple global >>> pools, e.g. for the 64-bit addressable one for the various encrypted >>> secure guest schemes. >> >> Ah yes, that had slipped my mind, and it's a fair point indeed. Since we're >> not concerned with a minimal fix for backports anyway I'm more than happy to >> focus on Will's approach. Another thing is that that looks to take us a >> quiet step closer to the possibility of dynamically resizing a SWIOTLB pool, >> which is something that some of the hypervisor protection schemes looking to >> build on top of this series may want to explore at some point. > > Ok, I'll split that nasty diff I posted up into a reviewable series and we > can take it from there.
For what it's worth, I attempted to boot Will's diff on top of Konrad's devel/for-linus-5.14 and it did not work; in fact, I got no output on my monitor period, even with earlyprintk=, and I do not think this machine has a serial console.
Robin's fix does work, it survived ten reboots with no issues getting to X and I do not see the KASAN and slub debug messages anymore but I understand that this is not the preferred solution it seems (although Konrad did want to know if it works).
I am happy to test any further patches or follow ups as needed, just keep me on CC.
Cheers, Nathan
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