Messages in this thread | | | Date | Fri, 04 Aug 2023 20:09:20 +0100 | From | Marc Zyngier <> | Subject | Re: [RFC PATCH 0/3] coresight: Support exclude_guest with Feat_TRF and nVHE |
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On Fri, 04 Aug 2023 11:13:10 +0100, James Clark <james.clark@arm.com> wrote: > > Hi, > > I'm looking for help in testing this and for feedback on whether it's > useful to anyone. Testing it requires hardware that has Feat_TRF (v8.4) > but no TRBE. This is because TRBE usage is disabled in nVHE guests. > > I don't currently have any access to any hardware, and the FVP model > can only do self hosted trace using TRBE. > > Currently with nVHE you would always get trace from guests, and > filtering out isn't possible without this patchset. In comparison, with > VHE guests, they never generate guest trace without [1]. I think the > existence of trace rather than lack of could suggest that this change is > less useful than [1]. Also the restricted set of hardware that it works > on supports that too.
It'd be nice to have some sort of feature parity, but it seems like a vanishingly small target of users having access to an ETM sink.
> > Apart from compilation and checking that the exclude guest settings > are correctly programmed on guest switch, this is untested by me.
I'll have a look at the series, but none of my HW fits in this description (my ARMv8.4+ boxes don't have any form of tracing).
Thanks,
M.
-- Without deviation from the norm, progress is not possible.
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