[bug report] KVM: arm64: BUG when reading kcore with kvm-arm.mode=protected

James Clark james.clark at linaro.org
Fri Oct 4 08:41:10 PDT 2024



On 02/10/2024 16:44, Oliver Upton wrote:
> +cc relevant folks
> 
> Hi James,
> 
> On Wed, Oct 02, 2024 at 02:23:32PM +0100, James Clark wrote:
>> Hi,
>>
>> I noticed this when running the Perf tests so I'm reporting it here (I don't
>> actually need kcore FWIW). I tested from 6.1 to 6.11 with the same results:
> 
> Yeah, this is (somewhat) intended behavior. By reading kcore you wind up
> reading from memory that isn't in a visible state for the host (e.g. hyp
> text).
> 
> Protected mode is very much a WIP, and is expected to be rough around the
> edges like this. Eventually the hypervisor will inject an abort into the
> host for disallowed memory accesses instead of tripping a BUG_ON(). We
> don't have that upstream right now.
> 

Thanks for the confirmation. I assumed as much but just wanted to be sure.



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