Re: [PATCH 2/2] dt-bindings: arm: cpus: Add edac-enabled property

[Tyler Hicks (Microsoft)]

On 2025-04-10 08:10:18, Marc Zyngier wrote:
> On Thu, 10 Apr 2025 07:00:55 +0100,
> Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> > 
> > On 10/04/2025 01:36, Vijay Balakrishna wrote:
> > > From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> > > 
> > > Some ARM Cortex CPUs like the A53, A57 and A72 have Error Detection And
> > > Correction (EDAC) support on their L1 and L2 caches. This is implemented
> > > in implementation defined registers, so usage of this functionality is
> > > not safe in virtualized environments or when EL3 already uses these
> > > registers. This patch adds a edac-enabled flag which can be explicitly
> > > set when EDAC can be used.
> > 
> > Can't hypervisor tell you that?
> 
> No, it can't. This is not an architecture feature, and KVM will gladly
> inject an UNDEF exception if the guest tries to use this.
> 
> Which is yet another reason why this whole exercise is futile.

Hi Marc - could you clarify why this is futile for baremetal or were you just
referring to virtualized environments?

Thanks!

Tyler

> 
> 	M.
> 
> -- 
> Without deviation from the norm, progress is not possible.