Re: [PATCH 0/2] KVM: arm64: nv: Fix SError injection at EL2

[Marc Zyngier <maz@kernel.org>]

On Thu, 18 Sep 2025 17:46:30 +0100,
Oliver Upton <oliver.upton@linux.dev> wrote:
> 
> FEAT_NV2 keeps us out of the loop on changes to HCR_EL2. That really
> sucks when the guest hypervisor toggles bits that affect the hyp
> context, such as TGE and xMO.
> 
> The architecture now allows an implementation to treat HCR_EL2.AMO as 1
> any time that HCR_EL2.{E2H,TGE} = {1, 0}, effectively allowing us to
> hide what would otherwise be a quality of emulation bug in SError
> injection.

Yup. Note that the same relaxation also applies to IMO/FMO (that's the
reason why this relaxation was originally introduced), but I don't
think we need to do anything on that front.

> Unfortunately there's nothing to be done for E2H0 VMs, although given
> the direction of the architecture the offending hypervisor should just
> get with the times...

I have no sympathy for these either. Eventually, they'll get on with
the program, or experience the fate of 32bit...

I'll drag this into 6.18.

Thanks,

	M.

-- 
Jazz isn't dead. It just smells funny.