Re: [PATCH v14 3/5] KVM: arm64: Manage GCS access and registers for guests

From: Mark Brown
Date: Sat Oct 05 2024 - 09:08:50 EST


On Sat, Oct 05, 2024 at 12:34:20PM +0100, Marc Zyngier wrote:
> Mark Brown <broonie@xxxxxxxxxx> wrote:

> > + if (!kvm_has_gcs(kvm)) {
> > + kvm->arch.fgu[HFGxTR_GROUP] |= (HFGxTR_EL2_nGCS_EL0 |
> > + HFGxTR_EL2_nGCS_EL1);
> > + kvm->arch.fgu[HFGITR_GROUP] |= (HFGITR_EL2_nGCSEPP |
> > + HFGITR_EL2_nGCSSTR_EL1 |
> > + HFGITR_EL2_nGCSPUSHM_EL1);

> Where is the handling of traps resulting of HFGITR_EL2.nGCSSTR_EL1?

These will trap with an EC of 0x2d which isn't known so I was expecting
this to get handled in the same way as for example a return of false
from kvm_hyp_handle_fpsimd() for SVE when unsupported, or for the
simiarly unknown SME EC, currently. I gather from your comment that
you're instead expecting to see an explicit exit handler for this EC
that just injects the UNDEF directly?

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