On Sat, 05 Oct 2024 11:37:30 +0100,
Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> GCS introduces a number of system registers for EL1 and EL0, on systems
> with GCS we need to context switch them and expose them to VMMs to allow
> guests to use GCS.
>
> In order to allow guests to use GCS we also need to configure
> HCRX_EL2.GCSEn, if this is not set GCS instructions will be noops and
> CHKFEAT will report GCS as disabled. Also enable fine grained traps for
> access to the GCS registers by guests which do not have the feature
> enabled.
>
> In order to allow userspace to control availability of the feature to
> guests we enable writability for only ID_AA64PFR1_EL1.GCS, this is a
> deliberately conservative choice to avoid errors due to oversights.
> Further fields should be made writable in future.
It appears I have accidentally dropped the branch fixing
ID_AA64PFR1_EL1. I'll make sure this goes in as quickly as possible.
>
> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/kvm_host.h | 12 ++++++++++++
> arch/arm64/include/asm/vncr_mapping.h | 2 ++
> arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 31 ++++++++++++++++++++++++++++++
> arch/arm64/kvm/sys_regs.c | 31 +++++++++++++++++++++++++++++-
> 4 files changed, 75 insertions(+), 1 deletion(-)
>
[...]
> @@ -4716,6 +4737,14 @@ void kvm_calculate_traps(struct kvm_vcpu *vcpu)
> kvm->arch.fgu[HFGxTR_GROUP] |= (HFGxTR_EL2_nPOR_EL1 |
> HFGxTR_EL2_nPOR_EL0);
>
> + 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?
M.
--
Without deviation from the norm, progress is not possible.
