[PATCH v8 26/38] KVM: arm64: Handle SME host state when running guests

[Mark Brown]

On Tue, Jan 25, 2022 at 11:59:02AM +0000, Marc Zyngier wrote:
> Mark Brown <broonie at kernel.org> wrote:

> > +	if (has_vhe()) {
> > +		if (system_supports_sme()) {

> nit:	if (has_vhe() && system_supports_sme()) {

> saves you one level of indentation.

Yes, for now.  IIRC there was some other stuff there when I had some of
the code for doing the register switching properly.

> > +			/* Also restore EL0 state seen on entry */
> > +			if (vcpu->arch.flags & KVM_ARM64_HOST_SME_ENABLED)
> > +				sysreg_clear_set(CPACR_EL1, 0,
> > +						 CPACR_EL1_SMEN_EL0EN |
> > +						 CPACR_EL1_SMEN_EL1EN);
> > +			else
> > +				sysreg_clear_set(CPACR_EL1,
> > +						 CPACR_EL1_SMEN_EL0EN,
> > +						 CPACR_EL1_SMEN_EL1EN);

> I find the use of CPACR_EL1_SMEN in some cases and its individual bits
> in some others pretty confusing. I understand that you have modelled
> it after the SVE code, but maybe this is a mistake we don't need to
> repeat. I'd be in favour of directly exposing the individual bits in
> all cases.

OK, it is just the KVM code that uses the plain ZEN.  I'll add a cleanup
patch for that at the start of the series for ZEN I guess otherwise it
looks worse, though that will inflate the size of the series a bit.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20220125/88346d43/attachment.sig>