[PATCH v2 23/28] arm64/sve: KVM: Treat guest SVE use as undefined instruction execution

[Dave Martin]

On Thu, Sep 14, 2017 at 02:31:13PM +0100, Alex Bennée wrote:
> 
> Dave Martin <Dave.Martin at arm.com> writes:
> 
> > When trapping forbidden attempts by a guest to use SVE, we want the
> > guest to see a trap consistent with SVE not being implemented.
> >
> > This patch injects an undefined instruction exception into the
> > guest in response to such an exception.
> 
> I do wonder if this should be merged with the previous trap enabling
> patch though?

Yes, that would make sense now I look at it.

Can I keep your Reviewed-by on the combined patch?

Cheers
---Dave

> 
> >
> > Signed-off-by: Dave Martin <Dave.Martin at arm.com>
> > ---
> >  arch/arm64/kvm/handle_exit.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> > index 17d8a16..e3e42d0 100644
> > --- a/arch/arm64/kvm/handle_exit.c
> > +++ b/arch/arm64/kvm/handle_exit.c
> > @@ -147,6 +147,13 @@ static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run)
> >  	return 1;
> >  }
> >
> > +static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run)
> > +{
> > +	/* Until SVE is supported for guests: */
> > +	kvm_inject_undefined(vcpu);
> > +	return 1;
> > +}
> > +
> >  static exit_handle_fn arm_exit_handlers[] = {
> >  	[0 ... ESR_ELx_EC_MAX]	= kvm_handle_unknown_ec,
> >  	[ESR_ELx_EC_WFx]	= kvm_handle_wfx,
> > @@ -160,6 +167,7 @@ static exit_handle_fn arm_exit_handlers[] = {
> >  	[ESR_ELx_EC_HVC64]	= handle_hvc,
> >  	[ESR_ELx_EC_SMC64]	= handle_smc,
> >  	[ESR_ELx_EC_SYS64]	= kvm_handle_sys_reg,
> > +	[ESR_ELx_EC_SVE]	= handle_sve,
> >  	[ESR_ELx_EC_IABT_LOW]	= kvm_handle_guest_abort,
> >  	[ESR_ELx_EC_DABT_LOW]	= kvm_handle_guest_abort,
> >  	[ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,
> 
> 
> --
> Alex Bennée
> 
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