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

Dave Martin
2017-09-29T13:00:30Z

On Thu, Sep 14, 2017 at 02:31:13PM +0100, Alex Bennée wrote:
>
> Dave Martin <Dave.Martin@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@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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