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

Alex Bennée
2017-09-29T14:43:40Z

Dave Martin <Dave.Martin@arm.com> writes:

> 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?

Sure.

>
> 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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