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

[Alex Bennée]

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

> 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?

Sure.

>
> 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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>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel


--
Alex Bennée