Hi Gavin,
On Sun, Apr 03, 2022 at 11:38:57PM +0800, Gavin Shan wrote:
> This supports SDEI_EVENT_REGISTER hypercall, which is used by guest
> to register event. The event won't be raised until it's registered
> and enabled. For those KVM owned events, they can't be registered
> if they aren't exposed.
>
> Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
> ---
> arch/arm64/kvm/sdei.c | 78 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 78 insertions(+)
>
> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
> index 3507e33ec00e..89c1b231cb60 100644
> --- a/arch/arm64/kvm/sdei.c
> +++ b/arch/arm64/kvm/sdei.c
> @@ -25,6 +25,81 @@ static struct kvm_sdei_exposed_event exposed_events[] = {
> for (idx = 0, event = &exposed_events[0]; \
> idx < ARRAY_SIZE(exposed_events); \
> idx++, event++)
> +#define kvm_sdei_for_each_event(vsdei, event, idx) \
> + for (idx = 0, event = &vsdei->events[0]; \
> + idx < ARRAY_SIZE(exposed_events); \
> + idx++, event++)
> +
> +static struct kvm_sdei_event *find_event(struct kvm_vcpu *vcpu,
> + unsigned int num)
> +{
> + struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei;
> + struct kvm_sdei_event *event;
> + int i;
> +
> + kvm_sdei_for_each_event(vsdei, event, i) {
> + if (event->exposed_event->num == num)
> + return event;
> + }
> +
> + return NULL;
> +}
I imagine you'll drop this hunk in the next spin.
> +static unsigned long hypercall_register(struct kvm_vcpu *vcpu)
Hmm, hypercall_ is not a very descriptive scope. Could you instead do
something like kvm_sdei_?
so for this one, kvm_sdei_event_register()? Provides decent context
clues to connect back to the spec as well.
> +{
> + struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei;
> + struct kvm_sdei_event *event;
> + unsigned int num = smccc_get_arg(vcpu, 1);
> + unsigned long ep_address = smccc_get_arg(vcpu, 2);
> + unsigned long ep_arg = smccc_get_arg(vcpu, 3);
We discussed using some structure to track the registered context of an
event. Maybe just build it on the stack then assign it in the array?
> + unsigned long route_mode = smccc_get_arg(vcpu, 4);
This is really 'flags'. route_mode is bit[0]. I imagine we don't want to
support relative mode, so bit[1] is useless for us in that case too.
The spec is somewhat imprecise on what happens for reserved flags. The
prototype in section 5.1.2 of [1] suggests that reserved bits must be
zero, but 5.1.2.3 'Client responsibilities' does not state that invalid
flags result in an error.
Arm TF certainly rejects unexpected flags [2].
[1]: DEN0054C https://developer.arm.com/documentation/den0054/latest
[2]: https://github.com/ARM-software/arm-trusted-firmware/blob/66c3906e4c32d675eb06bd081de8a3359f76b84c/services/std_svc/sdei/sdei_main.c#L260
--
Thanks,
Oliver
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