Hi Gavin,
On 1/12/22 3:33 AM, Gavin Shan wrote:
> Hi Eric,
>
> On 11/10/21 7:16 PM, Eric Auger wrote:
>> On 8/15/21 2:13 AM, Gavin Shan wrote:
>>> This supports SDEI_EVENT_CONTEXT hypercall. It's used by the guest
>>> to retrieved the original registers (R0 - R17) in its SDEI event
>>> handler. Those registers can be corrupted during the SDEI event
>>> delivery.
>>>
>>> Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
>>> ---
>>> arch/arm64/kvm/sdei.c | 40 ++++++++++++++++++++++++++++++++++++++++
>>> 1 file changed, 40 insertions(+)
>>>
>>> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
>>> index b022ce0a202b..b4162efda470 100644
>>> --- a/arch/arm64/kvm/sdei.c
>>> +++ b/arch/arm64/kvm/sdei.c
>>> @@ -270,6 +270,44 @@ static unsigned long
>>> kvm_sdei_hypercall_enable(struct kvm_vcpu *vcpu,
>>> return ret;
>>> }
>>> +static unsigned long kvm_sdei_hypercall_context(struct kvm_vcpu
>>> *vcpu)
>>> +{
>>> + struct kvm *kvm = vcpu->kvm;
>>> + struct kvm_sdei_kvm *ksdei = kvm->arch.sdei;
>>> + struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei;
>>> + struct kvm_sdei_vcpu_regs *regs;
>>> + unsigned long index = smccc_get_arg1(vcpu);
>> s/index/param_id to match the spec?
>
> Sure, but "reg_id" seems better here. As the parameter indicates the GPR
> index
> to be fetched on request of the guest kernel.
fine with me.
>
>>> + unsigned long ret = SDEI_SUCCESS;
>>> +
>>> + /* Sanity check */
>>> + if (!(ksdei && vsdei)) {
>>> + ret = SDEI_NOT_SUPPORTED;
>>> + goto out;
>>> + }
>>> +
>>> + if (index > ARRAY_SIZE(vsdei->state.critical_regs.regs)) {
>>> + ret = SDEI_INVALID_PARAMETERS;
>>> + goto out;
>>> + }
>> I would move the above after regs = and use regs there (although the
>> regs ARRAY_SIZE of both is identifical)
>
> Ok.
>
>>> +
>>> + /* Check if the pending event exists */
>>> + spin_lock(&vsdei->lock);
>>> + if (!(vsdei->critical_event || vsdei->normal_event)) {
>>> + ret = SDEI_DENIED;
>>> + goto unlock;
>>> + }
>>> +
>>> + /* Fetch the requested register */
>>> + regs = vsdei->critical_event ? &vsdei->state.critical_regs :
>>> + &vsdei->state.normal_regs;
>>> + ret = regs->regs[index];
>>> +
>>> +unlock:
>>> + spin_unlock(&vsdei->lock);
>>> +out:
>>> + return ret;
>>> +}
>>> +
>>> int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
>>> {
>>> u32 func = smccc_get_function(vcpu);
>>> @@ -290,6 +328,8 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
>>> ret = kvm_sdei_hypercall_enable(vcpu, false);
>>> break;
>>> case SDEI_1_0_FN_SDEI_EVENT_CONTEXT:
>>> + ret = kvm_sdei_hypercall_context(vcpu);
>>> + break;
>>> case SDEI_1_0_FN_SDEI_EVENT_COMPLETE:
>>> case SDEI_1_0_FN_SDEI_EVENT_COMPLETE_AND_RESUME:
>>> case SDEI_1_0_FN_SDEI_EVENT_UNREGISTER:
>>>
>
> Thanks,
> Gavin
>
Eric
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