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Subject: Re: [PATCH v4 11/21] KVM: arm64: Support SDEI_PE_{MASK, UNMASK}
 hypercall
To:     Gavin Shan <gshan@redhat.com>, kvmarm@lists.cs.columbia.edu
Cc:     maz@kernel.org, linux-kernel@vger.kernel.org,
        Jonathan.Cameron@huawei.com, pbonzini@redhat.com, will@kernel.org
References: <20210815001352.81927-1-gshan@redhat.com>
 <20210815001352.81927-12-gshan@redhat.com>
From:   Eric Auger <eauger@redhat.com>
Message-ID: <e5acdb48-fb16-ab18-4938-c03265c4cfbf@redhat.com>
Date:   Tue, 9 Nov 2021 21:31:30 +0100
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Hi Gavin,

On 8/15/21 2:13 AM, Gavin Shan wrote:
> This supports SDEI_PE_{MASK, UNMASK} hypercall. They are used by
> the guest to stop the specific vCPU from receiving SDEI events.
> 
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
>  arch/arm64/kvm/sdei.c | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
> index 458695c2394f..3fb33258b494 100644
> --- a/arch/arm64/kvm/sdei.c
> +++ b/arch/arm64/kvm/sdei.c
> @@ -551,6 +551,37 @@ static unsigned long kvm_sdei_hypercall_route(struct kvm_vcpu *vcpu)
>  	return ret;
>  }
>  
> +static unsigned long kvm_sdei_hypercall_mask(struct kvm_vcpu *vcpu,
> +					     bool mask)
> +{
> +	struct kvm *kvm = vcpu->kvm;
> +	struct kvm_sdei_kvm *ksdei = kvm->arch.sdei;
> +	struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei;
> +	unsigned long ret = SDEI_SUCCESS;
> +
> +	/* Sanity check */
> +	if (!(ksdei && vsdei)) {
> +		ret = SDEI_NOT_SUPPORTED;
> +		goto out;
> +	}
> +
> +	spin_lock(&vsdei->lock);
> +
> +	/* Check the state */
> +	if (mask == vsdei->state.masked) {
> +		ret = SDEI_DENIED;
are you sure? I don't this error documented in 5.1.12?

Besides the spec says:
"
This call can be invoked by the client to mask the PE, whether or not
the PE is already masked."
> +		goto unlock;
> +	}
> +
> +	/* Update the state */
> +	vsdei->state.masked = mask ? 1 : 0;
> +
> +unlock:
> +	spin_unlock(&vsdei->lock);
> +out:
> +	return ret;
In case of success the returned value is SUCESS for UNMASK but not for
MASK (see table in 5.1.12).

By the way I have just noticed there is a more recent of the spec than
the A:

ARM_DEN0054C

You should update the cover letter and [PATCH v4 02/21] KVM: arm64: Add
SDEI virtualization infrastructure commit msg


> +}
> +
>  int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
>  {
>  	u32 func = smccc_get_function(vcpu);
> @@ -588,7 +619,11 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
>  		ret = kvm_sdei_hypercall_route(vcpu);
>  		break;
>  	case SDEI_1_0_FN_SDEI_PE_MASK:
> +		ret = kvm_sdei_hypercall_mask(vcpu, true);
> +		break;
>  	case SDEI_1_0_FN_SDEI_PE_UNMASK:
> +		ret = kvm_sdei_hypercall_mask(vcpu, false);
> +		break;
>  	case SDEI_1_0_FN_SDEI_INTERRUPT_BIND:
>  	case SDEI_1_0_FN_SDEI_INTERRUPT_RELEASE:
>  	case SDEI_1_0_FN_SDEI_PRIVATE_RESET:
> 
Eric