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([2a01:e0a:59e:9d80:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id a18sm2308276wrw.5.2022.01.27.06.13.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 27 Jan 2022 06:13:44 -0800 (PST) Subject: Re: [PATCH v4 10/21] KVM: arm64: Support SDEI_EVENT_ROUTING_SET hypercall To: Gavin Shan , 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> <20210815001352.81927-11-gshan@redhat.com> <0d46c17b-1a37-cbf6-4d34-aa03d30e39ef@redhat.com> From: Eric Auger Message-ID: <9186a727-afa7-a32c-e46e-580b2bc07ef7@redhat.com> Date: Thu, 27 Jan 2022 15:13:43 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Gavin, On 1/12/22 3:54 AM, Gavin Shan wrote: > Hi Eric, > > On 11/10/21 2:47 AM, Eric Auger wrote: >> On 8/15/21 2:13 AM, Gavin Shan wrote: >>> This supports SDEI_EVENT_ROUTING_SET hypercall. It's used by the >>> guest to set route mode and affinity for the registered KVM event. >>> It's only valid for the shared events. It's not allowed to do so >>> when the corresponding event has been raised to the guest. >>> >>> Signed-off-by: Gavin Shan >>> --- >>>   arch/arm64/kvm/sdei.c | 64 +++++++++++++++++++++++++++++++++++++++++++ >>>   1 file changed, 64 insertions(+) >>> >>> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c >>> index 5dfa74b093f1..458695c2394f 100644 >>> --- a/arch/arm64/kvm/sdei.c >>> +++ b/arch/arm64/kvm/sdei.c >>> @@ -489,6 +489,68 @@ static unsigned long >>> kvm_sdei_hypercall_info(struct kvm_vcpu *vcpu) >>>       return ret; >>>   } >>>   +static unsigned long kvm_sdei_hypercall_route(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_event *kse = NULL; >>> +    struct kvm_sdei_kvm_event *kske = NULL; >>> +    unsigned long event_num = smccc_get_arg1(vcpu); >>> +    unsigned long route_mode = smccc_get_arg2(vcpu); >>> +    unsigned long route_affinity = smccc_get_arg3(vcpu); >>> +    int index = 0; >>> +    unsigned long ret = SDEI_SUCCESS; >>> + >>> +    /* Sanity check */ >>> +    if (!(ksdei && vsdei)) { >>> +        ret = SDEI_NOT_SUPPORTED; >>> +        goto out; >>> +    } >>> + >>> +    if (!kvm_sdei_is_valid_event_num(event_num)) { >>> +        ret = SDEI_INVALID_PARAMETERS; >>> +        goto out; >>> +    } >>> + >>> +    if (!(route_mode == SDEI_EVENT_REGISTER_RM_ANY || >>> +          route_mode == SDEI_EVENT_REGISTER_RM_PE)) { >>> +        ret = SDEI_INVALID_PARAMETERS; >>> +        goto out; >>> +    } >> Some sanity checking on the affinity arg could be made as well according >> to 5.1.2  affinity desc. The fn shall return INVALID_PARAMETER in case >> of invalid affinity. > > Yep, you're right. I didn't figure out it. I may put a comment here. > For now, the SDEI client driver in the guest kernel doesn't attempt > to change the routing mode. > >     /* FIXME: The affinity should be verified */ > >>> + >>> +    /* Check if the KVM event has been registered */ >>> +    spin_lock(&ksdei->lock); >>> +    kske = kvm_sdei_find_kvm_event(kvm, event_num); >>> +    if (!kske) { >>> +        ret = SDEI_INVALID_PARAMETERS; >>> +        goto unlock; >>> +    } >>> + >>> +    /* Validate KVM event state */ >>> +    kse = kske->kse; >>> +    if (kse->state.type != SDEI_EVENT_TYPE_SHARED) { >>> +        ret = SDEI_INVALID_PARAMETERS; >>> +        goto unlock; >>> +    } >>> + >> Event handler is in a state other than: handler-registered. > > They're equivalent as the handler is provided as a parameter when > the event is registered. > >>> +    if (!kvm_sdei_is_registered(kske, index) || >>> +        kvm_sdei_is_enabled(kske, index)     || >>> +        kske->state.refcount) { >> I am not sure about the refcount role here. Does it make sure the state >> is != handler-enabled and running or handler-unregister-pending? >> >> I think we would gain in readibility if we had a helper to check whether >> we are in those states? > > @refcount here indicates pending SDEI event for delivery. In this case, > chaning its routing mode is disallowed. OK. I guess you will document the refcount role somewhere. Thanks Eric > >>> +        ret = SDEI_DENIED; >>> +        goto unlock; >>> +    } >>> + >>> +    /* Update state */ >>> +    kske->state.route_mode     = route_mode; >>> +    kske->state.route_affinity = route_affinity; >>> + >>> +unlock: >>> +    spin_unlock(&ksdei->lock); >>> +out: >>> +    return ret; >>> +} >>> + >>>   int kvm_sdei_hypercall(struct kvm_vcpu *vcpu) >>>   { >>>       u32 func = smccc_get_function(vcpu); >>> @@ -523,6 +585,8 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu) >>>           ret = kvm_sdei_hypercall_info(vcpu); >>>           break; >>>       case SDEI_1_0_FN_SDEI_EVENT_ROUTING_SET: >>> +        ret = kvm_sdei_hypercall_route(vcpu); >>> +        break; >>>       case SDEI_1_0_FN_SDEI_PE_MASK: >>>       case SDEI_1_0_FN_SDEI_PE_UNMASK: >>>       case SDEI_1_0_FN_SDEI_INTERRUPT_BIND: >>> > > Thanks, > Gavin >