Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 543EDC433F5 for ; Wed, 12 Jan 2022 02:39:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348862AbiALCjQ (ORCPT ); Tue, 11 Jan 2022 21:39:16 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:45899 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236970AbiALCjM (ORCPT ); Tue, 11 Jan 2022 21:39:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1641955151; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EC8JqTc5p5dOk5517cNTRB8u9r50bke9P1vj8NyUUwE=; b=HhhZw5ncid6GvX452d6G8DiDXfixt6/i5nrIAHJrPaE1JVYI7y3UwZDQHlK0Db79APrhip N6RqPKecbcyzEFk7T3S4JKU71Dh2H/pe4fVLUkXvMZlp3zrYbw5yrXRPdzxFR6T7FNOyf8 n/JxZChkM2b269Ym5idSsMQ/78pE8qU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-307-A4nsJXNLPwWmzIuASfxBfg-1; Tue, 11 Jan 2022 21:39:08 -0500 X-MC-Unique: A4nsJXNLPwWmzIuASfxBfg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3B1B736393; Wed, 12 Jan 2022 02:39:07 +0000 (UTC) Received: from [10.72.12.29] (ovpn-12-29.pek2.redhat.com [10.72.12.29]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 87DDD6107E; Wed, 12 Jan 2022 02:38:59 +0000 (UTC) Reply-To: Gavin Shan Subject: Re: [PATCH v4 07/21] KVM: arm64: Support SDEI_EVENT_UNREGISTER hypercall To: Eric Auger , 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> <20210815001352.81927-8-gshan@redhat.com> <100a4aa0-6c2d-2fec-6f11-c7e64946ef0b@redhat.com> From: Gavin Shan Message-ID: <11022feb-16d7-8732-0d3a-12a65a4e39de@redhat.com> Date: Wed, 12 Jan 2022 10:38:56 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: <100a4aa0-6c2d-2fec-6f11-c7e64946ef0b@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Eric, On 11/10/21 1:05 AM, Eric Auger wrote: > On 8/15/21 2:13 AM, Gavin Shan wrote: >> This supports SDEI_EVENT_UNREGISTER hypercall. It's used by the >> guest to unregister SDEI event. The SDEI event won't be raised to >> the guest or specific vCPU after it's unregistered successfully. >> It's notable the SDEI event is disabled automatically on the guest >> or specific vCPU once it's unregistered successfully. >> >> Signed-off-by: Gavin Shan >> --- >> arch/arm64/kvm/sdei.c | 61 +++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 61 insertions(+) >> >> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c >> index b4162efda470..a3ba69dc91cb 100644 >> --- a/arch/arm64/kvm/sdei.c >> +++ b/arch/arm64/kvm/sdei.c >> @@ -308,6 +308,65 @@ static unsigned long kvm_sdei_hypercall_context(struct kvm_vcpu *vcpu) >> return ret; >> } >> >> +static unsigned long kvm_sdei_hypercall_unregister(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); >> + 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; >> + } >> + >> + /* Check if the KVM event exists */ >> + spin_lock(&ksdei->lock); >> + kske = kvm_sdei_find_kvm_event(kvm, event_num); >> + if (!kske) { >> + ret = SDEI_INVALID_PARAMETERS; >> + goto unlock; >> + } >> + >> + /* Check if there is pending events */ >> + if (kske->state.refcount) { >> + ret = SDEI_PENDING; > don't you want to record the fact the unregistration is outstanding to > perform subsequent actions? Otherwise nothing will hapen when the > current executing handlers complete? It's not necessary. The guest should retry in this case. >> + goto unlock; >> + } >> + >> + /* Check if it has been registered */ >> + kse = kske->kse; >> + index = (kse->state.type == SDEI_EVENT_TYPE_PRIVATE) ? >> + vcpu->vcpu_idx : 0; > you could have an inline for the above as this is executed in many > functions. even including the code below. Ok, it's a good idea. >> + if (!kvm_sdei_is_registered(kske, index)) { >> + ret = SDEI_DENIED; >> + goto unlock; >> + } >> + >> + /* The event is disabled when it's unregistered */ >> + kvm_sdei_clear_enabled(kske, index); >> + kvm_sdei_clear_registered(kske, index); >> + if (kvm_sdei_empty_registered(kske)) { > a refcount mechanism would be cleaner I think. A refcount isn't working well. We need a mapping here because the private SDEI event can be enabled/registered on multiple vCPUs. We need to know the exact vCPUs where the private SDEI event is enabled/registered. >> + list_del(&kske->link); >> + kfree(kske); >> + } >> + >> +unlock: >> + spin_unlock(&ksdei->lock); >> +out: >> + return ret; >> +} >> + >> int kvm_sdei_hypercall(struct kvm_vcpu *vcpu) >> { >> u32 func = smccc_get_function(vcpu); >> @@ -333,6 +392,8 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu) >> 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: >> + ret = kvm_sdei_hypercall_unregister(vcpu); >> + break; >> case SDEI_1_0_FN_SDEI_EVENT_STATUS: >> case SDEI_1_0_FN_SDEI_EVENT_GET_INFO: >> case SDEI_1_0_FN_SDEI_EVENT_ROUTING_SET: >> Thanks, Gavin