From mboxrd@z Thu Jan 1 00:00:00 1970 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 97ED2C433F5 for ; Wed, 11 May 2022 11:25:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238158AbiEKLZg (ORCPT ); Wed, 11 May 2022 07:25:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52300 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241309AbiEKLZD (ORCPT ); Wed, 11 May 2022 07:25:03 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 3E1F4236746 for ; Wed, 11 May 2022 04:24:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652268285; h=from:from: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=+hqVlDvCMcE/tiHufqNgKFkt8nO8gwuxe1+upIvX5Ak=; b=RDAIwLf+ffMOBstLcNlqrIA5b0WQlch6oJiAhrXH8sfgZqP06EOc/z7OAaWUxOKLjA7RDc 2tPCIZGWYrVIdzXszauav4SawfWD1aMCtHGrcbV0BW6w/3p/RyKzw0xaJqBr6zr7YodqEU 8dZISEd6ntkXejs8pvmB0inmSbJKLZQ= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-504-hvVlbODnP1-ixabgTo6srg-1; Wed, 11 May 2022 07:24:41 -0400 X-MC-Unique: hvVlbODnP1-ixabgTo6srg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EE3D185A5A8; Wed, 11 May 2022 11:24:40 +0000 (UTC) Received: from starship (unknown [10.40.192.26]) by smtp.corp.redhat.com (Postfix) with ESMTP id AA1822166B2F; Wed, 11 May 2022 11:24:38 +0000 (UTC) Message-ID: <94cec439f345313c1a909f6a012665dd10686d47.camel@redhat.com> Subject: Re: [PATCH v3 09/34] KVM: x86: hyper-v: Don't use sparse_set_to_vcpu_mask() in kvm_hv_send_ipi() From: Maxim Levitsky To: Vitaly Kuznetsov , kvm@vger.kernel.org, Paolo Bonzini Cc: Sean Christopherson , Wanpeng Li , Jim Mattson , Michael Kelley , Siddharth Chandrasekaran , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 11 May 2022 14:24:37 +0300 In-Reply-To: <20220414132013.1588929-10-vkuznets@redhat.com> References: <20220414132013.1588929-1-vkuznets@redhat.com> <20220414132013.1588929-10-vkuznets@redhat.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.5 (3.36.5-2.fc32) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Thu, 2022-04-14 at 15:19 +0200, Vitaly Kuznetsov wrote: > Get rid of on-stack allocation of vcpu_mask and optimize kvm_hv_send_ipi() > for a smaller number of vCPUs in the request. When Hyper-V TLB flush > is in use, HvSendSyntheticClusterIpi{,Ex} calls are not commonly used to > send IPIs to a large number of vCPUs (and are rarely used in general). > > Introduce hv_is_vp_in_sparse_set() to directly check if the specified > VP_ID is present in sparse vCPU set. > > Signed-off-by: Vitaly Kuznetsov > --- > arch/x86/kvm/hyperv.c | 37 ++++++++++++++++++++++++++----------- > 1 file changed, 26 insertions(+), 11 deletions(-) > > diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c > index 3cf68645a2e6..aebbb598ad1d 100644 > --- a/arch/x86/kvm/hyperv.c > +++ b/arch/x86/kvm/hyperv.c > @@ -1746,6 +1746,25 @@ static void sparse_set_to_vcpu_mask(struct kvm *kvm, u64 *sparse_banks, > } > } > > +static bool hv_is_vp_in_sparse_set(u32 vp_id, u64 valid_bank_mask, u64 sparse_banks[]) > +{ > + int bank, sbank = 0; > + > + if (!test_bit(vp_id / HV_VCPUS_PER_SPARSE_BANK, > + (unsigned long *)&valid_bank_mask)) > + return false; > + > + for_each_set_bit(bank, (unsigned long *)&valid_bank_mask, > + KVM_HV_MAX_SPARSE_VCPU_SET_BITS) { > + if (bank == vp_id / HV_VCPUS_PER_SPARSE_BANK) > + break; > + sbank++; > + } > + > + return test_bit(vp_id % HV_VCPUS_PER_SPARSE_BANK, > + (unsigned long *)&sparse_banks[sbank]); > +} > + > struct kvm_hv_hcall { > u64 param; > u64 ingpa; > @@ -2089,8 +2108,8 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) > ((u64)hc->rep_cnt << HV_HYPERCALL_REP_COMP_OFFSET); > } > > -static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector, > - unsigned long *vcpu_bitmap) > +static void kvm_hv_send_ipi_to_many(struct kvm *kvm, u32 vector, > + u64 *sparse_banks, u64 valid_bank_mask) I think the indentation is wrong here (was wrong before as well) > { > struct kvm_lapic_irq irq = { > .delivery_mode = APIC_DM_FIXED, > @@ -2100,7 +2119,10 @@ static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector, > unsigned long i; > > kvm_for_each_vcpu(i, vcpu, kvm) { > - if (vcpu_bitmap && !test_bit(i, vcpu_bitmap)) > + if (sparse_banks && > + !hv_is_vp_in_sparse_set(kvm_hv_get_vpindex(vcpu), > + valid_bank_mask, > + sparse_banks)) > continue; > > /* We fail only when APIC is disabled */ > @@ -2113,7 +2135,6 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) > struct kvm *kvm = vcpu->kvm; > struct hv_send_ipi_ex send_ipi_ex; > struct hv_send_ipi send_ipi; > - DECLARE_BITMAP(vcpu_mask, KVM_MAX_VCPUS); > unsigned long valid_bank_mask; > u64 sparse_banks[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; > u32 vector; > @@ -2175,13 +2196,7 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) > if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR)) > return HV_STATUS_INVALID_HYPERCALL_INPUT; > > - if (all_cpus) { > - kvm_send_ipi_to_many(kvm, vector, NULL); > - } else { > - sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask, vcpu_mask); > - > - kvm_send_ipi_to_many(kvm, vector, vcpu_mask); > - } > + kvm_hv_send_ipi_to_many(kvm, vector, all_cpus ? NULL : sparse_banks, valid_bank_mask); > > ret_success: > return HV_STATUS_SUCCESS; Overall looks good to me, but I might have missed something. Reviewed-by: Maxim Levitsky Best regards, Maxim Levitsky