From nobody Sun Apr 12 02:47:00 2026 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 B3D56C19F28 for ; Wed, 3 Aug 2022 13:45:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238116AbiHCNp6 (ORCPT ); Wed, 3 Aug 2022 09:45:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238001AbiHCNps (ORCPT ); Wed, 3 Aug 2022 09:45:48 -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 3DB191BEAC for ; Wed, 3 Aug 2022 06:45:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1659534345; 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=K+oxgk4T+NwDaR94J7G6p9nDk8ZYP0vBbLe54p9zMO8=; b=WxoyJskRxBrLHzbMNFS8+DMjfh6Ha2Sqr+d/rCIamUKaUc42emckIHz2tSWnnp8755E/qt sRDd10T/vWi1QKAj6t0pAzTRa+ZpIh6zBgCferpS1R4HHaP/Y6FKTMjRGrTvqA6OGTNXQZ OU2dcGitlmLFppncdOK0OwamUV9Ykn8= 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-146-p9A8tPOMP8q1oHuZjLdMOw-1; Wed, 03 Aug 2022 09:45:44 -0400 X-MC-Unique: p9A8tPOMP8q1oHuZjLdMOw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C9AAD8853C4; Wed, 3 Aug 2022 13:45:43 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.40.195.93]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7CC3D2026D4C; Wed, 3 Aug 2022 13:45:41 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org, Paolo Bonzini , Sean Christopherson Cc: Wanpeng Li , Jim Mattson , Michael Kelley , Siddharth Chandrasekaran , Yuan Yao , Maxim Levitsky , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v9 12/40] KVM: x86: hyper-v: Use preallocated buffer in 'struct kvm_vcpu_hv' instead of on-stack 'sparse_banks' Date: Wed, 3 Aug 2022 15:45:40 +0200 Message-Id: <20220803134540.399220-1-vkuznets@redhat.com> In-Reply-To: <20220803134110.397885-1-vkuznets@redhat.com> References: <20220803134110.397885-1-vkuznets@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" To make kvm_hv_flush_tlb() ready to handle L2 TLB flush requests, KVM needs to allow for all 64 sparse vCPU banks regardless of KVM_MAX_VCPUs as L1 may use vCPU overcommit for L2. To avoid growing on-stack allocation, make 'sparse_banks' part of per-vCPU 'struct kvm_vcpu_hv' which is allocated dynamically. Note: sparse_set_to_vcpu_mask() can't currently be used to handle L2 requests as KVM does not keep L2 VM_ID -> L2 VCPU_ID -> L1 vCPU mappings, i.e. its vp_bitmap array is still bounded by the number of L1 vCPUs and so can remain an on-stack allocation. Reviewed-by: Maxim Levitsky Signed-off-by: Vitaly Kuznetsov --- arch/x86/include/asm/kvm_host.h | 3 +++ arch/x86/kvm/hyperv.c | 6 ++++-- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_hos= t.h index 83c2331f7701..ca8183647b6d 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -644,6 +644,9 @@ struct kvm_vcpu_hv { } cpuid_cache; =20 struct kvm_vcpu_hv_tlb_flush_fifo tlb_flush_fifo[HV_NR_TLB_FLUSH_FIFOS]; + + /* Preallocated buffer for handling hypercalls passing sparse vCPU set */ + u64 sparse_banks[HV_MAX_SPARSE_VCPU_BANKS]; }; =20 /* Xen HVM per vcpu emulation context */ diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index d27fb4a6d94b..401649a9d288 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1910,6 +1910,8 @@ void kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu) =20 static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) { + struct kvm_vcpu_hv *hv_vcpu =3D to_hv_vcpu(vcpu); + u64 *sparse_banks =3D hv_vcpu->sparse_banks; struct kvm *kvm =3D vcpu->kvm; struct hv_tlb_flush_ex flush_ex; struct hv_tlb_flush flush; @@ -1923,7 +1925,6 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, st= ruct kvm_hv_hcall *hc) u64 __tlb_flush_entries[KVM_HV_TLB_FLUSH_FIFO_SIZE - 1]; u64 *tlb_flush_entries; u64 valid_bank_mask; - u64 sparse_banks[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; struct kvm_vcpu *v; unsigned long i; bool all_cpus; @@ -2075,11 +2076,12 @@ static void kvm_hv_send_ipi_to_many(struct kvm *kvm= , u32 vector, =20 static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) { + struct kvm_vcpu_hv *hv_vcpu =3D to_hv_vcpu(vcpu); + u64 *sparse_banks =3D hv_vcpu->sparse_banks; struct kvm *kvm =3D vcpu->kvm; struct hv_send_ipi_ex send_ipi_ex; struct hv_send_ipi send_ipi; u64 valid_bank_mask; - u64 sparse_banks[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; u32 vector; bool all_cpus; =20 --=20 2.35.3