From patchwork Mon Sep 13 13:16:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 510353 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E945EC433EF for ; Mon, 13 Sep 2021 14:49:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D48596103B for ; Mon, 13 Sep 2021 14:49:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235366AbhIMOvJ (ORCPT ); Mon, 13 Sep 2021 10:51:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:39016 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346907AbhIMOrR (ORCPT ); Mon, 13 Sep 2021 10:47:17 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B9A3063232; Mon, 13 Sep 2021 13:59:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631541542; bh=5HmtmxxPqkM5P2ZZ7KFz5rLwcy+22pd/Nuk+6xoBBS0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0mkbTk4O+R4JvivmpgXyJgYpRjqNJfewPYVihfln6rueu9/Mq5UiJ8QFHigOGcEjo pn3YAvxPqTI+wWisnjJcW4YTN32J3ZyZvZ2E/lAZkNPop9/MMmQIoBfqiydgB5Kzft QAUbQoLRfpN2bc4YuYSuBhA7DI5bum0Czz0qH4ZM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Halil Pasic , =?utf-8?q?Christian_Borntr=C3=A4ger?= , Claudio Imbrenda Subject: [PATCH 5.14 311/334] KVM: s390: index kvm->arch.idle_mask by vcpu_idx Date: Mon, 13 Sep 2021 15:16:05 +0200 Message-Id: <20210913131123.938038934@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210913131113.390368911@linuxfoundation.org> References: <20210913131113.390368911@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Halil Pasic commit a3e03bc1368c1bc16e19b001fc96dc7430573cc8 upstream. While in practice vcpu->vcpu_idx == vcpu->vcp_id is often true, it may not always be, and we must not rely on this. Reason is that KVM decides the vcpu_idx, userspace decides the vcpu_id, thus the two might not match. Currently kvm->arch.idle_mask is indexed by vcpu_id, which implies that code like for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) { vcpu = kvm_get_vcpu(kvm, vcpu_id); do_stuff(vcpu); } is not legit. Reason is that kvm_get_vcpu expects an vcpu_idx, not an vcpu_id. The trouble is, we do actually use kvm->arch.idle_mask like this. To fix this problem we have two options. Either use kvm_get_vcpu_by_id(vcpu_id), which would loop to find the right vcpu_id, or switch to indexing via vcpu_idx. The latter is preferable for obvious reasons. Let us make switch from indexing kvm->arch.idle_mask by vcpu_id to indexing it by vcpu_idx. To keep gisa_int.kicked_mask indexed by the same index as idle_mask lets make the same change for it as well. Fixes: 1ee0bc559dc3 ("KVM: s390: get rid of local_int array") Signed-off-by: Halil Pasic Reviewed-by: Christian Bornträger Reviewed-by: Claudio Imbrenda Cc: # 3.15+ Link: https://lore.kernel.org/r/20210827125429.1912577-1-pasic@linux.ibm.com Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman --- arch/s390/include/asm/kvm_host.h | 1 + arch/s390/kvm/interrupt.c | 12 ++++++------ arch/s390/kvm/kvm-s390.c | 2 +- arch/s390/kvm/kvm-s390.h | 2 +- 4 files changed, 9 insertions(+), 8 deletions(-) --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -957,6 +957,7 @@ struct kvm_arch{ atomic64_t cmma_dirty_pages; /* subset of available cpu features enabled by user space */ DECLARE_BITMAP(cpu_feat, KVM_S390_VM_CPU_FEAT_NR_BITS); + /* indexed by vcpu_idx */ DECLARE_BITMAP(idle_mask, KVM_MAX_VCPUS); struct kvm_s390_gisa_interrupt gisa_int; struct kvm_s390_pv pv; --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -419,13 +419,13 @@ static unsigned long deliverable_irqs(st static void __set_cpu_idle(struct kvm_vcpu *vcpu) { kvm_s390_set_cpuflags(vcpu, CPUSTAT_WAIT); - set_bit(vcpu->vcpu_id, vcpu->kvm->arch.idle_mask); + set_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.idle_mask); } static void __unset_cpu_idle(struct kvm_vcpu *vcpu) { kvm_s390_clear_cpuflags(vcpu, CPUSTAT_WAIT); - clear_bit(vcpu->vcpu_id, vcpu->kvm->arch.idle_mask); + clear_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.idle_mask); } static void __reset_intercept_indicators(struct kvm_vcpu *vcpu) @@ -3050,18 +3050,18 @@ int kvm_s390_get_irq_state(struct kvm_vc static void __airqs_kick_single_vcpu(struct kvm *kvm, u8 deliverable_mask) { - int vcpu_id, online_vcpus = atomic_read(&kvm->online_vcpus); + int vcpu_idx, online_vcpus = atomic_read(&kvm->online_vcpus); struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int; struct kvm_vcpu *vcpu; - for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) { - vcpu = kvm_get_vcpu(kvm, vcpu_id); + for_each_set_bit(vcpu_idx, kvm->arch.idle_mask, online_vcpus) { + vcpu = kvm_get_vcpu(kvm, vcpu_idx); if (psw_ioint_disabled(vcpu)) continue; deliverable_mask &= (u8)(vcpu->arch.sie_block->gcr[6] >> 24); if (deliverable_mask) { /* lately kicked but not yet running */ - if (test_and_set_bit(vcpu_id, gi->kicked_mask)) + if (test_and_set_bit(vcpu_idx, gi->kicked_mask)) return; kvm_s390_vcpu_wakeup(vcpu); return; --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -4044,7 +4044,7 @@ static int vcpu_pre_run(struct kvm_vcpu kvm_s390_patch_guest_per_regs(vcpu); } - clear_bit(vcpu->vcpu_id, vcpu->kvm->arch.gisa_int.kicked_mask); + clear_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.gisa_int.kicked_mask); vcpu->arch.sie_block->icptcode = 0; cpuflags = atomic_read(&vcpu->arch.sie_block->cpuflags); --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -79,7 +79,7 @@ static inline int is_vcpu_stopped(struct static inline int is_vcpu_idle(struct kvm_vcpu *vcpu) { - return test_bit(vcpu->vcpu_id, vcpu->kvm->arch.idle_mask); + return test_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.idle_mask); } static inline int kvm_is_ucontrol(struct kvm *kvm)