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 96724C636D3 for ; Mon, 30 Jan 2023 14:19:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237361AbjA3OTI (ORCPT ); Mon, 30 Jan 2023 09:19:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60578 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237417AbjA3OSR (ORCPT ); Mon, 30 Jan 2023 09:18:17 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 588603D91B for ; Mon, 30 Jan 2023 06:17:32 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 6EBD6B810C5 for ; Mon, 30 Jan 2023 14:17:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0E83C433D2; Mon, 30 Jan 2023 14:17:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675088237; bh=JRdR2tAV0xWWMvYrGkwM7jDSLYmM55/YMwHZllp6xF8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Cn+pGlcfX03C4+MtHuLTtRrDymtLekwAIgQrumSS9qeSpwHa04Pk6HAihNo8SUykN I2cZcigS4u2M9Zt59WPBQ+VXyTBIB+ivzgFCDLRdpexOdm6uj/NC0G039gEsxyZv8z o39nfFah5FCCDaeyoqvCVzr54PQQNdOz4Y1UTKlk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shanker Donthineni , Marc Zyngier Subject: [PATCH 5.15 161/204] KVM: arm64: GICv4.1: Fix race with doorbell on VPE activation/deactivation Date: Mon, 30 Jan 2023 14:52:06 +0100 Message-Id: <20230130134323.642829003@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230130134316.327556078@linuxfoundation.org> References: <20230130134316.327556078@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Marc Zyngier commit ef3691683d7bfd0a2acf48812e4ffe894f10bfa8 upstream. To save the vgic LPI pending state with GICv4.1, the VPEs must all be unmapped from the ITSs so that the sGIC caches can be flushed. The opposite is done once the state is saved. This is all done by using the activate/deactivate irqdomain callbacks directly from the vgic code. Crutially, this is done without holding the irqdesc lock for the interrupts that represent the VPE. And these callbacks are changing the state of the irqdesc. What could possibly go wrong? If a doorbell fires while we are messing with the irqdesc state, it will acquire the lock and change the interrupt state concurrently. Since we don't hole the lock, curruption occurs in on the interrupt state. Oh well. While acquiring the lock would fix this (and this was Shanker's initial approach), this is still a layering violation we could do without. A better approach is actually to free the VPE interrupt, do what we have to do, and re-request it. It is more work, but this usually happens only once in the lifetime of the VM and we don't really care about this sort of overhead. Fixes: f66b7b151e00 ("KVM: arm64: GICv4.1: Try to save VLPI state in save_pending_tables") Reported-by: Shanker Donthineni Signed-off-by: Marc Zyngier Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230118022348.4137094-1-sdonthineni@nvidia.com Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kvm/vgic/vgic-v3.c | 25 +++++++++++-------------- arch/arm64/kvm/vgic/vgic-v4.c | 8 ++++++-- arch/arm64/kvm/vgic/vgic.h | 1 + 3 files changed, 18 insertions(+), 16 deletions(-) --- a/arch/arm64/kvm/vgic/vgic-v3.c +++ b/arch/arm64/kvm/vgic/vgic-v3.c @@ -347,26 +347,23 @@ retry: * The deactivation of the doorbell interrupt will trigger the * unmapping of the associated vPE. */ -static void unmap_all_vpes(struct vgic_dist *dist) +static void unmap_all_vpes(struct kvm *kvm) { - struct irq_desc *desc; + struct vgic_dist *dist = &kvm->arch.vgic; int i; - for (i = 0; i < dist->its_vm.nr_vpes; i++) { - desc = irq_to_desc(dist->its_vm.vpes[i]->irq); - irq_domain_deactivate_irq(irq_desc_get_irq_data(desc)); - } + for (i = 0; i < dist->its_vm.nr_vpes; i++) + free_irq(dist->its_vm.vpes[i]->irq, kvm_get_vcpu(kvm, i)); } -static void map_all_vpes(struct vgic_dist *dist) +static void map_all_vpes(struct kvm *kvm) { - struct irq_desc *desc; + struct vgic_dist *dist = &kvm->arch.vgic; int i; - for (i = 0; i < dist->its_vm.nr_vpes; i++) { - desc = irq_to_desc(dist->its_vm.vpes[i]->irq); - irq_domain_activate_irq(irq_desc_get_irq_data(desc), false); - } + for (i = 0; i < dist->its_vm.nr_vpes; i++) + WARN_ON(vgic_v4_request_vpe_irq(kvm_get_vcpu(kvm, i), + dist->its_vm.vpes[i]->irq)); } /** @@ -391,7 +388,7 @@ int vgic_v3_save_pending_tables(struct k * and enabling of the doorbells have already been done. */ if (kvm_vgic_global_state.has_gicv4_1) { - unmap_all_vpes(dist); + unmap_all_vpes(kvm); vlpi_avail = true; } @@ -441,7 +438,7 @@ int vgic_v3_save_pending_tables(struct k out: if (vlpi_avail) - map_all_vpes(dist); + map_all_vpes(kvm); return ret; } --- a/arch/arm64/kvm/vgic/vgic-v4.c +++ b/arch/arm64/kvm/vgic/vgic-v4.c @@ -222,6 +222,11 @@ void vgic_v4_get_vlpi_state(struct vgic_ *val = !!(*ptr & mask); } +int vgic_v4_request_vpe_irq(struct kvm_vcpu *vcpu, int irq) +{ + return request_irq(irq, vgic_v4_doorbell_handler, 0, "vcpu", vcpu); +} + /** * vgic_v4_init - Initialize the GICv4 data structures * @kvm: Pointer to the VM being initialized @@ -282,8 +287,7 @@ int vgic_v4_init(struct kvm *kvm) irq_flags &= ~IRQ_NOAUTOEN; irq_set_status_flags(irq, irq_flags); - ret = request_irq(irq, vgic_v4_doorbell_handler, - 0, "vcpu", vcpu); + ret = vgic_v4_request_vpe_irq(vcpu, irq); if (ret) { kvm_err("failed to allocate vcpu IRQ%d\n", irq); /* --- a/arch/arm64/kvm/vgic/vgic.h +++ b/arch/arm64/kvm/vgic/vgic.h @@ -321,5 +321,6 @@ int vgic_v4_init(struct kvm *kvm); void vgic_v4_teardown(struct kvm *kvm); void vgic_v4_configure_vsgis(struct kvm *kvm); void vgic_v4_get_vlpi_state(struct vgic_irq *irq, bool *val); +int vgic_v4_request_vpe_irq(struct kvm_vcpu *vcpu, int irq); #endif