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 AC835C433EF for ; Mon, 20 Jun 2022 02:42:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233156AbiFTCmS (ORCPT ); Sun, 19 Jun 2022 22:42:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229998AbiFTCmS (ORCPT ); Sun, 19 Jun 2022 22:42:18 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E2DA028E for ; Sun, 19 Jun 2022 19:42:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1655692935; 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; bh=/oknfccPAIxyEAuYdT4y1IrsCu7NWdjJuGzW6X5z710=; b=PSzCY3UuIzA6rR+Nsr3B/Bg7uRAth8uXsrF5Q50GqFWZ7JnyP/rXU3ji2+WRc+R7ogko9J 6lO+XeORR5aQbuIYdEhI9bmvFvH6R39tvkmFgFZAP+lxxcJCHisDXFySa6aaoZPhRVEonN VymahPKcO5uJjudBSRuRzl95JySk0l8= 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-147-ROevF3OlOLOOELPM_umplw-1; Sun, 19 Jun 2022 22:42:06 -0400 X-MC-Unique: ROevF3OlOLOOELPM_umplw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 66EDE101A56C; Mon, 20 Jun 2022 02:42:05 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-16.pek2.redhat.com [10.72.12.16]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2CB65C08087; Mon, 20 Jun 2022 02:42:00 +0000 (UTC) From: Jason Wang To: cohuck@redhat.com, pasic@linux.ibm.com, jasowang@redhat.com, mst@redhat.com Cc: gor@linux.ibm.com, borntraeger@de.ibm.com, agordeev@linux.ibm.com, linux-s390@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V2] virtio: disable notification hardening by default Date: Mon, 20 Jun 2022 10:41:58 +0800 Message-Id: <20220620024158.2505-1-jasowang@redhat.com> MIME-Version: 1.0 Content-type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org We try to harden virtio device notifications in 8b4ec69d7e09 ("virtio: harden vring IRQ"). It works with the assumption that the driver or core can properly call virtio_device_ready() at the right place. Unfortunately, this seems to be not true and uncover various bugs of the existing drivers, mainly the issue of using virtio_device_ready() incorrectly. So let's having a Kconfig option and disable it by default. It gives us a breath to fix the drivers and then we can consider to enable it by default. Signed-off-by: Jason Wang --- Changes since V1: - tweak the Kconfig prompt - don't hold spinlock for IRQ path in s390 --- drivers/s390/virtio/virtio_ccw.c | 4 ++++ drivers/virtio/Kconfig | 11 +++++++++++ drivers/virtio/virtio.c | 2 ++ drivers/virtio/virtio_ring.c | 12 ++++++++++++ include/linux/virtio_config.h | 2 ++ 5 files changed, 31 insertions(+) diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c index 97e51c34e6cf..89bbf7ccfdd1 100644 --- a/drivers/s390/virtio/virtio_ccw.c +++ b/drivers/s390/virtio/virtio_ccw.c @@ -1136,8 +1136,10 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev, vcdev->err = -EIO; } virtio_ccw_check_activity(vcdev, activity); +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION /* Interrupts are disabled here */ read_lock(&vcdev->irq_lock); +#endif for_each_set_bit(i, indicators(vcdev), sizeof(*indicators(vcdev)) * BITS_PER_BYTE) { /* The bit clear must happen before the vring kick. */ @@ -1146,7 +1148,9 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev, vq = virtio_ccw_vq_by_ind(vcdev, i); vring_interrupt(0, vq); } +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION read_unlock(&vcdev->irq_lock); +#endif if (test_bit(0, indicators2(vcdev))) { virtio_config_changed(&vcdev->vdev); clear_bit(0, indicators2(vcdev)); diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index b5adf6abd241..96ec56d44b91 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -35,6 +35,17 @@ menuconfig VIRTIO_MENU if VIRTIO_MENU +config VIRTIO_HARDEN_NOTIFICATION + bool "Harden virtio notification" + help + Enable this to harden the device notifications and supress + the ones that are illegal. + + Experimental: not all drivers handle this correctly at this + point. + + If unsure, say N. + config VIRTIO_PCI tristate "PCI driver for virtio devices" depends on PCI diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index ef04a96942bf..21dc08d2f32d 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -220,6 +220,7 @@ static int virtio_features_ok(struct virtio_device *dev) * */ void virtio_reset_device(struct virtio_device *dev) { +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION /* * The below virtio_synchronize_cbs() guarantees that any * interrupt for this line arriving after @@ -228,6 +229,7 @@ void virtio_reset_device(struct virtio_device *dev) */ virtio_break_device(dev); virtio_synchronize_cbs(dev); +#endif dev->config->reset(dev); } diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 13a7348cedff..d9d3b6e201fb 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -1688,7 +1688,11 @@ static struct virtqueue *vring_create_virtqueue_packed( vq->we_own_ring = true; vq->notify = notify; vq->weak_barriers = weak_barriers; +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION vq->broken = true; +#else + vq->broken = false; +#endif vq->last_used_idx = 0; vq->event_triggered = false; vq->num_added = 0; @@ -2135,9 +2139,13 @@ irqreturn_t vring_interrupt(int irq, void *_vq) } if (unlikely(vq->broken)) { +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION dev_warn_once(&vq->vq.vdev->dev, "virtio vring IRQ raised before DRIVER_OK"); return IRQ_NONE; +#else + return IRQ_HANDLED; +#endif } /* Just a hint for performance: so it's ok that this can be racy! */ @@ -2180,7 +2188,11 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, vq->we_own_ring = false; vq->notify = notify; vq->weak_barriers = weak_barriers; +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION vq->broken = true; +#else + vq->broken = false; +#endif vq->last_used_idx = 0; vq->event_triggered = false; vq->num_added = 0; diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 9a36051ceb76..d15c3cdda2d2 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -257,6 +257,7 @@ void virtio_device_ready(struct virtio_device *dev) WARN_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION /* * The virtio_synchronize_cbs() makes sure vring_interrupt() * will see the driver specific setup if it sees vq->broken @@ -264,6 +265,7 @@ void virtio_device_ready(struct virtio_device *dev) */ virtio_synchronize_cbs(dev); __virtio_unbreak_device(dev); +#endif /* * The transport should ensure the visibility of vq->broken * before setting DRIVER_OK. See the comments for the transport -- 2.25.1