From patchwork Thu Feb 18 10:59:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jean-Philippe Brucker X-Patchwork-Id: 1441629 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256 header.s=google header.b=U/JKzeOJ; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4DhBmS2G3Cz9sCD for ; Thu, 18 Feb 2021 22:09:12 +1100 (AEDT) Received: from localhost ([::1]:35840 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lChBG-0001sB-9w for incoming@patchwork.ozlabs.org; Thu, 18 Feb 2021 06:09:10 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:46616) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lChAr-0001s0-NJ for qemu-devel@nongnu.org; Thu, 18 Feb 2021 06:08:45 -0500 Received: from mail-wm1-x32c.google.com ([2a00:1450:4864:20::32c]:38435) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lChAp-00026w-Nl for qemu-devel@nongnu.org; Thu, 18 Feb 2021 06:08:45 -0500 Received: by mail-wm1-x32c.google.com with SMTP id x4so2673090wmi.3 for ; Thu, 18 Feb 2021 03:08:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CXQSQo7Hc/L1KqnxrJ70hCx+zeK9zsPCAZ6m/8RQUh4=; b=U/JKzeOJ8e838ZV3Thg/eHlC9H8Gl/+HhVNT7v2eu6mkWDcEM+gxZnZBA7odMLc5Xc XaZASG+Moxzt97vHWowpbNVHT8PAiQrhiWAgidqsFWDQKH7lWPfRVeEM6VYfmcg47dES 3/uJSK0Ctqjk4Yl+sxPd4rFgBsD4zhQe9QJ5le2QxwLzlZy1jrr76bIQbokr+vAKuLFa SEuc1iclRIOuzw7F6rJZCLODI2UDrmp+bhKqNNepDPuYBujZkIcbYO2RKJUA5OOjq272 klW76pdmZONn/2R+J4ZRAcUz6dhI5fWwi/2+trZW1sCU+NMjkyFwH7POW89rzhWOE2MF iRXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CXQSQo7Hc/L1KqnxrJ70hCx+zeK9zsPCAZ6m/8RQUh4=; b=WAuBjAmH8XU4hJa8uGxlFQ6Ig2qyc6+M8rzpAq3kUS4CdAkeynlvQpnF9ihkC+gIa/ qMeVGscP7P+hoCpkZmjZh9Easj6SFBluBtvHr1ArewwBsHrURU5fHf1YQ2ahOqRojAzS hWFDZkpQmcCyiGted0mtYkd47i25sA2debb6U/WzBN0V0yKRtcNQQedMfpC/K/X63o5V ldJW411eMuf9FG043xcfp4HARahQxbv+/E6POuFPuwXGtjQnQ3MAGt0CvZek3Nd5qVKc KD9JkT9sc/qZJT33ebrketwIhaHxmmYTrMKyCTUbtn3Xn2I4IyXnjG4YMpaTenJxguOG qPtA== X-Gm-Message-State: AOAM530jXhH1O6R0cEnCA1TSKl3S6qprIxokhzZuhu0L99DktVOBTqDj 2FcOQuBkzB8IdsDa8tfuUPNQEg== X-Google-Smtp-Source: ABdhPJysJx2xiU3G0HpaKV4lMHn0APjr7vonhx3XBQysTFMCq4fv0sTNlvuZ2t1wIpA+ZSs6/qOT0Q== X-Received: by 2002:a05:600c:4ec6:: with SMTP id g6mr2993114wmq.72.1613646521709; Thu, 18 Feb 2021 03:08:41 -0800 (PST) Received: from localhost.localdomain ([2001:1715:4e26:a7e0:116c:c27a:3e7f:5eaf]) by smtp.gmail.com with ESMTPSA id o25sm18113717wmh.1.2021.02.18.03.08.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Feb 2021 03:08:41 -0800 (PST) From: Jean-Philippe Brucker To: eric.auger@redhat.com Subject: [PATCH] virtio-iommu: Default to bypass during boot Date: Thu, 18 Feb 2021 11:59:30 +0100 Message-Id: <20210218105929.1433230-1-jean-philippe@linaro.org> X-Mailer: git-send-email 2.30.0 MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::32c; envelope-from=jean-philippe@linaro.org; helo=mail-wm1-x32c.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jean-Philippe Brucker , qemu-devel@nongnu.org, mst@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Currently the virtio-iommu device must be programmed before it allows DMA from any PCI device. This can make the VM entirely unusable when a virtio-iommu driver isn't present, for example in a bootloader that loads the OS from storage. Similarly to the other vIOMMU implementations, default to DMA bypassing the IOMMU during boot. Add a "boot-bypass" option that lets users change this behavior. Signed-off-by: Jean-Philippe Brucker --- include/hw/virtio/virtio-iommu.h | 1 + hw/virtio/virtio-iommu.c | 23 +++++++++++++++++++++-- 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/include/hw/virtio/virtio-iommu.h b/include/hw/virtio/virtio-iommu.h index 273e35c04bc..4c66989ca4e 100644 --- a/include/hw/virtio/virtio-iommu.h +++ b/include/hw/virtio/virtio-iommu.h @@ -58,6 +58,7 @@ struct VirtIOIOMMU { GTree *domains; QemuMutex mutex; GTree *endpoints; + bool boot_bypass; }; #endif diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c index c2883a2f6c8..cd08dc39eca 100644 --- a/hw/virtio/virtio-iommu.c +++ b/hw/virtio/virtio-iommu.c @@ -689,6 +689,25 @@ static void virtio_iommu_report_fault(VirtIOIOMMU *viommu, uint8_t reason, } +static bool virtio_iommu_bypass_is_allowed(VirtIOIOMMU *s) +{ + VirtIODevice *vdev = &s->parent_obj; + + /* + * Allow bypass if: + * - boot_bypass is enabled and the BYPASS feature hasn't yet been + * acknowledged. + * - the BYPASS feature has been negotiated. + */ + if (s->boot_bypass && !(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK)) { + return true; + } + if (virtio_vdev_has_feature(vdev, VIRTIO_IOMMU_F_BYPASS)) { + return true; + } + return false; +} + static IOMMUTLBEntry virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr, IOMMUAccessFlags flag, int iommu_idx) @@ -715,8 +734,7 @@ static IOMMUTLBEntry virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr, .perm = IOMMU_NONE, }; - bypass_allowed = virtio_vdev_has_feature(&s->parent_obj, - VIRTIO_IOMMU_F_BYPASS); + bypass_allowed = virtio_iommu_bypass_is_allowed(s); sid = virtio_iommu_get_bdf(sdev); @@ -1156,6 +1174,7 @@ static const VMStateDescription vmstate_virtio_iommu = { static Property virtio_iommu_properties[] = { DEFINE_PROP_LINK("primary-bus", VirtIOIOMMU, primary_bus, "PCI", PCIBus *), + DEFINE_PROP_BOOL("boot-bypass", VirtIOIOMMU, boot_bypass, true), DEFINE_PROP_END_OF_LIST(), };