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 lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 15C3DC55171 for ; Fri, 31 Jul 2026 05:59:53 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wpgFb-0002fl-3K; Fri, 31 Jul 2026 01:57:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wpeM7-0005u2-Po; Thu, 30 Jul 2026 23:56:19 -0400 Received: from [115.124.30.112] (helo=out30-112.freemail.mail.aliyun.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wpeM1-0002Il-Td; Thu, 30 Jul 2026 23:56:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1785470170; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=g0QlwMTJgF93LRCAL5WkuhLzxPKgvA6nP6b0CC6j0SM=; b=VG9m03NaXvG3afWPmzSYG4tHPtVgWKF1GOFOatLsRY60jNfNu7bT70ivOu1F5lSttg/BsVgHzSrHF5pBicdPoIcpm6UQMPTqt2/0CLZmpu5IXkjZwo6tX9DU7WXotqVYoG7ct9HXtivcdkUontHaW3GkLcxemfcppzz0Rx+mOa8= X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R451e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=maildocker-contentspam033045098064; MF=blduan@linux.alibaba.com; NM=1; PH=DS; RN=7; SR=0; TI=SMTPD_---0X86jwUk_1785469857; Received: from ea134-sw16.eng.xrvm.cn(mailfrom:blduan@linux.alibaba.com fp:SMTPD_---0X86jwUk_1785469857 cluster:ay36) by smtp.aliyun-inc.com; Fri, 31 Jul 2026 11:50:58 +0800 From: Baolong Duan To: qemu-devel@nongnu.org Cc: qemu-riscv@nongnu.org, alistair23@gmail.com, dbarboza@ventanamicro.com, cxx194832@alibaba-inc.com, zengxiangyi.zxy@alibaba-inc.com, Baolong Duan Subject: [RFC PATCH v1 11/17] hw/virtio: force modern virtio for a CoVE guest Date: Fri, 31 Jul 2026 11:50:05 +0800 Message-Id: <20260731035011.4178103-12-blduan@linux.alibaba.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260731035011.4178103-1-blduan@linux.alibaba.com> References: <20260731035011.4178103-1-blduan@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Host-Lookup-Failed: Reverse DNS lookup failed for 115.124.30.112 (deferred) Received-SPF: pass client-ip=115.124.30.112; envelope-from=blduan@linux.alibaba.com; helo=out30-112.freemail.mail.aliyun.com X-Spam_score_int: -166 X-Spam_score: -16.7 X-Spam_bar: ---------------- X-Spam_report: (-16.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, ENV_AND_HDR_SPF_MATCH=-0.5, RCVD_IN_DNSWL_NONE=-0.0001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, UNPARSEABLE_RELAY=0.001, USER_IN_DEF_DKIM_WL=-7.5, USER_IN_DEF_SPF_WL=-7.5 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Fri, 31 Jul 2026 01:57:05 -0400 X-BeenThere: qemu-riscv@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-riscv-bounces+qemu-riscv=archiver.kernel.org@nongnu.org Sender: qemu-riscv-bounces+qemu-riscv=archiver.kernel.org@nongnu.org Devices have no direct access to the memory of a CoVE guest, so DMA has to be bounced through buffers that the guest shares explicitly. Offer VIRTIO_F_ACCESS_PLATFORM unconditionally, together with VIRTIO_F_VERSION_1 which Linux requires whenever ACCESS_PLATFORM is offered. Such a device therefore always negotiates in modern mode, so the legacy IOMMU_PLATFORM check in virtio-pci does not apply to it either. Signed-off-by: Baolong Duan --- hw/virtio/virtio-bus.c | 12 ++++++++++++ hw/virtio/virtio-pci.c | 9 ++++++++- 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c index 9b545acda3..2e2917236f 100644 --- a/hw/virtio/virtio-bus.c +++ b/hw/virtio/virtio-bus.c @@ -29,6 +29,7 @@ #include "hw/virtio/virtio-bus.h" #include "hw/virtio/virtio.h" #include "system/address-spaces.h" +#include "hw/riscv/cove.h" /* #define DEBUG_VIRTIO_BUS */ @@ -75,6 +76,17 @@ void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp) return; } + /* + * Devices cannot access the memory of a CoVE guest directly, so all DMA + * has to be bounced through buffers the guest shares explicitly: offer + * VIRTIO_F_ACCESS_PLATFORM unconditionally. VIRTIO_F_VERSION_1 has to be + * offered as well because Linux refuses ACCESS_PLATFORM without it. + */ + if (riscv_cove_vm_active()) { + vdev->host_features |= 1ULL << VIRTIO_F_ACCESS_PLATFORM; + vdev->host_features |= 1ULL << VIRTIO_F_VERSION_1; + } + if (klass->device_plugged != NULL) { klass->device_plugged(qbus->parent, &local_err); } diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index 6f5db5fc42..b257d4a09f 100644 --- a/hw/virtio/virtio-pci.c +++ b/hw/virtio/virtio-pci.c @@ -34,6 +34,7 @@ #include "hw/pci/msi.h" #include "hw/pci/msix.h" #include "hw/core/loader.h" +#include "hw/riscv/cove.h" #include "system/accel-irq.h" #include "system/kvm.h" #include "hw/virtio/virtio-pci.h" @@ -2048,7 +2049,13 @@ static void virtio_pci_device_plugged(DeviceState *d, Error **errp) return; } } - if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) { + /* + * A CoVE guest always negotiates in modern mode: ACCESS_PLATFORM, + * which shares its feature bit with IOMMU_PLATFORM, is forced + * together with VERSION_1, so this check does not apply. + */ + if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM) && + !riscv_cove_vm_active()) { error_setg(errp, "VIRTIO_F_IOMMU_PLATFORM was supported by" " neither legacy nor transitional device"); return; -- 2.34.1