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Thu, 10 Sep 2020 08:53:53 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A8A0B11C058; Thu, 10 Sep 2020 08:53:52 +0000 (GMT) Received: from oc3016276355.ibm.com (unknown [9.145.28.144]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 10 Sep 2020 08:53:52 +0000 (GMT) From: Pierre Morel To: linux-kernel@vger.kernel.org Cc: pasic@linux.ibm.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, mst@redhat.com, jasowang@redhat.com, cohuck@redhat.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, virtualization@lists.linux-foundation.org, thomas.lendacky@amd.com, david@gibson.dropbear.id.au, linuxram@us.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com Subject: [PATCH v12 1/2] virtio: let arch advertise guest's memory access restrictions Date: Thu, 10 Sep 2020 10:53:49 +0200 Message-Id: <1599728030-17085-2-git-send-email-pmorel@linux.ibm.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1599728030-17085-1-git-send-email-pmorel@linux.ibm.com> References: <1599728030-17085-1-git-send-email-pmorel@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-10_01:2020-09-10,2020-09-10 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=1 bulkscore=0 clxscore=1015 priorityscore=1501 mlxlogscore=999 mlxscore=0 phishscore=0 lowpriorityscore=0 spamscore=0 adultscore=0 malwarescore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009100079 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org An architecture may restrict host access to guest memory, e.g. IBM s390 Secure Execution or AMD SEV. Provide a new Kconfig entry the architecture can select, CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS, when it provides the arch_has_restricted_virtio_memory_access callback to advertise to VIRTIO common code when the architecture restricts memory access from the host. The common code can then fail the probe for any device where VIRTIO_F_ACCESS_PLATFORM is required, but not set. Signed-off-by: Pierre Morel Reviewed-by: Cornelia Huck Reviewed-by: Halil Pasic --- drivers/virtio/Kconfig | 6 ++++++ drivers/virtio/virtio.c | 15 +++++++++++++++ include/linux/virtio_config.h | 10 ++++++++++ 3 files changed, 31 insertions(+) diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index 5c92e4a50882..ef2d49430800 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -6,6 +6,12 @@ config VIRTIO bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG or CONFIG_S390_GUEST. +config ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS + bool + help + This option is selected if the architecture may need to enforce + VIRTIO_F_ACCESS_PLATFORM + menuconfig VIRTIO_MENU bool "Virtio drivers" default y diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index a977e32a88f2..a2b3f12e10a2 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -176,6 +176,21 @@ int virtio_finalize_features(struct virtio_device *dev) if (ret) return ret; + ret = arch_has_restricted_virtio_memory_access(); + if (ret) { + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { + dev_warn(&dev->dev, + "device must provide VIRTIO_F_VERSION_1\n"); + return -ENODEV; + } + + if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) { + dev_warn(&dev->dev, + "device must provide VIRTIO_F_ACCESS_PLATFORM\n"); + return -ENODEV; + } + } + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) return 0; diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 8fe857e27ef3..3f697c8c8205 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -540,4 +540,14 @@ static inline void virtio_cwrite64(struct virtio_device *vdev, virtio_cread_le((vdev), structname, member, ptr); \ _r; \ }) + +#ifdef CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS +int arch_has_restricted_virtio_memory_access(void); +#else +static inline int arch_has_restricted_virtio_memory_access(void) +{ + return 0; +} +#endif /* CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS */ + #endif /* _LINUX_VIRTIO_CONFIG_H */ -- 2.25.1