From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Pierre Morel Subject: [PATCH v9 1/2] virtio: let arch advertise guest's memory access restrictions Date: Wed, 19 Aug 2020 18:23:17 +0200 Message-Id: <1597854198-2871-2-git-send-email-pmorel@linux.ibm.com> In-Reply-To: <1597854198-2871-1-git-send-email-pmorel@linux.ibm.com> References: <1597854198-2871-1-git-send-email-pmorel@linux.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 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 An architecture may restrict host access to guest memory. 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 VIRTIO common code when the architecture restricts memory access from the host. Signed-off-by: Pierre Morel --- drivers/virtio/Kconfig | 6 ++++++ drivers/virtio/virtio.c | 15 +++++++++++++++ include/linux/virtio_config.h | 9 +++++++++ 3 files changed, 30 insertions(+) diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index 5809e5f5b157..509f3b4d8ba1 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 by any architecture enforcing + VIRTIO_F_IOMMU_PLATFORM + menuconfig VIRTIO_MENU bool "Virtio drivers" default y diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index a977e32a88f2..57ca41d77b09 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_IOMMU_PLATFORM)) { + dev_warn(&dev->dev, + "device must provide VIRTIO_F_IOMMU_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 bb4cc4910750..e380664642b4 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -459,4 +459,13 @@ static inline void virtio_cwrite64(struct virtio_device *vdev, _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