From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH v2 1/1] s390: virtio: let arch accept devices without IOMMU feature Date: Tue, 16 Jun 2020 14:22:44 +0800 Message-ID: References: <1592224764-1258-1-git-send-email-pmorel@linux.ibm.com> <1592224764-1258-2-git-send-email-pmorel@linux.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <1592224764-1258-2-git-send-email-pmorel@linux.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Pierre Morel , linux-kernel@vger.kernel.org Cc: pasic@linux.ibm.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, mst@redhat.com, cohuck@redhat.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org On 2020/6/15 下午8:39, Pierre Morel wrote: > An architecture protecting the guest memory against unauthorized host > access may want to enforce VIRTIO I/O device protection through the > use of VIRTIO_F_IOMMU_PLATFORM. > > Let's give a chance to the architecture to accept or not devices > without VIRTIO_F_IOMMU_PLATFORM. > > Signed-off-by: Pierre Morel Acked-by: Jason Wang > --- > arch/s390/mm/init.c | 6 ++++++ > drivers/virtio/virtio.c | 9 +++++++++ > include/linux/virtio.h | 2 ++ > 3 files changed, 17 insertions(+) > > diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c > index 87b2d024e75a..3f04ad09650f 100644 > --- a/arch/s390/mm/init.c > +++ b/arch/s390/mm/init.c > @@ -46,6 +46,7 @@ > #include > #include > #include > +#include > > pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir); > > @@ -162,6 +163,11 @@ bool force_dma_unencrypted(struct device *dev) > return is_prot_virt_guest(); > } > > +int arch_needs_iommu_platform(struct virtio_device *dev) > +{ > + return is_prot_virt_guest(); > +} > + > /* protected virtualization */ > static void pv_init(void) > { > diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c > index a977e32a88f2..30091089bee8 100644 > --- a/drivers/virtio/virtio.c > +++ b/drivers/virtio/virtio.c > @@ -167,6 +167,11 @@ void virtio_add_status(struct virtio_device *dev, unsigned int status) > } > EXPORT_SYMBOL_GPL(virtio_add_status); > > +int __weak arch_needs_iommu_platform(struct virtio_device *dev) > +{ > + return 0; > +} > + > int virtio_finalize_features(struct virtio_device *dev) > { > int ret = dev->config->finalize_features(dev); > @@ -179,6 +184,10 @@ int virtio_finalize_features(struct virtio_device *dev) > if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) > return 0; > > + if (arch_needs_iommu_platform(dev) && > + !virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) > + return -EIO; > + > virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK); > status = dev->config->get_status(dev); > if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) { > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > index a493eac08393..2c46b310c38c 100644 > --- a/include/linux/virtio.h > +++ b/include/linux/virtio.h > @@ -195,4 +195,6 @@ void unregister_virtio_driver(struct virtio_driver *drv); > #define module_virtio_driver(__virtio_driver) \ > module_driver(__virtio_driver, register_virtio_driver, \ > unregister_virtio_driver) > + > +int arch_needs_iommu_platform(struct virtio_device *dev); > #endif /* _LINUX_VIRTIO_H */