From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:29582 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726314AbgGII5t (ORCPT ); Thu, 9 Jul 2020 04:57:49 -0400 Date: Thu, 9 Jul 2020 10:57:33 +0200 From: Cornelia Huck Subject: Re: [PATCH v5 2/2] s390: virtio: PV needs VIRTIO I/O device protection Message-ID: <20200709105733.6d68fa53.cohuck@redhat.com> In-Reply-To: <1594283959-13742-3-git-send-email-pmorel@linux.ibm.com> References: <1594283959-13742-1-git-send-email-pmorel@linux.ibm.com> <1594283959-13742-3-git-send-email-pmorel@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: Pierre Morel Cc: linux-kernel@vger.kernel.org, pasic@linux.ibm.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, mst@redhat.com, jasowang@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, heiko.carstens@de.ibm.com, gor@linux.ibm.com On Thu, 9 Jul 2020 10:39:19 +0200 Pierre Morel wrote: > If protected virtualization is active on s390, the virtio queues are > not accessible to the host, unless VIRTIO_F_IOMMU_PLATFORM has been > negotiated. Use the new arch_validate_virtio_features() interface to > fail probe if that's not the case, preventing a host error on access > attempt > > Signed-off-by: Pierre Morel > --- > arch/s390/mm/init.c | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c > index 6dc7c3b60ef6..b8e6f90117da 100644 > --- a/arch/s390/mm/init.c > +++ b/arch/s390/mm/init.c > @@ -45,6 +45,7 @@ > #include > #include > #include > +#include > > pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir); > > @@ -161,6 +162,32 @@ bool force_dma_unencrypted(struct device *dev) > return is_prot_virt_guest(); > } > > +/* > + * arch_validate_virtio_features > + * @dev: the VIRTIO device being added > + * > + * Return an error if required features are missing on a guest running > + * with protected virtualization. > + */ > +int arch_validate_virtio_features(struct virtio_device *dev) > +{ > + if (!is_prot_virt_guest()) > + return 0; > + > + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { > + dev_warn(&dev->dev, "device must provide VIRTIO_F_VERSION_1\n"); I'd probably use "legacy virtio not supported with protected virtualization". > + return -ENODEV; > + } > + > + if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { > + dev_warn(&dev->dev, > + "device must provide VIRTIO_F_IOMMU_PLATFORM\n"); "support for limited memory access required for protected virtualization" ? Mentioning the feature flag is shorter in both cases, though. > + return -ENODEV; > + } > + > + return 0; > +} > + > /* protected virtualization */ > static void pv_init(void) > { Either way, Reviewed-by: Cornelia Huck