From mboxrd@z Thu Jan 1 00:00:00 1970 From: Halil Pasic Subject: Re: [PATCH v5 2/2] s390: virtio: PV needs VIRTIO I/O device protection Date: Thu, 9 Jul 2020 11:55:53 +0200 Message-ID: <20200709115553.2dde6ab1.pasic@linux.ibm.com> References: <1594283959-13742-1-git-send-email-pmorel@linux.ibm.com> <1594283959-13742-3-git-send-email-pmorel@linux.ibm.com> <20200709105733.6d68fa53.cohuck@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200709105733.6d68fa53.cohuck@redhat.com> Sender: kvm-owner@vger.kernel.org To: Pierre Morel Cc: Cornelia Huck , linux-kernel@vger.kernel.org, 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 List-Id: virtualization@lists.linuxfoundation.org On Thu, 9 Jul 2020 10:57:33 +0200 Cornelia Huck wrote: > 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 Punctuation at the end? Also 'that's not the case' refers to the negation 'VIRTIO_F_IOMMU_PLATFORM has been negotiated', arch_validate_virtio_features() is however part of virtio_finalize_features(), which is in turn part of the feature negotiation. But that is details. I'm fine with keeping the message as is. > > > > 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. I liked the messages in v4. Why did we change those? Did somebody complain? I prefer the old ones, but it any case: Acked-by: Halil Pasic > > > + return -ENODEV; > > + } > > + > > + return 0; > > +} > > + > > /* protected virtualization */ > > static void pv_init(void) > > { > > Either way, > > Reviewed-by: Cornelia Huck >