From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v5 2/2] s390: virtio: PV needs VIRTIO I/O device protection Date: Thu, 9 Jul 2020 12:58:09 +0200 Message-ID: <12b1ca5c-fc03-18c7-bdca-cedabc5f1e1d@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> <20200709115553.2dde6ab1.pasic@linux.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200709115553.2dde6ab1.pasic@linux.ibm.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" To: Halil Pasic Cc: gor@linux.ibm.com, linux-s390@vger.kernel.org, frankja@linux.ibm.com, kvm@vger.kernel.org, mst@redhat.com, heiko.carstens@de.ibm.com, Cornelia Huck , linuxram@us.ibm.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, borntraeger@de.ibm.com, thomas.lendacky@amd.com, david@gibson.dropbear.id.au List-Id: virtualization@lists.linuxfoundation.org On 2020-07-09 11:55, Halil Pasic wrote: > 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 Thanks, Pierre -- Pierre Morel IBM Lab Boeblingen