Pierre Morel
2020-Jul-07 08:44 UTC
[PATCH v4 0/2] s390: virtio: let arch validate VIRTIO features
Hi all, I changed the patch subject to reflect the content, becoming more general. 1) I removed the ack from Christian and Jason even far as I understand they gave it for the functionality more than for the implementation. @Jason, @Christian, please can I get back your acked-by with these changes? 2) previous patch had another name: [PATCH v3 0/1] s390: virtio: let arch choose to accept devices without IOMMU feature id: Message-Id: <1592390637-17441-2-git-send-email-pmorel at linux.ibm.com> 3) The new version generalize the validation of the features by the architecture, making it not IOMMU_PLATFORM specific anymore inside virtio.c The architecture specific code for s390 is now testing the virtio features. 4) Since I reworked the patch I also moved the arch specific code from arch/s390/mm/init.c to arch/s390/kernel/to uv.c 5) Finaly, I splitted the patch into generic virtio and arch specific code. Regards, Pierre Pierre Morel (2): virtio: let arch validate VIRTIO features s390: virtio: PV needs VIRTIO I/O device protection arch/s390/kernel/uv.c | 25 +++++++++++++++++++++++++ drivers/virtio/virtio.c | 19 +++++++++++++++++++ include/linux/virtio_config.h | 1 + 3 files changed, 45 insertions(+) -- 2.25.1 Changelog to v4: - separate virtio and arch code (Pierre) - moved code from arch/s390/mm/init.c to arch/s390/kernel/uv.c (Heiko) - moved validation inside the arch code (Connie) - moved the call to arch validation before VIRTIO_F_1 test (Michael) to v3: - add warning (Connie, Christian) - add comment (Connie) - change hook name (Halil, Connie) to v2: - put the test in virtio_finalize_features() (Connie) - put the test inside VIRTIO core (Jason) - pass a virtio device as parameter (Halil)
Pierre Morel
2020-Jul-07 08:44 UTC
[PATCH v4 1/2] virtio: let arch validate VIRTIO features
An architecture may need to validate the VIRTIO devices features based on architecture specificities. Signed-off-by: Pierre Morel <pmorel at linux.ibm.com> --- drivers/virtio/virtio.c | 19 +++++++++++++++++++ include/linux/virtio_config.h | 1 + 2 files changed, 20 insertions(+) diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index a977e32a88f2..3179a8aa76f5 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -167,6 +167,21 @@ void virtio_add_status(struct virtio_device *dev, unsigned int status) } EXPORT_SYMBOL_GPL(virtio_add_status); +/* + * arch_needs_virtio_iommu_platform - provide arch specific hook when finalizing + * features for VIRTIO device dev + * @dev: the VIRTIO device being added + * + * Permits the platform to provide architecture specific functionality when + * devices features are finalized. This is the default implementation. + * Architecture implementations can override this. + */ + +int __weak arch_validate_virtio_features(struct virtio_device *dev) +{ + return 0; +} + int virtio_finalize_features(struct virtio_device *dev) { int ret = dev->config->finalize_features(dev); @@ -176,6 +191,10 @@ int virtio_finalize_features(struct virtio_device *dev) if (ret) return ret; + ret = arch_validate_virtio_features(dev); + if (ret) + return ret; + 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..3f4117adf311 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -459,4 +459,5 @@ static inline void virtio_cwrite64(struct virtio_device *vdev, _r; \ }) +int arch_validate_virtio_features(struct virtio_device *dev); #endif /* _LINUX_VIRTIO_CONFIG_H */ -- 2.25.1
Pierre Morel
2020-Jul-07 08:44 UTC
[PATCH v4 2/2] s390: virtio: PV needs VIRTIO I/O device protection
S390, protecting the guest memory against unauthorized host access needs to enforce VIRTIO I/O device protection through the use of VIRTIO_F_VERSION_1 and VIRTIO_F_IOMMU_PLATFORM. Signed-off-by: Pierre Morel <pmorel at linux.ibm.com> --- arch/s390/kernel/uv.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c index c296e5c8dbf9..106330f6eda1 100644 --- a/arch/s390/kernel/uv.c +++ b/arch/s390/kernel/uv.c @@ -14,6 +14,7 @@ #include <linux/memblock.h> #include <linux/pagemap.h> #include <linux/swap.h> +#include <linux/virtio_config.h> #include <asm/facility.h> #include <asm/sections.h> #include <asm/uv.h> @@ -413,3 +414,27 @@ static int __init uv_info_init(void) } device_initcall(uv_info_init); #endif + +/* + * arch_validate_virtio_iommu_platform + * @dev: the VIRTIO device being added + * + * Return value: returns -ENODEV if any features of the + * device breaks the protected virtualization + * 0 otherwise. + */ +int arch_validate_virtio_features(struct virtio_device *dev) +{ + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { + dev_warn(&dev->dev, "device must provide VIRTIO_F_VERSION_1\n"); + return is_prot_virt_guest() ? -ENODEV : 0; + } + + if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { + dev_warn(&dev->dev, + "device must provide VIRTIO_F_IOMMU_PLATFORM\n"); + return is_prot_virt_guest() ? -ENODEV : 0; + } + + return 0; +} -- 2.25.1
Cornelia Huck
2020-Jul-07 09:26 UTC
[PATCH v4 1/2] virtio: let arch validate VIRTIO features
On Tue, 7 Jul 2020 10:44:36 +0200 Pierre Morel <pmorel at linux.ibm.com> wrote:> An architecture may need to validate the VIRTIO devices features > based on architecture specificities.s/specifities/specifics/> > Signed-off-by: Pierre Morel <pmorel at linux.ibm.com> > --- > drivers/virtio/virtio.c | 19 +++++++++++++++++++ > include/linux/virtio_config.h | 1 + > 2 files changed, 20 insertions(+) > > diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c > index a977e32a88f2..3179a8aa76f5 100644 > --- a/drivers/virtio/virtio.c > +++ b/drivers/virtio/virtio.c > @@ -167,6 +167,21 @@ void virtio_add_status(struct virtio_device *dev, unsigned int status) > } > EXPORT_SYMBOL_GPL(virtio_add_status); > > +/* > + * arch_needs_virtio_iommu_platform - provide arch specific hook when finalizings/arch_needs_virtio_iommu_platform/arch_validate_virtio_features/ :)> + * features for VIRTIO device dev > + * @dev: the VIRTIO device being added > + * > + * Permits the platform to provide architecture specific functionality whens/provide architecture specific functionality/handle architecture-specific requirements/ ?> + * devices features are finalized. This is the default implementation.s/devices/device/> + * Architecture implementations can override this. > + */ > + > +int __weak arch_validate_virtio_features(struct virtio_device *dev) > +{ > + return 0; > +} > + > int virtio_finalize_features(struct virtio_device *dev) > { > int ret = dev->config->finalize_features(dev); > @@ -176,6 +191,10 @@ int virtio_finalize_features(struct virtio_device *dev) > if (ret) > return ret; > > + ret = arch_validate_virtio_features(dev); > + if (ret) > + return ret; > + > 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..3f4117adf311 100644 > --- a/include/linux/virtio_config.h > +++ b/include/linux/virtio_config.h > @@ -459,4 +459,5 @@ static inline void virtio_cwrite64(struct virtio_device *vdev, > _r; \ > }) > > +int arch_validate_virtio_features(struct virtio_device *dev); > #endif /* _LINUX_VIRTIO_CONFIG_H */With the wording fixed, Reviewed-by: Cornelia Huck <cohuck at redhat.com>
Cornelia Huck
2020-Jul-07 09:46 UTC
[PATCH v4 2/2] s390: virtio: PV needs VIRTIO I/O device protection
On Tue, 7 Jul 2020 10:44:37 +0200 Pierre Morel <pmorel at linux.ibm.com> wrote:> S390, protecting the guest memory against unauthorized host access > needs to enforce VIRTIO I/O device protection through the use of > VIRTIO_F_VERSION_1 and VIRTIO_F_IOMMU_PLATFORM.Hm... what about: "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 enforce this."> > Signed-off-by: Pierre Morel <pmorel at linux.ibm.com> > --- > arch/s390/kernel/uv.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c > index c296e5c8dbf9..106330f6eda1 100644 > --- a/arch/s390/kernel/uv.c > +++ b/arch/s390/kernel/uv.c > @@ -14,6 +14,7 @@ > #include <linux/memblock.h> > #include <linux/pagemap.h> > #include <linux/swap.h> > +#include <linux/virtio_config.h> > #include <asm/facility.h> > #include <asm/sections.h> > #include <asm/uv.h> > @@ -413,3 +414,27 @@ static int __init uv_info_init(void) > } > device_initcall(uv_info_init); > #endif > + > +/* > + * arch_validate_virtio_iommu_platforms/arch_validate_virtio_iommu_platform/arch_validate_virtio_features/> + * @dev: the VIRTIO device being added > + * > + * Return value: returns -ENODEV if any features of the > + * device breaks the protected virtualization > + * 0 otherwise.I don't think you need to specify the contract here: that belongs to the definition in the virtio core. What about simply adding a sentence "Return an error if required features are missing on a guest running with protected virtualization." ?> + */ > +int arch_validate_virtio_features(struct virtio_device *dev) > +{Maybe jump out immediately if the guest is not protected?> + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { > + dev_warn(&dev->dev, "device must provide VIRTIO_F_VERSION_1\n"); > + return is_prot_virt_guest() ? -ENODEV : 0; > + } > + > + if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { > + dev_warn(&dev->dev, > + "device must provide VIRTIO_F_IOMMU_PLATFORM\n"); > + return is_prot_virt_guest() ? -ENODEV : 0; > + }if (!is_prot_virt_guest()) return 0; if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { dev_warn(&dev->dev, "legacy virtio is incompatible with protected guests"); return -ENODEV; } if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { dev_warn(&dev->dev, "device does not work with limited memory access in protected guests"); return -ENODEV; }> + > + return 0; > +}
Christian Borntraeger
2020-Jul-07 11:12 UTC
[PATCH v4 2/2] s390: virtio: PV needs VIRTIO I/O device protection
On 07.07.20 10:44, Pierre Morel wrote:> S390, protecting the guest memory against unauthorized host access > needs to enforce VIRTIO I/O device protection through the use of > VIRTIO_F_VERSION_1 and VIRTIO_F_IOMMU_PLATFORM. > > Signed-off-by: Pierre Morel <pmorel at linux.ibm.com> > --- > arch/s390/kernel/uv.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c > index c296e5c8dbf9..106330f6eda1 100644 > --- a/arch/s390/kernel/uv.c > +++ b/arch/s390/kernel/uv.c > @@ -14,6 +14,7 @@ > #include <linux/memblock.h> > #include <linux/pagemap.h> > #include <linux/swap.h> > +#include <linux/virtio_config.h> > #include <asm/facility.h> > #include <asm/sections.h> > #include <asm/uv.h> > @@ -413,3 +414,27 @@ static int __init uv_info_init(void) > } > device_initcall(uv_info_init); > #endif > + > +/* > + * arch_validate_virtio_iommu_platform > + * @dev: the VIRTIO device being added > + * > + * Return value: returns -ENODEV if any features of the > + * device breaks the protected virtualization > + * 0 otherwise. > + */ > +int arch_validate_virtio_features(struct virtio_device *dev) > +{ > + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { > + dev_warn(&dev->dev, "device must provide VIRTIO_F_VERSION_1\n");I think you only want to warn if is_prot_virt_guest is true? We certainly want to be able to run as a guest of older hypervisors with virtio 0.95, no?> + return is_prot_virt_guest() ? -ENODEV : 0; > + } > + > + if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { > + dev_warn(&dev->dev, > + "device must provide VIRTIO_F_IOMMU_PLATFORM\n");same here.> + return is_prot_virt_guest() ? -ENODEV : 0; > + } > + > + return 0; > +} >