| Message ID | 1597762711-3550-3-git-send-email-pmorel@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390: virtio: let arch validate VIRTIO features | expand |
On Tue, 18 Aug 2020 16:58:31 +0200 Pierre Morel <pmorel@linux.ibm.com> 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. > Define CONFIG_ARCH_HAS_RESTRICTED_MEMORY_ACCESS and export > arch_has_restricted_memory_access to fail probe if that's > not the case, preventing a host error on access attempt. > > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > --- > arch/s390/Kconfig | 1 + > arch/s390/mm/init.c | 30 ++++++++++++++++++++++++++++++ > 2 files changed, 31 insertions(+) > > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig > index 9cfd8de907cb..d4a3ef4fa27b 100644 > --- a/arch/s390/Kconfig > +++ b/arch/s390/Kconfig > @@ -820,6 +820,7 @@ menu "Virtualization" > config PROTECTED_VIRTUALIZATION_GUEST > def_bool n > prompt "Protected virtualization guest support" > + select ARCH_HAS_RESTRICTED_MEMORY_ACCESS > help > Select this option, if you want to be able to run this > kernel as a protected virtualization KVM guest. > diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c > index 6dc7c3b60ef6..aec04d7dd089 100644 > --- a/arch/s390/mm/init.c > +++ b/arch/s390/mm/init.c > @@ -45,6 +45,7 @@ > #include <asm/kasan.h> > #include <asm/dma-mapping.h> > #include <asm/uv.h> > +#include <linux/virtio_config.h> > > pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir); > > @@ -161,6 +162,35 @@ bool force_dma_unencrypted(struct device *dev) > return is_prot_virt_guest(); > } > > +#ifdef CONFIG_ARCH_HAS_RESTRICTED_MEMORY_ACCESS > +/* > + * arch_has_restricted_memory_access > + * @dev: the VIRTIO device being added > + * > + * Return an error if required features are missing on a guest running > + * with protected virtualization. > + */ > +int arch_has_restricted_memory_access(struct virtio_device *dev) > +{ > + if (!is_prot_virt_guest()) > + return 0; If you just did a return is_prot_virt_guest(); and did the virtio feature stuff in the virtio core, this function would be short and sweet :) > + > + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { > + dev_warn(&dev->dev, "device must provide VIRTIO_F_VERSION_1\n"); > + return -ENODEV; > + } > + > + if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { > + dev_warn(&dev->dev, > + "device must provide VIRTIO_F_IOMMU_PLATFORM\n"); > + return -ENODEV; > + } > + > + return 0; > +} > +EXPORT_SYMBOL(arch_has_restricted_memory_access); > +#endif > + > /* protected virtualization */ > static void pv_init(void) > {
On 2020-08-18 19:22, Cornelia Huck wrote: >> + */ >> +int arch_has_restricted_memory_access(struct virtio_device *dev) >> +{ >> + if (!is_prot_virt_guest()) >> + return 0; > > If you just did a > > return is_prot_virt_guest(); > > and did the virtio feature stuff in the virtio core, this function > would be short and sweet :) yes, the smaller the better, thanks Pierre
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 9cfd8de907cb..d4a3ef4fa27b 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -820,6 +820,7 @@ menu "Virtualization" config PROTECTED_VIRTUALIZATION_GUEST def_bool n prompt "Protected virtualization guest support" + select ARCH_HAS_RESTRICTED_MEMORY_ACCESS help Select this option, if you want to be able to run this kernel as a protected virtualization KVM guest. diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 6dc7c3b60ef6..aec04d7dd089 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -45,6 +45,7 @@ #include <asm/kasan.h> #include <asm/dma-mapping.h> #include <asm/uv.h> +#include <linux/virtio_config.h> pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir); @@ -161,6 +162,35 @@ bool force_dma_unencrypted(struct device *dev) return is_prot_virt_guest(); } +#ifdef CONFIG_ARCH_HAS_RESTRICTED_MEMORY_ACCESS +/* + * arch_has_restricted_memory_access + * @dev: the VIRTIO device being added + * + * Return an error if required features are missing on a guest running + * with protected virtualization. + */ +int arch_has_restricted_memory_access(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"); + return -ENODEV; + } + + if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { + dev_warn(&dev->dev, + "device must provide VIRTIO_F_IOMMU_PLATFORM\n"); + return -ENODEV; + } + + return 0; +} +EXPORT_SYMBOL(arch_has_restricted_memory_access); +#endif + /* protected virtualization */ static void pv_init(void) {
If protected virtualization is active on s390, the virtio queues are not accessible to the host, unless VIRTIO_F_IOMMU_PLATFORM has been negotiated. Define CONFIG_ARCH_HAS_RESTRICTED_MEMORY_ACCESS and export arch_has_restricted_memory_access to fail probe if that's not the case, preventing a host error on access attempt. Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> --- arch/s390/Kconfig | 1 + arch/s390/mm/init.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+)